Fig. 1.

Image obtained by 256-multi-slice coronary CT angiography. A and C show RCA and conus artery arise separately from the aorta. B and D indicate anomalous origin of LCA from the posterior cusp of the pulmonary artery. In D, note the very close proximity of LCA to the aorta. This close proximity, here called the “proximity error”, misleads the echocardiographer. E shows that the anomalous LCA arises from the posterior cusp (see text); note that RCA is not enlarged, indicative of poor or no intercoronary collateralization. F and G clearly show how the proximity of the anomalous LCA to the aorta can produce misleading images on echocardiogram.