[Value of spectrum analysis of the ultrasonic Doppler signal in the diagnosis of occlusive diseases of the carotid arteries].

Spectral analysis of the ultrasound Doppler's signal (SA UDS) was used to examine 216 patients with occlusive lesions of the carotid arteries followed by correlation of the data obtained to the carotid angiography data. Based on the doppler-angiographic correlations, diagnostic criteria for SA UDS were elaborated. It has been demonstrated that Amax is the most significant criterion, the increase of which by over 3.2 kHz points to the development of ICA stenosis. The magnitude of that characteristic exceeding 6.0 kHz indicates that ICA stenosis reaches more than 50%. The significance of SA UDS in ICA stenoses up to 50% amounted to 81.8%, in stenoses over 50%, it was 98.6%. In ICA occlusion the significance of the method was 99%.