Bio-Medical Materials and Engineering - Volume 26, issue s1

Authors: Wang, Rui | Zhou, Yongquan | Zhao, Chengyan | Wu, Haizhou

Article Type: Research Article

Abstract: Multi-threshold image segmentation is a powerful image processing technique that is used for the preprocessing of pattern recognition and computer vision. However, traditional multilevel thresholding methods are computationally expensive because they involve exhaustively searching the optimal thresholds to optimize the objective functions. To overcome this drawback, this paper proposes a flower pollination algorithm with a randomized location modification. The proposed algorithm is used to find optimal threshold values for maximizing Otsu’s objective functions with regard to eight medical grayscale images. When benchmarked against other state-of-the-art evolutionary algorithms, the new algorithm proves itself to be robust and effective through numerical experimental …results including Otsu’s objective values and standard deviations. Show more

Keywords: Flower pollination algorithm, randomized location, Otsu method, multi-threshold image segmentation, medical image segmentation

DOI: 10.3233/BME-151432

Citation: Bio-Medical Materials and Engineering, vol. 26, no. s1, pp. S1345-S1351, 2015

Authors: Hu, Liang | Cheng, Zhaoning | Wang, Manning | Song, Zhijian

Article Type: Research Article

Abstract: Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) is widely used for breast lesion differentiation. Manual segmentation in DCE-MRI is difficult and open to viewer interpretation. In this paper, an automatic segmentation method based on image manifold revealing was introduced to overcome the problems of the currently used method. First, high dimensional datasets were constructed from a dynamic image series. Next, an embedded image manifold was revealed in the feature image by nonlinear dimensionality reduction technique. In the last stage, k-means clustering was performed to obtain final segmentation results. The proposed method was applied in actual clinical cases and compared with the …gold standard. Statistical analysis showed that the proposed method achieved an acceptable accuracy, sensitivity, and specificity rates. Show more

Keywords: Breast lesion, manifold learning, DCE-MRI, tumor segmentation, dimensionality reduction

DOI: 10.3233/BME-151433

Citation: Bio-Medical Materials and Engineering, vol. 26, no. s1, pp. S1353-S1360, 2015

Authors: Le, Trong-Ngoc | Bao, Pham The | Huynh, Hieu Trung

Article Type: Research Article

Abstract: In this paper, a fully automatic scheme for measuring liver volume in 3D MR images was developed. The proposed MRI liver volumetry scheme consisted of four main stages. First, the preprocessing stage was applied to T1-weighted MR images of the liver in the portal-venous phase to reduce noise. The histogram of the 3D image was determined, and the second-to-last peak of the histogram was calculated using a neural network. Thresholds, which are determined based upon the second-to-last peak, were used to generate a thresholding image. This thresholding image was refined using a gradient magnitude image. The morphological and connected component …operations were applied to the refined image to generate the rough shape of the liver. A 3D geodesic-active-contour segmentation algorithm refined the rough shape in order to more precisely determine the liver boundaries. The liver volumes determined by the proposed automatic volumetry were compared to those manually traced by radiologists; these manual volumes were used as a “gold standard.” The two volumetric methods reached an excellent agreement. The Dice overlap coefficient and the average accuracy were 91.0 ±2.8% and 99.0 ±0.4%, respectively. The mean processing time for the proposed automatic scheme was 1.02 ±0.08 min (CPU: Intel, core i7, 2.8GHz), whereas that of the manual volumetry was 24.3 ±3.7 min (p < 0.001). Show more

Keywords: Liver volumetry, MR volumetry, resection, transplantation, magnetic resonance imaging

DOI: 10.3233/BME-151434

Citation: Bio-Medical Materials and Engineering, vol. 26, no. s1, pp. S1361-S1369, 2015

Authors: Huang, Po-Chia | Hsu, Ching-Han

Article Type: Research Article

Abstract: Pinhole SPECT for small animal has become a routine procedure in many applications of molecular biology and pharmaceutical development. There is an increasing demand in the whole body imaging of lab animals. A simple and direct solution is to scan the object along a helical trajectory, similar to a helical CT scan. The corresponding acquisition time can be greatly reduced, while the over-lapping and gap between consecutive bed positions can be avoided. However, helical pinhole SPECT inevitably leads to the tremendous increase in computational complexity when the iterative reconstruction algorithms are applied. We suggest a novel voxel-driven (VD) system model …which can be integrated with geometric symmetries from helical trajectory for fast iterative image reconstruction. Such a model construction can also achieve faster calculation and lower storage requirement of the system matrix. Due to the independence among various symmetries, it permits parallel coding to further boost computation efficiency of forward/backward projection. From phantom study, the results also indicate that the proposed VD model can adequately model the helical pinhole SPECT scanner with manageable storage size of system matrix and clinically acceptable computation loading of reconstruction. Show more

Keywords: Pinhole SPECT, helical trajectory, voxel-driven system model, ray-tracing algorithms

DOI: 10.3233/BME-151435

Citation: Bio-Medical Materials and Engineering, vol. 26, no. s1, pp. S1371-S1380, 2015

Authors: Liu, Ruigang | Fu, Feng | You, Fusheng | Shi, Xuetao | Dong, Xiuzhen

Article Type: Research Article

Abstract: Static imaging of the electrical impedance tomography can obtain the absolute electrical conductivity distribution at one section of the subject. The test is performed on a cylinder physical phantom in which slim rectangle, hollow cylinder, small rectangle or three cylinders are selected to simulate complex conductivity perturbation objects. The measurement data is obtained by a data acquisition system with 32 compound electrodes. A group of static images of conductivity distribution in the cylinder phantom are reconstructed by the modified Newton-Raphson algorithm with two kinds of regularization methods. The results show correct position, size, conductivity difference, and similar shape of the …perturbation objects in the images. Show more

Keywords: Electrical impedance, tomography, reconstruction algorithm, physical phantom, static imaging

DOI: 10.3233/BME-151436

Citation: Bio-Medical Materials and Engineering, vol. 26, no. s1, pp. S1381-S1388, 2015

Authors: Qi, Hongliang | Chen, Zijia | Guo, Jingyu | Zhou, Linghong

Article Type: Research Article

Abstract: Low-dose computed tomography reconstruction is an important issue in the medical imaging domain. Sparse-view has been widely studied as a potential strategy. Compressed sensing (CS) method has shown great potential to reconstruct high-quality CT images from sparse-view projection data. Nonetheless, low-contrast structures tend to be blurred by the total variation (TV, L1 -norm of the gradient image) regularization. Moreover, TV will produce blocky effects on smooth and edge regions. To overcome this limitation, this study has proposed an iterative image reconstruction algorithm by combining L1 regularization and smoothed L0 (SL0 ) regularization. SL0 is a smooth approximation …of L0 norm and can solve the problem of L0 norm being sensitive to noise. To evaluate the proposed method, both qualitative and quantitative studies were conducted on a digital Shepp-Logan phantom and a real head phantom. Experimental comparative results have indicated that the proposed L1 /SL0 -POCS algorithm can effectively suppress noise and artifacts, as well as preserve more structural information compared to other existing methods. Show more

Keywords: Sparse-view reconstruction, smoothed L0 regularization, L1 regularization, total variation

DOI: 10.3233/BME-151437

Citation: Bio-Medical Materials and Engineering, vol. 26, no. s1, pp. S1389-S1398, 2015

Authors: Sajjad, Muhammad | Mehmood, Irfan | Baik, Sung Wook

Article Type: Research Article

Abstract: Image super-resolution (SR) plays a vital role in medical imaging that allows a more efficient and effective diagnosis process. Usually, diagnosing is difficult and inaccurate from low-resolution (LR) and noisy images. Resolution enhancement through conventional interpolation methods strongly affects the precision of consequent processing steps, such as segmentation and registration. Therefore, we propose an efficient sparse coded image SR reconstruction technique using a trained dictionary. We apply a simple and efficient regularized version of orthogonal matching pursuit (ROMP) to seek the coefficients of sparse representation. ROMP has the transparency and greediness of OMP and the robustness of the L 1 …-minization that enhance the dictionary learning process to capture feature descriptors such as oriented edges and contours from complex images like brain MRIs. The sparse coding part of the K-SVD dictionary training procedure is modified by substituting OMP with ROMP. The dictionary update stage allows simultaneously updating an arbitrary number of atoms and vectors of sparse coefficients. In SR reconstruction, ROMP is used to determine the vector of sparse coefficients for the underlying patch. The recovered representations are then applied to the trained dictionary, and finally, an optimization leads to high-resolution output of high-quality. Experimental results demonstrate that the super-resolution reconstruction quality of the proposed scheme is comparatively better than other state-of-the-art schemes. Show more

Keywords: Image super-resolution, sparse representations, reconstruction, dictionary

DOI: 10.3233/BME-151438

Citation: Bio-Medical Materials and Engineering, vol. 26, no. s1, pp. S1399-S1407, 2015

Authors: Zhou, Ziying | Li, Yugang | Zhang, Fa | Wan, Xiaohua

Article Type: Research Article

Abstract: Electron tomography (ET) is an essential imaging technique for studying structures of large biological specimens. These structures are reconstructed from a set of projections obtained at different sample orientations by tilting the specimen. However, most of existing reconstruction methods are not appropriate when the data are extremely noisy and incomplete. A new iterative method has been proposed: adaptive simultaneous algebraic reconstruction with inter-iteration adaptive non-linear anisotropic diffusion (NAD) filter (FASART). We also adopted an adaptive parameter and discussed the step for the filter in this reconstruction method. Experimental results show that FASART can restrain the noise generated in the process …of iterative reconstruction and still preserve the more details of the structure edges. Show more

Keywords: electron tomography (ET), 3D reconstruction, iterative method, non-linear anisotropic diffusion (NAD) filter

DOI: 10.3233/BME-151439

Citation: Bio-Medical Materials and Engineering, vol. 26, no. s1, pp. S1409-S1415, 2015

Authors: Lee, Sangyong | Chin, Seongah

Article Type: Research Article

Abstract: Recently, advanced visualizing techniques in computer graphics have considerably enhanced the visual appearance of synthetic models. To realize enhanced visual graphics for synthetic medical effects, the first step followed by rendering techniques involves attaching albedo textures to the region where a certain graphic is to be rendered. For instance, in order to render wound textures efficiently, the first step is to recognize the area where the user wants to attach a wound. However, in general, face indices are not stored in sequential order, which makes sub-texturing difficult. In this paper, we present a novel mesh tagging algorithm that utilizes a …task for mesh traversals and level extension in the general case of a wound sub-texture mapping and a selected region deformation in a three-dimensional (3D) model. This method works automatically on both regular and irregular mesh surfaces. The approach consists of mesh selection (MS), mesh leveling (ML), and mesh tagging (MT). To validate our approach, we performed experiments for synthesizing wounds on a 3D face model and on a simulated mesh. Show more

Keywords: Wound synthesis, medical image synthesis, irregular mesh, regular mesh, mesh indexing

DOI: 10.3233/BME-151440

Citation: Bio-Medical Materials and Engineering, vol. 26, no. s1, pp. S1417-S1429, 2015

Authors: Jao, Jochi | Cheng, Mingye | Lee, Hsintien | Ting, Julius | Chen, Pochou

Article Type: Research Article

Abstract: Magnetic Resonance Imaging (MRI) has been one of the most revolutionary medical imaging modalities in the past three decades. It has been recognized as a potential technique in the clinical diagnosis of diseases as well as tumor differentiation. Although MRI has now become the preferred choice in many clinical examinations, there are some drawbacks, which still limit its applications. One of the crucial issues of MRI is the geometric distortion caused by magnetic field inhomogeneity and susceptibility effects. The farther the lesion from the center of a magnetic field (off-center field), the more severe the distortion becomes, especially in low-field …MRI. Hence, it might hinder the diagnosis and characterization of lesions in the presence of field inhomogeneity. In this study, an innovative multi-orientated water-phantom was used to evaluate the geometric distortion. The correlations between the level of image distortion and the relative off-center positions, as well as the variation of signal intensities, were both investigated. The image distortion ratios of axial, coronal and sagittal images were calculated. Show more

Keywords: Geometric distortion, field inhomogeneity, off-center field, multi-orientated water-phantom

DOI: 10.3233/BME-151441

Citation: Bio-Medical Materials and Engineering, vol. 26, no. s1, pp. S1431-S1438, 2015

Authors: Shi, Caiyun | Xie, Guoxi | Zhang, Xiaoyong | Su, Shi | Zhang, Yongqin | Zhang, Lijuan | Qiu, Bensheng | Liu, Xin

Article Type: Research Article

Abstract: Blood oxygenation level dependent functional MRI (BOLD fMRI) requires repeatedly scanning the same region to capture neuronal activities, so the sampling data is very sparse along the temporal direction, which offers an opportunity to accelerate the fMRI. In this paper, (k-t) space data is sparsely acquired and reconstructed for BOLD fMRI using a partial separability (PS) model with a ℓ 2 -norm constraint. The proposed approach achieves a high temporal resolution of 200 ms without compromising spatial resolution (3.5 × 3.5 × …4.0 mm3 ). A simulation based on the EPI data with the right finger tapping experiment demonstrates that the proposed method can realize high spatiotemporal fMRI with accurate reconstruction of the activation regions from highly undersampled data. Meanwhile, preliminary in vivo experiment results also demonstrate the potential application of the proposed method in fMRI. Show more

Keywords: fMRI (function magnetic resonance imaging), partial separability (PS) model, sparse sampling, BOLD

DOI: 10.3233/BME-151442

Citation: Bio-Medical Materials and Engineering, vol. 26, no. s1, pp. S1439-S1446, 2015

Authors: Lee, Min-Hee | Shin, Yong-Il | Lee, Sang Hyeon | Cha, Young Joo | Kim, Dong Youn | Han, Bong Soo | You, Sung H.

Article Type: Research Article

Abstract: Hemiparetic stroke is a common motor network disorder that affects a wide range of functional movements due to cortical and subcortical network lesions in stroke patients. Conventional magnetic resonance imaging (MRI) has been used to examine structural brain damage, but the integrity and connectivity of the whole brain are poorly understood. Hence, advanced neuroimaging with diffusion tensor imaging (DTI) has been developed to better localize fiber architecture and connectivity in the motor network or pathways that are responsible for motor impairments in hemiparetic stroke. To ascertain motor network connectivity between the involved and non-involved hemispheres in stroke patients, we analyzed …the DTI data from all right hemiparetic stroke patients using fractional anisotropy (FA) and network parameters, including node degree and edge betweenness centrality (EBC). The FA values were substantially lower in the left hemisphere than the right hemisphere. Similarly, the node degree and EBC were significantly lower in the left hemisphere than the right hemisphere. The present brain network analysis may provide a useful neuropathway marker for accurate diagnosis and therapeutic intervention. Show more

Keywords: Cerebrovascular accident, diffusion tensor imaging, brain network, fractional anisotropy

DOI: 10.3233/BME-151443

Citation: Bio-Medical Materials and Engineering, vol. 26, no. s1, pp. S1447-S1453, 2015

Authors: Fan, Xiaoli | Zhou, Qianxiang | Liu, Zhongqi | Xie, Fang

Article Type: Research Article

Abstract: Mental fatigue is considered to be a contributing factor responsible for numerous road accidents and various medical conditions and the efficiency and performance could be impaired during fatigue. Hence, determining how to evaluate mental fatigue is very important. In the present study, ten subjects performed a long-term visual search task with electroencephalogram recorded, and self-assessment and reaction time (RT) were combined to verify if mental fatigue had been induced and were also used as confirmatory tests for the proposed measures. The changes in relative energy in four wavebands ( δ , θ , α …, and β ), four ratio formulas [ ( α + θ ) / β , α / β , ( α + θ ) / ( α + β ) , and θ / β ] , and Shannon’s entropy (SE) were compared and analyzed between the beginning and end of the task. The results showed that a significant increase occurred in alpha activity in the frontal, central, posterior temporal, parietal, and occipital lobes, and a dip occurred in the beta activity in the pre-frontal, inferior frontal, posterior temporal, and occipital lobes. The ratio formulas clearly increased in all of these brain regions except the temporal region, where only α / β changed obviously after finishing the 60-min visual search task. SE significantly increased in the posterior temporal, parietal, and occipital lobes. These results demonstrate some potential indicators for mental fatigue detection and evaluation, which can be applied in the future development of countermeasures to fatigue. Show more

Keywords: Mental fatigue, EEG, ratio formulas, entropy, visual search

DOI: 10.3233/BME-151444

Citation: Bio-Medical Materials and Engineering, vol. 26, no. s1, pp. S1455-S1463, 2015

Authors: Shirazi, Muhammad Faizan | Cho, Nam Hyun | Jung, Woonggyu | Kim, Jeehyun

Article Type: Research Article

Abstract: Adaptive optics plays an important role in the correction of high-order aberrations to enhance lateral resolution. An OCT system coupled with a programmable phase modulator is designed to verify lateral resolution improvement. The Hamamatsu high-resolution, non-pixelized, optically addressed light modulator (PAL-SLM) PPM X7550 series is used to correct aberrations, utilizing a simple method based on phase information from OCT images. The advantages of this method are its high simplicity and low cost. A raster scanning technique is adopted to scan samples covered with scattering suspension. Metal lines covered with scattering suspension are imaged, and a respective correction is applied to …remove the aberration. Results demonstrate an improvement in lateral resolution on metal grid samples. Show more

Keywords: OCT, lateral resolution, aberration correction, adaptive optics, PAL-SLM

DOI: 10.3233/BME-151445

Citation: Bio-Medical Materials and Engineering, vol. 26, no. s1, pp. S1465-S1471, 2015

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

Article Type: Research Article

Abstract: Recently, digital stereo microscopes have been becoming increasingly popular in fields such as biomedicine and biotechnology. As such, being able to precisely match left/right feature pairs is critical, which is an important step in stereo matching. We hereby propose a dynamic interpolation method that combines two dimensional calibration and depth information to achieve stereo matching. In this experiment, we obtained the original scale-invariant feature transform feature point pairs and selected a pair of matching units. Based on the selected pair of matching elements and interpolated feature points shown in the left view of stereo microscope image, the dynamically interpolated feature …points in the right view were developed to perform stereo measurements. The experimental results revealed that the proposed method can realize stereo microscopic measurements; results with high reliability can be achieved with a large quantity of matching elements. Show more

Keywords: Dynamically interpolated feature points, stereo matching, stereo matching, digital stereo microscope

DOI: 10.3233/BME-151446

Citation: Bio-Medical Materials and Engineering, vol. 26, no. s1, pp. S1473-S1481, 2015

Authors: Shin, Seung-Won | Park, Jaebyung | Shin, Dong ho | Song, Chul-Gyu | Kim, Kyeong-Seop

Article Type: Research Article

Abstract: A real-time photoacoustic tomography (PAT) system is developed using a linear array probe and phantom images are acquired with a pattern of line structure. Moreover, it is attempted to detect line structures from the acquired images by Hough transform. This effort leads to the measurement of a process of magenta passing through a tube and acquisition of images at a speed of about 2 frame/sec. Besides, it is confirmed that the Hough transform applied on the acquired PAT images has the detection rate of about 50% for delineating a line structure.

Keywords: Photoacoustic image, back projection algorithm, ultrasonic imaging, Hough transform, line structure

DOI: 10.3233/BME-151447

Citation: Bio-Medical Materials and Engineering, vol. 26, no. s1, pp. S1483-S1490, 2015

Authors: Shi, Zhenghao | Xu, Binxin | Zhao, Minghua | Zhao, Jinwei | Wang, Yinghui | Liu, Yonghong | Zhang, Ming | He, Lifeng | Suzuki, Kenji

Article Type: Research Article

Abstract: Extraction of regions of interest plays an important rule in computer aided lung nodules detection. However, because of the complex background and structure, accurate and robust extraction of ROI s in medical image still remains a problem. Aim at this problem, a two-stage operations joint filter: Hessian-LoB , is proposed. The first stage is blobs (which being taken as candidate ROI s) detection and the second stage is ROI s extraction. In the first stage, the derivatives of a Hessian matrix at multiple scales are convolved with input images to localize blobs. Then in the second stage, Laplacian of bilateral …filter (LoB ) is convolved with the detected blobs to extract the final ROI s. Experiments show that the proposed filter can deal with images with noise and low brightness contrast, and is effectively in ROI extraction for lung nodule detection. Show more

Keywords: Region of interesting (ROI), extraction, hessian matrix, Laplacian of Bilateral (LoB)

DOI: 10.3233/BME-151448

Citation: Bio-Medical Materials and Engineering, vol. 26, no. s1, pp. S1491-S1499, 2015

Authors: Dai, Ning | Liu, Hao | Tang, Yuehong | Zhao, Jianning | Cheng, Xiaosheng

Article Type: Research Article

Abstract: Contour extraction of image stacks is a basic task in medical modeling. The existing level-set methods usually suffer from some problems (e.g. serious errors around sharp features, incorrect split of topology and contour occlusions). This paper proposes a novel method of multi-constraint level-set evolution to avoid above-mentioned problems. Interpolation constraint and deviation constraint are added to evolution processin addition to existing constraints (such as edge points and areas). In order to prevent occlusions, it proposes a method of three-phase level-set evolution. The first phase obtains a rough contour according to selected edge points. The second phase applies an expanding LSE …(level-set evolution). Missing edge points in the first phase are added when occlusions probably appear. In the third phase, occlusions are deleted and a refining evolution is implemented. As proved by final experiments, our method can steadily extract contours slice by slice when the shapes of previous contours (contours in the previous slice) are similar to current contours (contours in the current slice). Furthermore, there is no error propagation during the process of contour extraction. Show more

Keywords: Contour extraction, multi-constraint, level-set evolution

DOI: 10.3233/BME-151449

Citation: Bio-Medical Materials and Engineering, vol. 26, no. s1, pp. S1501-S1514, 2015

Authors: Qin, Shujia | Ding, Wei | Miao, Lei | Xi, Ning | Li, Hongyi | Yang, Chunmin

Article Type: Research Article

Abstract: The gastric slow wave and the spike potential can correspondingly represent the rhythm and the intensity of stomach motility. Because of the filtering effect of biological tissue, electrogastrogram (EGG) cannot measure the spike potential on the abdominal surface in the time domain. Thus, currently the parameters of EGG adopted by clinical applications are only the characteristics of the slow wave, such as the dominant frequency, the dominant power and the instability coefficients. The limitation of excluding the spike potential analyses hinders EGG from being a diagnosis to comprehensively reveal the motility status of the stomach. To overcome this defect, this …paper a) presents an EGG reconstruction method utilizing the specified signal components decomposed by the discrete wavelet packet transform, and b) obtains a frequency band for the human gastric spike potential through fasting and postprandial cutaneous EGG experiments for twenty-five human volunteers. The results indicate the lower bound of the human gastric spike potential frequency is 0.96±0.20 Hz (58±12 cpm), and the upper bound is 1.17±0.23 Hz (70±14 cpm), both of which have not been reported before to the best of our knowledge. As an auxiliary validation of the proposed method, synchronous serosa-surface EGG acquisitions are carried out for two dogs. The frequency band results for the gastric spike potential of the two dogs are respectively 0.83–0.90 Hz (50–54 cpm) and 1.05–1.32 Hz (63–79 cpm). They lie in the reference range 50–80 cpm proposed in previous literature, showing the feasibility of the reconstruction method in this paper. Show more

Keywords: Electrogastrogram (EGG), gastric spike potential, discrete wavelet transforms, wavelet packets

DOI: 10.3233/BME-151450

Citation: Bio-Medical Materials and Engineering, vol. 26, no. s1, pp. S1515-S1521, 2015

Authors: Wei, Qingguo | Wei, Zhonghai

Article Type: Research Article

Abstract: A brain-computer interface (BCI) enables people suffering from affective neurological diseases to communicate with the external world. Common spatial pattern (CSP) is an effective algorithm for feature extraction in motor imagery based BCI systems. However, many studies have proved that the performance of CSP depends heavily on the frequency band of EEG signals used for the construction of covariance matrices. The use of different frequency bands to extract signal features may lead to different classification performances, which are determined by the discriminative and complementary information they contain. In this study, the broad frequency band (8-30 Hz) is divided into 10 …sub-bands of band width 4 Hz and overlapping 2 Hz. Binary particle swarm optimization (BPSO) is used to find the best sub-band set to improve the performance of CSP and subsequent classification. Experimental results demonstrate that the proposed method achieved an average improvement of 6.91% in cross-validation accuracy when compared to broad band CSP. Show more

Keywords: Brain-computer interface, motor imagery, common spatial pattern, binary particle swarm optimization, frequency band selection

DOI: 10.3233/BME-151451

Citation: Bio-Medical Materials and Engineering, vol. 26, no. s1, pp. S1523-S1532, 2015

Authors: Liao, Mengjia | Guo, Yi | Qin, Yajie | Wang, Yuanyuan

Article Type: Research Article

Abstract: Activities recognition using a wearable device is a very popular research field. Among all wearable sensors, the accelerometer is one of the most common sensors due to its versatility and relative ease of use. This paper proposes a novel method for activity recognition based on a single accelerometer. To process the activity information from accelerometer data, two kinds of signal features are extracted. Firstly, five features including the mean, the standard deviation, the entropy, the energy and the correlation are calculated. Then a method called empirical mode decomposition (EMD) is used for the feature extraction since accelerometer data are non-linear …and non-stationary. Several time series named intrinsic mode functions (IMFs) can be obtained after the EMD. Additional features will be added by computing the mean and standard deviation of first three IMFs. A classifier called Adaboost is adopted for the final activities recognition. In the experiments, a single sensor is separately positioned in the waist, left thigh, right ankle and right arm. Results show that the classification accuracy is 94.69%, 86.53%, 91.84% and 92.65%, respectively. These relatively high performances demonstrate that activities can be detected irrespective of the position by reducing problems such as the movement constrain and discomfort. Show more

Keywords: Activity recognition, accelerometer, empirical mode decomposition (EMD), adaboost

DOI: 10.3233/BME-151452

Citation: Bio-Medical Materials and Engineering, vol. 26, no. s1, pp. S1533-S1539, 2015

Authors: Cao, Peng | Liu, Xiaoli | Bao, Hang | Yang, Jinzhu | Zhao, Dazhe

Article Type: Research Article

Abstract: The false-positive reduction (FPR) is a crucial step in the computer aided detection system for the breast. The issues of imbalanced data distribution and the limitation of labeled samples complicate the classification procedure. To overcome these challenges, we propose oversampling and semi-supervised learning methods based on the restricted Boltzmann machines (RBMs) to solve the classification of imbalanced data with a few labeled samples. To evaluate the proposed method, we conducted a comprehensive performance study and compared its results with the commonly used techniques. Experiments on benchmark dataset of DDSM demonstrate the effectiveness of the RBMs based oversampling and semi-supervised learning …method in terms of geometric mean (G-mean) for false positive reduction in Breast CAD. Show more

Keywords: Breast computer aided detection, false-positive reduction, imbalanced data learning, semi-supervised learning, restricted Boltzmann machines

DOI: 10.3233/BME-151453

Citation: Bio-Medical Materials and Engineering, vol. 26, no. s1, pp. S1541-S1547, 2015

Authors: Yang, Jianli | Bai, Yang | Li, Guojun | Liu, Ming | Liu, Xiuling

Article Type: Research Article

Abstract: Premature ventricular contraction (PVC) is one of the most serious arrhythmias. Without early diagnosis and proper treatment, PVC can result in significant complications. In this paper, a novel feature extraction method based on a sparse auto-encoder (SAE) and softmax regression (SR) classifier was used to differentiate PVCs from other common Non-PVC rhythms, including normal sinus (N), left bundle branch block (LBBB), right bundle branch block (RBBB), atrial premature contraction (APC), and paced beat (PB) rhythms. The proposed method was analyzed using 40 ECG records obtained from the MIT-BIH Arrhythmia Database. The proposed method exhibited an overall accuracy of 99.4%, with …a PVC recognition sensitivity and positive predictability of 97.9% and 91.8%, respectively. Show more

Keywords: PVC diagnosis, sparse auto-encoder, softmax regression, feature extraction

DOI: 10.3233/BME-151454

Citation: Bio-Medical Materials and Engineering, vol. 26, no. s1, pp. S1549-S1558, 2015

Authors: Wei, Chang-An | Dai, Huhe

Article Type: Research Article

Abstract: P wave and T wave in human-body electrocardiogram (ECG) signals often fuse together when atrial premature contract (APC) occurs. P waves within the fused signals are valuable for the measurement of P wave parameters as well as diagnosis of supra-ventricular arrhythmias. However, the problem of extracting P wave from the fused signals is seldom addressed. In this study, a novel T wave cancellation method for P wave extraction based on maximum a posteriori (MAP) estimation is proposed. In order to accurately cancel the T wave within the fused signal, T wave and the timing point of T wave peak are …estimated simultaneously. The estimated timing point of T wave peak is used as alignment reference point for T wave subtraction. Simulation results show that the proposed method outperform the traditional T wave cancellation method in terms of both normalized mean square error and cross-correlation index. The results for real ECGs with APC demonstrate that the extracted P waves using the proposed method are more similar to the non-overlapping P waves in terms of morphology than the ones using the traditional T wave cancellation method. Show more

Keywords: Electrocardiogram, P wave extraction, atrial premature contract, maximum a posteriori

DOI: 10.3233/BME-151455

Citation: Bio-Medical Materials and Engineering, vol. 26, no. s1, pp. S1559-S1568, 2015

Authors: Sánchez-González, Alain | García-Zapirain, Begoña | Maestro Saiz, Iratxe | Yurrebaso Santamaría, Izaskun

Article Type: Research Article

Abstract: Periodic activity in electroencephalography (PA-EEG) is shown as comprising a series of repetitive wave patterns that may appear in different cerebral regions and are due to many different pathologies. The diagnosis based on PA-EEG is an arduous task for experts in Clinical Neurophysiology, being mainly based on other clinical features of patients. Considering this difficulty in the diagnosis it is also very complicated to establish the prognosis of patients who present PA-EEG. The goal of this paper is to propose a method capable of determining patient prognosis based on characteristics of the PA-EEG activity. The approach, based on a parallel …classification architecture and a majority vote system has proven successful by obtaining a success rate of 81.94% in the classification of patient prognosis of our database. Show more

Keywords: Medical classification, bioinformatics, feature selection, EEG periodic activity

DOI: 10.3233/BME-151456

Citation: Bio-Medical Materials and Engineering, vol. 26, no. s1, pp. S1569-S1578, 2015

Authors: Li, Xu | Yang, Jiali | Ding, Mingyue | Yuchi, Ming

Article Type: Research Article

Abstract: Ultrasound (US) has emerged as a non-invasive imaging modality that can provide anatomical structure information in real time. To enable the experimental analysis of new 2-D array ultrasound beamforming methods, a pre-beamformed parallel raw data acquisition system was developed for 3-D data capture of 2D array transducer. The transducer interconnection adopted the row-column addressing (RCA) scheme, where the columns and rows were active in sequential for transmit and receive events, respectively. The DAQ system captured the raw data in parallel and the digitized data were fed through the field programmable gate array (FPGA) to implement the pre-beamforming. Finally, 3-D images …were reconstructed through the devised platform in real-time. Show more

Keywords: 2-D array transducer, 3-D imaging system, row-column scheme, real-time

DOI: 10.3233/BME-151457

Citation: Bio-Medical Materials and Engineering, vol. 26, no. s1, pp. S1579-S1585, 2015

Authors: Choi, Hyun Ho | Lee, Ju Hwan | Kim, Sung Min | Park, Sung Yun

Article Type: Research Article

Abstract: Here, the speckle noise in ultrasonic images is removed using an image fusion-based denoising method. To optimize the denoising performance, each discrete wavelet transform (DWT) and filtering technique was analyzed and compared. In addition, the performances were compared in order to derive the optimal input conditions. To evaluate the speckle noise removal performance, an image fusion algorithm was applied to the ultrasound images, and comparatively analyzed with the original image without the algorithm. As a result, applying DWT and filtering techniques caused information loss and noise characteristics, and did not represent the most significant noise reduction performance. Conversely, an image …fusion method applying SRAD-original conditions preserved the key information in the original image, and the speckle noise was removed. Based on such characteristics, the input conditions of SRAD-original had the best denoising performance with the ultrasound images. From this study, the best denoising technique proposed based on the results was confirmed to have a high potential for clinical application. Show more

Keywords: Ultrasound imaging, speckle noise, image fusion, discrete wavelet transform, SRAD

DOI: 10.3233/BME-151458

Citation: Bio-Medical Materials and Engineering, vol. 26, no. s1, pp. S1587-S1597, 2015

Authors: Hwang, Yoo Na | Lee, Ju Hwan | Kim, Ga Young | Jiang, Yuan Yuan | Kim, Sung Min

Article Type: Research Article

Abstract: This paper focuses on the improvement of the diagnostic accuracy of focal liver lesions by quantifying the key features of cysts, hemangiomas, and malignant lesions on ultrasound images. The focal liver lesions were divided into 29 cysts, 37 hemangiomas, and 33 malignancies. A total of 42 hybrid textural features that composed of 5 first order statistics, 18 gray level co-occurrence matrices, 18 Law’s, and echogenicity were extracted. A total of 29 key features that were selected by principal component analysis were used as a set of inputs for a feed-forward neural network. For each lesion, the performance of the diagnosis …was evaluated by using the positive predictive value, negative predictive value, sensitivity, specificity, and accuracy. The results of the experiment indicate that the proposed method exhibits great performance, a high diagnosis accuracy of over 96% among all focal liver lesion groups (cyst vs. hemangioma, cyst vs. malignant, and hemangioma vs. malignant) on ultrasound images. The accuracy was slightly increased when echogenicity was included in the optimal feature set. These results indicate that it is possible for the proposed method to be applied clinically. Show more

Keywords: Ultrasound, focal liver lesions, classification, artificial neural network

DOI: 10.3233/BME-151459

Citation: Bio-Medical Materials and Engineering, vol. 26, no. s1, pp. S1599-S1611, 2015

Authors: Aliabadi, Saeid | Yu, Jinhua | Wang, Yuanyuan

Article Type: Research Article

Abstract: The contrast and resolution have trade-off in medical ultrasound imaging. Most of adaptive beamformer can enhance the imaging resolution significantly but not improve the contrast at the same time. The principal component analysis (PCA) based beamformers such as the eigenspace-based minimum variance (ESBMV) beamformer provide a good imaging resolution. Neighbors of the focal point include the common noise, interface and signal components. Echo signal of the neighbor points can be used to suppress the noise and extract the signal component of the focal point. Based on this idea, in order to improve the quality of PCA based beamformers both in …the imaging contrast and resolution, a novel beamforming method is proposed. This proposed beamformer utilizes a kernel to select neighbor points. The number of eigenvectors is estimated by using any PCA method. Then the number of selected eigenvectors for each focal point is compared with the number of selected eigenvectors of its neighbor points and is changed to a new value. The selected eigenvectors of the covariance matrix is used to construct the signal subspace. The estimated signal subspace is projected onto the minimum variance (MV) weight vector to calculate the desire weight vector. Results of experiments show that the proposed beamformer can improve the imaging contrast significantly while keeping the resolution quality similar to ESBMV beamformer. Show more

Keywords: Ultrasound imaging, beamforming, minimum variance, eigenvalue

DOI: 10.3233/BME-151460

Citation: Bio-Medical Materials and Engineering, vol. 26, no. s1, pp. S1613-S1621, 2015

Authors: He, Xiaonian | Liu, Weixiang | Chen, Siping | Qin, Zhengdi

Article Type: Research Article

Abstract: In the field of ultrasonic imaging technology, the problem of geometric distortion is often encountered, especially in the ultrasonic near-field. In this study, a new approach is proposed to compensate for geometric distortion in the synthetic aperture ultrasonic imaging system. This approach is based on the synthetic aperture ultrasonic holographic B-scan (UHB) imaging system, which is a combination of ultrasonic holography based on the backward propagation principle and the conventional B-scan technique. To solve the geometric distortion problem, the operation of the spatial compression and resampling in the frequency domain are introduced. The main advantage of the approach is that …the real holographic value can be calculated without distortion by using the spatial interpolation function after the spatial frequency compression. After the compensation for geometric distortion is performed, the synthetic aperture technique based on the backward propagation principle is then applied in the process of the two-dimensional numerical imaging reconstruction. Both the simulation and measurement experiment show that the approach is promising. The geometric distortion that is dependent on the wave front angle can be effectively compensated. The spatial resolution is practically uniform throughout the depth range and close to the theoretical limit in the experiments. Show more

Keywords: Synthetic aperture ultrasonic imaging, geometric distortion, spatial compression, re-sampling, numerical imaging reconstruction

DOI: 10.3233/BME-151461

Citation: Bio-Medical Materials and Engineering, vol. 26, no. s1, pp. S1623-S1632, 2015

Authors: Zhang, Yaonan | Sun, Tingting | Teng, Yueyang | Li, Hong | Kang, Yan

Article Type: Research Article

Abstract: Myocardial elastography (ME) is a strain imaging technique used to diagnose myocardial diseases. Axial and lateral displacement calculations are pre-conditions of strain image acquisition in ME. W.N. Lee et al. proposed a normalized cross-correlation (NCC) and recorrelation method to obtain both axial and lateral displacements in ME. However, this method is not noise-resistant and of high computational cost. This paper proposes a predicted fast NCC algorithm based on W.N. Lee’s method, with the additions of sum-table NCC and a displacement prediction algorithm, to obtain efficient and accurate axial and lateral displacements. Compared to experiments based on the NCC and recorrelation …methods, the results indicate that the proposed NCC method is much faster (predicted fast NCC method, 69.75s for a 520×260 image; NCC and recorrelation method, 1092.25s for a 520×260 image) and demonstrates better performance in eliminating decorrelation noise (SNR of the axial and lateral strain using the proposed method, 5.87 and 1.25, respectively; SNR of the axial and lateral strain using the NCC and recorrelation method, 1.48 and 1.09, respectively). Show more

Keywords: Myocardial elastography (ME), displacement estimation, normalized cross-correlation, recorrelation, prediction

DOI: 10.3233/BME-151462

Citation: Bio-Medical Materials and Engineering, vol. 26, no. s1, pp. S1633-S1639, 2015

Authors: Chiang, Hsien-Wen | Liu, Ya-Ling | Chen, Tou-Rong | Chen, Chun-Lon | Chiang, Hsien-Jen | Chao, Shin-Yu

Article Type: Research Article

Abstract: This work aimed to investigate the spatial distribution of scattered radiation doses induced by exposure to the portable X-ray, the C-arm machine, and to simulate the radiologist without a shield of lead clothing, radiation doses absorbed by medical staff at 2 m from the central exposure point. Material and method: With the adoption of the Rando Phantom, several frequently X-rayed body parts were exposed to X-ray radiation, and the scattered radiation doses were measured by ionization chamber dosimeters at various angles from the patient. Assuming that the central point of the X-ray was located at the belly button, five detection …points were distributed in the operation room at 1 m above the ground and 1-2 m from the central point horizontally. Results: The radiation dose measured at point B was the lowest, and the scattered radiation dose absorbed by the prosthesis from the X-ray’s vertical projection was 0.07 ±0.03 μ Gy, which was less than the background radiation levels. The Fluke biomedical model 660-5DE (400 cc) and 660-3DE (4 cc) ion chambers were used to detect air dose at a distance of approximately two meters from the central point. The AP projection radiation doses at point B was the lowest (0.07±0.03 μ Gy) and the radiation doses at point D was the highest (0.26±0.08 μ Gy) .Only taking the vertical projection into account, the radiation doses at point B was the lowest (0.52 μ Gy), and the radiation doses at point E was the highest (4 μ Gy).The PA projection radiation at point B was the lowest (0.36 μ Gy) and the radiation doses at point E was the highest(2.77 μ Gy), occupying 10-32% of the maximum doses. The maximum dose in five directions was nine times to the minimum dose. When the PX and the C-arm machine were used, the radiation doses at a distance of 2 m were attenuated to the background radiation level. The radiologist without a lead shield should stand at point B of patient’s feet. Accordingly, teaching materials on radiation safety for radiological interns and clinical technicians were formulated. Show more

Keywords: Portable X-ray machine, dose, exposure, ionization chamber dosimeter

DOI: 10.3233/BME-151463

Citation: Bio-Medical Materials and Engineering, vol. 26, no. s1, pp. S1641-S1650, 2015

Authors: Pan, Lung Fa | Erdene, Erdenetsetseg | Chen, Chun Chi | Pan, Lung Kwang

Article Type: Research Article

Abstract: In this study, the phantom imaging quality of 64-slice CT acquisition protocol was quantitatively evaluated using Taguchi. The phantom acrylic line group was designed and assembled with multiple layers of solid water plate in order to imitate the adult abdomen, and scanned with Philips brilliance CT in order to simulate a clinical examination. According to the Taguchi L8 (27 ) orthogonal array, four major factors of the acquisition protocol were optimized, including (A) CT slice thickness, (B) the image reconstruction filter type, (C) the spiral CT pitch, and (D) the matrix size. The reconstructed line group phantom image was counted …by four radiologists for three discrete rounds in order to obtain the averages and standard deviations of the line counts and the corresponding signal to noise ratios (S/N). The quantified S/N values were analyzed and the optimal combination of the four factor settings was determined to be comprised of (A) a 1-mm thickness, (B) a sharp filter type, (C) a 1.172 spiral CT pitch, and (D) a 1024×1024 matrix size. The dominant factors included the (A) filter type and the cross interaction between the filter type and CT slice thickness (A×B). The minor factors were determined to be (C) the spiral CT pitch and (D) the matrix size since neither was capable of yielding a 95% confidence level in the ANOVA test. Show more

Keywords: 64-slice CT, reconstructed imaging, optimization, ANOVA, line phantom

DOI: 10.3233/BME-151464

Citation: Bio-Medical Materials and Engineering, vol. 26, no. s1, pp. S1651-S1658, 2015

Authors: Liao, Xiongfei | Wang, Yunlai | Lang, Jinyi | Wang, Pei | Li, Jie | Ge, Ruigang | Yang, Jack

Article Type: Research Article

Abstract: To evaluate the Elekta kilovoltage CBCT doses and the associated technical protocols with patient dosimetry estimation. Image guidance technique with cone-beam CT (CBCT) in radiation oncology on a daily basis can deliver a significant dose to the patient. To evaluate the patient dose from LINAC-integrated kV cone beam CT imaging in image-guided radiotherapy. CT dose index (CTDI) were measured with PTW TM30009 CT ion chamber in air, in head phantom and body phantom, respectively; with different combinations of tube voltage, current, exposure time per frame, collimator and gantry rotation range. Dose length products (DLP) were subsequently calculated to account for …volume integration effects. The CTDI and DLP were also compared to AcQSim™ simulator CT for routine clinical protocols. Both CTDIair and CTDIw depended quadratically on the voltage, while linearly on milliampere x seconds (mAs) settings. It was shown that CTDIw and DLP had very close relationship with the collimator settings and the gantry rotation ranges. Normalized CTDIw for Elekta XVI™ CBCT was lower than that of ACQSim simulator CT owing to its pulsed radiation output characteristics. CTDIw can be used to assess the patient dose in CBCT due to its simplicity for measurement and reproducibility. Regular measurement should be performed in QA & QC program. Optimal image parameters should be chosen to reduce patient dose during CBCT. Show more

Keywords: Cone-beam CT, CT dose index, dose-length product, image-guided radiotherapy

DOI: 10.3233/BME-151465

Citation: Bio-Medical Materials and Engineering, vol. 26, no. s1, pp. S1659-S1667, 2015

Authors: Park, S.I. | Lee, J.H. | Ham, H.J. | Jung, Y.J. | Park, M.S. | Lee, J. | Maeng, L.S. | Chung, Y.A. | Jang, K.S.

Article Type: Research Article

Abstract: Liver cirrhosis is a predominant risk factor for hepatocellular carcinoma (HCC). However, the exact mechanism of the progression from cirrhosis to cancer remains unclear. The uptake of 2-[18 F]-fluoro-2-deoxy-D-glucose (18 F-FDG) is widely used as a marker of increased glucose metabolism to monitor the progression of cancer with positron emission tomography (PET)/computed tomography (CT). Here we investigated the feasibility of using 18 F-FDG PET/CT in the diethylnitrosamine (DEN) mediated experimental hepatocellular carcinoma model. Rats received weekly intraperitoneal injections of DEN for 16 weeks for induction of HCC. We recorded starting from 0 days or 0 weeks after the last DEN …injection. The weight and survival rate of rats were then measured. Also, an 18 F-FDG PET scan and serum analysis were performed at minus 2, 0, plus 2, and plus 4 weeks after the last DEN injection. The body weight of rats was maintained between 350 g and 370 g during 14 and 20 weeks, and the rats were euthanized at 35 days after the last DEN injection. The serum levels of alanine transaminase (ALT), aspartate transaminase (AST), and alkaline phosphate (ALP) were significantly higher at zero weeks after the last DEN injection. The 18 F-FDG uptake for the quantitative evaluation of HCC was done by measuring the region of interest (ROI). At minus two weeks after the last DEN injection, the ROI of rats had significantly increased compared to the normal group, in a time-dependent manner. These results suggest that FDG uptake serves as a good screening test to evaluate the feasibility of DEN-induced HCC. Show more

Keywords: Hepatocellular carcinoma, PET/CT, 18F-FDG

DOI: 10.3233/BME-151466

Citation: Bio-Medical Materials and Engineering, vol. 26, no. s1, pp. S1669-S1676, 2015

Authors: Tseng, Hsien-Chun | Pan, Lung-Kang | Chen, Hsin-Yu | Liu, Wen-Shan | Hsu, Chang-Chieh | Chen, Chien-Yi

Article Type: Research Article

Abstract: This study is the first to use 10- to 90-kg tissue-equivalent phantoms as patient surrogates to measure peripheral skin doses (Dskin ) in lung cancer treatment through Volumetric Modulated Arc Therapy of the Axesse linac. Five tissue-equivalent and Rando phantoms were used to simulate lung cancer patients using the thermoluminescent dosimetry (TLD-100H) approach. TLD-100H was calibrated using 6 MV photons coming from the Axesse linac. Then it was inserted into phantom positions that closely corresponded with the position of the represented organs and tissues. TLDs were measured using the Harshaw 3500 TLD reader. The ICRP 60 evaluated the mean Dskin …to the lung cancer for 1 fraction (7 Gy) undergoing VMAT. The Dskin of these phantoms ranged from 0.51±0.08 (10-kg) to 0.22±0.03 (90-kg) mSv/Gy. Each experiment examined the relationship between the Dskin and the distance from the treatment field. These revealed strong variations in positions close to the tumor center. The correlation between Dskin and body weight was Dskin (mSv) = -0.0034x + 0.5296, where x was phantom’s weight in kg. R2 is equal to 0.9788. This equation can be used to derive an equation for lung cancer in males. Finally, the results are compared to other published research. These findings are pertinent to patients, physicians, radiologists, and the public. Show more

Keywords: Axesse linac, skin dose, TLD, tissue-equivalent phantom, ICRP 60

DOI: 10.3233/BME-151467

Citation: Bio-Medical Materials and Engineering, vol. 26, no. s1, pp. S1677-S1683, 2015

Authors: Deng, Luzhen | Mi, Deling | He, Peng | Feng, Peng | Yu, Pengwei | Chen, Mianyi | Li, Zhichao | Wang, Jian | Wei, Biao

Article Type: Research Article

Abstract: For lack of directivity in Total Variation (TV) which only uses x-coordinate and y-coordinate gradient transform as its sparse representation approach during the iteration process, this paper brought in Adaptive-weighted Diagonal Total Variation (AwDTV) that uses the diagonal direction gradient to constraint reconstructed image and adds associated weights which are expressed as an exponential function and can be adaptively adjusted by the local image-intensity diagonal gradient for the purpose of preserving the edge details, then using the steepest descent method to solve the optimization problem. Finally, we did two sets of numerical simulation and the results show that the proposed …algorithm can reconstruct high-quality CT images from few-views projection, which has lower Root Mean Square Error (RMSE) and higher Universal Quality Index (UQI) than Algebraic Reconstruction Technique (ART) and TV-based reconstruction method. Show more

Keywords: Computed tomography (CT), sparse projection, adaptive-weighted diagonal total variation (AwDTV), compressive sensing (CS)

DOI: 10.3233/BME-151468

Citation: Bio-Medical Materials and Engineering, vol. 26, no. s1, pp. S1685-S1693, 2015

Authors: Ran, Peng | Xiao, Xiaoming | He, Wei | Li, Zhangyong

Article Type: Research Article

Abstract: Because of the need for rapid detection and location of diseases in clinical applications, this work proposes a composite measurement of magnetic induction tomography (MIT) and electrical impedance tomography (EIT). This paper is composed of the following aspects: portable and integral hardware design, stable dual constant-current sources, the composite detection method, cross-plane data acquirement, 3-dimensional image reconstruction and so on. A qualitative evaluation of conductivity, resolution and relative position error were taken by combining the EIT and MIT methods via the experiment model. The sensitivities of both methods were analyzed to improve the imaging results. The reconstruction results reveal that …the system is capable of obtaining better physiological measurements, which is very useful in clinical monitoring, quick medical diagnosing and preliminary screening of community health. Show more

Keywords: Bioelectrical impedance measurement, magnetic induction tomography, cross evaluation and imaging, 3-dimensional image

DOI: 10.3233/BME-151469

Citation: Bio-Medical Materials and Engineering, vol. 26, no. s1, pp. S1695-S1702, 2015

Authors: Avcı, Cafer | Akbaş, Ahmet

Article Type: Research Article

Abstract: In this study, an efficient and robust method classifying the minute based occurrence of sleep apnea is aimed. Three respiration signals obtained from abdominal, chest and nasal way extracted from polysomnography recordings. Wavelet transform based on feature extraction methods are applied on the 1 minute length respiration signals. Dimension reduction process is facilitated by using principal component analysis. The features obtained from 8 recordings are used for the classification sleep apnea by using three ensemble classifiers. According to the results, the classification accuracies have been obtained between 92.07-98.43%, 92.75-98.68% and 92.42-98.61% by using three different ensemble classifier based on abdominal, …chest and nasal based analysis, respectively for AdaBoost, Random Forest and Random Subspace. However the best result is obtained analyzing nasal based respiratory signal by using Random Forest method. In this case accuracy is 98.68%. Show more

Keywords: Sleep apnea, respiratory signals, wavelet, ensemble, boosting, bagging

DOI: 10.3233/BME-151470

Citation: Bio-Medical Materials and Engineering, vol. 26, no. s1, pp. S1703-S1710, 2015

Authors: Lu, Qibing | Wang, Pan | Guo, Sihai | Sheng, Buyun | Liu, Xingxing | Fan, Zhun

Article Type: Research Article

Abstract: This paper introduces an automatic bond graph design method based on genetic programming for the evolutionary design of micro-resonator. First, the system-level behavioral model is discussed, which based on genetic programming and bond graph. Then, the geometry parameters of components are automatically optimized, by using the genetic algorithm with constraints. To illustrate this approach, a typical device micro-resonator is designed as an example in biomedicine. This paper provides a new idea for the automatic optimization design of biomedical sensors by evolutionary calculation.

Keywords: Genetic programming (GP), bond graph (BG), micro-resonator, evolutionary computation

DOI: 10.3233/BME-151471

Citation: Bio-Medical Materials and Engineering, vol. 26, no. s1, pp. S1711-S1719, 2015

Authors: Shi, Yu | Yan, Guozheng | Zhu, Bingquan | Liu, Gang

Article Type: Research Article

Abstract: Wireless power transmission (WPT) technology can solve the energy shortage problem of the video capsule endoscope (VCE) powered by button batteries, but the fixed platform limited its clinical application. This paper presents a portable WPT system for VCE. Besides portability, power transfer efficiency and stability are considered as the main indexes of optimization design of the system, which consists of the transmitting coil structure, portable control box, operating frequency, magnetic core and winding of receiving coil. Upon the above principles, the correlation parameters are measured, compared and chosen. Finally, through experiments on the platform, the methods are tested and evaluated. …In the gastrointestinal tract of small pig, the VCE is supplied with sufficient energy by the WPT system, and the energy conversion efficiency is 2.8%. The video obtained is clear with a resolution of 320×240 and a frame rate of 30 frames per second. The experiments verify the feasibility of design scheme, and further improvement direction is discussed. Show more

Keywords: Portable wireless power transmission, video capsule endoscope, resonant circuit, frequency stability

DOI: 10.3233/BME-151472

Citation: Bio-Medical Materials and Engineering, vol. 26, no. s1, pp. S1721-S1730, 2015

Authors: Jia, Guifeng | Yang, Pan | Zhou, Jie | Zhang, Hengyi | Lin, Chengyu | Chen, Jin | Cai, Guolong | Yan, Jing | Ning, Gangmin

Article Type: Research Article

Abstract: Mobile health (mHealth) technology has been proposed to alleviate the lack of sufficient medical resources for personal healthcare. However, usage difficulties and compliance issues relating to this technology restrict the effect of mHealth system-supported self-management. In this study, an mHealth framework is introduced to overcome these drawbacks and improve the outcome of self-management. We implemented a set of ease of use principles in the mHealth design and employed the quantitative Fogg Behavior Model to enhance users’ execution ability. The framework was realized in a prototype design for the mHealth system, which consists of medical apparatuses, mobile applications and a health …management server. The system is able to monitor the physiological status in an unconstrained manner with simplified operations, while supervising the healthcare plan. The results suggest that the present framework design is accessible for ordinary users and effective in improving users’ execution ability in self-management. Show more

Keywords: Self-management, mobile health, execution ability, ease of use, persuasive technology

DOI: 10.3233/BME-151473

Citation: Bio-Medical Materials and Engineering, vol. 26, no. s1, pp. S1731-S1740, 2015

Authors: Lim, Hyung-Gyu | Kim, Jong Hoon | Shin, Dong Ho | Woo, Seong Tak | Seong, Ki Woong | Lee, Jyung Hyun | Kim, Myoung Nam | Wei, Qun | Cho, Jin-Ho

Article Type: Research Article

Abstract: Many types of fully implantable hearing aids have been developed. Most of these devices are implanted behind the ear. To maintain the implanted device for a long period of time, a rechargeable battery and wireless power transmission are used. Because inductive coupling is the most renowned method for wireless power transmission, many types of fully implantable hearing aids are transcutaneously powered using inductively coupled coils. Some patients with an implantable hearing aid require a method for conveniently charging their hearing aid while they are resting or sleeping. To address this need, a wireless charging pillow has been developed that employs …a circular array coil as one of its primary parts. In this device, all primary coils are simultaneously driven to maintain an effective charging area regardless of head motion. In this case, however, there may be a magnetic weak zone that cannot be charged at the specific secondary coil’s location on the array coil. In this study, assuming that a maximum charging distance is 4 cm, a circular array coil—serving as a primary part of the charging pillow—was designed using finite element analysis. Based on experimental results, the proposed device can charge an implantable hearing aid without a magnetic weak zone within 4 cm of the perpendicular distance between the primary and secondary coils. Show more

Keywords: Wireless charging pillow, fully implantable hearing aid, inductive coupling, circular array coil, magnetic weak zone

DOI: 10.3233/BME-151474

Citation: Bio-Medical Materials and Engineering, vol. 26, no. s1, pp. S1741-S1747, 2015

Authors: Nguyen, Tan Loc | Won, Yonggwan

Article Type: Research Article

Abstract: Snoring detection is important for diagnosing obstructive sleep apnea syndrome (OSAS) and other respiratory sleep disorders. In general, audio signal processing such as snoring sound analysis uses the frequency characteristics of the signal. Recently, a correlational filter Multilayer Perceptron neural network (f-MLP) has been proposed, which has the first hidden layer of correlational filter operations in frequency domain. It demonstrated a superior classification performance for the pattern sets; of these, frequency information is the dominant feature for classification. The first hidden layer is implemented with the correlational filter operation; its output is the power spectrum of the filter output, while …the other layers are the same as the ordinary multilayer Perceptron (o-MLP). By using the back-propagation learning algorithm for the correlational filter layer, f-MLP was able to self-adapt the filter coefficients to produce its output with more discrimination power for classification in the higher layer. In this research, this f-MLP was applied for sleep snoring signal detection. As a result, the f-MLP achieved an average detection rate of 96% for the test patterns, compared to the conventional multilayer neural network that demonstrates an 82% average detection rate. Show more

Keywords: Sleep snoring, Fourier transform, correlational filter, classification, multilayer perceptron neural network

DOI: 10.3233/BME-151475

Citation: Bio-Medical Materials and Engineering, vol. 26, no. s1, pp. S1749-S1755, 2015

Authors: Zhou, Xi Y. | Tian, Xue W. | Lim, Joon S.

Article Type: Research Article

Abstract: In the data mining field, classification is a very crucial technology, and the Bayesian classifier has been one of the hotspots in classification research area. However, assumptions of Naive Bayesian and Tree Augmented Naive Bayesian (TAN) are unfair to attribute relations. Therefore, this paper proposes a new algorithm named Fuzzy Naive Bayesian (FNB) using neural network with weighted membership function (NEWFM) to extract regulated relations and weights. Then, we can use regulated relations and weights to construct a regulated network. Finally, we will classify the heart and Haberman datasets by the FNB network to compare with experiments of Naive Bayesian …and TAN. The experiment results show that the FNB has a higher classification rate than Naive Bayesian and TAN. Show more

Keywords: Naive Bayesian, Tree Augmented Naive Bayesian, Fuzzy Naive Bayesian, fuzzy neural network, weights

DOI: 10.3233/BME-151476

Citation: Bio-Medical Materials and Engineering, vol. 26, no. s1, pp. S1757-S1762, 2015

Authors: Ha, Jihwan | Kim, Hyunjin | Yoon, Youngmi | Park, Sanghyun

Article Type: Research Article

Abstract: MicroRNAs (miRNA) are known to be involved in the development of various diseases. Hence various scientists in the field have been utilized computational analyses to determine the relationship between miRNA and diseases. However, the knowledge of miRNA and disease is still very limited. Therefore, we combined Environmental Factor (EF) data to a miRNA global network. Increasing research has shown that relationship between miRNAs and EFs play a significant role in classifying types of diseases. Environmental Factors consist of radiation, drugs, viruses, alcohol, cigarettes, and stress. Our global network considered all the interactions between every pair of miRNAs, which has led …to precise analyses in comparison to local networks. As a result, our approaches’ performance demonstrated its effectiveness in identifying disease-related miRNA and this is the area under the ROC curve (AUC) of 74.46%. Furthermore, comparative experiment has shown that our approach performs comparable to other existing methods with an accuracy of 94%, 90% and 96% for breast cancer, colonic cancer, and lung cancer respectively. In conclusion, these results support that our research has broadened new biological insights on identifying disease-related miRNAs. Show more

Keywords: miRNA, disease, environmental factor, network, propagation algorithm

DOI: 10.3233/BME-151477

Citation: Bio-Medical Materials and Engineering, vol. 26, no. s1, pp. S1763-S1772, 2015

Authors: Kim, Ji-Sun | Kim, A-Hee | Oh, Han-Byeol | Goh, Bong-Jun | Lee, Eun-Suk | Kim, Jun-Sik | Jung, Gu-In | Baek, Jin-Young | Jun, Jae-Hoon

Article Type: Research Article

Abstract: A spectrophotometer is the basic measuring equipment essential to most research activity fields requiring samples to be measured, such as physics, biotechnology and food engineering. This paper proposes a system that is able to detect sample concentration and color information by using LED and color sensor. Purity and wavelength information can be detected by CIE diagram, and the concentration can be estimated with purity information. This method is more economical and efficient than existing spectrophotometry, and can also be used by ordinary persons. This contribution is applicable to a number of fields because it can be used as a colorimeter …to detect the wavelength and purity of samples. Show more

Keywords: Color information, color space, light emitting diode, spectrophotometer

DOI: 10.3233/BME-151478

Citation: Bio-Medical Materials and Engineering, vol. 26, no. s1, pp. S1773-S1780, 2015

Authors: Manzoor, Umar | Shahid, Sarosh | Zafar, Bassam

Article Type: Research Article

Abstract: Multiple sequence alignment plays a key role in the computational analysis of biological data. Different programs are developed to analyze the sequence similarity. This paper highlights the algorithmic techniques of the most popular multiple sequence alignment programs. These programs are then evaluated on the basis of execution time and scalability. The overall performance of these programs is assessed to highlight their strengths and weaknesses with reference to their algorithmic techniques. In terms of overall alignment quality, T-Coffee and Mafft attain the highest average scores, whereas K-align has the minimum computation time.

Keywords: Multiple sequence alignment, clustalW, k-align, muscle, mafft, t-coffee, progressive alignment

DOI: 10.3233/BME-151479

Citation: Bio-Medical Materials and Engineering, vol. 26, no. s1, pp. S1781-S1789, 2015

Authors: Jo, Heeseung | Koh, Gunhwan

Article Type: Research Article

Abstract: Due to next-generation sequencing (NGS) technology, genome sequencing is able to process much more data at low cost. In NGS data analysis, the mapping of sequences into a reference genome takes the largest amount of time to process. Although the Burrows-Wheeler Aligner (BWA) tool is one of the most widely used open-source software tools to align read sequences, it is still limited in that it does not fully support multi-thread mechanisms during the alignment steps. In this paper, we propose a BWA-MT tool, evolved from BWA but supporting multi-thread computation, designed to fully utilize the underlying multi-core architecture of computing …resources. By using multi-thread computation, BWA-MT can significantly shorten the time needed to generate an alignment for single-end read sequences. Meanwhile, it generates an identical Sequence Alignment Map (SAM) result file as BWA. To evaluate BWA-MT, we use an evaluation system equipped with twelve cores and 32 GB memory. As a workload, we used the hg19 human genome reference sequence and various numbers of read sequences from 1M to 40M. In our evaluation, BWA-MT displays up to 3.7 times faster performance and generates an identical SAM result file to BWA. Although the increased speed might be dependent on computing resources, we confirm that BWA-MT is highly efficient and effective. Show more

Keywords: genome sequencing, next-generation sequencing (NGS), burrow-wheeler aligner (BWA) tool, multi-thread

DOI: 10.3233/BME-151480

Citation: Bio-Medical Materials and Engineering, vol. 26, no. s1, pp. S1791-S1796, 2015

Authors: Song, Dandan | Li, Ning | Liao, Lejian

Article Type: Research Article

Abstract: Due to the generation of enormous amounts of data at both lower costs as well as in shorter times, whole-exome sequencing technologies provide dramatic opportunities for identifying disease genes implicated in Mendelian disorders. Since upwards of thousands genomic variants can be sequenced in each exome, it is challenging to filter pathogenic variants in protein coding regions and reduce the number of missing true variants. Therefore, an automatic and efficient pipeline for finding disease variants in Mendelian disorders is designed by exploiting a combination of variants filtering steps to analyze the family-based exome sequencing approach. Recent studies on the Freeman-Sheldon disease …are revisited and show that the proposed method outperforms other existing candidate gene identification methods. Show more

Keywords: Mendelian disorders, disease gene identification, whole-exome sequencing

DOI: 10.3233/BME-151481

Citation: Bio-Medical Materials and Engineering, vol. 26, no. s1, pp. S1797-S1803, 2015