The minimum error in estimating coronary luminal cross-sectional area from cineangiographic diameter measurements

A formal analysis of the error associated with the use of radiographic diameter measurements in estimating the luminal area of an elliptically-shaped coronary cross-section was performed. When two views are available, the maximum potential error was found to decrease rapidly as the angle between the views increased to 90 degrees, but this error was small (less than 25%) for orthogonal views only for mild degrees of ellipticity (major/minor axis ratio less than 2). Since, for each successive doubling of the number of radiographic views, a stepwise reduction in the potential error by an approximate factor of only one-half was found, a large number of views is required to eliminate the potential error associated with diameter assessment of highly elliptical lumena.