Can CT or MRI volumetry substitute scintigraphy in living kidney donor evaluation? A systematic review

Background

Current potential living kidney donor’s assessment includes functional and anatomical evaluation. Scintigraphy is recommended in some cases and some centers include this test in the donor’s protocol. Recent studies advocate for the avoidance of this test as CT or MRI volumetry showed to accurately assess donor’s renal function.

Objective

To summarize scientific evidence on image tests for pre-donation and/or post-nephrectomy renal function evaluation.

Evidence acquisition

This review followed the guidelines set by the European Association of Urology and adhered to PRISMA 2020 recommendations. The protocol was registered in PROSPERO on 10th December 2022 (ID: CRD42022379273).

Evidence synthesis

Twenty-one studies met the inclusion criteria after thorough screening and eligibility assessment. According to QUADAS-2, patient selection and flow/timing domains showed a predominant low risk of bias.

The correlation between split renal function (SRF) using CT and scintigraphy varied from weak (r = 0.21) to remarkably strong (r = 0.949). Bland–Altman agreement demonstrated moderate to excellent results, with mean differences ranging from -0.06% to 1.76%. The correlation between split renal volume (CT) and estimated glomerular filtration rate (eGFR) at 6 months or 1 year after nephrectomy showed a moderate correlation, with coefficients ranging from 0.708 to 0.83.

The correlation between SRF (MRI) and renal scintigraphy reported a moderate correlation, with correlation coefficients of 0.58 and 0.84. MRI and scintigraphy displayed a good agreement, with a 66% agreement observed and mean differences of ± 0.3%.

Conclusions

Despite study heterogeneity, MRI or CT-based renal volumetry appears promising compared to scintigraphy, with favorable correlations and agreement.