Three-dimensional densitometric assessment of coronary artery stenosis

Biplane densitometric measurements of area reduction percentages in coronary arteries should result in equal values for both planes. Strong discrepancies have, however, been reported by some authors. To examine the role of an inadequate spatial orientation of the cross sections relative to the X-rays of both planes, stenoses of sixty-four patients were measured in biplane digital angiograms. First, the densitometric areas of the reference and stenotic cross sections and the resulting area reduction percentages were computed in each plane. Then, the four spatial angles between vessel axis and X-rays needed to correct the densitometric areas for inadequate orientation of the corresponding cross sections in space were determined by 3D-reconstruction of the relevant vessel segments. Comparison of the interplane correlation of the area reduction percentages before and after correction of the densitometric cross sectional areas showed that the initial discrepancies were more than halved