Multidetector row CT urography: does supine or prone positioning produce better pelvecalyceal and ureteral opacification?

PurposeTo evaluate whether supine or prone positioning improves pelvicalyceal and ureteral opacification at multi-detector row computed tomographic (CT) urography.MethodsWe retrospectively reviewed the CT urograms of 114 consecutive patients performed for hematuria. Using a “split-bolus” technique, all patients were imaged 340 s after the injection of intravenous contrast, 63 in the supine and 51 in the prone position. The right and left pelvicalyceal systems and ureters were divided into six segments: anterior calyces, posterior calyces, renal pelvis, proximal ureter, mid ureter, and distal ureter. Two readers rated the opacification of each segment in consensus on a four-point scale from 0 (no opacification) to 3 (excellent opacification). Opacification scores were compared between supine and prone CT urograms using generalized estimating equation models.ResultsSupine positioning resulted in higher opacification scores of the renal pelvis and the posterior calyces than prone positioning (P<.01). Prone positioning resulted in higher opacification scores of the anterior calyces only (P<.01). No significant differences were seen between the supine and prone opacification scores for the proximal, mid, or distal ureters (P values all >.5).ConclusionSupine positioning results in overall greater opacification of the pelvicalyceal system compared to prone positioning at CT urography.