Study of the left renal variations by means of magnetic resonance imaging.

Purpose: A prospective study was designed to figure out the percentages of the left renal vein variations using routine lumbar spinal magnetic resonance imaging (MRI) in patients with neurological problems.

Methods: Between March 2010 and October 2010, the study population was recruited from a total of 2,644 consecutive patients who would undergo a routine lumbar spinal MRI examination. In addition to the routine MRI sequences, axial, balanced turbo field echo sequence (BTFE-BH SENSE) was applied after detection of a left renal vein variation.

Results: As the left renal vein variations, retroaortic left renal vein (RLRV) and circumaortic left renal vein were detected. The number of cases with the correspondent percentages of the total left renal vein variations, RLRV and circumaortic left renal vein were 71/2,644 (2.68%), 44/2,644 (1.66%) and 27/2,644 (1.02%), respectively. In cases with RLRV, the numbers of males and females with their correspondent percentages were 19/44 (43.2%) and 25/44 (56.8%), respectively. In cases with circumaortic left renal vein, the numbers of males and females with their correspondent percentages were 13/27 (48.1%) and 14/27 (51.9%), respectively. With Chi-square test, no statistically significant gender difference was found between the percentages of left renal vein variations (P = 0.83).

Conclusions: MRI is useful in detecting RLRV and circumaortic left renal vein. If a left renal vein variation is detected, an additional BTFE-BH SENSE sequence is suggested to confirm whether it is retroaortic or circumaortic.