Effect of posture on renal volume: evaluation using multi-posture MRI.

Measurement of renal volume is useful in the early detection and monitoring of renal disease. However, changes in renal volume during postural changes are not clear. Therefore, this study used multi-posture MRI system that can obtain renal images in any posture to assess the effect of posture on renal volume in the supine and upright positions. This study included 11 healthy volunteers (8 men and 3 women; mean age, 23.1 years; body mass index, 19.9 ± 1.3 kg/m2). Multi-posture MRI was used to compare renal volumes (total kidney, renal cortex, renal medulla, and renal pelvis volumes) between supine and upright positions. Wilcoxon signed-rank test was used. A P < 0.05 indicated significance. The total kidney, renal cortex, and renal medulla volumes in the upright position were significantly smaller than those in the supine position (P < 0.05 for all). Multi-posture MRI may provide new information on renal volume.