[Spectral analysis of frequencies by conventional Doppler effect examination of the supra-aortic trunks (author's transl)]

Abstract

Using a directional Doppler (4 MHz) coupled to a frequency analyser, authors investigate the supra-aortic trunks on 90 patients documented by arteriography. The analyser is made of a 16 filter bank system giving a spectrum composed of 16 frequency bands within range of 160 Hz to 4,800 Hz. Data analysis is made on a computer using the comparison means test and the discriminant analysis. Authors compare frequencies on normal common carotid arteries between a group (N = 102) with internal and external carotid arteries free of lesions on one hand, and a group (N = 75) with stenosis or occlusion of internal and/or external carotid arteries on the other hand. They don't note any significant difference for each on of the 16 frequency bands. Comparison of frequencies between normal subclavian arteries (N = 115) and subclavian arteries with proximal stenosis or occlusion (N = 24) shows a significant difference concerning the following bands : F12, F14, F15, F16 (p = 0.05), F13 (p = 0.01). Comparison of frequencies between normal internal carotid arteries (N = 108) and stenosed internal carotid arteries (N = 57) shows significant difference concerning : F11 (p = 0.05), F7, F8, F9, F12, F13, F14, F15, F16 (p = 0.01). On the other side, the discriminant function distinguishes a normal internal carotid artery from a stenosed internal carotid artery in 90% of cases, whatever the stenosis degree is. A discriminant function, added to this analyser, could obtain a frequency analysis easier and less expensive than by fast Fourier transform.