Role of Computed Tomography in Estimation of Residual Renal Function at One Year after Donor Nephrectomy: Comparison with Nuclear Scintigraphy

Computed tomography (CT) is routinely used for preoperative anatomical evaluation of renal donors, but recent studies show that it may be useful as a predictor of renal function too. This study aimed to compare CT volumetry-attenuation-based glomerular filtration rate (GFR) with Tc99m-diethylene-triamine-pentaacetic acid (DTPA) renal scintigraphy GFR and predict post-donor nephrectomy renal function. This is a prospective study involving 39 renal donors at a tertiary care hospital in northern India from 2014 to 2017. Renal volume and attenuation were determined by CT using a semiautomatic tool, and split renal function (SRF) was calculated for each side. CT-GFR was obtained using CT-SRF and global GFR from modification of diet in renal disease equation. At 12 months after nephrectomy, GFR was estimated from serum creatinine (eGFR). Predonation CT-GFR of preserved kidney was used to predict post-nephrectomy renal function which was compared with post-donation renal function calculated using serum creatinine as well as with DTPA-GFR. Pearson correlation coefficient and scatter diagram were used to assess and test the linear relationship between two continuous variables. The Statistical Package for the Social Sciences, version 23, was used for data analysis. There was a highly significant change in mean DTPA-GFR and mean CT-GFR compared to eGFR values (50.79-64.25, 26.50%, and 50.77-64.25, 26.55%, respectively). Similarly, there was a very good correlation between DTPA-GFR and eGFR (r = 0.968, P <0.001) as well as CT-GFR and eGFR (r = 0.968, P <0.001). CT volumetry-attenuation-based GFR accurately predicts post-donor nephrectomy renal function at 1 year similar to Tc99m-DTPA renal scintigraphy.