Bio-Medical Materials and Engineering - Volume 24, issue 1

Authors: Fu, Jian | Tan, Renbo

Article Type: Research Article

Abstract: X-ray phase contrast micro computed tomography (micro-CT) can non-destructively provide the internal structure information of soft tissues and low atomic number materials. It has become an invaluable analysis tool for biomedical specimens. Here an in-line phase contrast micro-CT reconstruction technique is reported, which consists of a projection extraction method and the conventional filter back-projection (FBP) reconstruction algorithm. The projection extraction is implemented by applying the Fourier transform to the forward projections of in-line phase contrast micro-CT. This work comprises a numerical study of the method and its experimental verification using a biomedical specimen dataset measured at an X-ray tube source …micro-CT setup. The numerical and experimental results demonstrate that the presented technique can improve the imaging contrast of biomedical specimens. It will be of interest for a wide range of in-line phase contrast micro-CT applications in medicine and biology. Show more

Keywords: X-ray in-line phase contrast imaging, micro computed tomography, reconstruction algorithm, X-ray tube source

DOI: 10.3233/BME-130827

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 431-437, 2014

Authors: Woo, SeongTak | Jung, EuiSung | Lim, HyungGyu | Lee, Jang Woo | Seong, Ki Woong | Won, Chul Ho | Kim, Myoung Nam | Cho, Jin Ho | Lee, Jyung Hyun

Article Type: Research Article

Abstract: Input for fully implantable hearing devices (FIHDs) is provided by an implantable microphone under the skin of the temporal bone. However, the implanted microphone can be affected when the FIHDs user chews. In this paper, a dual implantable microphone was designed that can filter out the noise from mastication. For the in vivo experiment, a fabricated microphone was implanted in a rabbit. Pure-tone sounds of 1 kHz through a standard speaker were applied to the rabbit, which was given food simultaneously. To evaluate noise reduction, the measured signals were processed using a MATLAB program based adaptive filter. To verify the …proposed method, the correlation coefficients and signal to-noise ratio before and after signal processing were calculated. By comparing the results, signal-to-noise ratio and correlation coefficients are enhanced by 6.07dB and 0.529 respectively. Show more

Keywords: Implantable microphone, in vivo experiment, adaptive filter, Mastication, fully implantable hearing devices

DOI: 10.3233/BME-130828

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 439-444, 2014

Authors: Wang, Zhigang | Tai, Lik-Ren | McLean, Donald | Wright, Emma J. | Florence, Gordon J. | Brown, Stuart I. | Andre, Pascal | Cuschieri, Alfred

Article Type: Research Article

Abstract: Safe and effective manipulation of soft tissue during laparoscopic procedures can be achieved by the use of mucoadhesive polymer films. A series of novel adhesive polymer films were formulated in house based on either Carbopol or Chitosan modified systems. The mechanical properties of the polymers and their adherence to bowel were evaluated using ex-vivo pig bowel immersed in 37°C water bath and connected to an Instron tensiometer. Young's modulus was 300 kPa for the Carbopol-polymer and 5 kPa for the Chitosan-polymer. The Chitosan-polymer exhibited much larger shear adhesion than its tensile adhesion: 3.4 N vs. 1.2. Both tensile and shear …adhesions contributed to the large retraction force (2.6 N) obtained during l polymer-bowel retraction testing. Work of adhesion at the polymer/serosa interface, defined as the area under the force curve, was 64 mJ, which is appreciably larger than that reported with existing polymers. In conclusion, adhesive polymers can stick to the serosal side of the bowel with an adhesive force, which is sufficient to lift the bowel, providing a lower retraction stress than that caused by laparoscopic grasping which induces high localized pressures on the tissue. Show more

Keywords: mucoadhesive polymer, mechanical property, adhesive force, laparoscopic surgery, bowel retraction

DOI: 10.3233/BME-130829

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 445-451, 2014

Authors: Yang, Hoe S. | Yoo, Ji W. | Lee, Bo A. | Choi, Chang K. | You, Joshua H.

Article Type: Research Article

Abstract: The present study established inter-tester and intra-tester reliabilities of ultrasound imaging and diagnostically differentiated muscle imbalances in lateral abdominal muscle sizes between normal adolescents and adolescents with idiopathic scoliosis (AIS). Fifteen adolescents with AIS were age- and gender-matched with 15 normal adolescents. There was no significant difference between bilateral abdominal muscles in normal adolescents, but there was a significant difference between bilateral abdominal muscles in adolescents with AIS (P<0.05). Overall, inter-tester and intra-tester reliabilities in normal and AIS adolescents ranged from 0.801–0.984. This novel study shows that using ultrasound imaging to measure lateral abdominal muscle thickness is: (1) highly reliable …between and within the testers; and (2) capable of distinguishing between subjects with and without pathological muscle morphology due to AIS. Show more

Keywords: Muscle thickness, Ultrasound imaging, Adolescent idiopathic scoliosis, Reliability

DOI: 10.3233/BME-130830

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 453-458, 2014

Authors: Wang, Lifang | Zhou, Xiaohua | Shen, Mingxiu | Sun, Yanping | Sun, Guifang

Article Type: Research Article

Abstract: Hemodynamics plays a crucial role in the formation, progression and rupture of intracranial aneurysms. Understanding these mechanisms is important to improve current diagnosis and treatment of intracranial aneurysms. In this study we simulate and analyze the pressure gradients and the blood flow fields in growing intracranial aneurysms. Firstly, the pressure gradients are obtained according to the blood velocity waveform at the axis of the inlet to the artery, which can be acquired by transcranial Doppler technology. Then, blood flow fields are calculated by solving the linearized Navier-Stokes equations and continuity equation using the Fourier series method. Results show that the …higher the aneurysm dilatation degree is, the lower the maximum oscillatory velocity will be. Therefore, the oscillatory velocity may be used to analyze the characteristics of blood flow signals from aneurysm and to forecast the size of aneurysm. This sensitive parameter can be utilized for the detection of vessel diseases, which is promising to provide a useful reference in clinical application. Show more

Keywords: hemodynamics, aneurysms, numerical simulation, oscillatory blood flow, pressure gradients

DOI: 10.3233/BME-130831

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 459-466, 2014

Authors: Lin, Haoming | Wang, Tianfu | Chen, Siping

Article Type: Research Article

Abstract: This paper describes a new method for shear wave velocity estimation that is capable of extruding outliers automatically without preset threshold. The proposed method is an adaptive random sample consensus (ARANDSAC) and the metric used here is finding the certain percentage of inliers according to the closest distance criterion. To evaluate the method, the simulation and phantom experiment results were compared using linear regression with all points (LRWAP) and radon sum transform (RS) method. The assessment reveals that the relative biases of mean estimation are 20.00%, 4.67% and 5.33% for LRWAP, ARANDSAC and RS respectively for simulation, 23.53%, 4.08% and …1.08% for phantom experiment. The results suggested that the proposed ARANDSAC algorithm is accurate in shear wave speed estimation. Show more

Keywords: Shear elasticity, shear wave speed, shear wave displacement, adaptive RANDSAC, radon sum

DOI: 10.3233/BME-130832

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 467-474, 2014

Authors: Wei, Qiang | Xu, Yuan-Qing | Tian, Fang-bao | Gao, Tian-xin | Tang, Xiao-ying | Zu, Wen-Hong

Article Type: Research Article

Abstract: A size-based blood cell sorting model with a micro-fence structure is proposed in the frame of immersed boundary and lattice Boltzmann method (IB-LBM). The fluid dynamics is obtained by solving the discrete lattice Boltzmann equation, and the cells motion and deformation are handled by the immersed boundary method. A micro-fence consists of two parallel slope post rows which are adopted to separate red blood cells (RBCs) from white blood cells (WBCs), in which the cells to be separated are transported one after another by the flow into the passageway between the two post rows. Effected by the cross flow, RBCs …are schemed to get through the pores of the nether post row since they are smaller and more deformable compared with WBCs. WBCs are required to move along the nether post row till they get out the micro-fence. Simulation results indicate that for a fix width of pores, the slope angle of the post row plays an important role in cell sorting. The cells mixture can not be separated properly in a small slope angle, while obvious blockages by WBCs will take place to disturb the continuous cell sorting in a big slope angle. As an optimal result, an adaptive slope angle is found to sort RBCs form WBCs correctly and continuously. Show more

Keywords: Blood cell separation, Lattice Boltzmann method, immersed Boundary, Microfludics, Cross flow

DOI: 10.3233/BME-130833

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 475-481, 2014

Authors: Zhu, Zhiwen | Zhang, Qingxin | Xu, Jia

Article Type: Research Article

Abstract: Nonlinear dynamic characteristics of shape memory alloy (SMA) intravascular stent under radial stochastic loads were studied in this paper. Von de Pol item was improved to interpret the hysteretic phenomena of SMA, and the nonlinear dynamic model of SMA intravascular stent under radial stochastic loads was developed. The conditions of stochastic stability of the system were obtained in singular boundary theory. The steady-state probability density function of the dynamic response of the system was given, and the stochastic Hopf bifurcation characteristics of the system were analyzed. Theoretical analysis and numerical simulation show that the stability of the trivial solution varies …with bifurcation parameters, and stochastic Hopf bifurcation appears in the process, which can cause stent fracture or loss. The results of this paper are helpful to application of SMA intravascular stent in biomedical engineering fields. Show more

Keywords: Shape memory alloy (SMA), intravascular stent, radial stochastic load, stochastic stability, stochastic bifurcation

DOI: 10.3233/BME-130834

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 483-489, 2014

Authors: Zhang, Chi | Wang, Ling | Li, Xiaoyun | Li, Shuyu | Pu, Fang | Fan, Yubo | Li, Deyu

Article Type: Research Article

Abstract: Circle of Willis (CoW) plays a significant role in maintaining the blood supply for the brain. Specifically, when the stenosis occurs in the internal carotid artery (ICA), abnormal structures of CoW would decrease the compensatory capacity, leading to the local insufficiency of cerebral blood supply. The present paper built a series of lumped parameter models for CoW, and simulated the blood redistribution caused by the unilateral ICA stenosis with different severities in cerebral arteries in the normal and abnormal CoW respectively. The results showed that when unilateral ICA stenosis occurred, the collateral circulation was built through the anterior communicating artery …and the ipsilateral posterior communicating artery, maintaining the flow in cerebral arteries. The absence of the two communicating arteries would cause an obvious decrease of flow in local cerebral arteries in the anterior circulation. In conclusion, the two arteries play a significant role in maintaining the balance of cerebral blood supply in the development of ICA stenosis. Show more

Keywords: Circle of Willis, internal carotid artery, stenosis, anatomical variation, lumped parameter model

DOI: 10.3233/BME-130835

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 491-499, 2014

Authors: Wang, Tianmiao | Li, Changsheng | Hu, Lei | Tang, Peifu | Zhang, Lihai | Du, Hailong | Luan, Sheng | Wang, Lifeng | Tan, Yiming | Peng, Cheng

Article Type: Research Article

Abstract: In traditional long bone fracture reduction surgery, there are some drawbacks such as low accuracy, high radiation for surgeons and a risk of infection. To overcome these disadvantages, a removable hybrid robot system is developed, which integrates a removable series-parallel mechanism with a motor-double cylinder (MDC) driven mode. This paper describes the mechanism in detail, analyses the principle and the method of the fracture reduction, presents the surgical procedure, and verifies the reduction accuracy by experiments with bone models. The results are shown as follows. The mean deviations of the axial displacement and lateral displacement are 1.60mm and 1.26mm respectively. …The standard deviations are 0.69mm and 0.30mm. The mean deviations of the side angle and turn inward are 2.06° and 2.22° respectively. The standard deviations are 0.50° and 0.99°. This minimally invasive robot features high accuracy and zero radiation for surgeons, and is able to conduct fracture reduction for long bones. Show more

Keywords: Hybrid robot, fracture reduction, long bone, surgical robot

DOI: 10.3233/BME-130836

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 501-509, 2014