Reproducibility of Computed Tomography Volumetry for Predicting Post-Donation Remnant Renal Function: A Retrospective Analysis

Abstract

Background: Recent studies indicate that split renal function calculated by computed tomography (CT) volumetry is equally or more useful than that calculated by nuclear renography for donated kidney side selection. However, it remains unclear if CT volumetry accurately reflects split renal function as measured by nuclear renography. Therefore, this study aimed to evaluate the reproducibility of CT volumetry.

Methods: Data from 141 donors who underwent living donor nephrectomy at Nara Medical University from March 2007 to June 2021 were reviewed. The correlation and agreement between the predicted postdonation estimated glomerular filtration rate (eGFR) by ^99mTc-diethylenetriamine penta-acetic acid (DTPA) scintigraphy and by CT volumetry were evaluated by the Pearson's correlation coefficient and Bland-Altman analysis, respectively. Moreover, a comparison in split renal function categorization between ^99mTc-DTPA scan and CT volumetry was performed.

Results: A total of 133 donors were included in the analysis. There was high correlation between the predicted postdonation eGFR by ^99mTc-DTPA scintigraphy and by CT. Moreover, there was agreement in the predicted postdonation eGFR between ^99mTc-DTPA scintigraphy and CT volumetry (Bland-Altman analysis [bias, 95% limits of agreement]; 0.83%, -5.6% to 7.3%). However, in one of 17 donors with absolute split renal function greater than 10% by ^99mTc-DTPA scintigraphy, this clinically significant difference was missed by CT volumetry.

Conclusion: There are donors for whom a clinically significant split renal function is not accurately reflected in CT volumetry. Future studies need to amend this discrepancy.