[Study of renal veins by multidetector-row computed tomography scans]

Abstract

Purpose: To determine the prevalence of renal vein variants. To investigate the distribution of renal veins.

Methods: We retrospectively reviewed spiral computed tomography (CT) scans of the abdomen performed during a two-month period. The same protocol was used for all CT scans: same multidetector-row CT scanner (Siemens(®)), 1 to 2-mm section thickness, injection of intravenous iomeprol. The study group included 121 patients, aged 21.7 to 93.4 years (mean age 60.9 ± 15.4 years). The sex ratio was 2/1, with 80 men and 41 women.

Results: Seventy-three percent of the study group (88 patients) had no variants of the renal veins. Indeed almost 40% (48 patients) had one artery and one vein on each side, with typical course, and 33% (40 patients) had course and/or number variants of the renal arteries. Variants of the right renal vein consisted in multiple veins in 20.6% (25 cases). We detected no case of multiple left renal veins, but we described variations of its course in 9.1% (11 cases): 5 cases of retroaortic left renal vein (4.1%) and 6 cases of circumaortic left renal vein (5%). Three of these 11 patients had an associated double right renal vein. The probability to have a right renal vein variant was significantly higher than a left one (OR = 2.6, P = 0.01). And we found a significantly higher risk of having a venous variant in women (OR = 2.4, P = 0.04). We detected no case of inferior vena cava variant.

Conclusion: In our study, prevalence of a circum- or retroaortic left renal vein appeared higher than previously reported in the literature (9.1%). Knowledge of anatomical variants of renal vasculature is crucial and this study puts the emphasis on variations of course and number of renal vessels. Those variations are not so uncommon and should be known by radiologists and also by surgeons. Their knowledge has major clinical implications in practice and it contributes to the safety of renal and retroperitoneal surgery.

Keywords: Circumaortic renal vein; Inferior vena cava; Renal vein; Retroaortic renal vein; Veine cave inférieure; Veine rénale; Veine rénale circumaortique; Veine rénale rétro-aortique.