Mean and standard deviation of the distance (a), short axis diameter (b), and cross-sectional area (c) gradients for the three major coronary arteries in 36 normal RCA, LAD, and LCx arteries, as well as corresponding gradients in 20 patients with LAD disease. Only the distance gradient has a significant difference between normal coronary arteries; the RCA is significantly closer to zero than the LAD and LCx (ANOVA p < 0.001). Patients with LAD stenosis have significantly different gradient magnitudes than normals (p < 0.011).