Effect of Prone and Supine Positioning on Computed Tomography Urography Examination.

OBJECTIVES: The aim of this study is to evaluate the effects of performing computed tomography (CT) urogram in the prone position in terms of diagnosis.

METHODS: CT urograms of 208 patients imaged randomly in the prone and supine positions were included in this study. A total of 199 patients and 370 collecting systems were examined in total. Axial raw data and reconstructed coronal thin and thick MIP images with a slice thickness of 5 mm were evaluated by 2 independent radiologists blinded to the initial diagnosis. Renal collecting system, ureters, and bladder were included in radiological evaluation. Anatomically, the renal collecting system was separated into 7 regions. Filling and dilatation of collecting systems were evaluated via images at urogram phase by scoring.

RESULTS: Filling in lower pole infundibulum (p = 0.006), distal ureter (p = 0.006); and highly dilated lower pole calyx (p = 0.020), pelvis (p = 0.006), and bladder (p < 0.001) were determined to be better in images in the prone position compared to the supine position. There were no statistical differences in other regions.

CONCLUSION: Better contrast material filling is achieved in dilated or non-dilated lower pole collecting system, dilated renal pelvis, non-dilated distal ureter of kidney, and in the bladder only by imaging the urogram phase in the prone position compared to the supine position. Additionally, presence of dilatation is a factor that could adversely affect filling. Studies in the future may investigate the contribution of prone positioning to CT urogram with larger series comparing it with other methods and modalities.