Anatomic and machine projection angles of various radiographic imaging systems used for cardiac angiography

Quantitation of coronary artery dimensions in serial angiographic studies requires an awareness of the variety, complexity, and implications of radiographic imaging equipment used for coronary arteriography. Recognition of the geometric complexities inherent in angiographic imaging systems is important in understanding complex image rotations and ensuring identity of projections when serial comparison is desired. Tables, figures, and formulae are provided to permit translation of machine angles into patient reference angles and vice versa.