Determination of coronary artery diameter and contrast medium concentration from angiograms - possibilities and limitations.

The quantification of coronary arterial stenosis is a great clinical importance. The coronarograms obtained with the usual X-ray systems are severely distorted. The principal effects, underlying this distortion are the focal spot dimensions, blurring due to object movements and noise due to individual X-ray photons. Some general assessment, as well as a simplified procedure are given. Under the assumptions of a cylindrical artery and a Gaussian curve for its density graph, a relation can be derived to calculate the artery diameter. Application to test objects show that this is a practicable method.