Visualization of the renal cortex by magnetic resonance imaging

One of the characteristics of magnetic resonance imaging (MR imaging) of the kidney is corticomedullary differentiation (CMD) without the use of a contrast medium. We investigated the con ditions under which corticomedullary differentiation is visualized on MR imaging in 10 controls, 19 patients with renal graft and 7 patients with nephrotic syndrome. T1 weighted images revealed CMD in 10 controls and 12 patients who had good graft function. Five out of 7 patients with chronic rejec tion episodes and 4 out of 7 patients with nephrotic syndrome revealed no CMD. The grading of CMD in 4 different pulse sequences, using the naked eye method, was inversely correlated with the serum creatinine and positively correlated with hematocrit. Furthermore, the visualization of CMD tended to be related to interstitial edema and fibrosis found in renal biopsies of nephrotics, even those within the normal range of renal function. In conclusion, CMD on MR imaging is affected by a combination of clinical parameters such as renal function, hematocrit and renal histological changes.