MR venography of left renal vein anomalies

The examinations of 71 patients having comprehensive 2D time of flight (TOF) abdominal magnetic resonance venography (MRV) in three planes (axial, sagittal and 10 degrees offset coronal) were evaluated to assess the appearances of anomalous left renal veins as shown by MRV. Six cases of circumaortic left renal vein (CLRV) (8.5%) and one example of retro-aortic left renal vein only (1.4%) were identified, an incidence higher than that in previous computed tomography (CT) studies but comparable to venographic and post-mortem investigations. All retro-aortic components passed in a caudal direction to join the inferior vena cava (IVC) inferior to the anterior limb. MRV acquired in the sagittal plane was found to be most useful for identifying these variants and provided highest signal by avoidance of in-plane flow saturation effects.