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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
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Functional MR Imaging of Language System : Comparative Study between Visual and Auditory Instructions in Word Generation Task
Journal of Biomedical Engineering Research, volume 24, issue 4, 2003, Pages 241~246
To evaluate the usefulness if functional MR imaging(MRI) for the determination of language dominance system and to assess differences in the visual and auditory instrument language generation task according to activation task or activated area. Functional maps of the language area were obtained during visual and auditory instructions in word generation tasks in 6 healthy volunteer with right-handness were examined on a 1.5T scanner and the EPI BOLD technique, and three pulse sequence technique get of the true axial planes. Both task consisted of 96 phases including 6 activations and rests contents. Postprocessing were done on MRDx program by using cross correlation method. Two task compare the blain activation area surveyed of 1anguage lateralization index. To evaluated of the detection rates of Broca. Wernicke, pre-frontal lobe, Supplementary Motor Area (SMA) and pre-motor cortex areas and the differences of language lateraliaztion among two word generation task To lateralization index survey in 1anguage area on right and left in brain get to activation area pixel in brain. Compared to visual and auditory instrument task in the language areas get to the lateralization index. Two language generation task high detection rates of Broca and Wernicke areas. The visual instruction no detected in the auditory area, and auditory instruction no detected in the visual area. There was statistics significant different of them among language generation task. 1'his indicated that language area obtained image of the brain functional MR imaging usefulness in the visual and auditory task instrument.
3D Segmentation of a Diagnostic Object in Ultrasound Images Using LoG Operator
Journal of Biomedical Engineering Research, volume 24, issue 4, 2003, Pages 247~257
This paper proposes a three-dimensional (3D) segmentation algorithm for extracting a diagnostic object from ultrasound images by using a LoG operator In the proposed algorithm, 2D cutting planes are first obtained by the equiangular revolution of a cross sectional Plane on a reference axis for a 3D volume data. In each 2D ultrasound image. a region of interest (ROI) box that is included tightly in a diagnostic object of interest is set. Inside the ROI box, a LoG operator, where the value of
is adaptively selected by the distance between reference points and the variance of the 2D image, extracts edges in the 2D image. In Post processing. regions of the edge image are found out by region filling, small regions in the region filled image are removed. and the contour image of the object is obtained by morphological opening finally. a 3D volume of the diagnostic object is rendered from the set of contour images obtained by post-processing. Experimental results for a tumor and gall bladder volume data show that the proposed method yields on average two times reduction in error rate over Krivanek's method when the results obtained manually are used as a reference data.
Hierarchical Non-Rigid Registration by Bodily Tissue-based Segmentation : Application to the Visible Human Cross-sectional Color Images and CT Legs Images
Journal of Biomedical Engineering Research, volume 24, issue 4, 2003, Pages 259~266
Non-rigid registration between different modality images with shape deformation can be used to diagnosis and study for inter-patient image registration, longitudinal intra-patient registration, and registration between a patient image and an atlas image. This paper proposes a hierarchical registration method using bodily tissue based segmentation for registration between color images and CT images of the Visible Human leg areas. The cross-sectional color images and the axial CT images are segmented into three distinctive bodily tissue regions, respectively: fat, muscle, and bone. Each region is separately registered hierarchically. Bounding boxes containing bodily tissue regions in different modalities are initially registered. Then, boundaries of the regions are globally registered within range of searching space. Local boundary segments of the regions are further registered for non-rigid registration of the sampled boundary points. Non-rigid registration parameters for the un-sampled points are interpolated linearly. Such hierarchical approach enables the method to register images efficiently. Moreover, registration of visibly distinct bodily tissue regions provides accurate and robust result in region boundaries and inside the regions.
A Study on Visuospatial Cognitive Performance Following Oxygen Administration using fMRI
Journal of Biomedical Engineering Research, volume 24, issue 4, 2003, Pages 267~273
The present study attempted to observe what changes the supply of highly concentrated (30%) oxygen cause to people's ability of visuospatial cognition, compared to air of normal oxygen concentration (21%). This study sampled eight male university students (the average age : 23.5) as subjects for functional Magnetic Resonance Imaging (MRI) study It also developed equipment that supplies 21% and 30% oxygen) at a constant rate of 8L/min. Two questionnaires containing 20 questions were developed to measure the ability of visuospatial cognition, and accuracy was calculated from the result of task performance. The experiment paradigm consisted of the run conducting tasks at 30%'s concentration of oxygen and another run at 21%'s concentration of oxygen. Each run was composed of four blocks and each block included eight control tasks and five visuospatial taks. 3T MRI was used and fMRI was obtained through the single-shot EPI method. The activation in the occipital-associated area, bilateral superior parietal lobes, bilateral inferior parietal lobes. bilateral precuneus, bilateral postcentral gyri, bilateral middle frontal gyri, bilateral inferior frontal gyri, bilateral medial frontal gyri, bilateral superior frontal gyri, bilateral cingulate gyri was significantly increased at the 30%'s concentration of oxygen rather than 21%'s. Furthermore, the result of task performance showed the accuracy increased at 30%'s concentration of oxygen rather than 21%'s. From the result of this study, it is concluded that the supply of highly concentrated oxygen has a positive effect on the ability of visuospatial cognition.
MR Angiography with Simultaneous Data Acquisition of Arteries and Veins(SAAV) Method and Artery-Vein Color Mapping in 0.3T MRI System
Journal of Biomedical Engineering Research, volume 24, issue 4, 2003, Pages 275~280
The method of simultaneous data acquisition of arteries and veins(SAAV) was suggested to obtain MR angiography of arteries and veins at 0.3T low filed MRI system (Magfinder, AlLab. Korea). Two separated artery- and vein-images were put together using AVCM(Artery-Vein Color Mapping) algorithm and presented in the same image. In this study, artery- and vein-separated angiograms of volunteer's neck were obtained. Two dimensioal blood-enhanced images wre sequentially obtained using SAAV pulse sequence based on time-of-flight(TOF) method with flow compensation. Imaging parameters were TR/TE=70/12msec. FOV=230mm, slice thickness = 3mm, flip angle=90
, matrix size=256
64mm. TSat TH/SPA=15/20mm, Ts_v=10msec and Ts_a=40ms. 3D MRA images were reconstructed using the maximum intensity projection(MIP) and the artery-vein color mapping(AVCM) algorithm. This study showed good possibility of clinical applications of MRA in 0.3T which provides valuable diagnostic information of clinical vascular diseases.
Design of the Blood Pressure Measurement System Using the Inflatable Oscillometric Method
Journal of Biomedical Engineering Research, volume 24, issue 4, 2003, Pages 281~286
Blood Pressure is one of the most fundamental Parameters which reflects physical conditions medically and the blood pressure measurement system using oscillometric method is a Non-Invasive Blood Pressure measurement device by measuring arterial Pressure through a cuff. In this paper. we designed a inflatable wrist blood pressure system which measures blood Pressure during the stepping inflation in the wrist cuff. The hardware system consists of a main power unit, a bladder in cuff unit, signal detection units, signal Processing units. a wireless data transmission unit, and a data display unit. We evaluated the reliability of this system by comparing and analyzing systolic. diastolic blood Pressure, and heart rate with other commercial blood Pressure measurement devices. Characteristic ratio values used to determine systolic and diastolic blood Pressure using MAA(Maximum Amplitude Algorithm) were 0.436 and 0.671 respectively.
Magnetic Noise Reduction in MCG Using Spatial Filters
Journal of Biomedical Engineering Research, volume 24, issue 4, 2003, Pages 287~292
Even though MCG has many advantages over ECG, MCG signa)s are easily corrupted by external magnetic noises Since multi-channel MCG signals are recorded simultaneously at many spatial positions, it is effective to apply spatial fitters as well as the conventional temporal filters to remove external magnetic noises. The spatial filters can be designed by utilizing the fact that the noise signals caused by external noise sources are more spatially correlated than the original MCG signals. In this paper, we introduce a spatial filtering method for the noise reduction in MCG based on the principal component analysis. Healthy volunteer study results obtained with a 61-channel MCG system are presented.
Study on the Modeling Technique for Prediction about Pressure Drop of an Intravenous Lung Assist Device
Journal of Biomedical Engineering Research, volume 24, issue 4, 2003, Pages 293~299
In this paper, the correlation of Pressure drop about the Newtonian and non-Newtonian fluid was investigated experimentally for vibrating intravascular lung assist device (VIVLAD) and we determined correlation equation to make a prediction about Pressure drop for designing VIVLAD. Design conditions to predict the pressure drop of the modules were studied through an experimental modeling before inserting the artificial lung assist device into as venous. Experiments were performed by distilled water, glycerol/water mixed solution(40% glycerol) of Newtonian fluids. and the bovine blood of non-Newtonian fluids. These fluids were flowed outside and parallel of hollow fiber membranes. Also we measured pressure drop according to the number of the fiber membranes which ware inserted into the inside diameter of shell of 3 cm, and developed the prediction equations by curve fitting method based on correlation between the experimental pressure drop and the frontal area or the packing density of device. The result showed that the Pressure drop and the friction factor of the water/glycerol mixed solution were similar to that of bovine blood. It was showed that the water/glycerol mixed solution (40% glycerol) could be used for measuring the pressure drop and the friction factor instead of the bovine blood. Also, we could estimate the prediction equation of pressure drop and friction factor as the function of Packing density at the number of hollow fibers. We obtained the reliance of the prediction equations because the pressure drop and the friction factor measured from the experiments were similar to that from the prediction equation. These results may be used to further usefulness for the design of VIVLAD.
Numerical Analysis of the Blood Flow in the Korean Artificial Heart Using Two Dimensional Model
Journal of Biomedical Engineering Research, volume 24, issue 4, 2003, Pages 301~307
In this study, we Presented computational results on the blood flow in the sac of the Korean artificial heart. Two dimensional unsteady flow was assumed and we utilized a finite element commercial code ADINA to simulate the blood flow. Rigid body-solid contact were considered between the actuator and the blood sac and fluid-structure interaction between the blood and the sac. The three geometric models proposed in the design process were simulated to assess the hemodynamic characteristics of the models According to the computational results, a strong flow to the outlet and a stagnated flow region near the inlet were observed during systole. The sac was filled with blood and recirculating flow was generated near the outlet during diastole. Shear stress during systole had its extreme values near the outlet edge whereas the magnitude of shear stress values were relative)v high near the inlet edge and the contacting surface with the actuator.
A Development of Rehabilitation System for Upper Limb Using Robot Manipulator
Journal of Biomedical Engineering Research, volume 24, issue 4, 2003, Pages 309~318
In this paper a 6 degree-of-freedom robot was studied for medical purpose. In the past the robot used for industry field was utilized for medical robot but in these days the robot used for rehabilitation. welfare, and service. This system was Proposed for a stroke patient or a patient who can not use one arm. A master-slave system was constructed to exercise either paralysis or abnormal arm using normal arms movement. Study on the human body motion result was applied to calculate a movement range of humans elbow and shoulder. In addition, a force-torque sensor is applied to estimate the rehabilitation extent of the patient in the slave robot. Therefore, the stability of the rehabilitation robot could be improved. By using the rehabilitation robot, the Patient could exercise by himself without any assistance In conclusion. the proposed system and control algorithm were verified by computer simulation and system experiment.
The Development of 63nm Diode Laser System for Photodynamic Therapy of Cancer
Journal of Biomedical Engineering Research, volume 24, issue 4, 2003, Pages 319~328
The purpose of this paper is to develop a medical laser system using the semiconductor diode laser in order to photodynamic cancel therapy as a light source. The ideal light source for photodynamic therapy would be a homogeneous nondiverging light with variable spot size and specific wavelength with stability. After due consideration in this point, in this paper, we used a diode laser resonator of 635nm wavelength. The development laser system have a statistical laser out beam with accuracy control using the constant current control of method and clinic-friendly with compact. In order to protect the diode resonator from the over-current, the rush-current and electrical fault, we specially designed. The most importance therapeutic factor are the radiation mode for cancer therapy. So we developed the radiation mode of CW(Continuous Wave), long pulse, short pulse, and burst pulse and can adjust the exposure time from several milli-second to several minute. The experimental result shows that laser beam power was increased linear from 10mW to 300mW according to the increasing input current and the increasing exposure time. The developed new compact diode laser system have a stability of output power and specific wavelength with easy control and transportable for many applications of PDT.
Computational Study on the Hemodynamic Behaviors of the Human Cardiovascular System with an Acute Arteriovenous Fistula
Journal of Biomedical Engineering Research, volume 24, issue 4, 2003, Pages 329~337
Blood in congenital or acquired AY fistula(arteriovenous fistula) flows from arteries directly to veins. detouring peripheral micro-circulation. This makes a great effect on the hemodynamics of human cardiovascular system. In this study, a computational method using lumped parameter mode) was proposed to simulate the cardiovascular hemodynamics of patients with acute AV fistula The cardiovascular system model with a fistula compartment in left lower limb was built using 17 standard lumped compartments. Using fourth order Runge-Kutta method. we solved numerically the unsteady linear set of the ordinary differential equations resulting from application of Kirchhoff's law to the lumped parameter hemodynamic model. The baroreceptor reflex system was implemented to explain the auto-regulation effect of the cardiovascular system with acute AV fistula.
Image-guided Surgery System Using the Stereo Matching Method
Journal of Biomedical Engineering Research, volume 24, issue 4, 2003, Pages 339~346
MRI provides anatomical structure information with superb spatial resolution that can be utilized in clinical surgeries. Advanced image processing techniques in conjunction with the MRI-guided surgery is expected to be of great importance in brain surgeries in the near future. In this paper, we introduce an image-guided surgery technique using the stereo matching method. To perform image-guided biopsy operations, we made MRI markers, camera markers and a detection probe marker. To evaluate the accuracy of the image-guided system. we made a silicone phantom. Using the phantom and markers, we have performed MRI-guided experiments with a 1.5 Tesla MRI system. It has been verified from phantom experiments that our system has a positioning error less than 1.5%. Compared with other image guided surgery system, our system shows better positioning accuracy.
A Computational Model for a Neuronal Membrane Considering the Extremely Low Frequency and Mobile Phone Frequency Electromagnetic Field Effect
Journal of Biomedical Engineering Research, volume 24, issue 4, 2003, Pages 347~354
In this paper, a computational method of an action potential including the effect of extremely low frequency and mobile phone (external) electromagnetic fields is Proposed. The method is based on the Hodgkin and Huxley model, applies the effect of the electromagnetic fields on the action Potential in terms of a binding factor into the injection current of the model, and calculates the Strength-Duration curve from numerical experiments for a frequency range of electromagnetic fields. In the numerical experiments, the coupled ordinary differential equations of the action potential and the state variables are solved solf-consistently by using Runge-Kutta Fehlberg method. The range of the frequency considered is from 1Hz through 100Hz and of 900MHz, which is specific for a mobile Phone. The Strength-Duration curves resulted showed good agreements with the equation suggested by Hodgkin and Huxley.
Development and Verification of Real Time Subjective Sensibility Evaluation System
Chung, Soon-Cheol ; Min, Byung-Chan ;
Journal of Biomedical Engineering Research, volume 24, issue 4, 2003, Pages 355~361
In the present study, a new Real Time Subjective Evaluation (RTSSE) system was developed. The system is composed of two parts: a sensibility input part and sensibility evaluation part. The sensibility input part receives values, which are recorded on an input board using a stylus and digital tablet, from each subject's evaluation of his/her own subjective sensibility towards a particular stimulus. The sensibility evaluation part displays the level of pleasantness and arousal on one or two dimensions in real time. An experiment was conducted in order to investigate the feasibility and effectiveness of the RTSSE system. The present study compared Galvanic Skin Response (GSR) with the RTSSE by presenting 28 subjects in their 20s with pictures arousing either positive or negative sensibility. Following the experiment, an off-line subjective assessment using a questionnaire was given to the same subjects. According to the correlation coefficients, changes in subjective sensibility caused by the positive visual stimulus were related more closely to GSR, from the positive visual stimulus, and changes in subjective sensibility caused by the negative visual stimulus were related more closely to GSR from the negative visual stimulus. The questionnaire results showed marked similarity to the average responses of the RTSSE. In conclusion, the most remarkable characteristic of the present system is that it not only assesses the average sensibility when stimuli are presented, but also shows the changing strength of sensibility over time.
Analysis of the Contact Pressure Distribution and Kinetics of Knee Implant Using the Simulator
Journal of Biomedical Engineering Research, volume 24, issue 4, 2003, Pages 363~367
Contact area and pressure are important factors which directly influence a life of knee implants. Since implant's mechanical functions should be experimentally evaluated for clinical use, many studies using a knee simulator and a pressure sensor system have been conducted. However it has not been reported that the contact pressure's distribution of a knee implant motion was estimated in real-time during a gate cycle. Therefore. the objective of this study was to analyze the contact pressure distribution for the motion of a joint using the knee simulator and I-scan sensor system. For this purpose, we developed a force-controlled dynamic knee simulator to evaluate the mechanical performance of artificial knee joint. This simulator includes a function of a soft tissue and has a 4-degree-of-freedom to represent an axial compressive load and a flexion angle. As axial compressive force and a flexion angle of the femoral component can be controlled by PC program. The pressure is also measured from I-scan system and simulator to visualize the pressure distribution on the joint contact surfaces under loading condition during walking cycle. The compressive loading curve was the major cause for the contact pressure distribution and its center move in a cycle as to a flexion angie. In conclusion, this system can be used to evaluate to the geometric interaction of femoral and tibial design due to a measured mechanical function such as a contact pressure, contact area and a motion of a loading center.
The Study of Changes in Compressive Strength of Trabecular Bone with PMMA Injection in Vertebroplasty
Journal of Biomedical Engineering Research, volume 24, issue 4, 2003, Pages 369~373
The compressed fracture of spine caused by osteoporosis is one of the most frequent diseases in bone fracture. Recently the vertebroplasty has drawn much attention as a medical treatment for the compressed fracture of spine, which strengthens the vertebral body and corrects deformity, and relieves pain in patients by injecting bone cement. But because there were no research about strengthening of mechanical properties of verbral body in bone cement injection, in this study, based on the properties of PMMA, we had measured the Young's modulus for different apparent densities of intact trabecular bone and PMMA injected one from a porcine and a cadaver. Young's modulus to apparent density had a form of a power series in intact trabecular bone and had a linear relation in PMMA injected bone.