Overestimation of stenosis severity by single plane geometric measurements

Degrees of stenosis (DS) obtained geometrically from the angiographic projection which shows the greatest apparent diameter reduction can be suspected of overestimating the lesion severity. In comparison, biplane measurements in more or less orthogonal projections should be more accurate. These points are, however, not quite trivial because the errors depend on the shapes of stenotic lumens and on the edge detection algorithms. To investigate these aspects, 29 lumens of different shapes were computer simulated. The results of the simulation were compared to data obtained in patients by measuring geometrically and densitometrically 25 stenoses in biplane coronary angiograms. The results of the simulation and the patient data agree with the initial expectations.