RESUMO
BACKGROUND: CT volumetry has previously been proposed as an alternative to scintigraphy for the evaluation of pre-donation split renal function and the prediction of post-donation renal function in living kidney donors. The aim of our study was to retrospectively assess the relevance of three CT volumetry techniques for estimating pre-donation kidney function and predicting the risk for chronic kidney disease (CKD) at 1-year post-nephrectomy in a French cohort of living donors using isotopic measures of kidney function. METHODS: Kidney volume was quantified pre-donation for 105 donors using three methods total parenchymal three-dimensional renal volume (3DRV), total parenchymal renal volume contouring (RVCt), and renal cortical volume (RCoV). Subjects also had a 51Cr-EDTA scintigraphy to measure glomerular filtration rate (mGFR) pre-donation and 1-year after donation. For each volume, we tested for association with mGFR using univariate regression models, and computed receiver operating characteristics analyses to assess their predictive potential of post-donation CKD. RESULTS: Our population was composed of healthy subjects, who were predominantly female (69%) with a median age at donation of 51yo. Median mGFR was 102â¯mL/min/1.73â¯m2 at pre-donation and 66â¯mL/min/1.73â¯m2 1-year after nephrectomy. The pre-donation median volume of the preserved kidney was 156â¯cm3, 163â¯cm3 and 99â¯cm3 for the 3DRV, RVCt and RCoV methods respectively, with a high correlation observed between each technique (Râ¯>â¯0.84). For all methods, total kidney volume was significantly associated with pre-donation mGFR (Pâ¯<â¯0.001). Preserved kidney volume was also strongly correlated with post-donation mGFR (Pâ¯<â¯0.0001), with the strongest correlation observed for RCoV (Râ¯=â¯0.60 vs. Râ¯=â¯0.39 and Râ¯=â¯0.51 for 3DRV and RVCt, respectively). Finally, the RCoV method yielded the best predictive value of 1-year post-donation CKD (AUCâ¯=â¯0.80 vs. AUCâ¯=â¯0.76 and 0.70 for RVCt and 3DRV, respectively). CONCLUSIONS: In our cohort of healthy donors with measured kidney function, cortical volumetry (RCoV) appears as the best volumetric technique to use as a surrogate to scintigraphy for estimating pre-donation split renal function and predicting post-donation renal outcomes.