Understanding multislice CT urography techniques: many roads lead to Rome

Abstract

CT urography has emerged as a serious alternative to conventional urography by utilizing the advantages of modern multislice CT techniques for the visualization of the entire upper urinary tract. Several different examination techniques have been developed in multislice CT (MSCT) urography for improving the opacification and distension of the urinary tract. All efforts in performing MSCT urography have to compromise between the best possible image quality and a reasonably low radiation exposure. Initial low-dose examination protocols are already available. Operating modern MSCT urography properly is not difficult, but it presupposes basic knowledge on the variety of current MSCT urography techniques, including such issues as present-day indications, split-bolus injection, compression, saline infusion, low-dose diuretic administration, hybrid scanning, timing of the acquisition delay, examination protocols, postprocessing, image analysis, and radiation exposure. This article is not intended to provide guidelines of how to conduct MSCT urography, but everyone will be able to understand the functionality of several robust operating MSCT urography techniques, which helps making an individual selection for the clinical practice. In the near future, systematic studies are awaited evaluating the morphologic and diagnostic accuracy of MSCT urography regarding diverse urinary tract disorders.

Recommendations for the improvement of bladder cancer quality of care in Canada: A consensus document reviewed and endorsed by Bladder Cancer Canada (BCC), Canadian Urologic Oncology Group (CUOG), and Canadian Urological Association (CUA), December 2015

“…153 CT urogram is the test of choice for evaluation of the upper tract. 160 If this is not available, intravenous pyelogram is a reasonable alternative.…”

Dual-Energy CT Iodine-Subtraction Virtual Unenhanced Technique to Detect Urinary Stones in an Iodine-Filled Collecting System: A Phantom Study

“…Subtraction of bone or calcium plaques from vessels on CT angiography using the dual-energy CT technique also appears promising [4]. Outside the realm of cardiovascular imaging, little experimentation with current dual-energy scanning techniques and subtraction imaging has been performed.As a routine component of CT urograms for hematuria or suspected urothelial tumor, unenhanced scans are routinely obtained mainly to evaluate for the presence of urinary stones, and pyelographic phase scans are obtained after administration of iodinated contrast material to evaluate for the presence of urothelial carcinoma [9][10][11][12]. If virtual unenhanced scans reconstructed from pyelographic phase scans would allow the detection of urinary stones by means of automated subtraction of the iodine from the collecting system and ureters, one of the main purposes of unenhanced scans could be achieved without obtaining true unenhanced scans.…”

CT Urography

“…Assessment for urologic malignancy is probably the most important reason for evaluating these patients; therefore, examinations with a high sensitivity for the detection of neoplasms are essential. The ability to detect other possible causes of hematuria is also important [1][2][3].…”