PURPOSE:

To evaluate whether supine or prone positioning improves pelvicalyceal and ureteral opacification at multi-detector row computed tomographic (CT) urography.

METHODS:

We 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.

RESULTS:

Supine 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).

CONCLUSION:

Supine positioning results in overall greater opacification of the pelvicalyceal system compared to prone positioning at CT urography.