Normal pattern of the left anterior descending artery (LAD) as seen on axial plane (A, B) and multiplanar reformation (C, D). The left anterior descending artery (arrow) is embedded through all of its length in the epicardial fat. *Interventricular septum. CCTA = coronary computed tomographic angiography.

Intramuscula LAD, superficial type, as seen on axial plane (A, B) and multiplanar reformation (C, D). The mid LAD (arrow) shows a typical deviation and straitening and is only partially surrounded by myocardium. Of note, an atherosclerotic plaque in the proximal LAD, whereas the intramuscular segment is free of disease. Abbreviations as in Figure 1.

Intramuscular LAD, deep type, as seen on axial plane (A, B) and multiplanar reformation (C, D). The mid LAD crosses deeply into the myocardium (arrows). Abbreviations as in Figure 1.

Intramuscular LAD, right ventricular type (arrow). In this variant it is frequently difficult to follow the LAD on sequential axial images (A, B) because it disappears between the right ventricular trabeculae, whereas the multiplanar reformation images easily show its intraventricular course (C, D). *Interventricular septum. RV = right ventricle; other abbreviations as in Figure 1.

Distal intramuscular LAD, deep type (arrow), as seen on multiplanar reformation (MPR) (A) and volume-rendering reformation (B). The latter allows an easy 3-dimensional demonstration of the anatomical relationship between the intramuscular segment and the apex, a useful information for the cardiac surgeon when planning coronary artery bypass grafting. Other abbreviations as in Figure 1.

A calcified plaque is located just proximal to the intramuscular segment (open arrow). No evidence of atherosclerosis is noted in the intramuscular segment (solid arrow).