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Baseline drift of electrocardiograph dealt with mathematical morphology filter in real-time.

Xianglin ZHU ; Jianning YANG ; Ping TANG ; Xin LING

Journal of Biomedical Engineering.2010;27(1):48-52.

We have done a research on mathematical morphology filter in order to eliminate baseline drift in the wave of electrocardiograph (ECG). Marago morphology filter type was chosen and flat structuring element filtering was found to be the best morphology filter modality for eliminating baseline drift, and the ratio of "signal numerical frequency to length of structuring element" determined the attenuation magnitude of the signal eliminated. We have come to the conclusion that the length of flat structuring element ought to be greater than or equal to the width of the signal component to be eliminated. The arithmetical algorithm was simulated with Matlab software, and was transplanted to DSP hardware platform. The result of experiment has shown that the arithmetic operation is simple and the method spends a short time (less than 1 ms) in eliminating the baseline drift of ECG effectively and instantly.
Algorithms ; Artifacts ; Electrocardiography ; instrumentation ; methods ; Equipment Design ; Humans ; Signal Processing, Computer-Assisted

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Research on control technology of functional electrical stimulation in wrist movements based on Hammerstein model.

Tengynan QIN ; Li CAO ; Kaiyu TONG

Journal of Biomedical Engineering.2010;27(1):42-47.

For most of nonlinear systems, control strategy is complicated. The adaptive control methods based on the model identification can effectively improve the control precision and stability. According to the nonlinear and time-changeable characteristics of the wrist movement in the functional electrical stimulation, modeling and identification of wrist movement based on Hammerstein model were implemented. By using M sequence and invert-repeated M sequence as excitation signal, the wrist model is divided into the linear dynamic part and the nonlinear static part. The characteristics of nonlinear part being taken into consideration, an adaptive control method based on time-changeable characteristics of linear part is presented. This method simplifies the control strategy, and it is validated by the simulation experiment of FES.
Computer Simulation ; Electric Stimulation ; methods ; Female ; Humans ; Male ; Models, Neurological ; Movement ; Movement Disorders ; physiopathology ; rehabilitation ; Nonlinear Dynamics ; Recovery of Function ; Wrist Joint ; physiopathology

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A comprehensive application research of multi b value diffusion weighted imaging.

Zhengyong LEI ; Li ZHU ; Weijun TANG ; Xiaoyuan FENG

Journal of Biomedical Engineering.2010;27(1):37-41.

This research introduces a new method to analyze the diffusion information of human brain. By use of the multi b value diffusion data and a new algorithm, a new diffusion parameter (Rd) was computed, and a new image was reconstructed. Through quantitative research on the brains of 25 normal adults, the new method can improve the signal-to-noise ratio (SNR) apparently and distinguish the different brain tissues effectively, compared to the apparent diffusion coefficient. The new method can improve the sensitivity to diffusion.
Adult ; Algorithms ; Brain ; anatomy & histology ; physiology ; Diffusion Magnetic Resonance Imaging ; methods ; Female ; Humans ; Image Processing, Computer-Assisted ; Male ; Middle Aged ; Sensitivity and Specificity

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Fetal electrocardiogram extraction based on nonlinear time series analysis.

Chen WANG ; Mingrong REN ; Pu WANG ; Shizhong FAN

Journal of Biomedical Engineering.2010;27(1):33-41.

This paper reports the applications of a local non-linear projection technique to extract the fetal component in single-lead recordings from the abdomen of a pregnant woman. We propose the general planning, and then we determine and illustrate four important parameters in the algorithm. The results of experiments show that the method is effective for separating the fetal ECG from the maternal trace and from the other contaminations.
Algorithms ; Electrocardiography ; methods ; Female ; Fetal Heart ; physiology ; Humans ; Nonlinear Dynamics ; Pregnancy ; Signal Processing, Computer-Assisted

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Experimental study of temperature sensor in temperature-guided radiofrequency catheter ablation.

Yundong HUANG ; Xuelian GU

Journal of Biomedical Engineering.2010;27(1):28-32.

In order to optimize temperature monitoring, the mean of temperature measured by Copper-CuNi thermocouple (TC) was compared with the actual temperature. By the use of the temperature response curve of TC, the data from monitoring temperature were analyzed in regard to the depth of installation, the diameter of TC hole and the material of ablation electrode. The accuracy and real-time of TC with a depth of 3.5 mm were better than those of 2.5 mm or 3 mm, when TC was installed in the ablation electrode TC hole. However, the difference of real-time performance was not obvious. When TC was installed in different TC holes with diameter of 0.44 mm, 0.42 mm, 0.33 mm respectively, TC with the diameter of 0.33 mm TC hole was noted to be of higher accuracy and better real-time to response temperature, compared with others. In terms of material quality, the slope of platinum temperature response curve was greater than that of stainless steel, while the accuracy of sensor temperature changed inconspicuously. As a result, the monitoring device of temperature should be put to the heat source as nearly as possible. Also, platinum ablation electrode with better thermal conductivity should be chosen.
Catheter Ablation ; instrumentation ; methods ; Electrodes ; Equipment Design ; Humans ; Platinum ; Temperature

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Detection of ventricular tachycardia and ventricular fibrillation based on joint entropy.

Jie CHEN ; Jun WANG

Journal of Biomedical Engineering.2010;27(1):24-27.

This is a research with the aim of using joint entropy method to analyze the dynamical complexity information on the electrocardiogram signals recording of normal sinus rhythm (NSR), ventricular tachycardia (VT) and ventricular fibrillation (VF). We included the symbolic dynamical theory and surrogate data concept in it. By calculating the joint entropy between original and surrogate time series, we quantified the dynamical complexity of original series. By computer analysis of actual heartbeat rhythm data, the rationality of joint entropy method was confirmed. The results indicated that the joint entropy values of different signals can be of use in distinguishing the NSR, VT and VF signals.
Diagnosis, Differential ; Electrocardiography ; Entropy ; Humans ; Signal Processing, Computer-Assisted ; Tachycardia, Ventricular ; diagnosis ; physiopathology ; Ventricular Fibrillation ; diagnosis ; physiopathology

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An algorithm for quick fitting of linear approximation distance thresholding.

Li TANG ; Zhiwen MO

Journal of Biomedical Engineering.2010;27(1):20-23.

In this paper is proposed a new method that approximates line segment with angle to control line as a basis for improving radial fitting. Experiments on selected records from the Massachusettes Institute of Technology and Boston's Beth Isral Hospital (MIT-BIH) arrhythmia database have revealed that the improved algorithm not only increases computation quantity, but also improves approximating quality and potentiates Real-time application of the linear approximation distance thresholding (LADT).
Algorithms ; Data Compression ; Electrocardiography ; methods ; Humans ; Signal Processing, Computer-Assisted

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Brain functions in major depressive disorder: a resting-state functional magnetic resonance imaging study.

Dongming LI ; Xiaoqi HUANG ; Qizhu WU ; Keo ZOU ; Xueli SUN ; Qiyong GONG

Journal of Biomedical Engineering.2010;27(1):16-19.

This study sought to reveal the difference in resting-state brain functions between subjects with major depressive disorder and normal controls. Fifty-three depressed patients diagnosed with DSM-IV and 38 normal controls underwent resting-state functional magnetic resonance imaging (fMRI), and the data were analyzed using a new method called Regional Homogeneity (ReHo). Then voxel wised comparison was made to derive the resting-state brain function differences between groups. Compared with normal controls, depressed subjects showed decreased ReHo in bilateral anterior cingulate cortex (ACC), left medial frontal gyrus, and left middle temporal gyrus. Significant decreased ReHo in ACC might suggest less spontaneous neuronal activities or lower baseline brain activities of ACC in depressed subjects in comparison with normal controls.
Adult ; Brain ; physiopathology ; Case-Control Studies ; Depressive Disorder, Major ; physiopathology ; Female ; Gyrus Cinguli ; physiopathology ; Humans ; Magnetic Resonance Imaging ; methods ; Male ; Middle Aged ; Young Adult

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Study based on ICA of "dorsal attention network" in patients with temporal lobe epilepsy.

Zhigen YANG ; Huinan WANG ; Zhiqiang ZHANG ; Yuan ZHONG ; Zhili CHEN ; Guangming LU

Journal of Biomedical Engineering.2010;27(1):10-15.

Many functional magnetic resonance imaging (fMRI) studies have revealed the deactivation phenomenon of default mode network in the patients with epilepsy; however, nearly not any of the reports has focused on the dorsal attention network of epilepsy. In this paper, independent component analysis (ICA) was used to isolate the dorsal attention network of 16 patients with temporal lobe epilepsy (TLE) and of 20 healthy normals; and a goodness-of-fit analysis was applied at the individual subject level to choose the interesting component. Intra-group analysis and inter-group analysis were performed. The results indicated that the dorsal attention network included bilateral intraparietal sulcus, middle frontal gyrus, human frontal eye field, posterior lobe of right cerebellum, etc. The TLE group showed decreased functional connectivity in most of the dorsal attention regions with the predominance in the bilateral intraparietal sulcus, middle frontal gyrus, and posterior lobe of right cerebellum. These data suggested that the intrinsic organization of the brain function might be disrupted in TLE. In addition, the decrease of goodness-of-fit scores suggests that activity in the dorsal attention network may ultimately prove a sensitive biomarker for TLE.
Adolescent ; Adult ; Attention ; physiology ; Attention Deficit and Disruptive Behavior Disorders ; etiology ; physiopathology ; Brain Mapping ; Epilepsy, Temporal Lobe ; pathology ; physiopathology ; psychology ; Female ; Humans ; Image Interpretation, Computer-Assisted ; Image Processing, Computer-Assisted ; methods ; Magnetic Resonance Imaging ; methods ; Male ; Nerve Net ; physiopathology ; Principal Component Analysis ; methods ; Young Adult

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Spine disc MR image analysis using improved independent component analysis based active appearance model and Markov random field.

Shijie HAO ; Shu ZHAN ; Jianguo JIANG ; Hong LI ; Rosse IAN

Journal of Biomedical Engineering.2010;27(1):6-15.

As there are not many research reports on segmentation and quantitative analysis of soft tissues in lumbar medical images, this paper presents an algorithm for segmenting and quantitatively analyzing discs in lumbar Magnetic Resonance Imaging (MRI). Vertebrae are first segmented using improved Independent component analysis based active appearance model (ICA-AAM), and lumbar curve is obtained with Minimum Description Length (MDL); based on these results, fast and unsupervised Markov Random Field (MRF) disc segmentation combining disc imaging features and intensity profile is further achieved; finally, disc herniation is quantitatively evaluated. The experiment proves that the proposed algorithm is fast and effective, thus providing doctors with aid in diagnosing and curing lumbar disc herniation.
Algorithms ; Humans ; Image Interpretation, Computer-Assisted ; methods ; Intervertebral Disc ; pathology ; Intervertebral Disc Displacement ; diagnosis ; pathology ; Lumbar Vertebrae ; pathology ; Magnetic Resonance Imaging ; Markov Chains

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