A nondestructive technique to measure wall displacement in the thoracic aorta.

OLSON, ROBERT M., AND DAVID K. SHELTON, JR. A nondestructive technique to measure wall displacement in the thoracic aorta. J. Appl. Physiol. 32(l): 147-151. 1972.-This paper presents a simple, highly precise, nonsurgical technique to follow aortic wall motion and consequently monitor pulsatile changes in thoracic aortic diameter. The diameter contours which result can be used in much the same way as pressure contours, because both contours are practically congruent. Pressure contours have been used to estimate cardiac output, to detect some valvular heart disease, and to detect such abnormalities of the aortic arch as coarctation. The technique utilizes an ultrasonic crystal mounted on an esophageal probe by means of a platform which can be tilted. Ultrasound is passed across the esophageal wall and reflects from the walls of the aortic arch. The reflected signals are processed, like radar, to track the position of the reflecting surface, i.e., the aortic walls.