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2015 Vol. 34, No. 4 Published: 2015-08-20 385 The Brain Network Research of Poststroke Depression Based on Partial Directed Coherence (PDC) Wang Chunfang1   Sun Changcheng1    Zhang Xi2     Wang Yongjun1     Qi Hongzhi2 & DOI: 10.3969/j.issn.0258-8021.2015.04.001 The aim of our study is to investigate the abnormal brain network of poststroke depression (PSD) patients.  Sixteen channels of resting state EEG of respectively 10 cases of PSD patients and control groups (poststroke nondepression (PSND) and healthy controls (CONT)) were collected for partial directed coherence (PDC) analysis. The average brain network diagrams for the three populations were built according to the onetailed single sample t test. Some parameters based on topology graph theory were compared among the three populations.  According to the statistical test (P<005), apparent difference was performed among the three groups in the brain network parameters of degree, average cluster coefficient and betweenness centrality when PDC=02. Compared with healthy subjects, stroke patients showed decreased information inflow to the dominant hemisphere (left). PSD patients performed weaker outflow information than PSND subjects in “emotional” related regions such as left frontal lobe and left temporal lobe. Comparatively to CONT and PSND populations, the cluster coefficient of PSD patients decreased by 24% and 18% respectively, indicating declined collectivization degree of brain network. The number of “core nodes” in PSD patients increased 22 times and 16 times respectively, showing transferred core nodes and lower core status.  Affected by stroke and depressed mood, PSD patients performed abnormal brain networks. 2015 Vol. 34 (4): 385-391 [Abstract] ( 753 ) HTML (1 KB)  PDF (1218 KB)  ( 1618 ) 392 Auto White Balance Algorithm for Electric Endoscope Images Based on  Local Color Temperature Estimation Bai Kunlun1     Chen Xiaodong1* Sun Xuebin1      Wang Yi1        Yu Daoyin< DOI: 10.3969/j.issn.0258-8021.2015.04.002 In the electronic endoscopic system, light source’s aging problem can lower color temperature and brightness of the images, which will affect the imaging quality seriously. To make up for the color temperature, auto whitebalance processing is required. By analyzing imaging characteristics, an algorithm model based on white patch theory is proposed. According to the spatial information of highlight spot, the local color temperature is established, by which way average chromaticity aberration correct factor increases from 903% to 7934% compared with classical algorithm. Subsample model is used to simplify the estimation of color temperature without losing image quality, and processing time is decreased by 5495%. The paper〖DK〗’s automatic white balance algorithm for electronicendoscope images can precisely restore color features for human tissues, and also inherits good realtime specialty. 〖KH2D〗 〖WTHZ〗Key words：〖WTBZ〗〖BP(〗┣┣（英）关键词┫┫〖BP)〗 2015 Vol. 34 (4): 392-398 [Abstract] ( 470 ) HTML (1 KB)  PDF (3197 KB)  ( 743 ) 399 Pupil Ultrasound Images Segmentation and Diameter Measurements Based on Improved Graph Cuts Zhou Yali1      Gao Yuzhi2      Zhou Hao1    Zhou Mi1      Zheng Y DOI: 10.3969/j.issn.0258-8021.2015.04.003 The traditional measurement of pupil diameter is manually measured, but for patients who have ocular trauma or loss of consciousness this method is inconvenience. Aiming to solve the problem of large manual interaction in pupil diameter measurement and the weak measuring robustness, we used improved graph cut segmentation algorithm to segment pupil ultrasound images and measure pupil diameters. In this paper, we improved the traditional graph cut algorithm in two aspects. One is using adaptive threshold region growing to take place of manually seeds selection, which ensures the segmentation results while reducing the amount of manual interaction. The other one is increasing gradient information of the image into data entry portion of the energy function, which reduces the small area in the segmentation results and enhances the weak edges of segmentation. The proposed method realized automatic segmentation of image and automatic measurement of the pupil diameter. By employing the method we acquired dynamic changes of patient pupil diameter and provide a basis for clinical diagnosis. To verify the validity of the algorithm, we used the method to measure the diameter of ten patients’ dynamic pupil ultrasound images, and compared the results with that obtained by manual measurements. It is shown that the absolute error is less than 0.2 mm, the correlation coefficient is at least 0.83. In conclusion, the modified graphcut algorithm improved segmentation results, achieved automatical measurements of pupil diameters using dynamic ultrasound pupil images, and can be expected to substitute manual measurements and reduce the amount of human interaction. 2015 Vol. 34 (4): 399-406 [Abstract] ( 556 ) HTML (1 KB)  PDF (8409 KB)  ( 387 ) 407 Artificial Neural Network Analysis for Vertebral Artery InStent Restenosis Qiao Aike#*Peng Kun    Niu Jing DOI: 10.3969/j.issn.0258-8021.2015.04.004 The purpose of this paper is to analyze risk factors causing the vertebral artery instent restenosis (ISR). Applying the artificial neural network (ANN), we further tried to give predictions on the occurrence of ISR. The first step of our strategy was to follow up 97 randomly picked clinical patients, figuring out the statistical relevance for each of the 12 possible factors leading to ISR. We then established a model to connect the factors with ISR using the back propagation (BP) neural network. The last procedure was to assess our results by comparing our predictions with the actual occurrence of ISR. Our observations show that, the average length of stent is (15±1.52) mm for ISR patients, and（17±1.50）mm for nonISR patients. The value of P=0.005 indicates a statistical significance. The average stent expansion is 1.17±0.16 for ISR patients and 115±025 for nonISR patients. P=0.01 exhibits a statistical significance. The side of vertebral artery for both ISR and nonISR patients is of statistical significance P=0.045. Moreover, the assessments show that the BP neural network prediction model is efficient. Diagnosis rate of nonISR is q1>=75%, while that of ISR is q2=100%. Stent length, vertebral sides and stent expansion are significant factors for the vertebral artery ISR. BP neural networks can be used to predict the occurrence of the vertebral artery ISR. 2015 Vol. 34 (4): 407-412 [Abstract] ( 335 ) HTML (1 KB)  PDF (756 KB)  ( 510 ) 413 Study on Imaging Effect of Different Excitation Patterns under Practical Electrical Impedance Tomography Conditions DOI: 10.3969/j.issn.0258-8021.2015.04.005 Using the commonly used adjacent excitation patternadjacent measurement pattern in the electrical impedance tomography (EIT), the practical detection system with finite measurement resolution (MR) and signaltonoise ratio (SNR) is always limited to distinguish tiny potential difference of electrodes and then finally make a great impact on image reconstruction. Based on the homogeneous field EIT boundary voltages analysis of adjacent excitation pattern, interval 6 electrodes and opposite excitation pattern in 16 electrodes array system, the MR and SNR requirements for imaging by practical EIT systems were analyzed, images reconstruction of three excitation patterns under different MR and different SNR conditions were simulated for three different image models A, B, C, which are positioned near to the center of the field, at the 1/2 radius of the field and near to the edge of the filed respectively. The combined TikhonovNoser regularization algorithm was adopted and image reconstruction errors function and structure similarity degree function for medical images quality evaluation were introduced to quantitative analysis the imaging effect. Imaging and evaluation results show that different excitation patterns have distinct index requirements of system MR and SNR. When MR was 1 mV, the imaging effect of interval 6 electrodes excitation pattern was the best, while adjacent excitation pattern was the best when MR was 0.01 mV. When MR was 0.01 mV, interval 6 electrodes excitation pattern was better than the adjacent excitation pattern for model A and B while the circumstance is opposite for model C. The critical value requirements of system SNR for Model A, B, C were 50 dB, 40 dB, 30 dB respectively under the interval 6 electrodes and opposite excitation patterns, which were 10 dB lower than the adjacent excitation pattern when imaging for all three models. The best imaging effects of all three model were under interval 6 electrodes excitation pattern when these SNR values near to critical values, followed by opposite excitation patterns. However, once the value of SNR was higher than the critical value, the best quality image was obtained under the adjacent excitation pattern. The main indexes impacting imaging results in low MR system and high MR system were different between the second smallest voltage and the smallest voltage and independent measurement number. It is advised to take interval 6 electrodes excitation pattern as the priority selection and opposite excitation pattern as the second one when system MR is relatively low, while choose adjacent excitation pattern when MR is high. For the 0.1 mV MR, interval 6 electrodes excitation pattern is suggested when imaging for model A and B and adjacent excitation pattern is suggested for model C. The factors impacting imaging results in low and high SNR system are the result of whole measurement voltage data and independent measurement number. When values of the system SNR are near to the critical values of 50 dB, 40 dB and 30 dB for model A, B, C respectively, interval 6 electrodes and opposite excitation pattern are suggested, and the adjacent excitation pattern is suggested once SNR exceeds critical value 10 dB. 2015 Vol. 34 (4): 413-420 [Abstract] ( 273 ) HTML (1 KB)  PDF (3578 KB)  ( 452 ) 421 The Effects of Bacterial Biofilm Thickness and Area on Hearing Gan Chaosun       Yao Wenjuan* Guo Cuipin        Ma Jianwei    Chen Yiqiang DOI: 10.3969/j.issn.0258-8021.2015.04.006 According to CT images of the right ear from a healthy volunteer, a 3D finite element model of the ear was established in PATRAN software by a selfcompiling program. Then NASTRAN software was used to make frequency response analysis for human ear finite element model. The model was carried through a frequency response analysis of normal ear structure and confirmed by the consistency in the calculated and experimental data after comparison. Combined with the clinical symptoms of otitis media, the effects of variation in thickness and area on hearing ability in the growth stage of bacterial biofilm were investigated. Results show that in the same frequency bands, the thickness variation of bacterial biofilm had the same regular pattern in the effects on hearing ability under different pressures. Thickness increase of bacterial biofilm decreased the stapes amplitude and stapes velocity in the same frequency band. The descend range of hearing ability was different in various frequency bands under the same pressure. The stapes amplitude and stapes velocity declined largely in low frequency band, the maximum value of the decline was 1.64 dB, and declined little in high frequency band. The maximum value of the decline was 1.04 dB. The area increase of bacterial biofilm decreased the stapes amplitude and stapes velocity in the same frequency band. The descend range of hearing ability was different in various frequency bands under the same pressure. The stapes amplitude and stapes velocity declined little in frequency band from 100-1 000 Hz, The maximum value of the decline was 0.18 dB, and declined largely in frequency band from 1 000 Hz to 10 000 Hz. The maximum value of the decline was 2.26 dB. In conclusion, the increase of thickness or area of bacterial biofilm caused the decline of hearing ability. The increase in the thickness caused more decline in the low frequency band than in the high frequency band, while the area increase caused opposite results. 2015 Vol. 34 (4): 421-428 [Abstract] ( 417 ) HTML (1 KB)  PDF (6816 KB)  ( 480 ) 429 Analysis on Secondary Flow Characteristics inside Bronchia of NonHeart Beating Donor Lung Xu Yi1* Deng Ruyi1       Liu Jing1,2 Liu Daoping2     Zhao Xiaogang3 DOI: 10.3969/j.issn.0258-8021.2015.04.007 Nonheart beating donor (NHBD) lung is expected to be the most potential donor source for clinical lung transplantation, and low temperature ventilation was normally thought to effectively protect the donor lung in vivo. A 3D asymmetric bronchial model with four levels was reconstructed, and computational fluid dynamics (CFD) technique was adopted here for investigating the sencond flow structures inside NHBD lung bronchia under three kind respiratory frequencies, i.e. 0.125 Hz,0.25 Hz and 0.5 Hz. The results show that no second flow structures exist inside main bronchia during inspiration process, and the maximum difference of dimensionless velocity across the main section is 0.67@0.125 Hz, 0.5@0.25 Hz and 0.3 @0.5 Hz, respectively. However, there are obvious differences for the expiration process, and the maximum difference of dimensionless velocity across the main section is 1.25, 1.1 and  1.06, respectively. Due to the asymmetric structure of bronchial and bifurcation rotation angles, the second flow structures always present for further daughter bronchias but the maximum difference of dimensionless velocity of them do not change significantly with increasing breathing rates (about 1.0). Generally, the flow structures inside left side are more complicated than the right side. The current work indicates that the second flow structures always exist when low temperature ventilation is utilized to pretect NHBD lung, which may be beneficial to develop the optimization method for preserving NHBD lung in situ. 2015 Vol. 34 (4): 429-437 [Abstract] ( 1239 ) HTML (1 KB)  PDF (23717 KB)  ( 114 ) 438 Analysis of Heating Mechanisms and Calculation of Temperature Rising Rate for Human Tissues in Radiofrequency Capacitive Hyperthermia Wang Zhuying* Liu Yongqian      Chen Xiaolin DOI: 10.3969/j.issn.0258-8021.2015.04.008 The purpose of this study is to clear up some misunderstandings in the heating mechanisms and in the temperature rising rate of different human tissues in radiofrequency (RF) capacitive hyperthermia. In this paper, the mechanisms of heating human tissues by RF capacitive hyperthermia are studied on the basis of electromagnetic field theory. According to the model of neglecting fringing effect of plate electrodes in which filled with different dielectric layers, the expressions of the ratios of power loss per unit volume, specific absorption rate (SAR), and temperature rising rate for any two dielectrics were derived. Substituting the known electrical parameters and physical parameters of human muscle, fat and cortical bone into those expressions, we found that the temperature rising rate of fat and bone was 18.9 and 20.2 times as many as that of muscle at 27.12 MHz, while 19.8 and 19.1 times at 40.68 MHz. We concluded that in RF capacitive hyperthermia process, the larger the conductivity of human tissue, the smaller the temperature rising rate. And the temperature rising rate for different tissue is very inhomogeneous in RF capacitive hyperthermia. 2015 Vol. 34 (4): 438-444 [Abstract] ( 309 ) HTML (1 KB)  PDF (907 KB)  ( 1142 ) 445 A Review of Active Contour Model Based Image Segmentation Algorithms Duan Dingna1      Zhang Huan1     Qiu Chenhui1    Xia Shunren1,2#* DOI: 10.3969/j.issn.0258-8021.2015.04.009 Active contour model is an important method for image segmentation. It combines underlying information with highlevel prior knowledge to achieve automatic segmentation for complex objects. Active contour model has been developed greatly in theory research and application, since it was proposed twenty years ago. This paper reviewed the development process of active contour model at first and describes the classical parametric active contour models and geometric active contour models, and presents briefly new hybrid active contour models as well as fast solution algorithms. After that, the relationship between these two kinds of models through theory basis, performance, efficiency and applications were introduced. The future prospect of active contour model was discussed as well. 2015 Vol. 34 (4): 445-454 [Abstract] ( 869 ) HTML (1 KB)  PDF (841 KB)  ( 2183 ) 455 The Opportunities and Challenges of Deep Brain Stimulation in the Future Wang Shouyan1*Wang Xuelian2      He Jianghong3 DOI: 10.3969/j.issn.0258-8021.2015.04.010 The treatment of neurological and psychiatric diseases remains challenging with huge population and lack of effective medication. Deep brain stimulation is an alternative reliable clinical approach for many patients with Parkinson’s disease, pain, etc. There is urgent demand in improving the clinical performance of deep brain stimulation and expanding benefit for larger population. This paper presents perspectives in scientific questions, technologies and key advancements related to the deep brain stimulation, i.e., the mechanisms of neuromodulation, intelligent stimulation strategy, precise operation technique, new indications, quantitative and remote rehabilitation, devices with advanced technology and integrated management system. The goals of future development are to refine deep brain stimulation for existing indications, develop novel clinical approach for new indications, reduce the clinical cost, improve the quality of clinical service, and optimize the medical treatment. 2015 Vol. 34 (4): 455-463 [Abstract] ( 388 ) HTML (1 KB)  PDF (2860 KB)  ( 1577 ) 464 Research Progress on Soft Tissue Cutting Model for Virtual Surgery Simulation Training System Cheng Qiangqiang1,3 Liu Xiaoping1,2 Xu Shaoping1* DOI: 10.3969/j.issn.0258-8021.2015.04.011 Virtual surgery simulation training system (VSSTS) solves the problems that exist in the traditional clinician training methods, such as long training period, high cost and lack of training objects. It is a costeffective alternative training method. As the most common and core type of surgical operations in all kinds of practical surgery, realistically simulating the cutting of soft tissue in real time has always been the difficult and hot issues on studying the virtual surgery simulation system. In this paper, we introduced all kinds of cutting models that have been proposed within the framework of mesh and meshless after giving a brief introduction of the development history of soft tissue cutting model. Then, we analyzed and summarized the advantages and disadvantages of the various modeling method and its applications in the real world virtual surgery simulation systems. In addition, we analyzed the hybrid mode that has been proposed in recent years and gave an outlook for the future of cutting simulation in terms of simulation effect and computing speed. 2015 Vol. 34 (4): 464-474 [Abstract] ( 612 ) HTML (1 KB)  PDF (12465 KB)  ( 177 ) 475 The Significance of Macrophage Phenotype in Injury as well as the Biomaterials Inducing Tissue Repair and Regeneration Hao Suisui      Xu Haiyan# * DOI: 10.3969/j.issn.0258-8021.2015.04.012 The body inflammatory reaction is a normal response to injury and the presence of foreign substances.The duration and intensity of inflammation has a direct impact on biocompatibility and stability of biomaterials in vivo.Macrophage is one of the major cell types in controlling body inflammatory and immune processes,hence,its response to biomaterials is critical for identifying the biomaterialbody reaction.In this review, the correlation between macrophage phenotype and injury as well as the tissue repair or regeneration，the interaction of macrophages with biomaterials, and the future development are introduced in detail. 2015 Vol. 34 (4): 475-480 [Abstract] ( 318 ) HTML (1 KB)  PDF (755 KB)  ( 476 ) 481 A Review of Cryoprotectant Permeation into Articular Cartilage Yu Xiaoyi1   Zhang Shaozhi2     Fan Juli3      Hu Changxing1 * DOI: 10.3969/j.issn.0258-8021.2015.04.013 Vitrification of articular cartilage (AC) has excited great interest due to the clinical and scientific significances of this tissue. Sufficient permeation throughout the tissue and minimization of accompanying damage to cells are required for successful vitrification of AC. The knowledge of permeation kinetics of cryoprotectant (CPA) in AC is important for designing the CPA addition protocol. In this review,  developments on the permeation of CPA into AC are summarized from two aspects: measurement of CPA diffusion in AC and mathematical modeling of CPA transport in AC. A great of efforts  have been made, which has led to the recent advancements in the field, but more investigations still deserved to be addressed, such as copermeation of multiple CPAs into AC, CPA permeation at subzero temperatures, and strengthening of CPA transport. 2015 Vol. 34 (4): 481-486 [Abstract] ( 382 ) HTML (1 KB)  PDF (2198 KB)  ( 551 ) 487 A Dataset for Salient Region Detection Based on Human Eye Movement Gao Xin     Yang Kaifu     Yao Dezhong#  Li Yongjie* DOI: 10.3969/j.issn.0258-8021.2015.04.014 2015 Vol. 34 (4): 487-491 [Abstract] ( 248 ) HTML (1 KB)  PDF (6457 KB)  ( 669 ) 492 t Test Analysis of FMRI Data Based on Multiscale Feature Extraction Zhi Lianhe1* ZHou Wengang2     Tan Sumin3 DOI: 10.3969/j.issn.0258-8021.2015.04.015 2015 Vol. 34 (4): 492-495 [Abstract] ( 492 ) HTML (1 KB)  PDF (6009 KB)  ( 455 ) 496 A Novel Method of Magnetic Resonance Electrical Impedance Tomography for Prostate Cancer Detection Liu Yang1       Guo Jianyan2* DOI: 10.3969/j.issn.0258-8021.2015.04.016 2015 Vol. 34 (4): 496-500 [Abstract] ( 371 ) HTML (1 KB)  PDF (5776 KB)  ( 383 ) 501 The Biological Microscope Design Applied to Observe Bioreactor Xu Bing1  Yu Yuanhua2        Li Qi2       Gong Ping2* DOI: 10.3969/j.issn.0258-8021.2015.04.017 2015 Vol. 34 (4): 501-506 [Abstract] ( 197 ) HTML (1 KB)  PDF (6717 KB)  ( 868 ) 507 The Finite Element Analysis of the Inner Fixation in Intracapsular Fracture during the Fracture Healing Process Qu Aili1,2  Wang Dongmei1* Jing Jie3 DOI: 10.3969/j.issn.0258-8021.2015.04.018 2015 Vol. 34 (4): 507-512 [Abstract] ( 303 ) HTML (1 KB)  PDF (1839 KB)  ( 452 )

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