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2015 Vol. 34, No. 2 Published: 2015-04-20 129 Study on the Quantification for Discrimination of Atrial Fibrillation with Premature Ventricular Contraction and Aberrant Ventricular Conduction Qian Mengyao   Rao Nini#* Liu Dingyu   Yang Yang   Zhang Ying   Wan Yongli DOI: 10.3969/j.issn.0258-8021.2015.02.001 For the clinical diagnosis of AF with premature ventricular contraction (AF with PVC) and AF with aberrant ventricular conduction (AF with AVC), there are no recognized standards, which make it very difficult for a cardiologist to accurately discriminate the two diseases. This paper intends to develop a highaccuracy calculation method to discriminate between these two types of diseases. Methods：By analyzing clinical features of AF with PVC and AF with AVC, we confirmed the ratio between coupling interval and compensatory pause as the identifiable characteristic parameter. The electrocardiogram (ECG) signal that to be detected was preprocessed, then we located QRST characteristic waves during each cardiac cycle of ECG signal. On this basis, we identified the wide freak QRS complexes, extract the two adjacent RR intervals corresponding to the coupling interval and compensatory pause in a wide freak QRS complex, and calculate their ratio. After comparing with a given discrimination threshold, the types of diseases were judged. Results： The 10 record data for the algorithm validation were downloaded from the MITBIH Arrhythmia Database, which include 4 026 and 949 beats of atrial fibrillation with premature ventricular contraction and with aberrant ventricular conduction, a total of 4 975 beats. For the mixed data containing AF with PVC and AF with AVC, the sensitivity and the positive predictive value of proposed method to discriminate AF with PVC reached 9315% and 9830% respectively,  which are better than that of traditional methods. Conclusions：The ratio between the coupling interval and compensatory pause can take the place of coupling interval, which is commonly used to discriminate between AF with PVC and AF with AVC at present. This work provides guidance in the diagnostic accuracy of AF with PVC and AF with AVC. 2015 Vol. 34 (2): 129-135 [Abstract] ( 389 ) HTML (1 KB)  PDF (886 KB)  ( 659 ) 136 Studies on Characteristics of ERP Underlying Structure Encoding and Feature Encoding of Facial Expressions Ji Shumei*Liu Yafei   Yuan Dongmei DOI: 10.3969/j.issn.0258-8021.2015.02.002 The eventrelated potentials (ERP) technique was used to analyze the early and late characteristics of facial expressions processing, to investigate the mechanisms underlying structure encoding and feature encoding. Three kinds of cartoon facial expressions (neutral, happy, angry) and three kinds of nonfacial cartoons were presented randomly, 14 volunteers were instructed to implement face and facial expression recognition tasks. Electroencephalography (EEG) was record with Neuroscan-64 cap. We analyzed the early component N170 and the late positive component (LPC) evoked by faces, nonfaces, and different emotional faces. Results indicated that there were significant differences between N170 evoked by facial cartoons and that evoked by nonfacial cartoons. The amplitudes of N170 at P7 evoked by facial cartoons and nonfacial cartoons were (-915±147) μV and (-691±121) μV. There were not significant differences among N170 evoked by different emotional faces, N170 was not regulated by facial emotion content. Expressional effects appeared at 350～550 ms after stimulus, there were significant differences among LPC evoked by different emotional faces. The amplitudes of LPC at CZ evoked by neutral, happy and angry facial expressions were (611±179)μV, (749±131) μV and (989±177)μV, respectively. These results suggest that early and late processing mechanisms of face recognition are different, the early component N170 reflects the processing of face structure encoding, so called the characterization of the whole face contour; while face emotional processing is mainly reflected in the late component, LPC reflects mechanism of face feature encoding. 2015 Vol. 34 (2): 136-142 [Abstract] ( 387 ) HTML (1 KB)  PDF (1284 KB)  ( 572 ) 143 The Role of the Prefrontal Cortex in the Characters Working Memory Research Based on the EEG Theta Band Characteristic Analysis Li Song   Jin Jingna   Wang Xin   Liu Zhipeng   Yin Tao#* DOI: 10.3969/j.issn.0258-8021.2015.02.003 The analysis of feature information for the prefrontal cortex EEG (electroencephalograph) theta bands (4～8 Hz) signal can reveal the function status and mechanism of the prefrontal cortex in the process of “information maintain and recall” phase within the working memory. Fifteen participants’ scalp EEG signals were collected during the experiment, in which participants did the working memory task with different memory loads, including 3 letters, 5 letters and 7 letters. The theta band signal of each electrode was extracted using morlet wavelet decomposition method. In terms of energy analysis, the Welch power spectral density was used to calculate the average power and the short time Fourier transform (STFT) was used for the timefrequency analysis. In terms of correlation analysis, the correlation coefficient based on the power spectrum between different electrodes was used for the correlation analysis and the phase locking value (PLV) between the different electrodes was used for the phase synchronization analysis. It is concluded that brain has the comparative function of the feature information of the theta band signal from the prefrontal cortex, central cortex and parietal cortex within different memory loads. The results are analysed by the paired t test and the F test of single factor analysis of variance. With the increase of the memory load, the power of the theta bands in the prefrontal cortex (electrode: Fp1, Fz, ofFp2, F3, F4) has more increased dramatically than that in the central lobe (electrode: C7, C3, Cz, C4, C8) and parietal lobe (electrode: P7, P3, Pz, P4, P8). The result has the statistical significance (P < 005, of which the Fz: P < 001 ).In terms of correlation analysis, with the lower letters memory load, the correlation coefficient of the ipsilateral regions, such as prefrontal lobe the central lobe (F3C3, F4C4), frontal lobeparietal lobe (F3P3, F4P4) is similar between the left region and right region in the brain. But with the increase of the memory load, relative to the left brain,the correlation coefficient of the right brain has increased obviously.In terms of phase synchronization, with the increase of the memory load, the right brain, such as the frontal lobethe central lobe (F4C4) and the prefrontal lobe, parietal lobe (F4P4) relative to the left brain markedly improved in phase synchronization, and the PLV compared value (PLV) increased obviously. The result has statistical significance (P < 005 ). During the “information maintain and recall” phase of the working memory, the degree of activity and informationexchange in the prefrontal cortex aresignificantly more than that in the middle and the parietal cortex. It may play a multifunction role that include maintain the information and call other cortexs. With the increase of the memory load, the brain will call more right brain cortex in working memory, and the rational logic model will translate into the perceptual image memory mode which can improve work efficiency.  2015 Vol. 34 (2): 143-152 [Abstract] ( 599 ) HTML (1 KB)  PDF (2142 KB)  ( 1022 ) 153 Correlation Analysis of Nonlinear Characteristics in EEG with CRSR Score and Visual Characterization of Rehabilitation Process in DOC Patients Hao Xueliang1Yang Wenwei1Li Jingqi2    Liu Xiaoping1 DOI: 10.3969/j.issn.0258-8021.2015.02.004 To provide an electrophysiology judgment method for evaluating the rehabilitation process of severe disorders of consciousness (DOC) patients, the correlation between EEG nonlinear characteristics and CRSR score was studied, and a visual characterization method was developed. The EEG data (acquired twice in a quiet state) of awareness patient’s (minimally conscious state, MCS, 10 and vegetative state, VS, 8) rehabilitation process were collected, nonlinear characteristics (approximate entropy, sample entropy, permutation entropy and complexity LZC) were calculated to compare the changes between nonlinear characteristics and CRSR score, and then were used to brain mapping for visual characterization. The CRSR score changes significantly both for MCS and VS patients (P<001). Approximate entropy and complexity LZC changes significantly for MCS patients (P<005), while only approximate entropy changes significantly for VS patients (P<005). There has significantly positive correlation of score changes between CRSR and nonlinear characteristics (approximate entropy for both MCS and VS, complexity LZC for MCS only), the correlation coefficients were calculated, 0851 and 0693 for MCS (approximate entropy and complexity LZC), and 0778 for VS (approximate entropy). Approximate entropy can be used to visualize patient’s brain function mapping.  Approximate entropy could be used as a potential method to evaluate the rehabilitation process for patients with awareness. 2015 Vol. 34 (2): 153-159 [Abstract] ( 435 ) HTML (1 KB)  PDF (2330 KB)  ( 848 ) 160 PatchBased SuperResolution Reconstruction for Lung 4DCT Images Wang Tingting   Wu Xiuxiu   Zhang Yu* DOI: 10.3969/j.issn.0258-8021.2015.02.005 Lung 4DCT is of great values in the application of tumor localization and individualized precise radiotherapy. However, due to the dose limitation, 4DCT data are in low resolution. In this paper, we proposed a patchbased superresolution reconstruction approach to enhance the resolution of 4DCT images. First, we divided the images into a number of overlapping patches. Then, Active Demons registration algorithm was utilized to adaptively select corresponding patches in each phase for the specific patch, and obtain the motion fields between the patches simultaneously. After that, iterative back projection (IBP) algorithm was adopted to reconstruct highresolution patch. At last, we assembled all patches into a final output high resolution image. A public dataset provided by the DIRlab at the University of Texas M.D. Anderson Cancer Center (Houston, TX) was employed to evaluate the proposed method. The dataset consists of 10 groups of lung 4DCT data, each group contains 10 phases. Images of different phases are selected to perform the above procedure for experiment. Quantitative evaluation results indicate that the proposed method significantly increases image average gradient value (892±050, P<0001) compared with back projection (BP) algorithm (765±044) and global IBP algorithm (792±043). Qualitative evaluation results also show that our approach can eliminate artifacts effectively and get clearer lung 4DCT images with significantly enhanced structures. 2015 Vol. 34 (2): 160-167 [Abstract] ( 403 ) HTML (1 KB)  PDF (7162 KB)  ( 222 ) 168 Hierarchical Optimization for MultiFundus Image Fusion Wei Lifang1   Yu Lun2* DOI: 10.3969/j.issn.0258-8021.2015.02.006 In order to remove the seams and ensure information details are not missed in the image fusion, the multiband blending image fusion method for multifundus image was proposed in this paper based on hierarchical optimization fusion. The mask image is achieved by multithreshold segmentation and Euclidean distance transform. And the improved weighted coefficients are designed based on the distance value in the overlap region and the layers of Gaussian image sum of Laplacian energy for the mask image. The combined objective evaluation was proposed that it is based on information entropy, spatial frequency and  definition. The registration error and overlap rate are used to realize hierarchical optimization multiband image fusion method for grouping fusion. And the image alone is put into next level directly. 75 group image sequences are applied involving 4 898 set of images (normal fundus image 2 952 pairs and disease fundus image 1 946 pairs) for testing and validation. The results show that the proposed method is effective that removes the seam and obtains the RMSE value of about (01±005) pixels in overlap region. The proposed method can make equilibrium between objective evaluation and subjective visual effect. 2015 Vol. 34 (2): 168-175 [Abstract] ( 350 ) HTML (1 KB)  PDF (7399 KB)  ( 291 ) 176 Synchronization between Posterior Temporal Lobe and other Brain Regions in the Working Memory Mei Dandan   Yan Zheng   Huang Ruimin* DOI: 10.3969/j.issn.0258-8021.2015.02.007 In this paper, the coherence method of electroencephalogram (EEG) was employed to establish functional networks to study the main areas which are responsible for the working memory (WM) —— the role and function of posterior temporal lobes presented in the processes of different WM modes. Twelve subjects performed our experiments which required the retention of either verbalizable strings of letters or abstract drawings. These two paradigms were designed specifically for corresponding to the two components of working memory —phonological loop and visualspatial sketch pad respectively. A 19channels EEG signal was recorded, based on which the coherent coefficient matrices were calculated. In consequence, the brain functional networks were constructed and discussed in this paper. Results showed that, compared with the resting state, for both phonological loop and visualspatial sketch pad, significantly increased θ (4～7 Hz) coherence values were detected between posterior temporal lobes (T5, T6) and other brain regions (P<005). This result suggested between the posterior temporal lobes and other brain regions the θ synchronization phenomenon could be observed during the process of working memory. Furthermore, the degrees of nodes T5 and T6 were largely different in the functional networks of the two components. However, both the degrees of T5 and T6 were bigger than other nodes, suggesting the left and right posterior temporal lobes may serve as specialized regions for the phonological loop and visualspatial sketch pad respectively. 2015 Vol. 34 (2): 176-183 [Abstract] ( 379 ) HTML (1 KB)  PDF (1461 KB)  ( 1221 ) 184 Classification of Principal Component Analysis on Complex Network and Application for White Matter Plasticity of Musicians Li Jianfu   Luo Cheng*   Dong Li   Yao Dezhong# DOI: 10.3969/j.issn.0258-8021.2015.02.008 The human brain is a complex network with multiple scales of time and space which includes large amount of connection information. Principal component analysis (PCA) can extract important features from vast quantities of information; therefore, it was used to explore important information from complex network in this study. As is widely known, musicians represent an ideal model to investigate experiencedriven plasticity changes in the human brain. It is a far more significant research that explores plasticity changes in brain networks of musicians. In this study, white matter brain networks of 16 musicians and 16 nonmusicians were firstly constructed by fiber tracking based on diffusionweighted imaging (DWI); secondly, PCA process was used to extract the feature networks of two the groups, support vector machine (SVM) classification method was then applied to each component, the component with best classification performance was obtained; finally, the first 1% connections with highest contribution to the component were considered to be the main connections which may represent the changes in the musicians’ white matter anatomical networks compared to nonmusicians. This method provides a new approach which utilizes the PCA based classification for complex network comparison issues. And, comparison analysis of the white matter anatomical brain network between musicians and nonmusicians indicated that musicians showed  enhanced information transfer efficient between motor, auditory, emotional, and memory related brain regions. These findings may extend the network level understanding of white matter plasticity in musicians who have had longterm musical training. 2015 Vol. 34 (2): 184-189 [Abstract] ( 393 ) HTML (1 KB)  PDF (2333 KB)  ( 491 ) 190 An Improved Image Reconstruction Algorithm Based on Iteration NR in Magnetic Induction Tomography Han Min1*Xue Yuyan1Qin Pan1Han Jie DOI: 10.3969/j.issn.0258-8021.2015.02.009 The image reconstruction process is a typical illposed problem in magnetic induction tomography (MIT), in which the numerical solution is unstable. To solve this problem, an improved iteration NewtonRaphson algorithm based on weighted matrix and L1norm regularization is improved. The proposed method adds the weight matrix in the objective function and adds L1norm regularization term in L2norm regularization penalty term. The analysis is made for three typical models in the data with and without noise, respectively. And the proposed algorithm is contrasted with Tikhonov regularization algorithm and iterative NR algorithm. In the data without noise, relative to Tikhonov regularization algorithm and iterative NR algorithm, the relative error is reduced by 011-014. And then, the correlation coefficient is raised by 13%-17%. The algorithm has good performance in imaging. In the data with noise, the relative error is reduced by 006-009, and the correlation coefficient is raised by 7%-10% in the proposed algorithm. The algorithm has good antinoise performance, which has offered theory basis for the study of reconstruction accuracy. 2015 Vol. 34 (2): 190-197 [Abstract] ( 349 ) HTML (1 KB)  PDF (3204 KB)  ( 504 ) 198 Finite Element Analysis of the Influence of Morphology of Coronary Artery Stenosis on Fractional Flow Reserve Qiao Aike1#*Hou Yingying1    Hou Yang2 DOI: 10.3969/j.issn.0258-8021.2015.02.010 In this paper, the influence of morphology of coronary artery stenosis on fractional flow reserve(FFR) was investigated.The stenosis ratio, length, number, arc, and offset were included in the morphology of coronary artery stenosis.Different idealized models of coronary artery stenosis based on clinical data were established in Pro/Engineering. Numerical simulations were carried out to analyze the hemodynamic parameters of the models.A steady blood flow velocity was assigned at the inlet. A constant pressure was assigned at the outlet. The CFX finite element numerical simulation was used to calculate the models. Then the pressure value at the distal end and proximal end of the stenosis was extracted for FFR analysis. The influence of factors on FFR was investigated by analyzing each factors and their corresponding fractional flow reserve. The stenosis is more likely to cause myocardial ischemia when the stenosis has larger ratio, longer size, more number, more irregular shape and bigger offset. Among the factors, the stenosis ratio and length affect the FFR value more strongly.It will be likely to cause FFR less than 080 and lead to myocardial ischemia when the stenosis ratio surpasses 70%, the number of stenosis is more than two with irregular shapes. The stenosis ratio, length, number, stenosis arc, and the stenosis offset have significant effect on FFR where the stenosis ratio and the number of stenosis have the most significant influence, while the distance between adjacent stenosis has little influence on FFR. 2015 Vol. 34 (2): 198-203 [Abstract] ( 573 ) HTML (1 KB)  PDF (2388 KB)  ( 821 ) 204 Automatic Detection of Vaginal Bacteria Based on Superpixel and Support Vector Machine DOI: 10.3969/j.issn.0258-8021.2015.02.011 The vaginal disorders or infections caused by bacteria may lead to serious diseases including ectopic pregnancy, infertility, acute or chronic pelvic inflammatory. In clinics, cytology screening is used to prevent vaginal disease; however, misdiagnosis and missed diagnosis occasionally occurred. Here we presented an algorithm for the automatic detection of vaginal bacteria based on the superpixel and support vector machine using images from Gram stain. The algorithm applied simple linear iterative clustering to compute superpixel. We characterized these superpixels areas using features of shape and color and histograms of oriented gradients, and then performed support vector machine classification.〓Fourty negative of BV and 60 indicative of BV images were chosen, one of 10 negative of BV and 20 indicative of BV images were used for training the classifier, the rest of the images for testing the algorithm. Results suggest that the proposed method reached the average ZSI of 8927%, showing promising potentials of clinical application. 2015 Vol. 34 (2): 204-211 [Abstract] ( 392 ) HTML (1 KB)  PDF (13294 KB)  ( 151 ) 212 The Effect of Crosslink on the Structures and Performance of Oxidized Bacterial Cellulose/Silk Fibroin Composite Films Wang Shuaiyan1     Huang Tao1    Lai Chen2      Xi Tingfei1,2#*Nan Fang1 DOI: 10.3969/j.issn.0258-8021.2015.02.012 The purpose of this study is to investigate two kinds of preparation methods on nanobacterial cellulose/silk fibroin composites and to compare the physical and chemical properties of the resulting composite products. One method is to mix directly bacterial cellulose or oxidized bacterial cellulose membranes with silk fibroin solution. Another one is to add crosslinking agents during the mixing process. The composite products were characterized using Fourier transforminfrared (FTIR) spectroscopy,13C NMR spectrum, Xray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM) and mechanical testing. Results show that fibroin can successfully be combined on the oxidized bacterial cellulose membrane, XPS results show that no matter adding crosslinking agents or not, C1s, O1s and N1s appeared no difference. BC/SF composite membrane, the comparison C/N molar ratio of without crosslinking agents and with them, reduced from 963 to 394, while the TBC/SF, C/N ratio increased from 503 to 741. The membrane surface of one group containing crosslinking agents is smoother than another, and the structure has obvious changes. There are significant differences in elongation at break of TBC/SF (P＜001). Based on this work, the performance of composite films prepared by adding crosslinking agents is better, and the materials described here demonstrate the potential in medical material applications, especially in a cellular vascular graft filed. 2015 Vol. 34 (2): 212-220 [Abstract] ( 335 ) HTML (1 KB)  PDF (5563 KB)  ( 495 ) 221 Progress of Intravascular Photoacoustic Imaging Sun Zheng*   Yuan Yuan   Wang Jiangjiang DOI: 10.3969/j.issn.0258-8021.2015.02.013 Intravascular photoacoustic (IVPA) imaging is a newly developed interventional imaging modality to detect and distinguish atherosclerotic plaques based on the differences between the optical absorption characteristics of different plaque tissues. It combines the contrast of optical absorption with the spatial resolution of ultrasound for deep imaging to obtain comprehensive information of morphology and component of atherosclerotic plaques. In this paper, the progress of IVPA imaging system as well as its applications in spectroscopy imaging, thermal imaging, molecular imaging and coronary stent imaging was reviewed. The current development of integrated IVPA/IVUS imaging catheter is then summarized. The existing problems and future directions in the design and implement IVPA system were also discussed. 2015 Vol. 34 (2): 221-228 [Abstract] ( 444 ) HTML (1 KB)  PDF (5719 KB)  ( 1214 ) 229 The Application of ShortTerm Nonlinear Methods to Heart Rate Variability Analysis Liu Hongduoer    Zhu Yi    Zhan Ping    Wang Zhigang    Peng Yi#* DOI: 10.3969/j.issn.0258-8021.2015.02.014 Nonlinear analysis brings about new insights into heart rate variability (HRV) changes under various physiological and pathological conditions, providing additional prognostic information and complementing traditional time and frequency domain analyses. Shortterm nonlinear analysis conforms to the nonlinearity and nonstationarity of heart rate dynamics. Several dominant methods, such as symbolic dynamics analysis, shortterm fractal scaling exponent (α1) analyzed by the detrended fluctuation analysis method, approximation entropy and sample entropy, recurrence quantification analysis, are introduced for their application to shortterm RR series. Furthermore, this article reviews some expansion of application, including shortterm nonlinear analysis coupled with longterm RR series, as well as risk stratification based on multidomain indexes including shortterm nonlinear ones. Several issues concerning the wide spread clinical use of HRV analysis were discussed. 2015 Vol. 34 (2): 229-236 [Abstract] ( 355 ) HTML (1 KB)  PDF (804 KB)  ( 838 ) 237 CCDBased Colloidal Gold Immunochromatographic Device Gui Chen   Dai Xuan   Wang Kan   Cui Daxiang* DOI: 10.3969/j.issn.0258-8021.2015.02.015 2015 Vol. 34 (2): 237-242 [Abstract] ( 273 ) HTML (1 KB)  PDF (7209 KB)  ( 135 ) 243 Exploration Research of Estimation Method on the Dielectric Properties of Biological Tissue in Terahertz Based on the Modified Fourth ColeCole Model Peng Yan1    Lu Mai2*Chen Xiaoqiang1      Tian Rui3 DOI: 10.3969/j.issn.0258-8021.2015.02.016 2015 Vol. 34 (2): 243-247 [Abstract] ( 388 ) HTML (1 KB)  PDF (738 KB)  ( 535 ) 248 Functional Electrical Stimulation (FES) with Kinect for PostStroke Rehabilitation on Hands Tu Junbo1,3Hu Xiaoling2    Zheng Xiaoxiang1#* DOI: 10.3969/j.issn.0258-8021.2015.02.017 2015 Vol. 34 (2): 248-252 [Abstract] ( 363 ) HTML (1 KB)  PDF (4605 KB)  ( 426 ) 253 Effect of Injection Rate on Cerebral Perfusion Magnetic Resonance Imaging Hemodynamics Zhang Xiaoqin1 Li Jiance1Wang Nana1Yang Yunjun1Wu Lijun2* DOI: 10.3969/j.issn.0258-8021.2015.02.018 2015 Vol. 34 (2): 253-256 [Abstract] ( 187 ) HTML (1 KB)  PDF (3918 KB)  ( 371 )

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