Dynamic aortic diameter measurements in Vivo using roentgen videometry

A technique for quantitation of the elastic characteristics of the aorta in vivo has been developed and tested in dogs and humans. The method depends upon angiocardiographic data recorded with a video system to quantitative pulsatile changes in vascular size. From such measurements of diameter and simultaneous intravascular pressure recorded at the same point in the aorta, vascular elasticity may be calculated. The data reduction method is unique and represents the prime contribution of this thesis. System noise was reduced with the aid of a digital computer averaging technique. Advantages and limitations of the method are discussed and data from experimental animal and human subject are presented to demonstrate its practicality.