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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of Biomedical Engineering Research
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Journal DOI :
The Korea Society of Medical and Biological Engineering
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Volume & Issues
Volume 24, Issue 6 - Dec 2003
Volume 24, Issue 5 - Oct 2003
Volume 24, Issue 4 - Aug 2003
Volume 24, Issue 3 - Jun 2003
Volume 24, Issue 2 - Apr 2003
Volume 24, Issue 1 - Feb 2003
Selecting the target year
Preprocessing Effect by Using k-means Clustering and Merging .Algorithms in MR Cardiac Left Ventricle Segmentation
Ik-Hwan Cho ; Jung-Su Oh ; Kyong-Sik Om ; In-Chan Song ; Kee-Hyun Chang ; Dong-Seok Jeong ;
Journal of Biomedical Engineering Research, volume 24, issue 2, 2003, Pages 55~60
For quantitative analysis of the cardiac diseases. it is necessary to segment the left-ventricle (LY) in MR (Magnetic Resonance) cardiac images. Snake or active contour model has been used to segment LV boundary. However, the contour of the LV front these models may not converge to the desirable one because the contour may fall into local minimum value due to image artifact inside of the LY Therefore, in this paper, we Propose the Preprocessing method using k-means clustering and merging algorithms that can improve the performance of the active contour model. We verified that our proposed algorithm overcomes local minimum convergence problem by experiment results.
MRI Quantification Analysis on Fall in Sick Times of the Cerebral Infarction Patients Using Object-Centered Hierarchical Planning
Journal of Biomedical Engineering Research, volume 24, issue 2, 2003, Pages 61~68
This paper presents a quantitative analysis method for fall in sick times of the cerebral infarction patients using three types of magnetic resonance image, which play an important role in deciding method of medical treatment. For this object, image characteristics obtained by three radiographic methods of MRI and their relation were analyzed by means of object centered hierarchical Planning method. This methode presents an approach to the knowledge based processes for image interpretation and analysis. To compare three type of MRI. a multiple warping algorithm and affine transform method performed for image matching. Then each fall in sick times level of cerebral infarction was quantified and pseudo-color mapping performed by comparing gray level value one another according to Previously obtained hand maid data. The result of this study was compared to a medical doctors decision.
Development of Virtual Endoscopy and Evaluation of Performance as a 3D Virtual Colonoscopy
Journal of Biomedical Engineering Research, volume 24, issue 2, 2003, Pages 69~75
Virtual colonoscopy is one of the Powerful tool for non-invasive colon examination and many in-vitro and in-vivo studies have shown its accuracy in Polyp or adenoma detection. But most of virtual colonoscopy requires high quality workstation and software and its cost is high to setup whole system. We developed PC-based 3D model creation and navigation program which has diverse functions. It can be easily installed to PC and connected to network system. The performance. when used as a virtual colonoscopy. is evaluated by calculating sensitivity of detection for the simulated polyp which is artificially made inside the Pig's colon and checked its clinical feasibility, Its total sensitivity is 76%. Grouping according to Polyps diameter, the sensitivity for detection of polyps 10 ㎜ or larger was 100%(40 of 40); 5.0-9.9 ㎜, 90.0(90 of 100): and smaller then 5 ㎜. 36.7%(22 of 60).
A Fast Flight-path Generation Algorithm for Virtual Colonoscopy System
Journal of Biomedical Engineering Research, volume 24, issue 2, 2003, Pages 77~82
Virtual colonoscopy is a non-invasive computerized procedure to detect polyps by examining the colon from a CT data set. To fly through the inside of colons. the extraction of a suitable flight-path is necessary to Provide the viewpoint and view direction of a virtual camera. However. manual path extraction by Picking Points is a very time-consuming and difficult task due 1,c, the long and complex shape of colon. Also, existing automatic methods are computationally complex. and tend to generate an improper and/or discontinuous path for complicated regions. In this paper, we propose a fast flight-path generation algorithm using the distance and order maps. The order map Provides all Possible directions of a path. The distance map assigns the Euclidean distance value from each inside voxel to the nearest background voxel. By jointly using these two maps. we can obtain a proper centerline regardless of thickness and curvature of an object. Also, we Propose a simple smoothing technique that guarantees not to collide with the surface of an object. The phantom and real colon data are used for experiments. Experimental results show that for a set of human colon data, the proposed algorithm can provide a smoothened and connected flight-path within a minute on an 800MHz PC. And it is proved that the obtained flight-Path provides successive volume-rendered images satisfactory for virtual navigation.
A Study for The X-ray Image Acquisition Experiment Using by Gas Electron Multipliers
Journal of Biomedical Engineering Research, volume 24, issue 2, 2003, Pages 83~89
The gas electron multiplier placed in the drift volume of conventional gas detectors, is a conceptually simple device for producing a large gas gain by concentrating the drift electric field over a very short distance to the point that electron avalanching occurs(〉 10
V/cm), greatly increasing the number of drifting electrons. This device consists of a thin insulating foil of several tens of urn in thickness. covered on each side with a thin metal layer(Cu), with tiny holes, usually 100
or less in diameter. and with a spacing of 100-200
through the entire foil. perforated by using chemical etching or high-powered laser beam technique In this study, we have investigated its operating properties with various experimental conditions, and demonstrated the possibility of using this device as a digital X-ray imaging sensor, by acquiring X-ray images based on the scintillation properties of the gas electron multiplier with standard CCD camera.
Automatic Detection of Optic Disc Boundary on Fundus Image
Journal of Biomedical Engineering Research, volume 24, issue 2, 2003, Pages 91~97
The Propose of this paper is hierarchical detection method for the optic disc in fundus image. We detected the optic disc boundary by using the Prior information. It is based on the anatomical knowledge of fundus which are the vessel information. the image complexity. and etc. The whole method can be divided into three stages . First, we selected the region of interest(ROI) which included optic disc region. This is used to calculate location and size of the optic disc which are prior knowledge to simplify image preprocessing. And then. we divided the fundus image into numberous regions with watershed algorithm and detected intial boundary of the optic disc by reducing the number of the separated regions in ROI. Finally, we have searching the defective parts of boundary as a result of serious vessel interference in order to detect the accurate boundary of optic disc and we have removing and interpolating them.
Classification of Schizophrenia Using an ANN and Wavelet Coefficients of Multichannel EEG
Journal of Biomedical Engineering Research, volume 24, issue 2, 2003, Pages 99~106
In this paper, a method of discriminating EEG for diagnoses of mental activity is proposed. The proposed method for classification of schizophrenia and normal EEG is based on the wavelet transform and the artificial neural network. The wavelet coefficients of
band are obtained using the wavelet transform. The magnitude, mean, and variance of wavelet coefficients for each EEG band are applied to the input data of the system's ANN. The architecture of the ANN s a four layered feedforward network with two hidden layer which implements the error back propagation learning algorithm. Through the classification of schizophrenia composed of 19 ANNs corresponding to 19 channels, the classifying system show that it can classify the 100% of the normal EEG group and the 86.67% of the schizophrenia EEG group.
A New QRS Detection Algorithm Using Index Function Based on Resonance Theory
Journal of Biomedical Engineering Research, volume 24, issue 2, 2003, Pages 107~112
This paper describes a new simple QRS detection algorithm using index function based on resonance theory. The ECG signal can be modeled with several sinusoidal pulses and its first difference has some relations with the amplitude and frequency of sinusoidal pulse. Based on above fact, an index function, similar to the square of the imaginary part of a simple R-L-C circuit, was designed. A QRS complex is detected by applying the adaptive method to the response of index function. The algorithm showed a performance comparable to or higher than the other algorithms. Because it does not require any complicated preprocessing or postprocessing, it can be implemented in real time.
The Study on the Diameter Ratio of the Artery-PTFE Anastomosis for the Optimized Deformed Shape
Journal of Biomedical Engineering Research, volume 24, issue 2, 2003, Pages 113~119
In this paper we introduced optimized deformed shape to prevent the blood vessel disease caused by the discord of deformed shape in the end-to-end anastomosis. This study considered the preliminary deformed shape induced by suture in the anastomosis of artery and PTFE, artificial blood vessel, with different diameters. Then we analyzed the final deformed shape of the anastomotic part under the systolic blood pressure. 120mmHg(16.0kPa). The final deformed shape of the anstomotic part was analyzed with respect to the change of initial diameter ratio(R
) and the PTFE thickness. Equivalent and circumferential stresses induced by the systolic blood pressure in the anastomosis were also analyzed with respect to the initial diameter ratio(R
). The results obtained were as follows : 1. Considering the preliminary deformed shape induced by suture and the systolic pressure in the anastomosis, not intimal hyperplasia, the optimal initial diameter ratio(R
) was 1.073. 2. As the initial diameter ratio(R
) became larger, higher equivalent and circumferential stresses were induced. And all the maximum stresses occurred on the side of PTFE 0.4mm apart from the anastomosis.
Gas Transfer and Hemolysis Characteristics of a New Type Intravenous Lung Assist Device
Journal of Biomedical Engineering Research, volume 24, issue 2, 2003, Pages 121~126
The purpose of this work was to assess and quantify whether the beneficial effects in long-term gas exchange at exciting frequency were obtained at different frequencies as well and then to develop a vibrating intravascular lung assist device(VIVLAD), for Patients suffering from acute respiratory distress syndrome(ARDS) or chronic respiratory problems. We investigate the optimal condition of the frequency band excited with new vibrator at state of limit hemolysis when blood hemolysis came to through a membrane vibration action. The experimental design and procedures were given for a device used to assess the effectiveness of membrane vibrations. Quantitative experimental measurements were performed to evaluate the performance of the device . and to identify membrane vibration dependence on blood hemolysis. We developed an analytical solution for the hydrodynamics of flow through a bundle of sinusoidally vibrated hollow fibers that is used to provide some insight into how wall vibrations might enhance the performance of the VIVLAD. In the result, it was measured that the effect of various excited frequencies in gas transfer rate and hemolysis from the maximum gas transfer rate at no vibration when the maximum gas transfer rates showed at module type 6, module type 6 consisted of 675 hollow fiber membranes The maximum oxygen transfer rate was caused by the occurrence of maximum amplitude and transfer of vibration to hollow fiber membranes when it was excited by the frequency band of 7Hz at each blood flow rate. because this frequency became the End mode resonance frequency of the flexible in blood flow. Also, when module type 6 was excited at an excited frequency of 7Hz. blood hemolysis was low. Therefore, we decided that the limit of hemolysis frequency is 7Hz . because maximum amplitude occurred at this frequency.
Development of the Hybrid Type Robot Using a Pneumatic Actuator For Physical Therapy Of Ankylosis
Journal of Biomedical Engineering Research, volume 24, issue 2, 2003, Pages 127~132
In this paper. the pneumatic service robot with a hybrid type is developed. A pneumatic has the advantages of good compliance , high Payload-to-weight and payload-to-volume ratios. high speed and force capabilities. Using pneumatic actuators. which have low stiffness. the service robot can guarantee safety. By suggesting a new serial-parallel hybrid type for the service robot which separates into Positioning motion and orienting motion, we can achieve large workspace and high strength-to-moving-weight ratio at the same time. A sliding mode controller can be designed for tracking the desired output using the Lyapunov stability theory and structural properties of pneumatic servo systems. Through many experiments of circular trajectory. the Pneumatic service robot is evaluated and verified.
Voluntary Motor Control Change after Gait Training in Patients with Spinal Cord Injury
Journal of Biomedical Engineering Research, volume 24, issue 2, 2003, Pages 133~140
In this study, muscle activity was measured using surface EMG (sEMG) during a voluntary maneuver (ankle dorsiflexion) in the supine position was compared pre and post gait training. Nine patients with incomplete spinal cord injury participated in a supported treadmill ambulation training (STAT), twenty minutes a day, five days a week for three months. Two tests, a gait speed test and a voluntary maneuver test, were made the same day, or at least the same week, pre and post gait training. Ten healthy subjects' data recorded using the same voluntary maneuvers were used for the reference. sEMG measured from ten lower limb muscles was used to observe the two features of amplitude and motor control distribution pattern, named response vector. The result showed that the average gait speed of patients increased significantly (p〈0.1) from 0.47
0.35 m/s to 0.68
0.52 m/s. In sEMG analysis, six out of nine patients showed a tendency to increase the right tibialis anterior activity during right ankle dorsiflexion from 109.7
but it was not significant (p〈0.055). In addition, only two patients showed increase of correlation coefficient and total muscle activity in the left fide during left dorsiflexion. Patients' muscle activity changes after gait training varied individually and generally depended on their muscle control abilities of the pre-STAT status. Response vector being introduced for quantitative analysis showed good Possibility to anticipate. evaluate, and/or guide patients with SCI, before and after gait training.