[Color Doppler sonography (angiodynography) in the assessment of the arterial vascular bed of the lower extremities].

With color Doppler ultrasonography, since its inception two years ago, through combination of color-coded flow and gray-coded vessel and tissue imaging, a new technique is available with which, based on the information derived from the Doppler principle, characterization is enabled of the direction of blood flow coded in red or blue, the velocity in varying color intensities and turbulent flow through color mixing. For determination of the velocity of flow at any point in the vessel, additionally, the pulsed Doppler method is available. The diagnosis of obstruction is based on delineation of plaques in the vascular lumen as well as changes in profile of the flowing blood. Color Doppler ultrasonography enables differentiation of high-grade stenosis from occlusion, aids and rapid localization of a stenosis and permits correction of the angle between the Doppler beam and flow in the vessel without providing quantitative evaluation of the degree of stenosis; the latter, however, can be mediated from the recorded velocity profile of the pulsed Doppler method Through demonstration of color-coded blood flow, the patency of bypass grafts can be documented. Additionally, information can be obtained with regard to the proximal and distal anastomoses, flow patterns in the region of preserve venous valves, stenoses and arterio-venous fistulas. Pseudoaneurysms are seen as cavity-like perivascular structures devoid of echo signals, the contiguous access to the lumen of which can be verified by display of pulsatile, systolic-diastolic flow in the color-coded image. With color Doppler ultrasonography abnormal flow patterns incurred through atherosclerotic changes in the vessel wall, stenoses, anastomoses, aneurysms and pseudoaneurysms can be reliably detected.(ABSTRACT TRUNCATED AT 250 WORDS)