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

ABSTRACT

PURPOSE: 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. MATERIALS AND METHODS: 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. RESULTS: Size-specific dose estimate of low-dose CT angiography (9.5 ± 0.8 mGy) was significantly lower than standard CT angiography (22.7 ± 4.1 mGy) (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). CONCLUSION: Low-dose CT angiography using ASiR-V is useful to evaluate renal vasculature for potential living renal donors. KEY POINTS • 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 ± 0.8 mGy) than with standard computed tomography (CT) angiography (22.7 ± 4.1 mGy). • Low-dose CT using ASiR-V is useful for living donor evaluation before nephrectomy.