A Nondestructive Ultrasonic Technique to Measure Diameter and Blood Flow in Arteries

The authors are with the Applied Physiology Branch. Environmental Science Division. U.S. Air Force School of Aerospace Medicine, Brooks AFB, Tex. 78235. A nondestructive technique to continuously monitor diameter and blood flow at the same point along the descending thoracic aorta has been developed. A probe was passed down the esophagus to a level 1 to 2 cm distal to the aortic arch. On its distal end were Doppler-shift velocity-detecting and pulse-echo position- sensing crystals. The pulse-echo system was used not only to measure the diameter of the aorta, but also to aim all of the probe crystals directly across the axis of the aorta. Information supplied by this system aided in the identification of the aorta and helped to avoid measurement artifacts such as the inclusion of other arteries, veins, or moving structures.