Comparison of urinary tract distension and opacification using single-bolus 3-phase vs split-bolus 2-phase multidetector row CT urography

Objective: To compare urinary tract distension and opacification obtained with single-bolus 3-phase and split-bolus 2-phase multidetector row computed tomographic urography (CTU) techniques. Methods: Twenty-six single-bolus 3-phase CTU examinations were retrospectively compared with 26 split-bolus 2-phase examinations. Two readers reviewed excretory-phase imaging to record quantitative measurements of urinary tract distension and qualitative measurements of urinary tract opacification. Results: Single-bolus 3-phase CTU technique provided better overall urinary tract distension than did split-bolus 2-phase technique (P = 0.05). Single-bolus CTU images demonstrated superior lower pole and interpolar region intrarenal collecting system distension when compared with split-bolus CTU images (P < 0.04). Qualitative opacification scores for the lower urinary tract were significantly higher, using single-bolus technique for only I of 2 reviewers. No significant differences between techniques in intrarenal collecting system opacification, ureteral distension, or ureteral opacification were identified. Conclusions: Improved urinary tract distension is obtained with single-bolus 3-phase CTU technique.