CT is widely used as a primary imaging technique for evaluation of urinary tract abnormalities. Recently, there has been increasing interest in using CT for the evaluation of the renal collecting system and ureters because of technical advances including MDCT and 3D software development. Detailed evaluation of the renal collecting system and ureters is possible with increased spatial resolution and isotropic data sets that can now be created using MDCT.
For evaluation of the renal collecting system and ureters, optimal opacification and distention is essential. Various techniques to optimize opacification and distention of the renal collecting system and ureters have been reported in the literature. To optimize opacification, abdominal compression [1-5], saline infusion [6, 7], multiple acquisitions [2], prone positioning [1, 6, 7], and furosemide administration [7] have been successfully used. Abdominal compression has also been used to improve distention of the renal collecting system [4].
As a part of a routine 3-phase CT examination in patients with suspected urinary tract abnormalities, we evaluated the degree of opacification of the renal collecting system and ureters on excretory-phase images obtained without abdominal compression, prone positioning, or IV administration of saline or furosemide. Instead, 750-1,000 mL of water was ingested as oral contrast and for diuresis. The purpose of this study is to evaluate the degree of opacification of the renal collecting system and ureters on excretory-phase contrast-enhanced CT using only oral ingestion of water without abdominal compression, saline infusion, or prone positioning.