Dimensions and anatomic variations of left main coronary artery in normal population: multidetector computed tomography assessment

Objectives The aim of our study was to determine the dimensions, morphology and anatomic variations of the left main coronary artery (LMCA) in normal participants, on multidetector computed tomography. Background Accurate imaging of LMCA dimensions and configuration is crucial to avoid misdiagnosis of LMCA disease. Materials and methods Seventy morphologically normal LMCAs of 70 participants were carefully selected from among 600 consecutive coronary computed tomography angiography studies performed in our institute. LMCA cross-sectional diameters and areas were obtained at three points of each vessel: ostium, midvessel and distal. The length, cross-sectional shape, three-dimensional (3D) morphology and position of origin were studied. Influences of age, body weight height and body surface area (BSA) on LMCA dimensions were evaluated. Results Different dimensions in each measured point of the LMCA were detected. Cross-sectional elliptic shape at ostium, mid-LMCA and distal LMCA was found in 66/70 (94%), 51/70 (73%) and 54/70 (77%) of the participants, respectively. On the basis of the 3D presentation, four types of LMCA were identified: biconcave-shape appearance (type 1), tapering morphology (type 2), combined morphology (type 3) and funnel-shape appearance (type 4). Fifty-two of the 70 participants had an LMCA orifice originating in the middle third of the aortic sinus, 15/70 in the posterior third and 3/70 in the anterior third. In men, significant correlation was found between LMCA cross-sectional area and body weight height and BSA. In women, no correlation was found regarding body weight height and BSA. . Conclusion LMCA is not a simple straight tube but usually has various anatomical configurations, variable dimensions and cross-sectional shapes. Ostial angulation is a normal variant usually associated with the posterior position of the LMCA orifice of origin in the aortic sinus. Coron Artery Dis 18:477-482 (c) 2007 Lippincott Williams & Wilkins.