Better visualization of the asymmetric lesion in coronary arteriography utilizing cranial and caudal angulated projections.

For optimum accuracy, coronary arterial lesions should be visualized as perpendicularly and circumferentially as possible to the course of the affected segments. In the presence of left ventricular enlargement or a heart lying transversely within the chest, the proximal left coronary artery and its two major branches, as well as the distal right coronary artery, show foreshortening or overlap in the standard transverse oblique projections, leading to serious underestimation of the degree of disease present. If the lesions are also asymmetric, then the underestimation will be further enhanced unless the vessel is viewed with added transverse axial projections obtained when an image-intensifier system mounted with a C-arm or U-arm is used.