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

Authors: Chen, Yanyan | Li, Ge | Zhu, Yanhe | Zhao, Jie | Cai, Hegao

Article Type: Research Article

Abstract: In this paper, a 6-DOF wearable upper limb exoskeleton with parallel actuated joints which perfectly mimics human motions is proposed. The upper limb exoskeleton assists the movement of physically weak people. Compared with the existing upper limb exoskeletons which are mostly designed using a serial structure with large movement space but small stiffness and poor wearable ability, a prototype for motion assistance based on human anatomy structure has been developed in our design. Moreover, the design adopts balls instead of bearings to save space, which simplifies the structure and reduces the cost of the mechanism. The proposed design also employs …deceleration processes to ensure that the transmission ratio of each joint is coincident. Show more

Keywords: Upper limb, parallel actuated joints, exoskeleton, rehabilitation

DOI: 10.3233/BME-141067

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2527-2535, 2014

Authors: Han, Kap Soo | Shin, Sun Hye | Yu, Chang Ho | Kwon, Tae Kyu

Article Type: Research Article

Abstract: This study investigated the characteristics of dynamic postural responses when subjects attempted to maintain an upright standing position on a support plate during continuous sinusoidal perturbation in the anterior-posterior direction. Fifteen healthy young subjects participated in the experiment. Body movement patterns during the perturbation were captured and analyzed using a 3D motion analysis system (APAS 3D motion analysis, Ariel Dynamics Inc.). Seven markers were attached on the subject's body to measure and analyze the motion patterns. The markers were positioned at the head, chest, hip, right knee, left knee, right ankle, and left ankle. Five different frequencies of motion were …applied to the support surface: 0.1, 0.5, 1.0, 1.5, and 2.0 Hz with a 4-cm path of motion at the base. The experiments measured dynamic postural responses in a condition were subjects had their eyes open. The results showed that the median frequency of the knee and ankle increased in all frequency bands. Following an increase in the frequency of the perturbation, the postural control strategy was changed from the ankle strategy to a combined strategy. These experimental results could be applied to the dynamic postural training for the elderly and to rehabilitation training for patients to improve their ability for postural control. Show more

Keywords: Postural control, dynamic postural balance, motion base, horizontal translation

DOI: 10.3233/BME-141068

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2537-2545, 2014

Authors: Ma, Jingtao | Xu, Yuanqing | Tian, Fangbao | Tang, Xiaoying

Article Type: Research Article

Abstract: Separation of two categories of cells in pinched flow fractionation(PFF) device is simulated by employing IB-LBM. The separation performances at low Reynolds number (about 1) under different pinched segment widths, flow ratios, cell features, and distances between neighboring cells are studied and the results are compared with those predicted by the empirical formula. The simulation indicates that the diluent flow rate should approximate to or more than the flow rate of particle solution in order to get a relatively ideal separation performance. The discrepancy of outflow position between numerical simulation and the empirical prediction enlarges, when the cells become more …flexible. Too short distance between two neighboring cells could lead to cell banding which would result in incomplete separation, and the relative position of two neighboring cells influences the banding of cells. The present study will probably provide some new applications of PFF, and make some suggestions on the design of PFF devices. Show more

Keywords: IB-LBM, pinched ow fractionation, cell separation

DOI: 10.3233/BME-141069

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2547-2554, 2014

Authors: Chen, Baoming | Song, Tianyi | Guo, Tao | Xiang, Haiyan | Liu, Yanyong | Qin, Yufei | Cao, Zhengtao | Yu, Mengsun

Article Type: Research Article

Abstract: Non-invasive pressure simulators that regenerate oscillometric waveforms promise an alternative to expensive clinical trials for validating oscillometric noninvasive blood pressure devices. However, existing simulators only provide oscillometric pressure in cuff and thus have a limited accuracy. It is promising to build a physical simulator that contains a synthetic arm with a built-in brachial artery and an affiliated hydraulic model of cardiovascular system. To guide the construction of this kind of simulator, this paper presents a computer model of cardiovascular system with a relatively simple structure, where the distribution of pressures and flows in aorta root and brachial artery can be …simulated, and the produced waves are accordant with the physical data. This model can be used to provide the parameters and structure that will be needed to build the new simulator. Show more

Keywords: Computer model, cardiovascular system, brachial artery, non-invasive pressure simulator

DOI: 10.3233/BME-141070

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2555-2561, 2014

Authors: Magdás, Annamária | Szilágyi, László | Belényi, Boglárka | Incze, Alexandru

Article Type: Research Article

Abstract: Hypertension in the elderly is characterized by isolated systolic hypertension and high variability, but its clinical significance is not yet fully understood. The goal of this paper was to assess circadian blood pressure variability (BPV) in elderly hypertensives, and to determine its relationship to cardiovascular risk factors. To achieve this goal, a number of 75 inefficiently treated hypertensive patients were studied, 45 elderly, aged over 60 years, 30 middle-aged, younger than 60 years. After 24-hour ambulatory blood pressure monitoring (ABPM), blood pressure (BP) values, pulse pressure (PP), morning surge were compared between the groups. BPV was calculated using average real …variability (ARV). The relationships between BPV, pulse pressure, left ventricular mass index (LVMI), and cardiovascular risk factors were assessed in both groups. As a result, it was found that left ventricular mass (p=0.01), PP, morning surge, 24-hour systolic ARV were significantly higher in the elderly group (p<0.05). In both groups, higher 24-hour BPV was associated with an increase in LVMI. In the elderly population 24-hour BPV was positively correlated to increased PP, total cholesterol and triglyceride levels (p<0.05). Moreover, it was concluded that ABPM-derived BP variability index could be an early predictive marker of end-organ damage in hypertension. Its reduction might be an important objective of hypertension management in elderly. Show more

Keywords: ABPM, blood pressure variability, cardiovascular risk factors, elderly

DOI: 10.3233/BME-141071

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2563-2569, 2014

Authors: Xiao, Jinzhuang | Gao, Junmin | Wang, Hongrui | Yang, Xincai

Article Type: Research Article

Abstract: More and more people suffer from lumbar muscle strain due to lack of exercise. Cycling serves as both a stylish model of fitness and a training method in exercise and rehabilitation. A few of previous studies have examined the changes in lower extremity muscle activities during indoor cycling, but fewer data pertain to the low back muscles. This study aims to analyze the functional status of erector spinae during cycling by learning the regularity and characteristics of changes in sEMG frequency domain index-mean frequency (MF) within ten minutes. The statistical results showed that the values of 70% subjects fluctuated within …the range of (0.04688±0.00125) Hz within the first 30 s and the values raised rapidly to the (150±10) Hz range after the 30 s. Moreover, the values trended to decline slowly in a fluctuating way after a while. However, no obvious regularity was observed among the remaining 30% of the subjects. Results of this study demonstrated that the muscle fatigue with a smaller level of low back began to emerge gradually after 30 s. Moreover, it is evident that cycling can be an incentive to the low back muscles in most people. Show more

Keywords: Cycling, sEMG, MF, erector spinae, muscle fatigue

DOI: 10.3233/BME-141072

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2571-2576, 2014

Authors: Zhang, Junxia | Si, Ying | Zhang, Yan | Liu, Yefang

Article Type: Research Article

Abstract: The first metatarsophalangeal (MTP) joint is a critical component for normal walking. The present study aimed to investigate the effects of restricting the flexion-extension motion of the first MTP joint on human walking gait. Ten male participants were recruited to perform walking trials under barefoot (BF) and the first MTP joint constraint (FMJC) conditions, respectively. The results showed that there were statistically significant differences in walking speed and stride length. The characteristics of angular displacement in three lower limb joints and ground reaction force (GRF) were almost identical in BF and FMJC. However, maxima, minima and range of motion of …three joint angles were significantly different. The utilized coefficient of friction (UCOF) increased significantly after FMJC, indicating that there may be a greater risk of slippage and falling when FMJC. Show more

Keywords: The first metatarsophalangeal joint, constraint, gait analysis

DOI: 10.3233/BME-141073

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2577-2584, 2014

Authors: Zhang, Yang | Wang, Yuan | He, Wenbo | Yang, Bin

Article Type: Research Article

Abstract: A novel Particle Tracking Velocimetry (PTV) algorithm based on Voronoi Diagram (VD) is proposed and briefed as VD–PTV. The robustness of VD–PTV for pulsatile flow is verified through a test that includes a widely used artificial flow and a classic reference algorithm. The proposed algorithm is then applied to visualize the flow in an artificial abdominal aortic aneurysm included in a pulsatile circulation system that simulates the aortic blood flow in human body. Results show that, large particles tend to gather at the upstream boundary because of the backflow eddies that follow the pulsation. This qualitative description, together with VD–PTV, …has laid a foundation for future works that demand high-level quantification. Show more

Keywords: Particle tracking velocimetry, Voronoi diagram, aortic blood flow, abdominal aortic aneurysm, pulsatile circulation system

DOI: 10.3233/BME-141074

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2585-2591, 2014

Authors: Sui, Jianfeng | Shull, Pete | Ji, Linhong

Article Type: Research Article

Abstract: Robot-assisted therapy has been proved effective for dyskinesia, and has many unique advantages compared with traditional treatment, such as repeatability, accuracy, objectivity. But some studies show that the effect of the robot-assisted rehabilitation for improving patients' activities of daily life (ADLs) is not obvious. This study introduces a novel auxiliary method-vibration stimulation combined with robots which may improve patients' ADLs. In controlled trials, two kinds of feedback-vibration and visual feedback are applied to prompt subjects for rehabilitation, and electromyographic signals (EMGs) and motion parameters are recorded in real time. Experimental results show that subjects' EMGs using vibration feedback are similar …to healthy people, and characteristics of motion are closer to the theoretical value compared with control group. Vibration stimulation may serve as a kind of efficient auxiliary means to improve the efficiency of neurological rehabilitation. Show more

Keywords: Vibration stimulation, neurological rehabilitation, neuroplasticity, rehabilitation robot

DOI: 10.3233/BME-141075

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2593-2601, 2014

Authors: Park, Ji H. | Shurtleff, Timothy | Engsberg, Jack | Rafferty, Sandy | You, Joshua Y. | You, Isaac Y. | You, Sung H.

Article Type: Research Article

Abstract: While the novel robotic hippotherapy system has gradually gained clinical application for therapeutic intervention on postural and locomotor control in individuals with neurological or musculoskeletal impairments, the system's validity and reliability for the robotic hippotherapy system has not been well established. The objective of the current study was to investigate the validity and test-retest reliability of the robotic hippotherapy system by comparing with real horse movements. The 3-axis accelerometer sensors attached on the robotic and real horse saddles were used to collect 3-dimensional acceleration data at a preferred walking velocity. Linear regression analysis showed an excellent correlation in the time-to-peak …acceleration (TPA) (R2 =0.997), but little correlation in X-axis acceleration between the real and robotic horses (R2 =0.177), thus confirming consistent time control and a certain degree of variability between the robotic and real horse movements. The mean resultant accelerations for a real horse and robotic horse were 3.22 m/s2 and 0.67 m/s2 , respectively, accounting for almost five times greater acceleration in the real horse than the robotic horse. Show more

Keywords: Robotic hippotherapy, acceleration

DOI: 10.3233/BME-141076

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2603-2610, 2014

Authors: Yao, Li | Xu, Hui | Li, Andong

Article Type: Research Article

Abstract: The Kinect-based physical rehabilitation receives increasing recognition as an approach to provide convenience for the patients who need the therapy usually from the health professions. Most of the previous studies were driven from the patients' point of view. This paper proposes a system aiming to simplify the recovery instruction from therapists, increasing patients' motivation to participate in the rehabilitation exercise. Furthermore, the architecture for developing such rehabilitation system is designed by motion capture, human action recognition and standard exercises prototype with Kinect device.

Keywords: Rehabilitation, kinect, motion capture, therapist-oriented

DOI: 10.3233/BME-141077

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2611-2618, 2014

Authors: Kazembakhshi, Siamak | Luo, Yunhua

Article Type: Research Article

Abstract: Image-based finite element (FE) modeling of human bones has been increasingly applied as a useful tool in biomedical engineering. However, most existing image-based FE models assume isotropic mechanical properties for bones, although bones are typically anisotropic material. In this study, we attempted to construct anisotropic FE models from medical computed tomography (CT) scans by modifying the existing empirical relations of bone elasticity-density. The hypothesis adopted in the study is that bone anisotropy is generated by the variations of bone density and the proposed anisotropic relations should degenerate to the isotropic ones if bone density variation is taken zero. The effect …of considering bone anisotropy in FE models was investigated by numerical studies. The obtained numerical results showed that the relative error in the finite element solutions produced respectively by the isotropic and anisotropic FE models can be as large as 50%. We concluded from this preliminary study that the consideration of anisotropy in bone FE models has a significant effect on the accuracy of bone behavior predicted by the FE models. However, well-designed bone tests have to be conducted to validate the anisotropic bone elasticity-density relation proposed in this study. Show more

Keywords: bone, finite element model, computed tomography, anisotropy, elasticity modulus

DOI: 10.3233/BME-141078

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2619-2626, 2014

Authors: Zhang, Yi | Shi, Tingchun

Article Type: Research Article

Abstract: Larynx has a complex structure with joints and multiple functions. In order to study the artificial larynx and artificial auricle scaffold, a three-dimensional digital model of laryngeal joint is established in this paper using MIMICS with its biomechanical properties analyzed and calculated by using the finite element method. This model is based on the CT scanned images of 281 layers with an interlamellar spacing of 1.25 mm. The obtained data are denoised, segmented and smoothed before being loaded into MIMICS. By further optimizations, an accurate and complete 3D model can be obtained. Subsequently, a 3D FEM of the normal larynx …joint is performed which allows observations from any dimensions and angles. Compared with natural laryngeal joint, this model has good geometric similarity and mechanically similar throat voicing functions. Show more

Keywords: laryngeal joints, finite element, laryngeal reconstruction, three-dimensional reconstruction

DOI: 10.3233/BME-141079

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2627-2634, 2014

Authors: Zhang, Mingming | Zhao, Zongya | He, Ping | Wang, Jue

Article Type: Research Article

Abstract: Gap junctions are the mechanism for striatal fast-spiking interneurons (FSIs) to interconnect with each other and play an important role in determining the physiological functioning of the FSIs. To investigate the effect of gap junctions on the firing activities and synchronization of the network for different external inputs, a simple network with least connections and a Newman-Watts small-world network were constructed. Our research shows that both properties of neural networks are related to the conductance of the gap junctions, as well as the frequency and correlation of the external inputs. The effect of gap junctions on the synchronization of network …is different for inputs with different frequencies and correlations. The addition of gap junctions can promote the network synchrony in some conditions but suppress it in others, and they can inhibit the firing activities in most cases. Both the firing rate and synchronization of the network increase along with the increase of the electrical coupling strength for inputs with low frequency and high correlation. Thus, the network of coupled FSIs can act as a detector for synchronous synaptic input from cortex and thalamus. Show more

Keywords: Network, fast-spiking interneurons, synchronization, firing rate, small-world

DOI: 10.3233/BME-141080

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2635-2644, 2014

Authors: Bai, Long | Cui, Yuhong | Zhang, Yixia | Zhao, Na

Article Type: Research Article

Abstract: The mechanical behavior of blood cells in the vessels has a close relationship with the physical characteristics of the blood and the cells. In this paper, a numerical simulation method was proposed to understand a single-blood cell's behavior in the vessels based on fluid-solid interaction method, which was conducted under adaptive time step and fixed time step, respectively. The main programme was C++ codes, which called FLUENT and ANSYS software, and UDF and APDL acted as a messenger to connect FLUENT and ANSYS for exchanging data. The computing results show: (1) the blood cell moved towards the bottom of the …flow chamber in the beginning due to the influence of gravity, then it began to jump up when reached a certain height rather than touching the bottom. It could move downwards again after jump up, the blood cell could keep this way of moving like dancing continuously in the vessels; (2) the blood cell was rolling and deforming all the time; the rotation had oscillatory changes and the deformation became conspicuously when the blood cell was dancing. This new simulation method and results can be widely used in the researches of cytology, blood, cells, etc. Show more

Keywords: Fluid-solid interaction, numerical simulation, jumping, rolling, deformation

DOI: 10.3233/BME-141081

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2645-2655, 2014

Authors: Li, Kun | Zhang, Song | Yang, Lin | Luo, Zhichang | Gu, Guanxiong

Article Type: Research Article

Abstract: Objective: There are many similarities between the photoplethysmography(PPG) pulse wave and the radial pulse when a body is in a stationary state, but the difference between them under conditions of movement is not yet clear. Finding these differences may help further understanding of the cardiovascular system. Methods: PPG and radial pulse wave were recorded simultaneously while subjects were conducting a bicycle exercise test that included the resting and exercise state, while the K and K' parameters were being acquired from the PPG and radial pulse, respectively. Furthermore, the pulse objective pattern is observed via the time domain waveform and XY …graph. Results: When the body's state of movement changes dramatically, there is a time difference between the pulse parameter K and the pulse amplitude, and the difference of the pulse pattern is enhanced during the exercising phase. Conclusion: Radial pulse waves are not the same as PPG during exercise in either the pulse parameter or the pulse pattern. This information can be used to further evaluate the state of arterial circulation and microcirculation. Show more

Keywords: photoplethysmography(PPG), radial pulse wave, waveform parameter, waveform pattern

DOI: 10.3233/BME-141082

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2657-2664, 2014

Authors: Zhao, Zijian

Article Type: Research Article

Abstract: Robotized endoscope holder in laparoscopic surgeries allows surgeons to control the endoscope without the assistants' intervention. In this paper, a new method is proposed for the automatic 3D-tracking of laparoscopic instruments in real-time to provide more convenient interactions between surgeons and the robotized endoscope holder. The method is based on the 3D position measurements of the insertion points of the instruments and the strip markers, combined with the depth estimation of the instruments. The results of our experiments show that our method is fast and robust in the simulated laparoscopic surgeries.

Keywords: Laparoscopic surgery, tool tracking, localization of instrument, robotized camera holder

DOI: 10.3233/BME-141083

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2665-2672, 2014

Authors: Liu, Jiquan | Wang, Bin | Hu, Weiling | Zong, Yun | Si, Jianmin | Duan, Huilong

Article Type: Research Article

Abstract: Biopsy is a traditional endoscopic surveillance of premalignant gastric lesions, and endoscopic tattooing is used for marking the biopsy's location. However, the tattooing has several disadvantages. For example, the procedure is an invasive operation and may not be durable due to the diffusion. Moreover, it is procedurally cumbersome with an associated risk of technical failure. In this study, a computer aided endoscopic navigation system (CAEN system) was developed for a non-invasive biopsy procedure. The CAEN system consists of a new, designed six degree of freedom (6-DOF) tracking endoscope device and a computer simulated work station. During the procedure, the endoscopist …uses the tip of the tracking endoscope to touch the lesion. Then, the lesion's location is recorded in the work station, which then guides the endoscopist in retargeting the lesions in the follow-ups. The clinical experimental results demonstrate that the accuracy at the angularis is 5.2±2.8 mm, at the antral lesser curvature is 7.2±2.0 mm, at the antral greater curvature is 6.3±3.1 mm, at the antral posterior wall is 8.2±1.6 mm, and at the antral anterior wall is 7.9±1.3 mm. The mean accuracy is 7.5 mm, and the P-value is 0.023, which is likely suitable for clinical practice. Furthermore, the proposed CAEN system requires less procedural time than the tattooing. Show more

Keywords: Endoscopic biopsy marking, non-invasive procedure, 6-DOF endoscope device, hand-eye calibration, computer simulated work station

DOI: 10.3233/BME-141084

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2673-2679, 2014

Authors: Kim, Ji-Won | Kwon, Yuri | Jeon, Hyung-Min | Bang, Min-Jung | Jun, Jae-Hoon | Eom, Gwang-Moon | Lim, Do-Hyung

Article Type: Research Article

Abstract: The purpose of this study was to investigate 1) the effect of feet distance on static postural balance and 2) the location of natural feet distance and its possible role in the relationship of feet distance and postural balance. Static balance tests were performed on a force platform for 100 s with six different feet distances (0, 5, 10, 15, 20, 25 cm). Measures of postural balance included mean amplitude of horizontal ground reaction force (GRF) as well as the mean distance and velocity of the center of pressure (COP). All measures were discomposed into anterioposterior and mediolateral directions. ANOVA …and post-hoc comparison were performed for all measures with feet distance as an independent factor. Also measured was the feet distance at the natural stance preferred by each subject. All measures significantly varied with feet distance (p<0.001). Mean distance of COP showed monotonic decrease with feet distance. Mean amplitude of horizontal GRF as well as mean velocity of COP showed U-shaped pattern (decrease followed by increase) with the minimum at the feet distance of 15cm or 20 cm, near which the natural feet distance of 16.5 (SD 3.8) cm was located. COP is regarded to be an approximation of the center of mass (hence the resultant performance of postural control) in an inverted pendulum model with the horizontal GRF ignored. On the other hand, horizontal GRF is the direct cause of horizontal acceleration of a center of mass. The present result on horizontal GRF shows that the effort of postural control is minimized around the feet distance of natural standing and implies why the natural stance is preferred. Show more

Keywords: Stance width, postural stability, preferred stance, center of pressure, ground reaction force

DOI: 10.3233/BME-141085

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2681-2688, 2014

Authors: Lee, Wei-chen | Huang, Ching-Hang | Chung, Shan-Chen | Wei, Ching-chih

Article Type: Research Article

Abstract: The aim of this research was to develop an efficient and accurate method to fabricate a dental implant surgical guide. The surgical guide is adapted from the patient's vacuum-formed clear template with the use of a plate with three ceramic balls, a six-axis drilling machine and its fixture. The plate, with the ceramic balls used as radiographic markers, is glued to the template, and the patient bites this template during a CT scan. Then, the surgeon can plan the locations and orientations of the implants on the CT-based model in the dental planning software. The drilling information is exported directly …to the computer-controlled drilling machine for subsequent drilling on the template to complete the surgical guide. This method allows the surgical guide to be made without any measurements, which reduces the fabrication time, but increases the drilling accuracy. The preliminary results show that the average location error was 0.31 ± 0.17 mm and the average orientation error was 0.53 ± 0.24° , which can be considered accurate in comparison with the results reported in the literature. Show more

Keywords: Dental implant surgical guide, drilling machine, radiographic marker, fixture, vacuum-formed template

DOI: 10.3233/BME-141086

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2689-2695, 2014

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