Investigation of the clinical value of assessing renal size on computed tomography in autosomal dominant polycystic kidney disease.

We examined relationship between serum creatinine concentration (Scr) and renal size on CT scans on 32 occasions in 25 patients with autosomal dominant polycystic kidney disease (ADPKD). As a result, a significant correlation was observed when the Scr was less than 5 mg/dl, as shown by the correlation coefficient (r) and P values of 0.803 and 0.0001, respectively. However, these values changed to 0.482 and 0.0093, respectively when 2 cases with Scr 6.2 and 6.4 mg/dl were included, and further changed to 0.005 and 0.9775 when an additional 4 cases with Scr 7.8, 9.9, 11.1 and 20.1 mg/dl were included. Renal size is therefore thought to be a useful parameter of renal function when the Scr is less than 5 mg/dl in ADPKD, but not when the Scr exceeds 6 mg/dl, and is regarded as useless for predicting the time at which dialysis would be required.