Anatomical observations on the renal veins and inferior vena cava at magnetic resonance angiography

Purpose To describe the renal vein and inferior vena cava (IVC) anatomy found at abdominal magnetic resonance (MR) angiography. Methods Gadolinium-enhanced, three-dimensional, time-of-flight MR angiograms of 150 patients were evaluated for the number and configuration of the renal veins, and the number, configuration, and dimensions of the IVC. Data were analyzed with the Student's ttest. Results Retroaortic left renal veins were found in 7% of patients, circumaortic left renal veins in 5%, multiple right renal veins in 8%, and duplicated IVCs in 0.7%. The length of the infrarenal IVC averaged 94 mm in females and 110 mm in males (p<0.00001). The length of the infrarenal IVC in patients with circumaortic and retroaortic left renal veins averaged 76 mm and 46 mm, respectively. The mean maximal caval diameter was 23.5±4 mm. No megacavae (diameter of the mid-IVC > 28 mm) were identified. Conclusion Variant renal vein and IVC anatomy can be identified at MR angiography.