A noncontact method for three-dimensional analysis of vascular elasticity in vivo and in vitro.

A new method is described to measure the deformation of the blood vessel wall simultaneously in longitudinal and circumferential directions. This information is of paramount importance for further characterization of the elastic properties of the arterial wall. The new method consists of a closed-circuit TV system in conjunction with a video dimension analyzer (VDA). The VDA utilizes the video signal from the TV camera and forms a DC voltage proportional to the distance between two selected points in the scene. The resulting analog voltage, calibrated in dimensional units, is recorded. Dimensional changes in two directions, due to intraluminal pressure oscillations, are tracked continuously. The measurement can be performed in vivo on exposed vessels as well as in vitro on excised specimens. Distortion caused by the end effects is completely eliminated. For further data analysis, the wall thickness of the artery is determined microscopically. Stress and strain relationship in longitudinal and circumferential directions is calculated for every intraluminal pressure change. This approach yields data on mechanical properties of the vessel wall in a far more physiological way than the hitherto used direct-contact techniques.