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Relationship between age and the energy density distribution of fundamental and harmonic frequency component in electrocardiogram energy spectrum.

Dianzhong ZHANG ; Xiaohong TAN

Journal of Biomedical Engineering.2005;22(6):1144-1147.

In a least square method, an exponential function fits the energy density distribution of fundamental and harmonic frequency component in a long-term ECG energy spectrum. A distributing index of the function was used to quantify divergence and convergence degree of energy density. The function fits locally the ECG energy spectrum data that were collected from the young (21-34 yr) group and elderly (68-81 yr) group rigorously energy density ratio of the harmonic to fundamental frequency component and recognizability number of harmonic frequency component were significantly less in the young group than in the elderly group (P < 0.01), the center frequency f0 and energy density at center frequency f0 did not differ between the two age groups. These data indicate that the characteristic parameter values presented in this study can serve as a new measurement of heart rate fluctuations.
Age Factors ; Electrocardiography ; methods ; Heart Rate ; physiology ; Humans ; Principal Component Analysis ; Signal Processing, Computer-Assisted

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Study on technique of thermal imaging and soft-sensing.

Jinghui QU ; Qimei LIAO ; Xing ZHANG

Journal of Biomedical Engineering.2005;22(6):1140-1143.

The differences of body surface temperature reflect the changes of the status of body tissues. In this regard, detecting and forecasting the changes of the surface temperature is the objective of the technique of medical thermal diagnosis, and how to diagnose the disease earlier with the use of thermal images is a common problem in the field of medical diagnostics and biological engineering. The authors put forward that utilizing the soft-sensing techniques in the field of engineering will be a good solution.
Body Temperature ; Diagnosis, Computer-Assisted ; Humans ; Image Interpretation, Computer-Assisted ; methods ; Infrared Rays ; Neural Networks (Computer) ; Skin Temperature ; Thermography ; methods

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Study of fluoroscopic triggering technique in 3D-dynamic contrast enhancement magnetic resonance angiography.

Ling TAO ; Huinan WANG ; Zhiliang TIAN

Journal of Biomedical Engineering.2005;22(6):1134-1139.

In the examination of 3D DCE-MRA, it is the key of success or failure to measure and compute the delaying scan time accurately. Now, the timing technique used widely in clinic is test injection bolus, which is limited by inadequate perfectibility, limited spatial resolution and technique complexity. In this article is presented a technique in which contrast arrival is detected in the targeted vasculature in real time using MR fluoroscopy. Upon detection the operator triggers a 3D MR angiographic acquisition which uses an elliptical centric view order. It is shown that the view order intrinsically provides a high degree of venous suppression, a high degree of immunity to motion effects and a high degree of spatial resolution. The reliability of fluoroscopic triggering in bolus detection is shown to be over 95%. The technique provides high quality contrast-enhanced MR angiograms for many vascular regions.
Contrast Media ; Fluoroscopy ; methods ; Humans ; Image Enhancement ; methods ; Imaging, Three-Dimensional ; Magnetic Resonance Angiography ; methods

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Image segmentation in tongue characterization.

Yuzhong WANG ; Jie YANG ; Yue ZHOU ; Yuanjie ZHENG ; Yiqin WANG

Journal of Biomedical Engineering.2005;22(6):1128-1133.

Tongue diagnosis is one of the essential methods of traditional Chinese medical diagnosis. The accuracy of tongue diagnosis can be improved by tongue characterization. Tongue area segmentation and homogeneous regions segmentation in tongue are important contents of preprocess of tongue image. An algorithm based on edge detection and Gradient vector flow (GVF) active contour for tongue area segmentation and another algorithm based on unsupervised segmentation of color-texture for homogeneous regions segmentation in tongue were presented. Totally about 1500 tongue images were collected. Results of tongue area segmentation achieved accuracy rate of 94.3% and results of homogeneous regions segmentation in tongue were approved by traditional Chinese medical experts. The experiments results show robustness of the algorithms. This work establishes solid foundation for feature selecting of Tongue diagnosis.
Algorithms ; Color ; Diagnosis, Computer-Assisted ; Humans ; Image Interpretation, Computer-Assisted ; methods ; Image Processing, Computer-Assisted ; Medicine, Chinese Traditional ; methods ; Pattern Recognition, Automated ; methods ; Tongue ; pathology

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Auto sleep staging and sleep quality estimation based on BP neural network.

Jianping LIU ; Chongxun ZHENG

Journal of Biomedical Engineering.2005;22(6):1124-1127.

To estimate the sleep quality, a 3-layer BP neural network was studied. The EEG complexity and the power spectrum of sleep-multigraph served as the input vector of the network . All-night sleep-stage scoring was performed. Then several parameters (sleep period, shallow sleep period, deep sleep period, REM period, ratio of the wakeful period and sleep one) were defined to estimate the sleep quality. The experiments revealed that the estimated sleep condition was the same as the subjects' impression. The data on six cases of all-night sleep show that this method is available to estimate the sleep quality.
Electroencephalography ; methods ; Humans ; Neural Networks (Computer) ; Polysomnography ; methods ; Signal Processing, Computer-Assisted ; Sleep ; physiology ; Sleep Stages ; physiology

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Numerical simulation of the relationship between blood pressure and blood stream of arteries.

Xiaoping SHI

Journal of Biomedical Engineering.2005;22(6):1121-1127.

The quantitative relationship between blood pressure and blood stream of arteries, which is delineated by hemodynamics, is rather complex to understand and analyze mathematically. An equivalent simulated mathematical model was utilized to numerically describe this sort of relationship. The physiological essence of layered flowage inside the artery was opened out. The numerical simulation was accomplished using several sets of real parameters. Some important conclusions about quantitative relationship of the layered flowage were drawn through the simulation results. The research results presented in this paper have important reference value in respect of quantitative research of circulation physiology and clinical diagnosis and analysis of some illness within circulation system.
Arteries ; physiology ; Blood Flow Velocity ; physiology ; Blood Pressure ; physiology ; Computer Simulation ; Hemodynamics ; physiology ; Humans ; Models, Cardiovascular ; Numerical Analysis, Computer-Assisted ; Pulsatile Flow ; physiology

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Tongue image color recognition in traditional Chinese medicine.

Yonggang WANG ; Jie YANG ; Yue ZHOU ; Yiqin WANG

Journal of Biomedical Engineering.2005;22(6):1116-1120.

The problem of color recognition of substances and coats in tongue images was decomposed into two steps, i. e. region separation and color recognition. In the first step, a new method based on the JSEG and the k-NN algorithms was proposed to separate coats and substances, where a prior template and some standard color patches were designed to assist the classification. Color recognition in a fine scale was carried out by the nearest neighbour method on the basis of the first step. The experiments showed the method proposed in this paper was simple and highly robust, and can be applied to tongue characterization effectively. In addition, the two important preprocessing algorithms namely color calibration and segmentation of tongue images were improved to obtain better results than the former.
Color ; Diagnosis, Computer-Assisted ; Humans ; Image Interpretation, Computer-Assisted ; methods ; Medicine, Chinese Traditional ; methods ; Pattern Recognition, Automated ; methods ; Tongue ; pathology ; physiopathology

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The effect of extracellular perfusion on dielectric spectroscopy of skeletal muscle cells.

Qing MA ; Lihong WANG ; Xiaorong HOU

Journal of Biomedical Engineering.2005;22(6):1112-1115.

The dielectric spectroscopy of the skeletal muscle cells is approached by extracellular perfusion, using curve fitting and numerical calculation with nonlinear Cole-Cole equation, and the dielectric parameter of skeletal muscle cells is compared after perfusion, The results show: (1) the permittivy at low frequency (epsilon1) and the conductivity at hight frequency (kappa(h)) reduces in keeping with extracellular perfusate; (2) the effect of extracellular perfusion on the characteristic frequency (f(c1),f(c2)) is small; (3) the extracellular perfusion mostly influences the peaks of deltaepsilon" and tgdelta for the skeletal muscle cells.
Animals ; Bufo bufo ; Electric Conductivity ; Electricity ; Electrophysiology ; Extracellular Fluid ; physiology ; Muscle, Skeletal ; cytology ; physiology ; Spectrum Analysis ; methods

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Bayesian representation of prior information and MCMC method in microwave imaging.

Xiang ZHAO ; Kama HUANG ; Xing CHEN ; Liping YAN

Journal of Biomedical Engineering.2005;22(6):1108-1111.

Microwave imaging for dielectric objects was considered in this paper. Applying Bayesian approach to represent prior information about permittivity distribution of observed object by prior probability density and combine measurements information of scattering field, we obtained posterior probability density that included synthetic information about the observed object. And then, Gibbs sampler, one of Markov Chain Monte Carlo method, was used to sample the posterior probability density. The sample mean was regarded as an evaluation of the permittivity distribution. The results of simulation imaging with "blocky" objects showed that this set of methods made good use of information and had the advantages of feasibility and very strong anti-noise ability. In addition,it is capable of describing (definite or indefinite) prior information in a convenient and controllable way, as well as capable of giving the "complete" solution, i.e., the occurrence probability of every permittivity distribution.
Bayes Theorem ; Computer Simulation ; Image Processing, Computer-Assisted ; methods ; Markov Chains ; Microwaves ; Models, Theoretical ; Monte Carlo Method ; Neoplasms ; diagnosis

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Effective control of excitable waves in 2D cardiac excitable media.

Li LI ; Li LIU ; Guangcai ZHANG ; Guangrui WANG ; Zhi QU

Journal of Biomedical Engineering.2005;22(6):1104-1107.

We propose a method for effective control of patter on dissipative system by use of little perturbation analysis, and apply this nonuniform feed back method to control the polarization wave of heart represented by FHN equation. In the numerical experiment, we successfully alter the propagating direction of planar waves and drift the spiral waves to boundary without resonant repulsion. The effective control of the excited system will be used to study the mechanism of defibrillation and that is our interesting work.
Action Potentials ; Arrhythmias, Cardiac ; physiopathology ; Computer Simulation ; Heart Conduction System ; physiopathology ; Humans ; Models, Cardiovascular ; Myocardial Contraction ; Myocardium ; Myocytes, Cardiac ; cytology ; physiology

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