Development of an intravascular impedance catheter for detection of fatty lesions in arteries

Recent studies show that the presence of fatty lesions in the atherosclerotic vessel wall is a risk factor for acute occlusion of blood vessels. Although fat has a high electrical resistivity, existing impedance catheter systems cannot be used for detection of these lesions because artifacts owing to impedance variations in the extravascular surroundings have a major and irretraceable effect on the measurement. Standard algorithms used in attempt to compensate for these artifacts suffer from severe instability problems. The authors defined design guidelines to be met by a new impedance catheter system in order to make a robust reconstruction algorithm possible and have built an experimental in travascular impedance catheter (IIC) system according to these guidelines, using a normalized differential measurement procedure. With this IIC, the authors performed experiments on human iliac arteries from the section ward (fixed specimens), showing that plastic models of arterial fatty lesions (8 mm/sup 3/) can be detected reliably.