Low-dose CT angiography using ASiR-V for potential living renal donors: a prospective analysis of image quality and diagnostic accuracy.

Abstract

To assess image quality and diagnostic accuracy of low-dose computed tomography (CT) angiography using adaptive statistical iterative reconstruction V (ASiR-V) for evaluating the anatomy of renal vasculature in potential living renal donors. Eighty of 100 potential living renal donors were prospectively enrolled and underwent multiphase CT angiography (e.g., unenhanced, arterial, and venous phases) to evaluate the kidney for donation. Either low-dose using ASiR-V or standard protocol was randomly applied. Image quality was analyzed qualitatively and quantitatively with contrast-to-noise ratio (CNR) and signal-to-noise ratio (SNR). Renal artery and vein number, early branching vessel from renal arteries, and drainage of left-sided ascending lumbar vein to left renal vein were assessed. Reference standard for renal vasculature was surgical confirmation. Size-specific dose estimate of low-dose CT angiography (9.5 ± 0.8mGy) was significantly lower than standard CT angiography (22.7 ± 4.1mGy) (p < 0.001). Thus, radiation dose was reduced by 58.2% with low-dose CT. Both CNR and SNR of low-dose CT were significantly higher than those of standard CT (p < 0.001). Between the two CT methods, image quality was similar qualitatively (p > 0.05). Of 80 participants, 44 (55.0%) underwent nephrectomy. Both CT methods accurately predicted the anatomy of renal vasculature (standard CT, 100% for all variables; low-dose CT, 96.6% for renal vessel number or early branching vessel and 85.7% for drainage of left-sided ascending lumbar vein to left renal vein; p > 0.05 for all comparisons). Low-dose CT angiography using ASiR-V is useful to evaluate renal vasculature for potential living renal donors. • In this prospective study, adaptive statistical iterative reconstruction V (ASiR-V) allowed 58.2% dose reduction while maintaining diagnostic image quality for renal vessels. • As compared with the standard protocol, the dose with ASiR-V was significantly lower (9.5 ± 0.8mGy) than with standard computed tomography (CT) angiography (22.7 ± 4.1mGy). • Low-dose CT using ASiR-V is useful for living donor evaluation before nephrectomy.