Effect of vessel orientation on videodensitometry quantitative coronary arteriography

Abstract

Cross-sectional area measurement using videodensitometry coronary arteriography is a function of the out-of-plane angle of the vessel segment with respect to the face of the image intensifier. Therefore, absolute cross-sectional area measurement using videodensitometry requires correction for the out-of-plane angle. In this study, a simple technique to measure the out-of-plane angle of a vessel segment using images from two different projections is presented. The technique was tested using vessel phantoms imaged at different out-of-plane angles. A vessel segment with an out-of-plane angle of less than 20 degrees introduces less than 5% error in the cross-sectional area measurements. However, an out-of-plane angle of 60 degrees can introduce more than 90% error. The results of the measurements show that correction for the out-of-plane angle reduces the error in cross-sectional area measurement to less that 5%. The correction for the out-of-plane angle makes it possible to measure the absolute cross-sectional area using videodensitometery, which can be used to assess a diseased vessel segment with any complex geometry.

Quantification of breast arterial calcification using full field digital mammography

“…The out of plane angle can possibly be calculated using mammography images acquired at two different projections. 24 However, it is not clear yet whether the knowledge of calcium distribution within the breast is of any clinical utility.…”

“…The error from a known difference in magnification can be easily corrected. 24 However, as the true location of any calcification is unknown, the error can only be predicted for any given location. In clinical implementation, the calcified vessel will be assumed to be in the middle of the compressed breast.…”