Measurement of distensibility of blood vessels using cineangiograms.

We developed a new, cineangiographic method to accurately measure the dynamic changes in the internal diameter of human arteries in vivo. Cine films were digitized at a spatial resolution of 4 microns/pixel, using a line image sensor. The vessel edges, with a Gaussian fit to a unilateral profile curve of the vessel, were determined with the aid of a computer program. We measured contrast-filled cylinder vessel models (2 to 7 mm in diameter) and evaluated precision, accuracy and linearity of the diameter measurement. A pulsatile vessel model of about 3.9 mm in internal diameter was used to examine the reliability of our method for detecting arterial wall motion. If the coefficient of variation of the vessel diameter determined cineangiographically was less than 2.2% we considered the cineangiograms sufficiently accurate to determine the internal vessel diameter and evaluate arterial distensibility.