Prevelance of renal artery origin levels and renal vascular variations: evaluation with MDCT angiography

Introduction and Objective: The purpose of this study is to contribute to the literature with detailed research such as the prevalence of renal artery origin levels, renal artery (RA) and renal vein (RV) variations separately and together, categorization of multiple renal artery and vein variations, the distribution of these variations with respect to gender on multi-detector computed tomographic (MDCT) angiography in a wide patient population. Results: Renal artery origins; both main renal arteries most commonly at the upper edge of the L1 vertebrae corpus and both main renal arteries originating mainly between the upper edge of the L1 vertebrae and the lower edge of the L2 vertebrae (right main renal artery 88.9% and left main renal artery 92.4%). Ratios of renal artery variations; the frequency of uni- or bilateral early branching of main renal artery were found to be 13.8% (right 9.1%, left 5.5%) and 0.5% whereas uni- or bilateral multiple renal arteries were found to be 21.4% (right % 19.4, left % 20.6) and 7% respectively. When the multiple renal arteries were categorized according to their numbers, the frequency of double renal artery was 19.2% on the right and 19.3% on the left; the frequency of triple renal artery was 1.8% on the right and 2% on the left; The frequency of quadruple renal artery was 0.3% on the left. Bilateral double renal artery incidence was 4.2% and bilateral double hilar artery variation was the most common. When multiple renal arteries were classified as hilar, superior polar and inferior polar, the frequency of hilar accessory artery was 16.8% on the right and 16.8% on the left; superior polar artery frequency was 3.7% on the right and 4.7% on the left; inferior polar artery frequency was 1.5% on the right and 0.9% on the left. Ratios of renal vein variations; unilateral multiple renal vein 29.3% (right 28.9%, left 1.2%), bilateral renal vein 0.2%; unilateral late venous confluence 20.4% (right 9.2%, left 12.7%), bilateral late venous confluence 1.3%; circumaortic left renal vein was 3.4%, retroaortic left renal vein was found to be 5.8%. When multiple renal veins were classified, the frequency of double renal vein was 26.8% on the right and 1.1% on the left; the frequency of the triple renal vein was 2.0% on the right and 0.1 on the left; the frequency of quadruple renal vein was 0.1% in the right and the frequency of bilateral double renal vein was 0.5%. The frequency of coexistence of renal artery and vein variations were found to be 22.9% and the most frequent coexistent variation were found to be presence of left hilar artery and double renal vein on the right side. Conclusion: We found that the prevalance of early branching of the main renal artery, variations of late venous confluens in the main renal veins, coexistent of renal artery and vein variations may be higher than the rates reported in the literature.It is important to consider this situation in interventional and surgical procedures.