ABSTRACT
This research was conducted to investigate frequency response of blood vessel wall. The principal frequency of blood vessel wall, f1 was found to decrease with progression of atherosclerosis and irregularity of the vibration trajectory of blood vessel wall was found to increase. When an aneurysm appeared, a new vibration wave was found to appear in the high frequency region, f2. When the aneurysm wall has enough strength, intensity of high frequency wave was found to increase. However, it decreases with decrease in the strength of aneurysm wall. The visco-elastic deterioration of blood vessel wall was found to well correlate with the changing characteristics of f1. A two-dimensional representation of f1 and f2 was conducted which tracks the progression of atherosclerosis and aneurysm. It will enable us to diagnose the introduction period of operation of blood vessel wall of atherosclerosis with an aneurysm.
Subject(s)
Aneurysm , Atherosclerosis , Blood Vessels , Pulsatile Flow , Aneurysm/diagnostic imaging , Aneurysm/physiopathology , Atherosclerosis/diagnostic imaging , Atherosclerosis/physiopathology , Blood Vessels/diagnostic imaging , Blood Vessels/physiopathology , Humans , Models, Cardiovascular , Rheology/methods , Ultrasonography, Doppler/methodsABSTRACT
Previously, one of the authors developed a noninvasive measurement method of acceleration and deceleration during the expansion process of the blood vessel wall under pulsatile pressure flow by measuring the strain rate of the blood vessel wall using a supersonic Doppler effect sensor aided by computer analysis (DPC method). In this paper, on the basis of the analysis of chaos theory, that is, the complexity of science, the unstable behavior of the blood vessel wall with an aneurysm was investigated by identifying the characteristic DPC wave forms induced by the onset and progression of aneurysm. These results showed that unstable dynamic behavior of the blood vessel wall occurs due to the progression of the aneurysm. Furthermore, using the theoretical analysis of chaos, this unstable behavior of the blood vessel wall was quantified and the fundamental principle of a noninvasive diagnostic method of the progressive degree of aneurysm was proposed.
