Correlation analysis of renal scan and volumetric perfusion CT in the assessment of living kidney donors

Objective : to evaluate the correlation between renal scan (RSc) and volumetric multislice computed tomography (perfusion CT) in living kidney donors, with the goal of identifying interchangeable functional parameters and optimizing the preoperative assessment of split renal function. Materials and methods . The study included 54 living kidney donors (totaling 108 kidneys). Split renal function was assessed using RSc with 99mTc-mercaptoacetyltriglycine (MAG3) and contrast-enhanced volumetric MSCT. Key parameters from nephroscintigraphy included renal plasma flow (RPF), time to maximum tracer accumulation (Tmax), and excretion half-life (T½). Single-photon emission computed tomography (SPECT) analysis included arterial flow (AF), blood volume (BV), extraction fraction (FE), and indexed extraction fraction (IFE). Correlation between modalities was analyzed using Pearson’s correlation coefficient and Bland–Altman plots. Results . Significant correlations were observed between RSc and volumetric MCT parameters. A strong negative correlation was found between Tmax and AF (r = –0.75, p < 0.001), indicating an inverse relationship between blood flow velocity and renal filtration capacity. Similarly, T½ showed a negative correlation with FE (r = –0.75, p < 0.01), suggesting that a shorter tracer half-life corresponds to more efficient renal extraction. A strong positive correlation between RPF and IFE (r = 0.79, p < 0.001) supports the feasibility of using indexed CT perfusion as a surrogate for assessing RPF. Bland-Altman analysis showed that differences between the two diagnostic methods remained within clinically acceptable limits, confirming their potential interchangeability in preoperative donor assessment. Conclusion . The study demonstrates the potential for partial interchangeability between RSc and volumetric CT perfusion in the preoperative assessment of kidney donors. While CT perfusion offers superior accuracy in assessing renal blood flow, nephroscintigraphy remains the method of choice for evaluating excretory function. The combined use of both modalities improves diagnostic accuracy and kidney donor selection, thereby improving the safety of kidney transplant programs.