Impedance rheography: a new method for recording spontaneous arterial section variation.

The aim of this work is to define, on the basis of impedance rheography, a method to record arterial section variations without either inertia or the production of wall-strain. High frequency current (2 MHz) is employed to measure the impedance variations of the deforming artery. The modulating envelope is representative of arterial section variations. This method permits the recording of arterial section variations by a peri-arterial method or an external method on superficial arteries (without denudation). A comparison between arterial section variations and arterial pressure variations at the same point shows that the arterial wall behaves as a non-linear pressure gauge: Rheogram-pressure curves are similar to volume-arterial pressure curves. The great precision with which this method describes the chronology of arterial deformations is of great interest in defining viscous properties of the arterial wall and following their evolution during pathologic alterations such as atherosclerosis.