| Co-Investigator(Kenkyū-buntansha) |
FUKADA Hidetoshi Kagawa Medical School, Second Department of internal Medicine, Research Associat, 医学部・附属病院, 助手 (20211518)
NAKAJIMA Shigeru Kagawa Medical School, Second Department of internal Medicine, Research Associat, 医学部・附属病院, 助手 (80172310)
HIRABAYASHI Koichi Kagawa Medical School, Second Department of internal Medicine, Research Associat, 医学部, 助手 (80240894)
MORITA Hisaki Kagawa Medical School, Second Department of internal Medicine, Assistant Profess, 医学部・附属病院, 講師 (70145051)
SENDA Syoichi Kagawa Medical School, Second Department of internal Medicine, Assistant Profess, 医学部・附属病院, 助教授 (30145049)
|
|---|
| Research Abstract |
1.Development of intravascular ultrasound imaging (IVUS) system :
In order to visuarize the shape of atherosclerotic lesion, and predict its histlogical components with ultrasound technique, we developed high frequency IVUS system (intravascular echography system). A 1mmX1mm ultrasound transducer with 15MHz or 20MHz center frequency, is mounted at the tip of catheter, and the arterial cross-sectional image is depicted by its mechanical 360ﾟ rotation. The cross-sectional image is consist of 1024 radial ultrasonic beams capable of detail tissue characterization of arterial wall. And, with 30/sec high frame rate, we could gain almost real time images of arterial wall.
2.Arterial wall tissue characterization by analysis of radio-frequency (RF) signals using IVUS We also developed the RF signals analysis system for ultrasonic tissue characterization of arterial wall using IVUS.For the specimens of human aortae and common iliac arteries, we calculated Integrated Backscatter (IB) value, a numer
… More
ical expression of the reflected power of ultrasonic signals, from the region of interest (ROI) fixed on arterial wall, and compared the IB value with its tissue character. The fatty lesion group's IB value was lower than the controls', while the fibrous and calcified lesion groups were higher. So, in order to find a quantifiable value for tissue characteristics, we experimented with the IB value obtainable from RF signals, and found it a useful objective index for the evaluation of atherosclerosis.
3.Estimation of the arterial wall elastic property :
From the relationship between arterial cross-sectional area obtained from IVUS echograms, and simultaneous intraluminal pressure, we evaluated the arterial wall elastic property. In the animal experiment, we showed the administration of nifedipine increased arterial wall distensibility. And, in human aorta, we compared the regional aortic wall distensibility, so clarified the distensibility of lower abdominal aorta decreased remarkedly compared with thoracic descending aorta. Less
|
