Bio-Medical Materials and Engineering - Volume 24, issue 6

Authors: Gao, Zhen-hai | Fan, Da | Wang, Deping | Zhao, Hui | Zhao, Kaishu | Chen, Chaoyang

Article Type: Research Article

Abstract: In this study a musculoskeletal model of driver steering maneuver was established. The model was driven by the steering angle and steering torque when performing typical steering test. The simulation was calculated using inverse dynamics. Maximum muscle activity and the muscle activity of each muscle were studied afterwards. The key muscles that generated steering torque were scapular portion of deltoid, infraspinatus, latissimus dorsi, subscapularis, triceps long head and triceps lateral head. Muscle co-contraction was analyzed quantitatively and was significantly different from muscle activity. This paper presents a preliminary research on the mechanical properties of upper limb muscles during steering maneuver. …The results can serve as references for vehicle design and performance evaluation using the physiological characteristics of drivers. Show more

Keywords: Driver, steering maneuver, musculoskeletal model, inverse dynamics, muscles of upper limb

DOI: 10.3233/BME-141087

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2697-2706, 2014

Authors: Kim, Ji-Won | Kwon, Yuri | Ho, Yeji | Jeon, Hyeong-Min | Bang, Min-Jung | Jun, Jae-Hoon | Eom, Gwang-Moon | Park, Byung Kyu | Cho, Yeong Bin

Article Type: Research Article

Abstract: Incidence of falling among elderly female has been reported to be much higher than that of elderly male. Although the gender differences in the elderly were reported for the static postural sway, there has been no investigation of the gender difference for the dynamic postural sway. This study investigates how age and gender affect the postural sway during dynamic squat and stand-up movement. 124 subjects (62 subjects for each of young and elderly) performed consecutive squat and stand-up movement, 2 times in one session, and 2 sessions per subject. Center of pressure (COP) was measured using force platform during the …test. Outcome measures included peak-to-peak sways of the COP (COP sway) in the sagittal plane (anteroposterior) and frontal plane (mediolateral) and also those normalized by body height. Two-way ANOVA and post-hoc comparisons were performed for the outcome measures with the independent factors of age and gender. All outcome measures, excluding mediolateral COP sway, showed significant interaction of age and gender (p<0.05). Post-hoc test revealed that only female showed increase in COP sway with age. When normalized by height, increase in COP sways (both directions) with age significant only in women resulted in greater sways in elderly female than elderly male. This may be related to the greater fall rate of elderly female than that of elderly men while performing dynamic activities. Show more

Keywords: COP sway, dynamic activities, squat and stand-up, gender difference

DOI: 10.3233/BME-141088

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2707-2713, 2014

Authors: Wang, Yu | Shen, Xuanjing | Chen, Haipeng | Zhai, Yujie

Article Type: Research Article

Abstract: To realize effective and rapid dynamic biometric identification with low computational complexity, a video-based facial texture program that extracts local binary patterns from three orthogonal planes in the frequency domain of the Gabor transform (GLBP-TOP) was proposed. Firstly, each normalized face was transformed by Gabor wavelet to get the enhanced Gabor magnitude map, and then the LBP-TOP operator was applied to the maps to extract video texture. Finally, weighted Chi square statistics based on the Fisher Criterion were used to realize the identification. The proposed algorithm was proved effective through the biometric experiments using the Honda/UCSD database, and was robust …against changes of illumination and expressions. Show more

Keywords: Biometric identification, gabor filters, LBP-TOP, fisher criterion

DOI: 10.3233/BME-141089

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2715-2724, 2014

Authors: Wang, Hang | He, Yong | Yang, Min | Yan, Qingguo | You, Fusheng | Fu, Feng | Wang, Ting | Huo, Xuyang | Dong, Xiuzhen | Shi, Xuetao

Article Type: Research Article

Abstract: The dielectric properties of human liver were determined by characterization of tissue absorption and coupling of electromagnetic energy in the electromagnetic field. In this study the ex-vivo dielectric properties of human hepatocellular carcinoma (well and moderately differentiated), liver hemangioma, hepatic fibrosis (stages S1 and S2), and normal liver tissue were measured and analyzed over the frequency range of 10 Hz to 100 MHz. The dielectric properties over the frequency range can reflect tissue information including biological macromolecules, vesicles, and cellular membrane; these information aids in distinguishing different physiological states and lesions. The ex-vivo conductivity, permittivity, resistivity, as well as the …characteristic parameters between the lesions and normal liver were analyzed and their differences were also verified. The data can contribute to developing bioelectric applications for tissue diagnostics and creating more accurate computer models for medical applications. Show more

Keywords: Dielectric property, characteristic parameters, liver cancer, hepatic fibrosis

DOI: 10.3233/BME-141090

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2725-2732, 2014

Authors: Xie, Zhihua | Liu, Guodong

Article Type: Research Article

Abstract: To improve the performance of infrared face recognition for time-lapse data, a new construction of blood perfusion is proposed based on bio-heat transfer. Firstly, by quantifying the blood perfusion based on Pennes equation, the thermal information is converted into blood perfusion rate, which is stable facial biological feature of face image. Then, the separability discriminant criterion in Discrete Cosine Transform (DCT) domain is applied to extract the discriminative features of blood perfusion information. Experimental results demonstrate that the features of blood perfusion are more concentrative and discriminative for recognition than those of thermal information. The infrared face recognition based on …the proposed blood perfusion is robust and can achieve better recognition performance compared with other state-of-the-art approaches. Show more

Keywords: Feature extraction, infrared image, face recognition, blood perfusion, bio-heat transfer model

DOI: 10.3233/BME-141091

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2733-2742, 2014

Authors: Fan, Shengli | Yu, Mei | Wang, Yigang | Jiang, Gangyi

Article Type: Research Article

Abstract: Stereo light microscopes (SLM) with narrow vision and shallow depth of field are widely used in micro-domain research. In this paper, we propose a depth estimation method of micro objects based on geometric transformation. By analyzing the optical imaging geometry, the definition of geometric transformation distance is given and the depth-distance relation express is obtained. The parameters of geometric transformation and express are calibrated with calibration board images captured in aid of precise motorized stage. The depth of micro object can be estimated by calculating the geometric transformation distance. The proposed depth-distance relation express is verified using an experiment in …which the depth map of an Olanzapine tablet surface is reconstructed. Show more

Keywords: Stereo light microscope, camera calibration, depth reconstruction, geometric transformation distance

DOI: 10.3233/BME-141092

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2743-2749, 2014

Authors: Wang, Ting | Dong, Junyu | Sun, Xin | Zhang, Shu | Wang, Shengke

Article Type: Research Article

Abstract: Facial nerve paralysis is a common disease due to nerve damage. Most approaches for evaluating the degree of facial paralysis rely on a set of different facial movements as commanded by doctors. Therefore, automatic recognition of the patterns of facial movement is fundamental to the evaluation of the degree of facial paralysis. In this paper, a novel method named Active Shape Models plus Local Binary Patterns (ASMLBP) is presented for recognizing facial movement patterns. Firstly, the Active Shape Models (ASMs) are used in the method to locate facial key points. According to these points, the face is divided into eight …local regions. Then the descriptors of these regions are extracted by using Local Binary Patterns (LBP) to recognize the patterns of facial movement. The proposed ASMLBP method is tested on both the collected facial paralysis database with 57 patients and another publicly available database named the Japanese Female Facial Expression (JAFFE). Experimental results demonstrate that the proposed method is efficient for both paralyzed and normal faces. Show more

Keywords: Facial paralysis, facial movement, active shape models, local binary patterns

DOI: 10.3233/BME-141093

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2751-2760, 2014

Authors: Jin, Bo | Vai, Mang I.

Article Type: Research Article

Abstract: Ultrasonic diagnosis that is convenient and nondestructive to the human body is widely used in medicine. In clinical, ultrasonic backscattered signals characteristics are utilized to acquire information of the human body tissues to perform diagnosis. In this paper, an adaptive ultrasonic backscattered signal processing technique for instantaneous characteristic frequency detection based on the marginal spectrum is presented. In the beginning, the ultrasonic backscattered signal is decomposed into a series of intrinsic mode functions (IMFs) by the Ensemble Empirical Mode Decomposition (EEMD) algorithm. Then the Hilbert spectrum is gained by the Hilbert transform on the IMFs decomposed and screened. Finally, the …time-frequency information in the Hilbert spectrum is utilized to extract the instantaneous characteristic frequency based on the marginal spectrum features to detect the objective. With this technique, the spacing between tissues can be estimated for tissue characterization by processing multiple echoes even in the complicated environment. In the simulation study, comparing with the FFT, the technique presented shows its strong noise immunity and indicates its validity in instantaneous characteristic frequency detection. Show more

Keywords: Ultrasonics, EEMD, Hilbert spectral analysis, instantaneous characteristic frequency, simulations

DOI: 10.3233/BME-141094

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2761-2770, 2014

Authors: Zhu, Haijiang | Yang, Ping | Yao, Tianbin

Article Type: Research Article

Abstract: This paper investigates a 3D reconstruction based on the ultrasonic scanned data for tissue mimicking material (TMM) sample. A two-step varied window filter is developed to smooth ultrasound backscatter signals at first. Next, the anisotropic diffusion filter with a triangular window is presented to reduce the noise of the 2D images by aligning one-dimensional signals. Finally, the 3D structure of the object embedded in the TMM sample is reconstructed using the detected edges images. The performance of the proposed method is analyzed and validated through a number of experiments in both 2D imaging and 3D reconstruction.

Keywords: 3D ultrasound reconstruction, tissue mimicking materials, two-step varied window filter, anisotropic diffusion filter

DOI: 10.3233/BME-141095

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2771-2781, 2014

Authors: Zhang, Zhihong | Liu, Haolin | Cheng, Yangjie

Article Type: Research Article

Abstract: Ultrasound elastography is the method of obtaining relative stiffness information of biological tissue, which plays an important role in early diagnosis. Generally, a gradient-based strain imaging algorithm assumes that motion only occurs in an axial direction. However, because tissue has different relative stiffness, the scatter presents lateral motion under high freehand compression. Therefore, errors occur in estimating the cross-correlation phase in the calculation window. A 2D elastography algorithm with lateral displacement estimation using statistics was proposed to reduce errors. The new method was investigated through simulation, and the experiment confirmed that errors introduced by lateral tissue movement have been greatly …reduced with no sacrifice of real-time ultrasonic imaging quality. Show more

Keywords: 2D elastography, lateral motion, cross-correlation, statistics

DOI: 10.3233/BME-141096

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2783-2791, 2014

Authors: Yoo, Ji Won | Lee, Nam-Gi | Kim, Hee-Jung | Cho, Hyo-Min | You, Joshua H.

Article Type: Research Article

Abstract: While the abdominal adipose tissue has been identified as an important pathomarker for the cardiometabolic syndrome in adults, the relationships between the cardiometabolic risk factors and abdominal adipose morphology or physical performance levels have not been examined in children with obesity. Therefore, the specific aim of this study was to investigate the relationships between risk factors (BMI and physical activity levels and abdominal fat layers including subcutaneous, intra-abdominal preperitoneal and mesenteric fat thickness in children with obesity. 30 children with obesity (mean±SD = 10.0±4.5 yrs; 9 girls; BMI > 20) underwent physical performance (curl-ups, sit and reach, push-ups, and a …400-m run), ultrasound measurement of thickness of fat composition of the abdomen, blood pressure, oxygen consumption. Pearson correlation analysis showed significant correlations, ranging from -0.523- 0.898 between the intra-abdominal adipose tissue thickness, cardiometabolic risk factors (BMI, blood pressure, heart rate), and the curl-up physical performance test. In conclusion, the present study provides a compelling evidence that the intra-abdominal adipose tissue morphological characteristics were associated with BMI, physical performance, and most importantly cardiometabolic risk factors (blood pressure and heart rate), which eventually contribute to the development of cardiometabolic syndrome in adulthood. Show more

Keywords: Ultrasound, BMI, child obesity, cardiometabolic syndrome

DOI: 10.3233/BME-141097

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2793-2799, 2014

Authors: Peng, Bo | Lai, Junliang | Wang, Ling | Liu, Dong C.

Article Type: Research Article

Abstract: Ultrasound elastography has been widely applied in clinical diagnosis. To produce high-quality elastograms, displacement estimation is important to generate ne displacement map from the original ratio-frequency signals. Traditional displacement estimation methods are based on the local information of signals pair, such as cross-correlation method, phase zero estimation. However, the tissue movement is nonlocal during realistic elasticity process due to the compression coming from the surface. Recently, regularized cost functions have been broadly used in ultrasound elastography. In this paper, we tested the using of analytic minimization of adaptive regularized cost function, a combination of different regularized cost functions, to correct …the displacement estimation calculated by cross-correlation method directly or by lateral displacement guidance. We have demonstrated that the proposed method exhibit obvious advantages in terms of imaging quality with higher levels of elastographic signal-to-noise ratio and elastographic contrast-to-noise ratio in the simulation and phantom experiments respectively. Show more

Keywords: Ultrasound elastography, adaptive regularized cost function, analytic minimization, displacement estimation

DOI: 10.3233/BME-141098

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2801-2810, 2014

Authors: Li, Xingsong | Deng, Yinhui | Yu, Jinhua | Wang, Yuanyuan | Shamdasani, Vijay

Article Type: Research Article

Abstract: Backscatter and attenuation parameters are not easily measured in clinical applications due to tissue inhomogeneity in the region of interest (ROI). A least squares method(LSM) that fits the echo signal power spectra from a ROI to a 3-parameter tissue model was used to get attenuation coefficient imaging in fatty liver. Since fat's attenuation value is higher than normal liver parenchyma, a reasonable threshold was chosen to evaluate the fatty proportion in fatty liver. Experimental results using clinical data of fatty liver illustrate that the least squares method can get accurate attenuation estimates. It is proved that the attenuation values have …a positive correlation with the fatty proportion, which can be used to evaluate the syndrome of fatty liver. Show more

Keywords: Attenuation imaging, least squares method, fatty liver, quantitative ultrasound

DOI: 10.3233/BME-141099

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2811-2820, 2014

Authors: Li, Xinyao | Yao, Yuan | Ni, Dong | Chen, Siping | Li, Shengli | Lei, Baiying | Wang, Tianfu

Article Type: Research Article

Abstract: Currently, placental maturity staging is mainly based on subjective observation of the physician. To address this issue, a new method is proposed for automatic staging of placental maturity based on B-mode ultrasound images. Due to small variations in the placental images, dense descriptor is utilized in place of the sparse descriptor to boost performance. Dense sampled DAISY descriptor is investigated for the demonstrated scale and translation invariant properties. Moreover, the extracted dense features are encoded by vector locally aggregated descriptor (VLAD) for performance boosting. The experimental results demonstrate an accuracy of 0.874, a sensitivity of 0.996 and a specificity of …0.874 for placental maturity staging. The experimental results also show that the dense features outperform the sparse features. Show more

Keywords: Placental staging, daisy descriptor, dense sampling, vector locally aggregated descriptor

DOI: 10.3233/BME-141100

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2821-2829, 2014

Authors: Shen, Yuanyuan | Zhang, Aili | Guo, Jinxuan | Dan, Guo | Chen, Siping | Yu, Hao

Article Type: Research Article

Abstract: Blood-Brain Barrier (BBB) can be opened locally, noninvasively and reversibly by low frequency focused ultra-sound (FUS) in the presence of microbubbles. In this study, Evans blue (EB) dye extravasation across BBB was enhanced by 1 MHz FUS at acoustic pressure of 0.35MPa in the presence of microbubbles at clinically comparable dosage. The spatial distribution of EB extravasation was visualized using fluorescence imaging method. The center region of BBB disruption area showed more enhanced fluorescence signal than the surrounding region in general. However, EB dye deposition was heterogeneous in the center region. The findings in this study indicated potential use of …fluorescence imaging to evaluate large molecules delivery across BBB. Show more

Keywords: Fluorescence imaging, Evans blue, Blood-Brain Barrier disruption, Focused Ultrasound, microbubble

DOI: 10.3233/BME-141101

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2831-2838, 2014

Authors: Shi, Zhenghao | Si, Chunjiao | Feng, Yaning | He, Lifeng | Suzuki, Kenji

Article Type: Research Article

Abstract: One of the major problems for computer-aided pulmonary nodule detection in chest radiographs is that a high falsepositive (FP) rate exists. In an effort to overcome this problem, a new method based on the MTANN (Massive Training Artificial Neural Network) is proposed in this paper. An MTANN comprises a multi-layer neural network where a linear function rather than a sigmoid function is used as its activity function in the output layer. In this work, a mixture of multiple MTANNs were employed rather than only a single MTANN. 50 MTANNs for 50 different types of FPs were prepared firstly. Then, several …effective MTANNs that had higher performances were selected to construct the MTANNs mixture. Finally, the outputs of the multiple MTANNs were combined with a mixing neural network to reduce various different types of FPs. The performance of this MTANNs mixture in FPs reduction is validated on three different versions of commercial CAD software with a validation database consisting of 52 chest radiographs. Experimental results demonstrate that the proposed MTANN approach is useful in cutting down FPs in different CAD software for detecting pulmonary nodules in chest radiographs. Show more

Keywords: False Positive, cutting down, Mixture of MTANNs, Commercial CAD

DOI: 10.3233/BME-141102

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2839-2846, 2014

Authors: Zhang, Xuehe | Zhu, Yanhe | Li, Changle | Zhao, Jie | Li, Ge

Article Type: Research Article

Abstract: To address the lack of 3D space information in the digital radiography of a patient femur, a pose estimation method based on 2D–3D rigid registration is proposed in this study. The method uses two digital radiography images to realize the preoperative 3D visualization of a fractured femur. Compared with the pure Digital Radiography or Computed Tomography imaging diagnostic methods, the proposed method has the advantages of low cost, high precision, and minimal harmful radiation. First, stable matching point pairs in the frontal and lateral images of the patient femur and the universal femur are obtained by using the Scale Invariant …Feature Transform method. Then, the 3D pose estimation registration parameters of the femur are calculated by using the Iterative Closest Point (ICP) algorithm. Finally, based on the deviation between the six degrees freedom parameter calculated by the proposed method, preset posture parameters are calculated to evaluate registration accuracy. After registration, the rotation error is less than l.5°, and the translation error is less than 1.2 mm, which indicate that the proposed method has high precision and robustness. The proposed method provides 3D image information for effective preoperative orthopedic diagnosis and surgery planning. Show more

Keywords: SIFT, femur, 2D–3D registration, pose estimation

DOI: 10.3233/BME-141103

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2847-2855, 2014

Authors: Hao, Liling | Li, Gang | Xu, Lisheng

Article Type: Research Article

Abstract: Magnetic detection electrical impedance tomography (MDEIT) is an imaging modality that aims to reconstruct the cross-sectional conductivity distribution of a volume from the magnetic flux density surrounding an object. The MDEIT inverse problem is inherently ill-posed, necessitating the use of regularization. The most commonly used L2 norm regularizations generate the minimum energy solution, which blurs the sharp variations of the reconstructed image. Consequently, this paper presents the total variation (TV) regularization to preserve discontinuities and piecewise constancy of the MDEIT reconstructed image. The primal dual-interior point method (PD-IPM) is employed for minimizing the TV penalty in this paper. The …proposed method is validated by MDEIT simulated data. In comparison with the performance of L2 norm regularization, the results show that TV regularized algorithm produces sharper images and has better robustness to noise. The TV regularized algorithm preserves local smoothness and piecewise constancy, leading to improvements in the localization of the reconstructed conductivity images in MDEIT. Show more

Keywords: Magnetic detection electrical impedance tomography, inverse problem, regularization, total variation, primal du- al-interior point method

DOI: 10.3233/BME-141104

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2857-2864, 2014

Authors: Wang, Shaoze | Ding, Yong | Dai, Hang | Qian, Dahong | Yu, Xinfeng | Zhang, Minming

Article Type: Research Article

Abstract: A generalized relative quality (RQ) assessment scheme is proposed here based on the Bayesian inference theory, which is reasonable to make use of full reference (FR) algorithms when the evaluation of the quality of homogeneous medical images is required. Each FR algorithm is taken as a kernel to represent the level of quality. Although, various kernels generate different order of magnitude, a normalization process can rationalize the quality index within 0 and 1, where 1 represent the highest quality and 0 represents the lowest quality. To validate the performance of the proposed scheme, a series of reconstructed susceptibility weighted imaging …images are collected, where each image has its subjective scale. Both experimental results and a ROC analysis show that the RQ obtained from the proposed scheme is consistent with subjective evaluation. Show more

Keywords: Relative quality, full reference, Bayesian inference, reconstructed image, subjective evaluation

DOI: 10.3233/BME-141105

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2865-2873, 2014

Authors: Rachim, Vega Pradana | Li, Gang | Chung, Wan-Young

Article Type: Research Article

Abstract: Sleep apnea is often diagnosed using an overnight sleep test called a polysomnography (PSG). Unfortunately, though it is the gold standard of sleep disorder diagnosis, a PSG is time consuming, inconvenient, and expensive. Many researchers have tried to ameliorate this problem by developing other reliable methods, such as using electrocardiography (ECG) as an observed signal source. Respiratory rate interval, ECG-derived respiration, and heart rate variability analysis have been studied recently as a means of detecting apnea events using ECG during normal sleep, but these methods have performance weaknesses. Thus, the aim of this study is to classify the subject into …normal- or apnea-subject based on their single-channel ECG measurement in regular sleep. In this proposed study, ECG is decomposed into five levels using wavelet decomposition for the initial processing to determine the detail coefficients (D3–D5) of the signal. Approximately 15 features were extracted from every minute of ECG. Principal component analysis and a support vector machine are used for feature dimension reduction and classification, respectively. According to classification that been done from a data set consisting of thirty-five patients, the proposed minute-to-minute classifier specificity, sensitivity, and subject-based classification accuracy are 95.20%, 92.65%, and 94.3%, respectively. Furthermore, the proposed system can be used as a basis for future development of sleep apnea screening tools. Show more

Keywords: Apnea, wavelet decomposition, principal component analysis, support vector machine, electrocardiogram

DOI: 10.3233/BME-141106

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2875-2882, 2014

Authors: Zhu, Junjiang | He, Lingsong | Gao, Zhiqiang

Article Type: Research Article

Abstract: Feature extraction is a crucial aspect of computer-aided arrhythmia diagnosis using an electrocardiogram (ECG). A location, width and magnitude (LWM) model is proposed for extracting each wave's features in the ECG. The model is a stream of Gaussian function in which three parameters (the expected value, variance and amplitude) are applied to approximate the P wave, QRS wave and T wave. Moreover, the features such as the P–Q intervals, S–T intervals, and so on are easily obtained. Then, a mixed approach is presented for estimating the parameters of a real ECG signal. To illustrate this model's associated advantages, the extracted …parameters combined with R–R intervals are fed to three classifiers for arrhythmia diagnoses. Two kinds of arrhythmias, including the premature ventricular contraction (PVC) heartbeats and the atrial premature complexes (APC) heartbeats, are diagnosed from normal beats using the data from the MIT–BIH arrhythmia database. The results in this study demonstrate that using these parameters results in more accurate and universal arrhythmia diagnoses. Show more

Keywords: ECG, feature extraction, classification, arrhythmia diagnosis, parametric Gaussian functions

DOI: 10.3233/BME-141107

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2883-2891, 2014

Authors: Zhang, Yaonan | Gao, Yuan | Jiao, Jinling | Li, Xian | Li, Sai | Yang, Jun

Article Type: Research Article

Abstract: Information regarding the motion, strain and synchronization are important for cardiac diagnosis and therapy. Extraction of such information from ultrasound images remains an open problem till today. In this paper, a novel method is proposed to extract the boundaries of left ventricles and track these boundaries in ultrasound image sequences. The initial detection of boundaries was performed by an active shape model scheme. Subsequent refinement of the boundaries was done by using local variance information of the images. The main objective of this paper is the formulation of a new boundary tracking algorithm using ant colony optimization technique. The experiments …conducted on the simulated image sequences and the real cardiac ultrasound image sequences shows a positive and promising result. Show more

Keywords: Active shape model, image segmentation, boundary tracking, ant colony optimization, motion estimation

DOI: 10.3233/BME-141108

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2893-2899, 2014

Authors: Tian, Yin | Li, Fali | Xu, Peng | Yuan, Zhen | Zhao, Dechun | Zhang, Haiyong

Article Type: Research Article

Abstract: Steady-state visual evoked potentials (SSVEP) are the visual system responses to a repetitive visual stimulus flickering with the constant frequency and of great importance in the study of brain activity using scalp electroencephalography (EEG) recordings. However, the reference influence for the investigation of SSVEP is generally not considered in previous work. In this study a new approach that combined the canonical correlation analysis with infinite reference (ICCA) was proposed to enhance the accuracy of frequency recognition of SSVEP recordings. Compared with the widely used periodogram method (PM), ICCA is able to achieve higher recognition accuracy when extracts frequency within a …short span. Further, the recognition results suggested that ICCA is a very robust tool to study the brain computer interface (BCI) based on SSVEP. Show more

Keywords: Steady-state visual evoked potentials, canonical correlation analysis with infinite reference, frequency recognition, periodogram, brain computer interface

DOI: 10.3233/BME-141109

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2901-2908, 2014

Authors: Deng, Zhipeng | Zhang, Chungang | Yu, Ping | Shao, Jun | Liang, Fuyou

Article Type: Research Article

Abstract: Continuous monitoring of stroke volume (SV) or cardiac output (CO) has long been the subject of numerous studies. The majority of existing methods are calibration-dependent, requiring invasive measurements of CO to initialize the estimation algorithms, thus limiting their application to the clinical setting. In the present study, a new calibration-free method aimed at home-based use has been developed, which allows noninvasive estimation of SV from oscillometric signals measured at the wrist. The estimation equation was constructed based on the PRAM method, with significant modifications to incorporate more patient-specific information. Furthermore, the estimation equation was optimized based on the clinical data …acquired from 96 patients (the ‘Training’ group) to obtain the best comparison of estimated SV with echocardiographic SV. The resulting estimation equation was then applied directly to another patient group (the ‘Testing’ group) to examine its validity. Obtained results demonstrate that our estimations correlated closely with the measurements in both patient groups. In addition to being noninvasive and calibration-free, the proposed method can be fully automated, which may be valuable for the future development of home-based cardiac monitoring systems. Show more

Keywords: Stroke volume, oscillometric signals, noninvasive estimation, coefficient optimization

DOI: 10.3233/BME-141110

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2909-2918, 2014

Authors: Jiang, Jun | Zhou, Zongtan | Yin, Erwei | Yu, Yang | Hu, Dewen

Article Type: Research Article

Abstract: Recently, the integration of different electrophysiological signals into an electroencephalogram (EEG) has become an effective approach to improve the practicality of brain-computer interface (BCI) systems, referred to as hybrid BCIs. In this paper, a hybrid BCI was designed by combining an EEG with electrocardiograph (EOG) signals and tested using a target selection experiment. Gaze direction from the EOG and the event-related (de)synchronization (ERD/ERS) induced by motor imagery from the EEG were simultaneously detected as the output of the BCI system. The target selection mechanism was based on the synthesis of the gaze direction and ERD activity. When an ERD activity …was detected, the target corresponding to the gaze direction was selected; without ERD activity, no target was selected, even when a subjects gaze was directed at the target. With this mechanism, the operation of the BCI system is more flexible and voluntary. The accuracy and completion time of the target selection tasks during the online testing were 89.3% and 2.4 seconds, respectively. These results show the feasibility and practicality of this hybrid BCI system, which can potentially be used in the rehabilitation of disabled individuals. Show more

Keywords: hybrid brain computer interface, EEG, EOG, event-related (de)synchronization, target selection

DOI: 10.3233/BME-141111

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2919-2925, 2014

Authors: Cao, Rui | Wu, Zheng | Li, Haifang | Xiang, Jie | Chen, Junjie

Article Type: Research Article

Abstract: Generally, an alcoholic's brain shows explicit damage. However, in cognitive tasks, the correlation between the topological structural changes of the brain networks and the brain damage is still unclear. Scalp electrodes and synchronization likelihood (SL) were applied to the constructions of the EGG functional networks of 28 alcoholics and 28 healthy volunteers. The graph-theoretic analysis showed that in cognitive tasks, compared with the healthy control group, the brain networks of alcoholics had smaller clustering coefficients in β1 bands, shorter characteristic path lengths, increased global efficiency, but similar small-world properties. The abnormal topological structure of the alcoholics may be related to …the local-function brain damage and the compensation mechanism adopted to complete tasks. This conclusion provides a new perspective for alcoholrelated brain damage. Show more

Keywords: alcoholic, EEG, brain functional network, graph theory

DOI: 10.3233/BME-141112

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2927-2936, 2014

Authors: Wei, Yu | Jun, Yang | Lin, Sun | Hong, Li

Article Type: Research Article

Abstract: Electroencephalograph (EEG) signals feature extraction and processing is one of the most difficult and important part in the brain-computer interface (BCI) research field. EEG signals are generally unstable, complex and have low signal-noise ratio, which is difficult to be analyzed and processed. To solve this problem, this paper disassembles EEG signals with the empirical mode decomposition (EMD) algorithm, extracts the characteristic values of the major intrinsic mode function (IMF) components, and then classifies them with fuzzy C-means (FCM) method. Also, comparison research is done between the proposed method and several current EEG classification methods. Experimental results show that the classification …accuracy based on the EEG signals of the second BCI competition in 2003 is up to 78%, which is superior to those of the comparative EEG classification methods. Show more

Keywords: Brain-computer interface (BCI), intrinsic mode function (IMF), fuzzy C-means (FCM)

DOI: 10.3233/BME-141113

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2937-2943, 2014

Authors: Lu, Meng | Di, Jia

Article Type: Research Article

Abstract: Diffusion tensor imaging (DTI) is a tractography algorithm that provides the only means of mapping white matter fibers. Furthermore, because of its wealth of applications, diffusion MRI tractography is gaining importance in clinical and neuroscience research. This paper presents a novel brain white matter fiber reconstruction method based on the snake model by minimizing the energy function, which is composed of both external energy and internal energy. Internal energy represents the assembly of the interaction potential between connected segments, whereas external energy represents the differences between predicted DTI signals and measured DTI signals. Through comparing the proposed method with other …tractography algorithms in the Fiber Cup test, the present method was shown to perform superiorly to the majority of the other methods. In fact, the proposed test performed the third best out of the ten available methods, which demonstrates that present method can accurately formulate the brain white matter fiber reconstruction. Show more

Keywords: Diffusion tensor imaging, brain white matter, fiber tracking, snake model, energy minimization

DOI: 10.3233/BME-141114

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2945-2953, 2014

Authors: Liu, Dazhong | Zhong, Ning

Article Type: Research Article

Abstract: This paper reviewed the meaning of the statistic index and the properties of the complex network models and their physiological explanation. By analyzing existing problems and construction strategies, this paper attempted to construct complex brain networks from a different point of view: that of clustering first and constructing the brain network second. A clustering-guided (or led) construction strategy towards complex brain networks was proposed. The research focused on the discussion of the task-induced brain network. To discover different networks in a single run, a combined-clusters method was applied. Afterwards, a complex local brain network was formed with a complex network …method on voxels. In a real test dataset, it was found that the network had small-world characteristics and had no significant scale-free properties. Meanwhile, some key bridge nodes and their characteristics were identified in the local network by calculating the betweenness centrality. Show more

Keywords: Complex brain network, functional connectivity, clustering, functional magnetic resonance imaging

DOI: 10.3233/BME-141115

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2955-2962, 2014

Authors: Wang, Linyuan | Tong, Li | Yan, Bin | Lei, Yu | Wang, Lijun | Zeng, Ying | Hu, Guoen

Article Type: Research Article

Abstract: Statistical model is essential for constraint-free visual image reconstruction, as it may overfit training data and have poor generalization. In this study, we investigate the sparsity of the distributed patterns of visual representation and introduce a suitable sparse model for the visual image reconstruction experiment. We use elastic net regularization to model the sparsity of the distributed patterns for local decoder training. We also investigate the relationship between the sparsity of the visual representation and sparse models with different parameters. Our experimental results demonstrate that the sparsity needed by visual reconstruction models differs from the sparsest one, and the l2-norm …regularization introduced in the EN model improves not only the robustness of the model but also the generalization performance of the learning results. We therefore conclude that the sparse learning model for visual image reconstruction should reflect the spasity of visual perceptual experience, and have a solution with high but not the highest sparsity, and some robustness as well. Show more

Keywords: sparse learning model, visual image reconstruction, sparsity, elastic net

DOI: 10.3233/BME-141116

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2963-2969, 2014

Authors: Chung, Soon-Cheol | Choi, Mi-Hyun | Kim, Hyung-Sik | You, Na-Rae | Hong, Sang-Pyo | Lee, Jung-Chul | Park, Sung-Jun | Baek, Ji-Hye | Jeong, Ul-Ho | You, Ji-Hye | Lim, Dae-Woon | Kim, Hyun-Jun

Article Type: Research Article

Abstract: This study investigated neuronal activation differences under two conditions: driving only and distracted driving. Driving and distraction tasks were performed using a Magnetic Resonance (MR)-compatible driving simulator with a driving wheel and pedal. The experiment consisted of three blocks, and each block had both a Rest phase (1 min) and a Driving phase (2 min). During the Rest phase, drivers were instructed to simply look at the stop screen without performing any driving tasks. During the Driving phase, each driver was required to drive at 110 km/h under two conditions: driving only and driving while performing additional distraction tasks. The …results show that the precuneus, inferior parietal lobule, supramarginal gyrus, middle frontal gyrus, cuneus, and declive are less activated in distracted driving than in driving only. These regions are responsible for spatial perception, spatial attention, visual processing and motor control. However, the cingulate gyrus and sub-lobar regions (lentiform nucleus and caudate), which are responsible for error monitoring and control of unnecessary movement, show increased activation during distracted driving compared with driving only. Show more

Keywords: Distraction, driving, fMRI, MR-compatible driving simulator

DOI: 10.3233/BME-141117

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2971-2977, 2014

Authors: Jorge-Hernandez, Fernando | Garcia Chimeno, Yolanda | Garcia-Zapirain, Begonya | Cabrera Zubizarreta, Alberto | Gomez Beldarrain, Maria Angeles | Fernandez-Ruanova, Begonya

Article Type: Research Article

Abstract: Graph theory is also widely used as a representational form and characterization of brain connectivity network, as is machine learning for classifying groups depending on the features extracted from images. Many of these studies use different techniques, such as preprocessing, correlations, features or algorithms. This paper proposes an automatic tool to perform a standard process using images of the Magnetic Resonance Imaging (MRI) machine. The process includes pre-processing, building the graph per subject with different correlations, atlas, relevant feature extraction according to the literature, and finally providing a set of machine learning algorithms which can produce analyzable results for physicians …or specialists. In order to verify the process, a set of images from prescription drug abusers and patients with migraine have been used. In this way, the proper functioning of the tool has been proved, providing results of 87% and 92% of success depending on the classifier used. Show more

Keywords: Functional MRI (fMRI), graph theory, migraine, machine learning, synchronization likelihood

DOI: 10.3233/BME-141118

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2979-2986, 2014

Authors: Wang, Liye | Tang, Xiaoying | Liu, Weifeng | Peng, Yuhua | Gao, Tianxin | Xu, Yong

Article Type: Research Article

Abstract: In the neural science society, multi-subject brain decoding is of great interest. However, due to the variability of activation patterns across brains, it is difficult to build an effective decoder using fMRI samples pooled from different subjects. In this paper, a hierarchical model is proposed to extract robust features for decoding. With feature selection for each subject treated as a separate task, a novel multi-task feature selection method is introduced. This method utilizes both complementary information among subjects and local correlation between brain areas within a subject. Finally, using fMRI samples pooled from all subjects, a linear support vector machine …(SVM) classifier is trained to predict 2-D stimuli-related images or 3-D stimuli-related images. The experimental results demonstrated the effectiveness of the proposed method. Show more

Keywords: Multi-subject brain decoding, fMRI, hierarchical model, multi-task feature selection, classification

DOI: 10.3233/BME-141119

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2987-2994, 2014

Authors: García Chimeno, Yolanda | García Zapirain, Begonya | Saralegui Prieto, Ibone | Fernandez-Ruanova, Begonya

Article Type: Research Article

Abstract: Functional Magnetic Resonance Imaging (fMRI) and Diffusion Tensor Imaging (DTI) are a source of information to study different pathologies. This tool allows to classify subjects under study, analysing in this case, the functions related to language in young patients with dyslexia. Images are obtained using a scanner and different tests are performed on subjects. After processing the images, the areas that are activated by patients when performing the paradigms or anatomy of the tracts were obtained. The main objective is to ultimately introduce a group of monocular vision subjects, whose brain activation model is unknown. This classification helps to assess …whether these subjects are more akin to dyslexic or control subjects. Machine learning techniques study systems that learn how to perform non-linear classifications through supervised or unsupervised training, or a combination of both. Once the machine has been set up, it is validated with the subjects who have not been entered in the training stage. The results are obtained using a user-friendly chart. Finally, a new tool for the classification of subjects with dyslexia and monocular vision was obtained (achieving a success rate of 94.8718% on the Neuronal Network classifier), which can be extended to other further classifications. Show more

Keywords: Classifier, dyslexic, fMRI, PCA, monocular vision

DOI: 10.3233/BME-141120

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2995-3002, 2014

Authors: Bertora, Franco | Borceto, Alice | Viale, Andrea | Sandini, Giulio

Article Type: Research Article

Abstract: A study of the motor cortex during the programming, execution and mental representation of voluntary movement is of great relevance; its evaluation in conditions close to reality is necessary, given the close integration of the visuomotor, sensory feedback and proprioceptive systems, as of yet, a functional Magnetic Resonance Imaging (fMRI) scanner allowing a human subject to maintain erect stance, observe the surroundings and conserve limb freedom is still a dream. The need for high field suggests a solenoid magnet geometry that forces an unnatural posture that affects the results, particularly when the motor cortex is investigated. In contrast in a …motor functional study, the scanner should allow the subject to sit or stand, with unobstructed sight and unimpeded movement. Two approaches are presented here to solve this problem. In the first approach, an increased field intensity in an open magnet is obtained lining the “back wall” of the cavity with a sheet of current: this boosts the field intensity at the cost of the introduction of a gradient, which has to be canceled by the introduction of an opposite gradient; The second approach is an adaptation of the “double doughnut” architecture, in which the cavity widens at the center to provide additional room for the subject. The detailed design of this kind of structure has proven the feasibility of the solution. Show more

Keywords: Functional magnetic resonance, cerebral activation, motor cortex, driving simulator, magnet design, MRI scanner

DOI: 10.3233/BME-141121

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3003-3015, 2014

Authors: Cheng, Sainan | Liu, Qiang | Lv, Yubo | Han, Wenwen | Yu, Ke | Li, Yuchao | Gong, Tao | Zhang, Yi

Article Type: Research Article

Abstract: Fractional anisotropy (FA) is currently an ideal index capable of reflecting the white matter structure. 1 H magnetic resonance spectroscopy (1 H-MRS) is often used as a noninvasive concentration measurement of important neurochemicals in vivo. This study was conducted to investigate the relationship between FA and metabolite concentrations by comparing 1 H-MRS of bilateral medium corona radiata in healthy adults. The data of diffusion tensor imaging (DTI) and 1 H-MRS were acquired from 31 healthy adults using a 3.0 T MR system. All subjects were divided into three groups: the total group (mean age=42 years), the junior group (mean age=29 …years) and the senior group (mean age=56 years). There was a negative correlation between FA and age in three groups (r=-0.146, r=-0.204, r=-0.162, p<0.05). The positive correlation of FA with corresponding concentrations of N-acetylaspartate (NAA) was significant in three groups (r=0.339, r=0.213, r=0.430, respectively, p<0.05). The positive correlation of FA with the corresponding NAA/Cr was only significant difference between the total 353 samples and the junior group (r=0.166, r=0.305, respectively, p<0.05). Combining 1 H-MRS with DTI reveals the relationship between structure and metabolic characteristics of white matter. Show more

Keywords: Diffusion tensor imaging (DTI), magnetic resonance spectroscopy (MRS), white matter

DOI: 10.3233/BME-141122

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3017-3024, 2014

Authors: Yang, Fei | Zhang, Lei | Lu, Weigang | Zuo, Wangmeng | Wang, Kuanquan | Zhang, Henggui | Li, Yeming

Article Type: Research Article

Abstract: A crucial role during the implementation of volume visualization is to identify the optimal transfer function, since the vital information and structure can be highlighted and revealed. The boundary of the volume is shared by respective portion of the two materials formed out of it, which causes undesirable thickening and ambiguity of the boundary explored via traditional LH (Low and High) histogram. To address this issue, initially a modified LH histogram construction method is introduced to intuitively and conveniently visualize cardiac volume for user interaction. Subsequently, the f-LH histogram is presented to further identify and visualize each portion of the …boundary accurately. An appropriate multidimensional transfer function generation is proposed by using variables in f-LH space and spatial information, for visualizing the multi-boundary cardiac volume data. Show more

Keywords: Interactive visualization, partial effect, multidimensional transfer function, multi-boundary data

DOI: 10.3233/BME-141123

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3025-3032, 2014

Authors: Eum, Nyeon Sik | Han, Jung Hyun | Seong, Ki Woong | Lee, Jong Ha | Park, Hee Joon

Article Type: Research Article

Abstract: The portable visible and near-infrared (NIR) imaging equipment for a pre-clinical test with small animals was designed and developed in this paper. The developed equipment is composed of a CCD camera, a focusing lens, an objective lens, a NIR band pass filter and a NIR filter driving motor. An NIR ray is mainly used for imaging equipment because it has high light penetration depth in biological tissue. Therefore, NIR fluorescent agents are available for chemical conjugation to targeting molecules in vivo. This equipment can provide a visible image, NIR image and merged image simultaneously. A communication system was specifically established …to check obtained images through a smart pad in real time. It is less dependent on space and time than the conventional system. Show more

Keywords: Visible/NIR image, animal imaging, fluorescence, mobile-based, merged image

DOI: 10.3233/BME-141124

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3033-3041, 2014

Authors: Xu, Yuanyuan | Wang, Yawei | Ji, Ying | Jin, Weifeng | Bu, Min | Shang, Xuefu

Article Type: Research Article

Abstract: A phase retrieval method is introduced in quantitative phase imaging (QPI) based on two-step phase-shifting technique. By acquiring two measured interferograms and calculating the addition and subtraction between them, the quantitative phase information can be directly retrieved. This method is illustrated by both theory and simulation experiments of a ball. The results of the simulation and the experiment of the red blood cell show a good agreement, demonstrating its application for studying cells.

Keywords: Biotechnology, quantitative phase imaging, phase retrieval, two-step phase shifting, addition and subtraction

DOI: 10.3233/BME-141125

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3043-3048, 2014

Authors: Ding, Yong | Dai, Hang | Zhang, Hang

Article Type: Research Article

Abstract: For improving the detection of micro-calcifications (MCs), this paper proposes an automatic detection of MC system making use of multi-fractal spectrum in digitized mammograms. The approach of automatic detection system is based on the principle that normal tissues possess certain fractal properties which change along with the presence of MCs. In this system, multi-fractal spectrum is applied to reveal such fractal properties. By quantifying the deviations of multi-fractal spectrums between normal tissues and MCs, the system can identify MCs altering the fractal properties and finally locate the position of MCs. The performance of the proposed system is compared with the …leading automatic detection systems in a mammographic image database. Experimental results demonstrate that the proposed system is statistically superior to most of the compared systems and delivers a superior performance. Show more

Keywords: Automatic detection, mammographic calcifications, multi-fractal spectrum

DOI: 10.3233/BME-141126

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3049-3054, 2014

Authors: Ergen, Burhan | Baykara, Muhammet

Article Type: Research Article

Abstract: The developments of content based image retrieval (CBIR) systems used for image archiving are continued and one of the important research topics. Although some studies have been presented general image achieving, proposed CBIR systems for archiving of medical images are not very efficient. In presented study, it is examined the retrieval efficiency rate of spatial methods used for feature extraction for medical image retrieval systems. The investigated algorithms in this study depend on gray level co-occurrence matrix (GLCM), gray level run length matrix (GLRLM), and Gabor wavelet accepted as spatial methods. In the experiments, the database is built including hundreds …of medical images such as brain, lung, sinus, and bone. The results obtained in this study shows that queries based on statistics obtained from GLCM are satisfied. However, it is observed that Gabor Wavelet has been the most effective and accurate method. Show more

Keywords: Content-based image retrieval, GLCM, GLRLM, Gabor wavelet

DOI: 10.3233/BME-141127

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3055-3062, 2014

Authors: Yuan, Zhen | Ieong, Fong H. | Jiang, Huabei | Sobel, Eric S.

Article Type: Research Article

Abstract: The goal of this study is to capture the quantitative optical features of degenerative finger joints based on x-ray aided three-dimensional (3D) diffuse optical tomography (DOT). It is anticipated that the fused imaging technique can be applied to identifying the significant differences between osteoarthritis (OA) and psoriatic arthritis (PA). For a case study, total 6 subjects were selected to study the distal interphalangeal (DIP) finger joints. 2 OA patients, 2 PA patients and 2 healthy subjects were examined clinically first. Their DIP finger joints were then scanned by the multimodality imaging method. Our findings suggested that the developed multimodality imaging …approach may aid to contradistinguish OA patients from PA patients with the healthy control, which is essential for a better diagnosis and treatment of inflammatory arthritis in humans. Show more

Keywords: diffuse optical tomography, osteoarthritis, psoriatic arthritis, x-ray

DOI: 10.3233/BME-141128

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3063-3071, 2014

Authors: Zhai, Yi | Wang, Yan | Wang, Zhaoqi | Liu, Yongji | Zhang, Lin | He, Yuanqing | Chang, Shengjiang

Article Type: Research Article

Abstract: An achromatic element eliminating only longitudinal chromatic aberration (LCA) while maintaining transverse chromatic aberration (TCA) is established for the eye model, which involves the angle formed by the visual and optical axis. To investigate the impacts of higher-order aberrations on vision, the actual data of higher-order aberrations of human eyes with three typical levels are introduced into the eye model along visual axis. Moreover, three kinds of individual eye models are established to investigate the impacts of higher-order aberrations, chromatic aberration (LCA+TCA), LCA and TCA on vision under the photopic condition, respectively. Results show that for most human eyes, the …impact of chromatic aberration on vision is much stronger than that of higher-order aberrations, and the impact of LCA in chromatic aberration dominates. The impact of TCA is approximately equal to that of normal level higher-order aberrations and it can be ignored when LCA exists. Show more

Keywords: Visual optics, eye model, optical design, optical effects on vision, aberrations

DOI: 10.3233/BME-141129

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3073-3081, 2014

Authors: Chan, Yu-Chen

Article Type: Research Article

Abstract: Although considerable attention has been paid to the cognitive structure of humor, its emotional structure tends to be overlooked. Humor is often associated with the single emotion of mirth or amusement, while other aspects of its rich emotional structure are ignored. The purpose of the present study was to explore this structure by analyzing the content of a Taiwanese corpus of 204 ‘negative’ jokes to identify the basic emotion was induced and the emotional shift pattern of the joke. Additionally, the corpus might be used to compare emotional reversal jokes (negative to positive emotion) and regular jokes (neutral to positive …emotion) as an aid when preparing materials for use in functional Magnetic Resonance Imaging (fMRI) investigations on the neural substrates of humor. In terms of basic emotions, 82 fear jokes, 61 disgust jokes, 42 sadness jokes and 19 anger jokes were found. The most common type of emotional shift was from negative to positive, with the punch lines of 114 jokes providing relief from the negative emotion by either diverting attention away from it or dissolving it entirely. Show more

Keywords: Joke corpus, emotional reversal, emotional shift pattern, negative joke, humor

DOI: 10.3233/BME-141130

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3083-3090, 2014

Authors: Yoo, Ie Ryung | Chung, Soo Kyo | Park, Hye Lim | Choi, Woo Hee | Kim, Young Kyoon | Lee, Kyo Young | Wang, Young-Pil

Article Type: Research Article

Abstract: This paper aimed to evaluate the prognostic value of maximum standardized uptake value (SUVmax) and metabolic tumor volume (MTV) of the primary tumor on 18 F-FDG PET/CT scan in early stage non-small cell cancer (NSCLC) patients without lymph node (LN) metastasis. In the experiment, eighty NSCLC patients pathologically staged as T1N0 or T2N0 were included (M:F=50:30; mean age, 64.8 years). All patients had preoperative 18 F-FDG PET/CT scan and curative surgery. FDG uptake in the primary tumor was measured by SUVmax and MTV with various SUV threshold values. SUVmax, MTV of the primary tumor, age, tumor size, histology and differentiation …grade were analyzed for association with disease-free survival (DFS). The experimental results showed that the histology types included adenocarcinoma (n=58), squamous cell carcinoma (n=20), and others (n=2); Twenty-two (27.5%) of the 80 patients had a recurrence during follow-up at a median time of 29.1 months; The median SUVmax was 5.26, and the median MTV2.5 was 2.2 cm3 . Univariate analysis showed higher SUVmax (>4), greater MTV (MTV2.5 >4 cm3 ), and non-squamous histology were significantly associated with shorter period DFS (p=0.001, p=0.030 and p<0.001). In multivariate analysis, higher SUVmax (p=0.004) and adenocarcinoma histology (p=0.005) were associated with shorter DFS. Therefore, high SUVmax (>4) of the primary tumor on preoperative 18 F-FDG PET/CT scan is an independent prognostic factor of shorter DFS in early stage of NSCLC. Show more

Keywords: Non-small-cell lung cancer, PET/CT, standardized uptake value, metabolic tumor volume, early stage

DOI: 10.3233/BME-141131

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3091-3103, 2014

Authors: Fu, Jian | Yu, Guangyuan | Fan, Dekai

Article Type: Research Article

Abstract: X-ray phase contrast computed tomography (CT) uses the phase shift that x-rays undergo when passing through matter, rather than their attenuation, as the imaging signal and may provide better image quality in soft-tissue and biomedical materials with low atomic number. Here a geometry-constraint-scan imaging technique for in-line phase contrast micro-CT is reported. It consists of two circular-trajectory scans with x-ray detector at different positions, the phase projection extraction method with the Fresnel free-propagation theory and the filter back-projection reconstruction algorithm. This method removes the contact-detector scan and the pure phase object assumption in classical in-line phase contrast Micro-CT. Consequently it …relaxes the experimental conditions and improves the image contrast. This work comprises a numerical study of this technique and its experimental verification using a biomedical composite dataset measured at an x-ray tube source Micro-CT setup. The numerical and experimental results demonstrate the validity of the presented method. It will be of interest for a wide range of in-line phase contrast Micro-CT applications in biology and medicine. Show more

Keywords: X-ray in-line phase contrast imaging, micro computed tomography, geometry-constraint scanning mode, reconstruction algorithm

DOI: 10.3233/BME-141132

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3105-3111, 2014

Authors: Cui, Xueli | Gao, Xin | Xia, Wei | Liu, Yangchuan | Liang, Zhiyuan

Article Type: Research Article

Abstract: To build a patient specific respiratory motion model with a low dose, a novel method was proposed that uses a limited number of 3D lung CT volumes with an external respiratory signal. 4D lung CT volumes were acquired for patients with in vitro labeling on the upper abdominal surface. Meanwhile, 3D coordinates of in vitro labeling were measured as external respiratory signals. A sequential correspondence between the 4D lung CT and the external respiratory signal was built using the distance correlation method, and a 3D displacement for every registration control point in the CT volumes with respect to time can …be obtained by the 4D lung CT deformable registration. A temporal fitting was performed for every registration control point displacements and an external respiratory signal in the anterior-posterior direction respectively to draw their fitting curves. Finally, a linear regression was used to fit the corresponding samples of the control point displacement fitting curves and the external respiratory signal fitting curve to finish the pulmonary respiration modeling. Compared to a B-spline-based method using the respiratory signal phase, the proposed method is highly advantageous as it offers comparable modeling accuracy and target modeling error (TME); while at the same time, the proposed method requires 70% less 3D lung CTs. When using a similar amount of 3D lung CT data, the mean of the proposed method's TME is smaller than the mean of the PCA (principle component analysis)-based methods' TMEs. The results indicate that the proposed method is successful in striking a balance between modeling accuracy and number of 3D lung CT volumes. Show more

Keywords: Motion model, 4D lung CT, external respiratory signal, deformable registration, temporal fitting

DOI: 10.3233/BME-141133

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3113-3120, 2014

Authors: Shi, Han | Du, Dong | Su, Zhihong | Peng, Qiyu

Article Type: Research Article

Abstract: Positron Emission Tomography (PET) systems using detectors with Depth of Interaction (DOI) capabilities could achieve higher spatial resolution and better image quality than those without DOI. Up till now, most DOI methods developed are not cost-efficient for a whole body PET system. In this paper, we present a DOI decoding method based on flood map for low-cost conventional block detector with four-PMT readout. Using this method, the DOI information can be directly extracted from the DOI-related crystal spot deformation in the flood map. GATE simulations are then carried out to validate the method, confirming a DOI sorting accuracy of 85.27%. …Therefore, we conclude that this method has the potential to be applied in conventional detectors to achieve a reasonable DOI measurement without dramatically increasing their complexity and cost of an entire PET system. Show more

Keywords: Positron emission tomography, depth of interaction, GATE simulation

DOI: 10.3233/BME-141134

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3121-3127, 2014

Authors: Qiao, Huiting | Wang, Libin | Li, Deyu | Wang, Daifa | Wang, Yu

Article Type: Research Article

Abstract: Positron emission tomography (PET) has been widely used in early diagnosis of tumors. Though standardized uptake value (SUV) is a common diagnosis index for PET, it will be affected by the size of the tumor. To explore how the tumor size affects imaging diagnosis index, dynamic PET images were simulated to study the relationship between tumor size and the imaging diagnosis index. It was found that the SUV of the region of the tumor varied with scan time, and the SUV was always lower than the true value of tumor. Even more deviations were found in SUV with a reduced …tumor size. The diagnosis index SUVmax was more reliable than SUV, for it declined only when the volume of tumor was less than 3 mm3 . Therefore, the effect of tumor size on the SUV and SUVmax that are used as diagnosis indices in the early diagnosis of tumors should not be neglected. Show more

Keywords: Standardized uptake value, maximum standardized uptake value, positron emission tomography, tumor size, diagnosis

DOI: 10.3233/BME-141135

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3129-3136, 2014

Authors: Yong, Jin Rim | Qi, Shouliang | van Triest, Han J.W. | Kang, Yan | Qian, Wei

Article Type: Research Article

Abstract: Extraction of lung tumors is a fundamental step for further quantitative analysis of the tumor, but is challenging for juxta-pleural tumors due to the adhesion to the pleurae. An automatic algorithm for segmentation of juxta-pleural tumors based on the analysis of the geometric and morphological features was proposed. Initially, the lung is extracted by means of thresholding using 2D Otsu's method. Next a center point is suggested to find a starting point and endpoint of outward facing pleura. A model based on the variation of incline angle was adopted to identify potentially affected regions, and to full segment juxta-pleural tumors. …The results were compared with the manual segmentation by two radiologists. Averaged for ten experimental datasets, the accuracy calculated by Dice index between the results of the algorithm and by the two radiologists is 91.2%. It indicates the proposed method has comparable accuracy with the experts (the inter-observer variability is 92.4%), but requests much less manual interactions. The proposed algorithm can be used for segmenting juxta-pleural tumors from CT images, and help improve the diagnosis, pre-operative planning and therapy response evaluation. Show more

Keywords: Juxta-pleural tumor segmentation, morphological analysis, incline angle

DOI: 10.3233/BME-141136

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3137-3144, 2014

Authors: Gan, Hong-Seng | Tan, Tian-Swee | Wong, Liang-Xuan | Tham, Weng-Kit | Sayuti, Khairil Amir | Abdul Karim, Ahmad Helmy | bin Abdul Kadir, Mohammed Rafiq

Article Type: Research Article

Abstract: In medical image segmentation, manual segmentation is considered both labor- and time-intensive while automated segmentation often fails to segment anatomically intricate structure accordingly. Interactive segmentation can tackle shortcomings reported by previous segmentation approaches through user intervention. To better reflect user intention, development of suitable editing functions is critical. In this paper, we propose an interactive knee cartilage extraction software that covers three important features: intuitiveness, speed, and convenience. The segmentation is performed using multi-label random walks algorithm. Our segmentation software is simple to use, intuitive to normal and osteoarthritic image segmentation and efficient using only two third of manual segmentation's …time. Future works will extend this software to three dimensional segmentation and quantitative analysis. Show more

Keywords: Interactive segmentation, Knee cartilage, Magnetic resonance image, Random walks, User interface

DOI: 10.3233/BME-141137

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3145-3157, 2014

Authors: Liu, Hao | Zhao, Jianning | Dai, Ning | Qian, Hongbo | Tang, Yuehong

Article Type: Research Article

Abstract: Separation of the femur head and acetabulum is one of main difficulties in the diseased hip joint due to deformed shapes and extreme narrowness of the joint space. To improve the segmentation accuracy is the key point of existing automatic or semi-automatic segmentation methods. In this paper, we propose a new method to improve the accuracy of the segmented acetabulum using surface fitting techniques, which essentially consists of three parts: (1) design a surface iterative process to obtain an optimization surface; (2) change the ellipsoid fitting to two-phase quadric surface fitting; (3) bring in a normal matching method and an …optimization region method to capture edge points for the fitting quadric surface. Furthermore, this paper cited vivo CT data sets of 40 actual patients (with 79 hip joints). Test results for these clinical cases show that: (1) the average error of the quadric surface fitting method is 2.3 (mm); (2) the accuracy ratio of automatically recognized contours is larger than 89.4%; (3) the error ratio of section contours is less than 10% for acetabulums without severe malformation and less than 30% for acetabulums with severe malformation. Compared with similar methods, the accuracy of our method, which is applied in a software system, is significantly enhanced. Show more

Keywords: Acetabulum, segmentation, ellipsoid fitting, edge points, computer tomography

DOI: 10.3233/BME-141138

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3159-3177, 2014

Authors: Jia, Tong | Zhang, Hao | Meng, Haixiu

Article Type: Research Article

Abstract: Lung vessels often interfere with the detection of lung nodules. In this paper, a novel computer-aided lung nodule detection scheme on vessel segmentation is proposed. This paper describes an active contour model which can combine image region mean gray value and image edge energy. It is used to segment and remove lung vessels. A selective shape filter based on Hessian Matrix is used to detect suspicious nodules and remove omitted lung vessels. This paper extracts density, shape and position features of suspicious nodules, and uses a Rule-Based Classification (RBC) method to identify true positive nodules. In the experiment results, the …detection sensitivity is about 90% and FP is 1/scan. Show more

Keywords: Lung vessel segmentation, lung nodule detection, active contour model, CT image

DOI: 10.3233/BME-141139

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3179-3186, 2014

Authors: Mao, Yihao | Liu, Hong | Ye, Rong | Shi, Yonghong | Song, Zhijian

Article Type: Research Article

Abstract: Plaque assaying, measurement of the number, diameter, and area of plaques in a Petri dish image, is a standard procedure gauging the concentration of phage in biology. This paper presented a novel and effective method for implementing automatic plaque assaying. The method was mainly comprised of the following steps: In the training stage, after pre-processing the images for noise suppression, an initial training set was readied by sampling positive (with a plaque at the center) and negative (plaque-free) patches from the training images, and extracting the HOG features from each patch. The linear SVM classifier was trained in a self-learnt …supervised learning strategy to avoid possible missing detection. Specifically, the training set which contained positive and negative patches sampled manually from training images was used to train the preliminary classifier which exhaustively searched the training images to predict the label for the unlabeled patches. The mislabeled patches were evaluated by experts and relabeled. And all the newly labeled patches and their corresponding HOG features were added to the initial training set to train the final classifier. In the testing stage, a sliding-window technique was first applied to the unseen image for obtaining HOG features, which were inputted into the classifier to predict whether the patch was positive. Second, a locally adaptive Otsu method was performed on the positive patches to segment the plaques. Finally, after removing the outliers, the parameters of the plaques were measured in the segmented plaques. The experimental results demonstrated that the accuracy of the proposed method was similar to the one measured manually by experts, but it took less than 30 seconds. Show more

Keywords: Plaque assay, HOG, SVM, local adaptive image segmentation

DOI: 10.3233/BME-141140

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3187-3198, 2014

Authors: Wu, Huiqun | Geng, Xingyun | Zhang, Xiaofeng | Qiu, Mingyan | Jiang, Kui | Tang, Lemin | Dong, Jiancheng

Article Type: Research Article

Abstract: The optic disc (OD) is one of the important anatomic structures on the retina, the changes of which shape and area may indicate disease processes, thus needs computerized quantification assistance. In this study, we proposed a self-adaptive distance regularized level set evolution method for OD segmentation without the periodically re-initializing steps in the level set function execution to a signed distance function during the evolution. In that framework, preprocessing of an image was performed using Fourier correlation coefficient filtering to obtain initial boundary as the beginning contour, then, an accurate boundary of the optic disc was obtained using the self-adaptive …distance regularized level set evolution method. One hundred eye fundus color numerical images from public database were selected to validate our algorithm. Therefore, we believe that such automatic OD segmentation method could assist the ophthalmologist to segment OD more efficiently, which is of significance for future computer-aided early detection of glaucoma and retinopathy diseases. Show more

Keywords: Optic disk, retinal imaging, level set evolution, imaging informatics

DOI: 10.3233/BME-141141

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3199-3206, 2014

Authors: Li, Fang | Song, Zhijian

Article Type: Research Article

Abstract: Surface registration is widely used in image-guided neurosurgery to achieve spatial registration between the patient space and the image space. Coarse registration, followed by fine registration, is an important premise to ensure the robustness and efficiency of surface registration. In this paper, a coarse registration algorithm based on the principal axes is proposed to achieve this goal. The extraction of the principal axes relies on the approximated surface with an adaptive Gaussian kernel, the width of which is consistent with neighborhood relation so that it is applicable for various scanning data. Determining the corresponding centers of translation is another problem …for aligning different scanning data, which is solved through heuristics. Six pairs of points on two surfaces with the farthest projections on the principal axes were regarded as the candidates of translation centers, and then through tentative alignments of local regions around them, a pair of candidates with the minimum registration error was selected as the optimal translation centers. Automatic registration of two scans of a head phantom is presented in this paper. Experimental results confirmed the robustness of the algorithm and its feasibility in clinical applications. Show more

Keywords: Image-guided neurosurgery, coarse registration, principal axes, adaptive Gaussian kernel, heuristics

DOI: 10.3233/BME-141142

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3207-3214, 2014

Authors: Guo, Song | Luan, Fangjun | Song, Xiaoyu | Li, Changyou

Article Type: Research Article

Abstract: To better analyze images with the Gaussian white noise, it is necessary to remove the noise before image processing. In this paper, we propose a self-adaptive image denoising method based on bidimensional empirical mode decomposition (BEMD). Firstly, normal probability plot confirms that 2D-IMF of Gaussian white noise images decomposed by BEMD follow the normal distribution. Secondly, energy estimation equation of the ith 2D-IMF (i=2,3,4,......) is proposed referencing that of ith IMF (i=2,3,4,......) obtained by empirical mode decomposition (EMD). Thirdly, the self-adaptive threshold of each 2D-IMF is calculated. Eventually, the algorithm of the self-adaptive image denoising method based on BEMD is …described. From the practical perspective, this is applied for denoising of the magnetic resonance images (MRI) of the brain. And the results show it has a better denoising performance compared with other methods. Show more

Keywords: Image denoising, BEMD, self-adaption, Gaussian white noise, energy

DOI: 10.3233/BME-141143

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3215-3222, 2014

Authors: Geng, Lei | Shao, Yi-Ting | Xiao, Zhi-Tao | Zhang, Fang | Wu, Jun | Li, Min | Shan, Chun-Yan

Article Type: Research Article

Abstract: It has been demonstrated that shape, area and depth of the optic disc are relevant indices of diabetic retinopathy. In this paper, we present a new fundus optic disc localization and segmentation method based on phase congruency (PC). Firstly, in order to highlight the optic disc, channel images with the highest contrast between optic disc and background are selected in LAB, YUV, YIQ and HSV spaces respectively. Secondly, with the use of PC, features of four selected channel images can be extracted. Multiplication operation is then used to enhance PC detection results. Thirdly, window scanning and gray accumulating are utilized …to locate the optic disc. Finally, iterative OTSU automatic threshold segmentation and Hough transform are performed on location images, before the final optic disc segmentation result can be obtained. The experimental results showed that the proposed method can effectively and accurately perform optic disc location and segmentation. Show more

Keywords: Fundus image, phase congruency, optic disc localization, optic disc segmentation, diabetic retinopathy

DOI: 10.3233/BME-141144

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3223-3229, 2014

Authors: Cong, Jinyu | Wei, Benzheng | Yin, Yilong | Xi, Xiaoming | Zheng, Yuanjie

Article Type: Research Article

Abstract: Simple Linear Iterative Clustering (SLIC) algorithm is increasingly applied to different kinds of image processing because of its excellent perceptually meaningful characteristics. In order to better meet the needs of medical image processing and provide technical reference for SLIC on the application of medical image segmentation, two indicators of boundary accuracy and superpixel uniformity are introduced with other indicators to systematically analyze the performance of SLIC algorithm, compared with Normalized cuts and Turbopixels algorithm. The extensive experimental results show that SLIC is faster and less sensitive to the image type and the setting superpixel number than other similar algorithms such …as Turbopixels and Normalized cuts algorithms. And it also has a great benefit to the boundary recall, the robustness of fuzzy boundary, the setting superpixel size and the segmentation performance on medical image segmentation. Show more

Keywords: Medical image, superpixels, SLIC, image segmentation, performance evaluation

DOI: 10.3233/BME-141145

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3231-3238, 2014

Authors: Bian, Zijian | Tan, Wenjun | Yang, Jinzhu | Liu, Jiren | Zhao, Dazhe

Article Type: Research Article

Abstract: The quantitative analysis of the airway tree is of critical importance in the CT-based diagnosis and treatment of popular pulmonary diseases. The extraction of airway centerline is a precursor to identify airway hierarchical structure, measure geometrical parameters, and guide visualized detection. Traditional methods suffer from extra branches and circles due to incomplete segmentation results, which induce false analysis in applications. This paper proposed an automatic and robust centerline extraction method for airway tree. First, the centerline is located based on the topological thinning method; border voxels are deleted symmetrically to preserve topological and geometrical properties iteratively. Second, the structural information …is generated using graph-theoretic analysis. Then inaccurate circles are removed with a distance weighting strategy, and extra branches are pruned according to clinical anatomic knowledge. The centerline region without false appendices is eventually determined after the described phases. Experimental results show that the proposed method identifies more than 96% branches and keep consistency across different cases and achieves superior circle-free structure and centrality. Show more

Keywords: Airway tree, centerline extraction, topological thinning, graph-theoretic analysis

DOI: 10.3233/BME-141146

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3239-3249, 2014

Authors: Geng, Chen | Yang, Jian | Dai, Yakang | Liu, Zhaobang | Dong, Yuefang

Article Type: Research Article

Abstract: Computed tomography angiography (CTA) is a major noninvasive technology for imaging coronary artery disease, and effective and accurate vessel tracking method can help radiologists diagnose the disease more accurately. In this paper, a novel 3D vessel tracking method based on CTA data is presented. The method is comprised of preprocessing, a novel spherical operator, and hierarchical clustering, where the spherical operator consists of rays that are casted different directions in a spherical coordinate system. The vascular boundary is extracted by the spherical operator, and the tracking direction is also obtained by the hierarchical clustering. The method is evaluated with the …Rotterdam Coronary Artery Algorithm Evaluation Framework. Results indicate that our method outperforms current state-of-the-art methods in terms of the overlap ratio on the vessel tracking of coronary arteries in CTA data. Show more

Keywords: 3D vessel tracking, spherical operator, hierarchical clustering

DOI: 10.3233/BME-141147

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3251-3258, 2014

Authors: Zhang, Zulin | Yi, Xinzhong | Peng, Hong

Article Type: Research Article

Abstract: This paper proposes a tissue membrane system-based framework to deal with the optimal image fusion problem. A spatial domain fusion algorithm is given, and a tissue membrane system of multiple cells is used as its computing framework. Based on the multicellular structure and inherent communication mechanism of the tissue membrane system, an improved velocity-position model is developed. The performance of the fusion framework is studied with comparison of several traditional fusion methods as well as genetic algorithm (GA)-based and differential evolution (DE)-based spatial domain fusion methods. Experimental results show that the proposed fusion framework is superior or comparable to the …other methods and can be efficiently used for image fusion. Show more

Keywords: Membrane computing, membrane systems, tissue membrane systems, image fusion

DOI: 10.3233/BME-141148

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3259-3266, 2014

Authors: Yang, Jinzhu | Ma, Shuang | Sun, Qi | Tan, Wenjun | Xu, Mengjia | Chen, Nan | Zhao, Dazhe

Article Type: Research Article

Abstract: Traditional Hessian multiscale filter consider only the local geometric feature but not the global grayscale information. In medical image analysis, Hessian filter is usually used to enhance the blood vessels. However, it also produces some pseudo vascular structures or some isolate noise points, such as the nasal soft tissues that have the similar shape with the vessels in MRA data, which will increase the difficulty of cerebrovascular segmentation. To resolve this issue, an improved Hessian multiscale filter is proposed in this paper. An image grayscale factor is added to the vascular similarity function computed by Hessian matrix eigenvalue. This method …is experimented on brain MRA data and lung CTA data. Experimental results show that this method can enhance vascular structures, and simultaneously reduce the appearance of the pseudo vascular structures and the isolated noise points. Show more

Keywords: Hessian filter, multiscale enhancement, grayscale, CT image, MRA image

DOI: 10.3233/BME-141149

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3267-3275, 2014

Authors: Li, Hong | Liu, Kaihua | Sun, Hang | Bao, Nan | Wang, Xu | Tian, Shi | Qi, Shouliang | Kang, Yan

Article Type: Research Article

Abstract: Computed tomography (CT) radiation dose can be reduced significantly by region of interest (ROI) CT scan. Automatically positioning the heart in CT scout images is an essential step to realize the ROI CT scan of the heart. This paper proposed a fully automatic heart positioning method in CT scout image, including the anteroposterior (A-P) scout image and lateral scout image. The key steps were to determine the feature points of the heart and obtaining part of the heart boundary on the A-P scout image, and then transform the part of the boundary into polar coordinate system and obtain the whole …boundary of the heart using slant elliptic equation curve fitting. For heart positioning on the lateral image, the top and bottom boundary obtained from A-P image can be inherited. The proposed method was tested on a clinical routine dataset of 30 cases (30 A-P scout images and 30 lateral scout images). Experimental results show that 26 cases of the dataset have achieved a very good positioning result of the heart both in the A-P scout image and the lateral scout image. The method may be helpful for ROI CT scan of the heart. Show more

Keywords: CT scout, heart positioning, ROI scan, automatic positioning method

DOI: 10.3233/BME-141150

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3277-3286, 2014

Authors: Nawaz, Shoukat | Fu, Jian | Fan, Dekai

Article Type: Research Article

Abstract: X-ray computed tomography (CT) is a powerful clinical diagnosis tool and has been used widely in many clinical and biological settings. Metal artifacts, caused by high density implants, are commonly encountered in clinical CT applications, thereby affecting the detection of abnormal structures and undermining CT's diagnostic value. In this paper, we developed a metal artifact reduction approach based on image segmentation and forward-projection. We further demonstrate the usefulness of our approach by using a biomedical specimen consisting of muscles, bones and metals. Our aim is to remove the inaccurate metal artifact pixels in the original CT slices and exactly reconstruct …the soft-tissue using the forward projections with no metal information. During the reconstruction, artifacts are reduced by replacing the metal projection using the forward projection. The presented work is of interest for CT biomedical applications. Show more

Keywords: Computed tomography, metal artifacts, image segmentation, forward-projection

DOI: 10.3233/BME-141151

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3287-3293, 2014

Authors: Lee, Gihyoun | Na, Sung Dae | Cho, Jin-Ho | Kim, Myoung Nam

Article Type: Research Article

Abstract: This paper presents a voice activity detection (VAD) approach using a perceptual wavelet entropy neighbor slope (PWENS) in a low signal-to-noise (SNR) environment and with a variety of noise types. The basis for our study is to use acoustic features that have large entropy variance for each wavelet critical band. The speech signal is decomposed by the proposed perceptual wavelet packet decomposition (PWPD), and the VAD function is extracted by PWENS. Finally, VAD is decided by the proposed VAD decision rule using two memory buffers. In order to evaluate the performance of the VAD decision, many speech samples and a …variety of SNR conditions were used in the experiment. The performance of the VAD decision is confirmed using objective indexes such as a graph of the VAD decision and the relative error rate. Show more

Keywords: Voice activity detection, wavelet transform, wavelet decomposition, neighbor slope, entropy

DOI: 10.3233/BME-141152

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3295-3301, 2014

Authors: Na, Sung Dae | Lee, Gihyoun | Lee, Jyung Hyun | Kim, Myoung Nam

Article Type: Research Article

Abstract: In this paper, a new method for individual tooth segmentation was proposed. The proposed method is composed of enhancement and extraction of boundary and seed of watershed algorithm using trisection areas by morphological characteristic of teeth. The watershed algorithm is one of the conventional methods for tooth segmentation; however, the method has some problems. First, molar region detection ratio is reduced because of oral structure features that is low intensities in molar region. Second, inaccurate segmentation occurs in incisor region owing to specular reflection. To solve the problems, the trisection method using morphological characteristic was proposed, where three tooth areas …are made using ratio of entire tooth to each tooth. Moreover, the enhancement is to improve the intensity of molar using the proposed method. In addition, boundary and seed of watershed are extracted using trisection areas applied other parameters each area. Finally, individual tooth segmentation was performed using extracted boundary and seed. Furthermore, the proposed method was compared with conventional methods to confirm its efficiency. As a result, the proposed method was demonstrated to have higher detection ratio, better over segmentation, and overlap segmentation than conventional methods. Show more

Keywords: Segmentation, tooth, watershed, oral scanner

DOI: 10.3233/BME-141153

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3303-3309, 2014

Authors: Birtane, Sibel | Korkmaz, Hayriye

Article Type: Research Article

Abstract: In this paper, 2-steps software using image processing and enhancement technologies is developed to obtain a scoliosis patient's spine pattern from 2D coronal X-Ray images without manual land marking. Then, a Rule-based Fuzzy classifier is implemented on those images to classify the spine patterns using the King-Moe classification approach.

Keywords: Image processing, scoliosis, king-moe type classification, fuzzy logic, computer aided classification, rule-based classification

DOI: 10.3233/BME-141154

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3311-3319, 2014

Authors: Liu, Xi | Liu, Lixiong

Article Type: Research Article

Abstract: We analyzed the principle of the traditional local binary fitting operation, Gaussian kernel function weighted summation (GKFWS), to develop a novel level set model in this paper. In this model, the traditional GKFWS operation is replaced with the median filter operation in the second procedure of local fitting of the energy domain. Furthermore, we incorporated the edge stopping function of GAC model into it to introduce the edge information for segmentation. Experiments on synthetic and real images demonstrate that this model has promising performance in terms of computational cost, robustness to noises and segmentation of images with intensity inhomogeneity.

Keywords: Active contour, median filter, image segmentation, level set, edge information

DOI: 10.3233/BME-141155

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3321-3332, 2014

Authors: Yin, Lim Khai | Rajeswari, Mandava

Article Type: Research Article

Abstract: To segment an image using the random walks algorithm; users are often required to initialize the approximate locations of the objects and background in the image. Due to its segmenting model that is mainly reflected by the relationship among the neighborhood pixels and its boundary conditions, random walks algorithm has made itself sensitive to the inputs of the seeds. Instead of considering the relationship between the neighborhood pixels solely, an attempt has been made to modify the weighting function that accounts for the intensity changes between the neighborhood nodes. Local affiliation within the defined neighborhood region of the two nodes …is taken into consideration by incorporating an extra penalty term into the weighting function. Besides that, to better segment images, particularly medical images with texture features, GLCM variance is incorporated into the weighting function through kernel density estimation (KDE). The probability density of each pixel belonging to the initialized seeds is estimated and integrated into the weighting function. To test the performance of the proposed weighting model, several medical images that mainly made up of 174-brain tumor images are experimented. These experiments establish that the proposed method produces better segmentation results than the original random walks. Show more

Keywords: Random walks, weighting function, gray-level co-occurrence, kernel density estimation

DOI: 10.3233/BME-141156

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3333-3341, 2014

Authors: Zhang, Ziqun | Zhang, Ran | Song, Zhijian

Article Type: Research Article

Abstract: Skull defect reconstruction is an important aspect of surgical repair. Historically, a skull defect prosthesis was created by the mirroring technique, surface fitting, or formed templates. These methods are not based on the anatomy of the individual patient's skull, and therefore, the prosthesis cannot precisely correct the defect. This study presented a new hybrid level set model, taking into account both the global optimization region information and the local accuracy edge information, while avoiding re-initialization during the evolution of the level set function. Based on the new method, a skull defect was reconstructed, and the skull prosthesis was produced by …rapid prototyping technology. This resulted in a skull defect prosthesis that well matched the skull defect with excellent individual adaptation. Show more

Keywords: Skull defect, image segmentation, level set method, rapid prototyping

DOI: 10.3233/BME-141157

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3343-3351, 2014

Authors: Xia, Yong | Liu, Yixuan | Wang, Kuanquan

Article Type: Research Article

Abstract: Having the ability to visualize the heart clearly and precisely would be beneficial for pathology research, presurgical planning, and clinical approaches. Multi-dimensional transfer functions were employed to improve the overall performance of images. To provide a satisfactory visualization quality on the shape and boundaries of the heart, a new hybrid transfer function combining structure size with gradient was designed to highlight the area of the heart. Initially, a histogram of gradient and histogram of size was computed and then classification was performed for providing the spatial information. Finally, several hybrid strategies were presented for the design of the transfer function, …including opacity and color. By experimental evaluation, the proposed hybrid transfer function visualized the cardiac outline and internal structure more clearly and easily. Show more

Keywords: visualization of heart, multi-dimensional transfer function, histogram of structure size, histogram of gradient

DOI: 10.3233/BME-141158

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3353-3359, 2014

Authors: Bao, Nan | Chen, Yu | Yue, Yong | Li, Hong | Cui, Zhiming | Zhuang, Jinfeng | Tian, Shi | Kang, Yan

Article Type: Research Article

Abstract: The rigid registration is a key step of Image Guided Surgery (IGS), and the point-pair method is the main way used for registration. However the configuration of fiducial points has a great influence on the registration accuracy at the target point. Now almost all the optimization method of fiducial points configuration relies on the empirical simulation-based Fitzpatrick's target registration error (TRE). In this paper, a phantom and some markers were designed and some experiments were conducted to measure and compare the affecting factors on the registration. By the markers repeated selections, the fiducial location error (FLE) has a small deviation …of maximum 0.4 mm, and the average of the Fitzpatrick's TRE (F-TRE) has almost 86% proportion to the average of the actual TRE (A-TRE), but the standard deviation (STD) just has 7% proportion. Also, the experiment result showed that six fiducial markers already had the 86% accuracy, and spreading the fiducial markers led to 30% reduction in mean of A-TRE and 40% reduction in STD of A-TRE comparing with the centralized. Overall, to find a strategy of optimization, reducing the TRE has the great meaning to support safer and more accurate minimally IGS procedures. Show more

Keywords: Image guided surgery, target registration error, registration, fiducial markers, number and distribution

DOI: 10.3233/BME-141159

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3361-3371, 2014

Authors: Ji, Bing | Yang, Qing | Genever, Paul G. | Fagan, Michael J.

Article Type: Research Article

Abstract: Multiple myeloma (MM)-induced bone disease is mortal for most MM patients. Bisphosphonates are first-line treatment for MM-induced bone disease, since it can inhibit osteoclast activity and the resultant bone resorption by suppressing the differentiation of osteoclast precursors into mature osteoclasts, promoting osteoclast apoptosis and disrupting osteoclast function. However, it is still unclear whether bisphosphonates have an anti-tumour effect. In our previous work, a computational model was built to simulate the pathology of MM-induced bone disease. This paper extends this proposed computational model to investigate the efficacy of bisphosphonates treatment and then clear the controversy of this therapy. The extended model …is validated through the good agreement between simulation results and experimental data. The simulation results suggest that bisphosphonates indeed have an anti-tumour effect. Show more

Keywords: Multiple myeloma, MM-induced bone disease, bisphosphonates, anti-tumour, computational model

DOI: 10.3233/BME-141160

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3373-3378, 2014

Authors: Wu, Yixiao | Yang, Ran | Jia, Sen | Li, Zhanjun | Zhou, Zhiyang | Lou, Ting

Article Type: Research Article

Abstract: This work was aimed at studying the method of computer-aided diagnosis of early knee OA (OA: osteoarthritis). Based on the technique of MRI (MRI: Magnetic Resonance Imaging) T2 Mapping, through computer image processing, feature extraction, calculation and analysis via constructing a classifier, an effective computer-aided diagnosis method for knee OA was created to assist doctors in their accurate, timely and convenient detection of potential risk of OA. In order to evaluate this method, a total of 1380 data from the MRI images of 46 samples of knee joints were collected. These data were then modeled through linear regression on an …offline general platform by the use of the ImageJ software, and a map of the physical parameter T2 was reconstructed. After the image processing, the T2 values of ten regions in the WORMS (WORMS: Whole-organ Magnetic Resonance Imaging Score) areas of the articular cartilage were extracted to be used as the eigenvalues in data mining. Then,a RBF (RBF: Radical Basis Function) network classifier was built to classify and identify the collected data. The classifier exhibited a final identification accuracy of 75%, indicating a good result of assisting diagnosis. Since the knee OA classifier constituted by a weights-directly-determined RBF neural network didn't require any iteration, our results demonstrated that the optimal weights, appropriate center and variance could be yielded through simple procedures. Furthermore, the accuracy for both the training samples and the testing samples from the normal group could reach 100%. Finally, the classifier was superior both in time efficiency and classification performance to the frequently used classifiers based on iterative learning. Thus it was suitable to be used as an aid to computer-aided diagnosis of early knee OA. Show more

Keywords: Knee OA, MR T2 mapping, RBF neural network, computer-aided diagnosis

DOI: 10.3233/BME-141161

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3379-3388, 2014

Authors: Zhu, Lei | Zheng, Ran | Jin, Hai | Zhang, Qin | Zhang, Wei

Article Type: Research Article

Abstract: Silicosis remains one of the most harmful occupational respiratory diseases. It threatens the workers exposed to dust environment. Chest radiograph is the main available image source for silicosis diagnosis according to the diagnostic criteria of pneumoconiosis (DCP). Automatic detection and recognition of silicosis in chest radiograph has great importance on aiding the process of silicosis diagnosis. This paper proposes a multi-scale opacity detection approach to detect all suspected opacities from the chest radiograph. A support vector machine (SVM) based computer-aided silicosis diagnosis is proposed to recognize silicosis opacity from a large amount of candidate regions, and gives processing result for …radiologist reference. Comprehensive experiments conducted on real world chest radiographs demonstrate that the proposed approach can reveal changes of silicosis pathology well, and it can be adopted as an effective tool for automatic silicosis diagnosis. Show more

Keywords: Silicosis, diagnostic criteria of pneumoconiosis, chest radiograph, support vector machine, silicosis pathology

DOI: 10.3233/BME-141162

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3389-3395, 2014

Authors: Li, Peng | Bi, Tingting | Huang, Jiuling | Li, Siben

Article Type: Research Article

Abstract: The frequent occurrence of breast cancer and its serious consequences have attracted worldwide attention in recent years. Problems such as low rate of accuracy and poor self-adaptability still exist in traditional diagnosis. In order to solve these problems, an AdaBoost-SVM classification algorithm, combined with the cluster boundary sampling preprocessing techniques (CBS-AdaBoost-SVM), is proposed in this paper for the early diagnosis of breast cancer. The algorithm uses machine learning method to diagnose the unknown image data. Moreover, not all of the characteristics play positive roles for classification. To address this issue the paper delete redundant features by using Rough set attribute …reduction algorithm based on the genetic algorithm (GA). The effectiveness of the proposed methods are examined on DDSM by calculating its accuracy, confusion matrix, and receiver operating characteristic curves, which give important clues to the physicians for early diagnosis of breast cancer. Show more

Keywords: Computer-aided diagnosis, image data mining, support vector machine, clustering sampling

DOI: 10.3233/BME-141163

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3397-3404, 2014

Authors: Song, In-Uk | Kim, Joong-Seok | Chung, Sung-Woo | Lee, Kwang-Soo | Oh, Jin-Kyoung | Chung, Yong-An

Article Type: Research Article

Abstract: Cognitive dysfunction is a common feature of Parkinson's disease (PD). Recent research has focused on the detection and management of subjective memory impairment (SMI) as the stage that precedes mild cognitive impairment (MCI). Nevertheless, few clinical studies have biomarkers of SMI in PD. Therefore, this study was designed to investigate differences in perfusion brain SPECT between PD with SMI (PD+SMI) and PD without SMI (PD-SMI) to identify a potential prodromal biomarker of progression to dementia in patients with PD. In this study, 30 PD patients with SMI and 24 PD patients without SMI have been recruited. All subjects underwent perfusion …brain SPECT and neuropsychological testing. Brain SPECT images were analyzed by using the SPM program and comparing between patients with PD+SMI and PD-SMI. The PD+SMI and PD-SMI groups did not differ in any neuropsychological tests, except for MMSE. Despite a significant difference in MMSE scores, all scores of both groups were in the normal range. Brain SPECT analysis of PD+SMI patients showed hypoperfusion in the frontal and inferior temporal regions, anterior cingulate and thalamus compared with PD-SMI patients. This pilot study investigated the role of decreased brain perfusion SPECT findings in PD+SMI patients compared with PD-SMI patients as a predictive biomarker of pre-dementia as the stage that precedes MCI in PD. Larger, prospective studies are warranted for further investigation of the pathophysiology of neuronal systems during cognitive decline. Show more

Keywords: Parkinson's disease, subjective memory impairment, perfusion SPECT

DOI: 10.3233/BME-141164

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3405-3410, 2014

Authors: Liu, Yubin | Li, Zhifang | Li, Hui | Yuan, Zhen

Article Type: Research Article

Abstract: In this study, the change of tumors' chemical composition in the temperature range of 20~70°C is quantified for photothermal tumor therapy by photoacoustic spectroscopy (PAS) with the wavelengths of 700~1000 nm. Based on the measured photoacoustic signals, two absorption peaks at the wavelengths of 750nm and 950nm are identified. It is also observed that high temperature (>55°C) is able to induce the physical and chemical degeneration of tumors. According to the in vitro tests, a new chemical species, met-hemoglobin, which is absent in normal blood, is generated at high temperature with enhanced near-infrared absorption.

Keywords: PAS, photothermal therapy, photoacoustic signals, hemoglobin

DOI: 10.3233/BME-141165

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3411-3418, 2014

Authors: Bianchi, Mariana | Adur, Javier | Ruff, Silvana Y. | Izaguirre, María F. | Carvalho, Hernandes F. | Cesar, Carlos L. | Casco, Víctor H.

Article Type: Research Article

Abstract: Murine induced colon cancer has been used to demonstrate that Second Harmonic Generation (SHG) microscopy images, combined with Two-Photon Excitation Fluorescence (TPEF) and specific quantization scoring methods allow distinguishing early alterations in colon mucosa. TPEF was used only to identified crypts and submucosa regions, whereas the image analysis was used to get quantitative data (Integrated Intensity and Aspect Ratio scoring) of different cancer stages. The submucosa amount of collagen fibers was significant and their orientation suffering proportional changes with the development of the pathological processes. Both after the fourth and eighth weeks after colon cancer induction, integrated intensity and aspect …ratio values have shown significant statistical differences compared with control samples. Thus, SHG microscopy has proved to be a useful quantitative tool to highlight early changes of submucosa and the progression of these through the cancer development. Show more

Keywords: Colon cancer, early detection, second harmonic generation, two-photon excitation fluorescence

DOI: 10.3233/BME-141166

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3419-3426, 2014

Authors: Li, Sujiao | Zhang, Zhengxiang | Wang, Jue

Article Type: Research Article

Abstract: Prevention of pressure sores remains a significant problem confronting spinal cord injury patients and the elderly with limited mobility. One vital aspect of this subject concerns the development of cushions to decrease pressure ulcers for seated patients, particularly those bound by wheelchairs. Here, we present a novel cushion system that employs interface pressure distribution between the cushion and the buttocks to design custom contoured foam cushion. An optimized normalization algorithm was proposed, with which interface pressure distribution was transformed into the carving depth of foam cushions according to the biomechanical characteristics of the foam. The shape and pressure-relief performance of …the custom contoured foam cushions was investigated. The outcomes showed that the contoured shape of personalized cushion matched the buttock contour very well. Moreover, the custom contoured cushion could alleviate pressure under buttocks and increase subjective comfort and stability significantly. Furthermore, the fabricating method not only decreased the unit production cost but also simplified the procedure for manufacturing. All in all, this prototype seat cushion would be an effective and economical way to prevent pressure ulcers. Show more

Keywords: Prototype, manufacture system, custom-contoured cushion (CCC), pressure sores, optimized normalization algorithm

DOI: 10.3233/BME-141167

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3427-3438, 2014

Authors: Huan, Cheng | Qu, Yuanming | Ren, Zongming

Article Type: Research Article

Abstract: The purpose of this study was to assess gender-related distinction in the performance of Cushing's disease (CD) regarding clinical features, radiological findings, neurological and endocrine status, surgical outcome, and quality of life in Han Chinese. A retrospective study was conducted on 87 patients treated by trans-sphenoidal surgery, between 2006 and 2011, at a single treatment center in Shandong Provincial Hospital, China. Features of CD were compared and quality of life was analyzed between genders. The female-to-male ratio was 2.78: 1. Results showed that men have a younger age of diagnosis (P<0.001), a larger adenoma diameter (P<0.001), and a higher invasion …rate (P=0.032) and apoplexy rate (P=0.04) than women. To be specific, compared with women, men are more prone to suffering from osteoporosis, hypokalemia, sexual dysfunction, and hypertension (P<0.05), have significantly higher preoperative and postoperative (six months after surgery) cortisol levels (P<0.001, P=0.003) and a higher recurrence rate (30.43% vs. 7.81%; P=0.028). No significant differences were seen in the CushingQoL scores between genders. Therefore, male patients with CD need more careful and long-term follow-up than female patients. Show more

Keywords: Cushing's disease, gender differences, transsphenoidal surgery, CushingQoL scores

DOI: 10.3233/BME-141168

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3439-3446, 2014

Authors: Zhang, Bowen | Chai, Hua | Yang, Ziyi | Liang, Yong | Chu, Gejin | Liu, Xiaoying

Article Type: Research Article

Abstract: Heart disease has become the number one killer of human health, and its diagnosis depends on many features, such as age, blood pressure, heart rate and other dozens of physiological indicators. Although there are so many risk factors, doctors usually diagnose the disease depending on their intuition and experience, which requires a lot of knowledge and experience for correct determination. To find the hidden medical information in the existing clinical data is a noticeable and powerful approach in the study of heart disease diagnosis. In this paper, sparse logistic regression method is introduced to detect the key risk factors using …L1/2 regularization on the real heart disease data. Experimental results show that the sparse logistic L1/2 regularization method achieves fewer but informative key features than Lasso, SCAD, MCP and Elastic net regularization approaches. Simultaneously, the proposed method can cut down the computational complexity, save cost and time to undergo medical tests and checkups, reduce the number of attributes needed to be taken from patients. Show more

Keywords: Heart disease, feature selection, sparse logistic regression, L1/2 regularization

DOI: 10.3233/BME-141169

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3447-3454, 2014

Authors: Zhang, Liang | Liu, Peiguo | Dong, Xiuzhen | Zhou, Dongming | Shi, Xuetao

Article Type: Research Article

Abstract: In this paper, a convenient and noninvasive scanning imaging method using microwave frequency band for abnormal subepidermal tissues detection is proposed in the aim to improve diagnosis and prognosis in clinical environments. This method is based on the reflective detection technology with coaxial probe that is used to measure the dielectric properties of tissues. An improved equivalent circuit and simulated annealing algorithm (SA) were used in this work to analyze the dielectric properties of tissues. Computational simulations incorporating a simplified model of subcutaneous hemorrhage described in this work were used to evaluate this method. The dielectric properties data of tissues …in the model of simulation is derived from the literature. The simulation results demonstrated the potential of this method to detect abnormal subepidermal tissues conveniently and expose them in the image accurately. Show more

Keywords: Coaxial probe, dielectric properties, scanning imaging, simulated annealing, subepidermal tissues

DOI: 10.3233/BME-141170

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3455-3462, 2014

Authors: He, Ying | Jiang, Pengjun | Han, Shanshan | Wang, Rong | Li, Yue | Teng, Yichao | Gao, Tianxin

Article Type: Research Article

Abstract: Near-infrared spectroscopy (NIRS) was used to investigate the cerebral oxygenation of Moyamoya and healthy subjects. Continuous recordings of NIRS signals for 20 min (20 min signals) were obtained from 17 healthy subjects (age: 37.4±11.3) and 17 Moyamoya subjects (age: 40.1±11.2). Spectral analysis based on wavelet transformation identified five frequency intervals (I, 0.0095 Hz to 0.02 Hz; II, 0.02 Hz to 0.06 Hz; III, 0.06 Hz to 0.15 Hz; IV, 0.15 Hz to 0.40 Hz; and V, 0.40 Hz to 2.00 Hz) in the 20 min signals and three frequency intervals (III, 0.06 Hz to 0.15 Hz; IV, 0.15 Hz to …0.40 Hz; and V, 0.40 Hz to 2.00 Hz) in the 3 min signals (the first 3 min signals were continuously extracted from the 20 min signals). Significant differences (p < 0.05) were found in frequency intervals III and V. The former exhibited the myogenic activity of smooth muscle inside the blood vessels in both 20 min and 3 min signal analyses; the latter showed hemodynamic oscillation caused by heart pumping. This finding agrees with the vascular pathological changes in Moyamoya disease. As a potential screening method for Moyamoya disease, the simple threshold method exhibited 73.5% accuracy. Show more

Keywords: Moyamoya disease, near-infrared spectroscopy, cerebral oxygenation, wavelet transformation, screening

DOI: 10.3233/BME-141171

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3463-3469, 2014

Authors: Yang, Jian | Fu, Tianyu | Ai, Danni | Xing, Huijun | Li, Qin | Wang, Yongtian

Article Type: Research Article

Abstract: Shoulder instability is a major threat to people's daily life. Many patients suffer from shoulder instability such as the loss of the glenoid and humeral head. In clinical practice, an accurate 3D structure estimation of damaged joints is necessary to diagnose and treat bone defects. This study quantifies osteoarticular defects through the modeling and visualization of osteoarticular structures. An improved algorithm to extract the 3D structure of the bones is proposed. The bone contour is then automatically extracted using prior shape and gray scale intensity distribution of joint CT images. Joint structures with mirror symmetry are matched using the Iterative …Closest Point registration algorithm. Osteoarticular defects can be quantified on the basis of the symmetric information of the bones. Experimental results demonstrate that the proposed method can effectively segment the joint structures from the CT image. In addition, the proposed mirror symmetrical method can effectively estimate osteoarticular defects. Show more

Keywords: Joint bone, segmentation, modeling, quantitative analysis

DOI: 10.3233/BME-141172

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3471-3478, 2014

Authors: Zhou, Zhengdong | Chen, Yuanhua | Yu, Zili | Wang, Dongdong | Zhao, Chunsheng | Xu, Jun | Song, Wei | Li, Bing | Shen, Junshu | Zhu, Xixu

Article Type: Research Article

Abstract: Intensity-Modulated Radiation Therapy (IMRT) mathematically forms a large-scale optimization problem. The development of an IMRT plan is computationally expensive resulting in time-consuming, inefficient, and difficult to develop high-quality IMRT plans. By combining prior knowledge with proposed novel measures derived from both Overlap Volume Histogram (OVH) descriptors and Dose Volume Histograms (DVHs), a novel quality control method for IMRT planning is proposed to assure the high quality of IMRT plan. Clinical approved nasopharyngeal IMRT plans were employed for the experiments, where the reference plan is firstly retrieved from IMRT plan database for each query case by using measures derived from both …OVH descriptors and DVHs. Then the DVHs of the reference plan are served as additional goals for the IMRT plan re-optimization. The experimental results show that the proposed method can effectively pick out those IMRT plans, whose quality could be improved substantially (i.e. the doses of their Clinical Targets Volume (CTV) could be effectively increased) and the dose of their Organs at Risk (OARs) could be reduced after the IMRT plan has being re-optimized. In conclusion, the proposed methods can effectively guarantee the high quality of the IMRT planning. Show more

Keywords: Intensity-modulated radiation therapy (IMRT), quality control, overlap volume histogram (OVH), prior knowledge

DOI: 10.3233/BME-141173

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3479-3485, 2014

Authors: Wang, Chunxi | Cai, Xiangjun | Liang, Faqi | Chu, Futao | Chen, Gang | Duan, Zhiquan

Article Type: Research Article

Abstract: The celiomesenteric trunk is a rare anomaly characterized by a common origin of the celiac axis and superior mesenteric artery from the aorta, which accounts for less than 1% of all celiac artery anomalies, so the aneurysm occurred in such trunk is even rarer. There have been few reports on how to diagnose and deal with such malformed celiomesenteric trunk aneurysms till now. This paper tries to summarize the experience of how to expose and excise such kind of aneurysm according to the seven cases' data. The clinic data were collected retrospectively. There were seven cases with celiomesenteric trunk aneurysm …from February 2000 to February 2013, including 5 males and 2 females aged 35~62. The operations were done including aneurysm resection and vascular reconstruction under general anesthesia. The operated patients were followed-up at the sixth month and each year post operation. The vascular stomas were detected or examined by Color Doppler Sonography, spiral Computed Tomography angiography (SCTA). The seven operated patients were cured and discharged from hospital, and they were followed up for 3~10 years (mean time 5 years), with four patients being followed up longer than 5 years. No sign of intestinal ischemia or hepatic ischemia or splenic ischemia was found, and no image of anastomosis stricture or stenosis was found during the follow-up. Five patients are alive now while two patients were dead, with one dying of large area myocardial infarction unexpectedly at 6 years post operation and the other dying of cerebral infarction abruptly at 4 years post operation. It is an effective and safe method to treat the celiomesenteric trunk aneurysm by using by-pass operation with artificial blood vessels, originating from inferior kidney aorta to visceral arteries including hepatic artery, splenic artery and superior mesenteric artery. Its short-term and middle-term effects are relatively better. Show more

Keywords: Celiomesenteric trunk, superior mesenteric artery, celiac trunk, aneurysm, operation

DOI: 10.3233/BME-141174

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3487-3492, 2014

Authors: Eguiluz-Perez, Gonzalo | Garcia-Zapirain, Begonya

Article Type: Research Article

Abstract: People with Multiple Sclerosis (MS) need regular physical activities along with medical treatment despite their ability or disability level. However, poorly performed exercises could aggravate muscle imbalances and worsen their health. The goal of our work is to create a comprehensive system, encompassing a face-to-face sessions performed by MS patients one day a week at the medical center with exercises at home the rest of the week through a web platform in combination with a tracking tool to analyze the position of patients during exercise and correct them in real-time. The whole system is currently testing during six months with …ten participants, five persons with MS and 5 professionals related with MS. Two tests, the Functional Independence Measure and the Berg Balance Scale will be act as a barometer for measuring the degree of independence obtained by the people with MS and also the validity of the whole system as a rehabilitation tool. Preliminary results about the usability of the system using SUS scale, 72 and 76 points over 100 (patients and professionals respectively), demonstrate that our system is usable for both patients and professionals. Show more

Keywords: Multiple Sclerosis, telerehabilitation, web application, verticality analysis

DOI: 10.3233/BME-141175

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3493-3502, 2014

Authors: Tran, Thang Viet | Chung, Wan-Young

Article Type: Research Article

Abstract: This paper proposes the design and implementation of a low-voltage and low-power body sensor node based on the IEEE 802.15.4 standard to collect electrocardiography (ECG) and photoplethysmography (PPG) signals. To achieve compact size, low supply voltage, and low power consumption, the proposed platform is integrated into a ZigBee mote, which contains a DC-DC booster, a PPG sensor interface module, and an ECG front-end circuit that has ultra-low current consumption. The input voltage of the proposed node is very low and has a wide range, from 0.65 V to 3.3 V. An RF energy harvester is also designed to charge the …battery during the working mode or standby mode of the node. The power consumption of the proposed node reaches 14 mW in working mode to prolong the battery lifetime. The software is supported by the nesC language under the TinyOS environment, which enables the proposed node to be easily configured to function as an individual health monitoring node or a node in a wireless body sensor network (BSN). The proposed node is used to set up a wireless BSN that can simultaneously collect ECG and PPG signals and monitor the results on the personal computer. Show more

Keywords: Body sensor network, electrocardiography, photoplethysmography, low-power node, radio frequency energy harvester

DOI: 10.3233/BME-141176

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3503-3510, 2014

Authors: Viqueira Villarejo, María | Maeso García, Jose | García Zapirain, Begoña | Méndez Zorrilla, Amaia

Article Type: Research Article

Abstract: This paper describes a study dealing with a technological solution to measure gait quality in people suffering from multiple sclerosis (MS) by selecting objective parameters that focus on their step. Android mobile technology, online services and four wireless pressure sensors are used in concert for this purpose. The objective of this work is the early detection of deterioration of the patient so that a physician can quickly intervene. Tests were carried out on a group of 8 persons with MS, and these results were compared with a control a group of 6 healthy participants. The results indicated a statistical difference …in 7 of 40 general step features, with a minimum σ=0.013 and a maximum σ=0.029. These characteristics showed differences between first and fifth metatarsals for each group. It was concluded that these parameters can be used to evaluate gait degeneration in people with MS and that further information could be obtained from measurements with sensors to monitor activities such as bending and inertial sensors. Show more

Keywords: Gait analysis, objective parameterization, sensors

DOI: 10.3233/BME-141177

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3511-3522, 2014

Authors: Viqueira Villarejo, María | García Zapirain, Begoña | Méndez Zorrilla, Amaia

Article Type: Research Article

Abstract: This paper presents a shoe-integrated sensor device which collects objective information concerning the gait quality in patients' physical rehabilitation. It involves four pressure sensors, two bending sensors, an ultrasonic sensor and a 9dof IMU, an Inertial Measurement Unit with three accelerometers, three gyroscopes and three magnetometers. The device includes a SDRAMPS with the aim of storing the information for long periods of time. The collected data can be sent to the server for later visualization by the specialist and the patient on a web platform. An interface shows the data in real time, allowing it to verify the connections and …to check different movements. Show more

Keywords: Gait, sensor, wireless

DOI: 10.3233/BME-141178

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3523-3528, 2014

Authors: Tan, Yee-Yong | Chung, Wan-Young

Article Type: Research Article

Abstract: Promising development in the light emitting diode (LED) technology has spurred the interest to adapt LED for both illumination and data transmission. This has fostered the growth of interest in visible light communication (VLC), with on–going research to utilize VLC in various applications. This paper presents a mobile–health monitoring system, where healthcare information such as biomedical signals and patient information are transmitted via the LED lighting. A small and portable receiver module is designed and developed to be attached to the mobile device, providing a seamless monitoring environment. Three different healthcare information including ECG, PPG signals and HL7 text information …is transmitted simultaneously, using a single channel VLC. This allows for a more precise and accurate monitoring and diagnosis. The data packet size is carefully designed, to transmit information in a minimal packet error rate. A comprehensive monitoring application is designed and developed through the use of a tablet computer in our study. Monitoring and evaluation such as heart rate and arterial blood pressure measurement can be performed concurrently. Real–time monitoring is demonstrated through experiment, where non–hazardous transmission method can be implemented alongside a portable device for better and safer healthcare service. Show more

Keywords: Visible light communication, light emitting diode, mobile–health monitoring system, healthcare

DOI: 10.3233/BME-141179

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3529-3538, 2014

Authors: Moon, Yeon-Kwan | Lee, Jyung Hyun | Park, Hee-Joon | Cho, Jin-Ho | Choi, Hyun-Chul

Article Type: Research Article

Abstract: Recently, several medical devices that use wireless communication are under development. In this paper, the small size frequency shift keying (FSK) transmitter and a monofilar antenna for the capsule endoscope, enabling the medical device to transmit VGA-size images of the intestine. To verify the functionality of the proposed wireless communication system, computer simulations and animal experiments were performed with the implemented capsule endoscope that includes the proposed wireless communication system. Several fundamental experiments are carried out using the implemented transmitter and antenna, and animal in-vivo experiments were performed to verify VGA image transmission.

Keywords: Capsule endoscope, wireless communication, antenna

DOI: 10.3233/BME-141180

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3539-3547, 2014

Authors: Lopez-Samaniego, Leire | Garcia-Zapirain, Begonya | Mendez-Zorrilla, Amaia

Article Type: Research Article

Abstract: This paper presents the results of research that applies cognitive therapies associated with memory and mathematical problem-solving in elderly people. The exercises are programmed in an iPad and can be performed both from the Tablet and in an interactive format with a LEGO robot. The system has been tested with 2 men and 7 women over the age of 65 who have slight physical and cognitive impairment. Evaluation with the SUS resulted in a mean of 48.45 with a standard deviation of 5.82. The score of overall satisfaction was 84.37 with a standard deviation of 18.6. Interaction with the touch …screen caused some usability problems due to the elderly people's visual difficulties and clicking accuracy. Future versions will include visualization with more color contrast and less use of the keyboard. Show more

Keywords: iPad, cognitive rehabilitation, objective-C, system usability scale (SUS)

DOI: 10.3233/BME-141181

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3549-3556, 2014

Authors: Chang, Yen-Ching

Article Type: Research Article

Abstract: The discrete-time fractional Gaussian noise (DFGN) has been proven to be a regular process. Therefore, an autoregressive (AR) model of an infinite order can describe DFGN based on Wold and Kolmogorov theorems. A fast estimation algorithm on the Hurst exponent of DFGN or discrete-time fractional Brownian motion (DFBM) has been proposed, but the algorithm did not consider the order selection of AR model. Recently, a Hurst exponent estimator based on an AR model with six existing methods of order selection has been proposed to raise the accuracy of estimating the Hurst exponent. Although the estimation accuracy has been confirmed to …be better than the one without order selection, the estimator still requires computing all parameter sets through the Levinson algorithm. In order to lower computational cost, this paper proposes an efficient method of order selection, simply called data induction, which uses simulation data to induce an appropriate threshold of terminating the Levinson algorithm before computing all parameter sets. Experimental results show that the proposed data-induction method has a competitive advantage over six existing methods of order selection in terms of lowering computational cost and raising the accuracy. Show more

Keywords: Fractional Brownian motion, fractional Gaussian noise, Hurst exponent, autoregressive, order selection

DOI: 10.3233/BME-141182

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3557-3568, 2014

Authors: Ishaq, Rizwan | García Zapirain, Begoña

Article Type: Research Article

Abstract: This paper presents the single channel speech enhancement system using subband Kalman filtering by estimating optimal Autoregressive (AR) coefficients and variance for speech and noise, using Weighted Linear Prediction (WLP) and Noise Weighting Function (NWF). The system is applied for normal and Oesophageal speech signals. The method is evaluated by Perceptual Evaluation of Speech Quality (PESQ) score and Signal to Noise Ratio (SNR) improvement for normal speech and Harmonic to Noise Ratio (HNR) for Oesophageal Speech (OES). Compared with previous systems, the normal speech indicates 30% increase in PESQ score, 4 dB SNR improvement and OES shows 3 dB HNR …improvement. Show more

Keywords: Kalman filter, autoregressive, speech enhancement, weighted linear prediction

DOI: 10.3233/BME-141183

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3569-3578, 2014

Authors: Zhang, Ziyi | Liu, Peiguo | Zhou, Dongming | Zhang, Liang | Lei, Hengdong

Article Type: Research Article

Abstract: Biomedical magnetic induction measurement is a promising method for the detection of intracerebral hemorrhage (ICH), especially in China. Aiming at overcoming the problem of low sensitivity, a magnetic induction sensor is chosen to replace the conventional sensors. It uses a two-arm Archimedean spiral coil as the exciter and a circular coil as the receiver. In order to carry out high-fidelity simulations, the Chinese head model with real anatomical structure is introduced into this novel sensor for the first time. Simulations have been carried out upon early stage ICH measurements. By calculating the state sensitivity and time sensitivity of the perturbation …phase of two types of sensors using the electromagnetic software, we conclude that the primary signal received can be largely reduced using the novel sensor, which could effectively increase the time and state sensitivity simultaneously. Show more

Keywords: Intracerebral hemorrhage (ICH), magnetic induction measurement, sensor sensitivity, two-arm archimedean spiral coil (TAASC), Chinese head model

DOI: 10.3233/BME-141184

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3579-3587, 2014

Authors: Lin, Jium-Ming | Lu, Hung-Han | Lin, Cheng-Hung

Article Type: Research Article

Abstract: This paper proposes a bio-potential measurement apparatus including a wireless device for transmitting acupuncture bio-potential information to a remote control station for health conditions analysis and monitor. The key technology of this system is to make replaceable foam-rubber cushions, double-side conducting tapes, chip and antenna on the radio frequency identification (RFID) tag. The foam-rubber cushions can be wetted with salt-water and contact with the acupuncture points to reduce contact resistance. Besides, the double-side conducting tapes are applied to fix foam-rubber cushions. Thus, one can peel the used cushions or tapes away and supply new ones quickly. Since the tag is …a flexible plastic substrate, it is easy to deploy on the skin. Besides, the amplifier made by CMOS technology on RFID chip could amplify the signals to improve S/N ratio and impedance matching. Thus, cloud server can wirelessly monitor the health conditions. An example shows that the proposed system can be used as a wireless health condition monitor, the numerical method and the criteria are given to analyze eleven bio-potentials for the important acupunctures of eleven meridians on a person's hands and legs. Then a professional doctor can know the performance of an individual and the cross-linking effects of the organs. Show more

Keywords: RFID tag, bio-potential, flexible substrate, wireless health monitor, wetted replaceable foam-rubber cushion

DOI: 10.3233/BME-141185

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3589-3596, 2014

Authors: Tsai, Jang-Zern | Chen, Ching-Jung | Shie, Dung-Ting | Liu, Jen-Tsai

Article Type: Research Article

Abstract: The piezoelectric biosensor have been widely used in ultra-small mass detection of biomolecular, based on PZT piezoelectric material can create a variety of compositions geometrically; it could widely develop a high-frequency resonator and measure the change of the slightest mass while improve the limited detection simultaneously. Therefore, the piezoelectric biosensor of this study was fabricated by a spin-coating method and backside etching process for improving the characteristic of piezoelectric biosensor. The result exhibited that the 250 μm × 250 μm working size has the most favorable piezoelectric characteristic. The tunability was approximately 38.56 % and it showed that reducing the …substrate thickness could obtain a clear resonance signal in a range of 60 to 380 MHz. In theory calculated for gravimetric sensing, it could achieve 0.1 ng sensing sensitivity. In gravimetric sensing, the sensing range was between 50,000~100,000 CFU/ml. Sensing range was lower in clinical urinary tract infection (100,000 CFU/ml), thus demonstrating its usefulness for preventive medicine. It can understand the piezoelectric sensor of this study has potential application in the future for biomedical gravimetric sensing. Show more

Keywords: Lead zirconate titanate (PZT), piezoelectric, biosensor, resonance-frequency, escherichia coli (E. coli)

DOI: 10.3233/BME-141186

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 3597-3604, 2014