Anatomical variations in branching pattern of arcus aorta: 64-slice CTA appearance

To review the 64-slice CTA (computed tomography angiography) appearance of anatomical variations in branching pattern of the arcus aorta, and to determine their prevalence in 1001 cases. 1001 cases that underwent carotid CTA (performed by a 64-slice scanner) were included in the study. Seven types of aortic arch were found. In 853 cases (853/1001, 85.2 %) classical branching pattern of arcus aorta (three branches; TB, LCC, LS) was observed. Variations were present in 147 cases (147/1001, 14.7 %). One case (1/1001, 0.1 %) had right aortic arch. The most frequent variation was origination of LCC from TB (arch with 2 branches, TB with LCC and LS) which was observed in 78 cases (78/1001, 7.8 %). Origination of LV directly from the aortic arch (four branches; TB, LCC, LV, LS or TB, LCC, LS, LV) was observed in 51 cases (51/1001, 5.1 %). In two cases (2/1001, 0.2 %) truncus bicaroticus (3 branches; RS, common trunk for carotids, LS) was present. In seven cases (7/1001, 0.7 %) aortic arch had four branches in the order of RCC, RS, LCC and LS. In one case (1/1001, 0.1 %) left truncus brachiocephalicus (three branches; RS, RCC, LTB) was present. Seven cases (7/1001, 0.7 %) had aberrant RS (RCC, LCC, LS, RS). Variations in branching pattern of arcus aorta are not rare and being aware of them before surgical and interventional procedures of this region is important. CTA can depict the anatomical features of the aortic arch and is valuable as a road map.