A real-time ultrasonic imaging system for carotid arteriography

A real-time ultrasonic imaging system for the noninvasive assessment of atherosclerotic vascular disease has been developed. This instrument displays cross-sectional images of the artery and surrounding tissues plus superimposed profiles of blood flow within the vessel. The anatomical structure is depicted by a 10-MHz B-scan subsystem operating at 15 frames/sec. An instantaneous profile of the blood flow velocity is produced by a 5-MHz pulsed Doppler subsystem that can display the velocity at up to 20 individual points along a line segment intersecting the artery. Cross-sectional high-resolution gray-scale images, both transverse and longitudinal, of the major vessels in the neck in the region of the carotid bifurcation are presented. These images also demonstrate the skin, subcutaneous fat, muscle, and thyroid gland. Estimates of severity of atherosclerotic disease measured as percentage of lumen diameter obstructed by each lesion, are essentially the same as subsequent estimates made using roentgen angiography. Pulsating blood flow profiles in the common carotid have been clearly displayed; however, clinical applicability of the Doppler subsystem is not yet demonstrated.