Inter-observer and inter-modality concordance of non-contrast MR angiography and CT angiography for preoperative assessment of potential renal donors

Magnetic resonance angiography (MRA) is rapidly being employed as an effective substitute for CTA, particularly in situations of poor kidney function. We aimed to examine the inter-observer and inter-modality reliability of non-contrast MR angiography (NC-MRA) and CTA as a non-invasive tool for assessing the anatomical findings of potential living kidney donors. All potential donors were referred from specialized kidney transplantation center and underwent NC-MRA of the renal arteries using a respiratory-triggered magnetization prepared 3D balanced steady-state free precession (b-SSFP) with inversion recovery pulses and fat saturation (Inhance 3D Inflow Inversion Recovery (IFIR)). Two experienced radiologists reviewed NC-MRA images and were asked to evaluate both renal arteries anatomy and their branching pattern, presence of accessory or aberrant renal arteries, and identify any anatomical variant. Lin’s correlation test was performed to test MRA readings by each of the two observers against CTA findings which considered as the gold standard for assessment of renal arteries. Additionally, observers were asked to assess the image quality. The study included 60 potential kidney donors (43 males and 17 females) with mean age ± SD of 31.3 ± 5.6 years. Excellent to very good inter-observer agreement was found between both observers in the assessment of renal arteries by NC-MRA. There was perfect concordance between MRA and CTA findings in detecting early arterial division, caliber, and length of left extra-parenchymal segmental branches. Moderate concordance was found in the assessment of the supplied segments of extra-parenchymal segmental renal arterial branches and substantial concordance between both MRA observers’ findings in the remaining variables of the study. There was excellent agreement between both observers in the assessment of image quality parameters. NC-MRA for the renal arteries is an effective alternative for CTA without the risks of radiation or contrast media.