The anatomic evaluation of the internal mammary artery using multidetector CT angiography.

To determine the normal anatomic features and variations of the internal mammary arteries (IMAs) and to describe the relationship between the diameter and distance to the sternal edge of the IMAs, gender, and location (right-left) of the IMAs in patients who underwent multidetector computed tomography (MDCT) angiography of the thorax for various reasons. A total of 164 patients who underwent MDCT angiography of the thoracic vascular structures for various reasons were analyzed retrospectively. The right and left IMAs were analyzed individually, and normal anatomic features and variations were recorded. The relationships between gender, side and diameter of the IMAs, and distance to the sternal edge of the IMAs were evaluated. There were 328 (164 right, 164 left) IMAs in 164 patients (110 males, 54 females; mean age, 43.96 years). A total number of five arteries (1.5%) had anatomic variation. Whereas 325 IMAs had an origin separate from the subclavian artery, three LIMA of the 328 arteries (0.91%) had a common origin with the thyrocervical trunk or costocervical trunk. Two (0.6%) IMAs (one LIMA and one RIMA) in the same patient were duplicated at the level of the first and second costal cartilage. There were no statistically significant correlations between age and diameter or between gender and diameter of the RIMA and LIMA at the origin and level of tracheal bifurcation (P > 0.05). Mean distance between the lateral margin of the sternum and midpoint of LIMA and RIMA were 12.42 mm and 13.00 mm, respectively. The normal anatomic features and variations of the IMAs have an important role in cardiovascular bypass surgery, breast reconstruction, and percutaneous transthoracic procedures. MDCT angiography allows a precise and detailed evaluation of IMAs.