MRI evaluation of the adaptive response of the contralateral kidney following nephrectomy in patients with renal cell carcinoma.

PURPOSE: To study the adaptive responses of the contralateral kidney and its association with renal outcome in patients with renal cell carcinoma (RCC) following radical nephrectomy (RN). MATERIALS AND METHODS: Eleven patients with RCC scheduled for RN and 15 control patients scheduled for adrenalectomy (Control) were prospectively recruited. All subjects underwent 4 MRI studies: 1 before surgery and 3 at 1 week, 1 month and 3 months after surgery, respectively. T2-weighted imaging and dynamic contrast-enhanced imaging were performed to estimate the renal volume and renal blood flow (RBF) of the contralateral kidney, respectively. The patients' serum creatinine levels were examined to determine the estimated glomerular filtration rate (e-GFR). The changes in renal volume at 3 months and both RBF and e-GFR during the serial follow-up were compared and associations between both of them were measured in both groups. RESULTS: In the RN group, RBF increased at 1 week (2.78 ± 0.93 mL/min/g, P = 0.002) and 1 month (2.65 ± 0.85 mL/min/g, P = 0.002), compared with presurgical values (1.94 ± 0.61 mL/min/g), and it returned to presurgical levels at 3 months (2.11 ± 0.73 mL/min/g, P = 0.432). In contrast, e-GFR decreased at 1 week (56.4 ± 20.3 mL/min/1.73 m(2) , P = 0.049) and 1 month (52.4 ± 18.8 mL/min/1.73 m(2) , P = 0.027), compared with presurgical values (66.3 ± 18.3 mL/min/1.73 m(2) ), and it returned to presurgical levels at 3 months (73.3 ± 29.5 mL/min/1.73 m(2) , P = 0.496). The renal volume increased at 3 months compared with baseline (198 ± 87 versus 329 ± 175 mL, P < 0.001). The change in renal volume was correlated with the change in RBF at 1 week (r = 0.609, P = 0.047). CONCLUSION: In patients with RCC following RN, an early increase in RBF of the contralateral kidney is associated with late renal hypertrophy which might normalize glomerular hyperfiltration and restore renal function.