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Updated: Jul 11, 2026

Ultrasonography of the Adult Male Urinary Tract for Urinary Functional Testing
Published on: August 14, 2019
Comparison of urinary tract distension and opacification using single-bolus 3-Phase vs split-bolus 2-phase
Jonathan R Dillman1, Elaine M Caoili, Richard H Cohan
1Department of Radiology, University of Michigan Medical Center, Ann Arbor, MI 48109-0302, USA.
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 < or = 0.04). Qualitative opacification scores for the lower urinary tract were significantly higher, using single-bolus technique for only 1 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.
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