Triple-bolus CT urography: an optimized approach for vascular assessment in ureteropelvic junction obstruction

Abstract Objectives To evaluate the diagnostic value of triple-bolus computed tomography urography (TB-CTU) for ureteropelvic junction obstruction (UPJO) in comparison with split-bolus CTU (SB-CTU). Methods In this single-centre retrospective study, patients under clinical suspicion of UPJO referred from the urology clinic for CTU examination from January 1, 2017 to January 31, 2022, were included. CTU examinations were performed with SB or TB protocols. The images were reviewed by 2 radiologists for assessment of arterial and venous renal pelvis enhancement and arteriovenous differentiation. Interobserver agreement on arteriovenous differentiation was calculated. Results A total of 23 TB-CTU and 70 SB-CTU examinations were included. The Hounsfield unit (HU) values for the renal artery, renal vein, and upper urinary tract were all significantly higher in the TB group. The proportion of high enhancement of arteries and veins was also significantly higher in the TB group (P < .001). Both radiologists evaluated TB-CTU as providing greater arteriovenous differentiation with strong interobserver agreement (κ = 0.77). Conclusions TB-CTU exhibited superior arteriovenous differentiation in comparison with SB-CTU, with an acceptable radiation dose. Advances in knowledge For patients with suspicion of UPJO, TB-CTU may be the imaging modality of choice for evaluating anatomical structures for further management.