Multi-detector Computed Tomography Urography For Diagnosing Upper Urinary Tract Urothelial Tumor

Main Category: Urology / Nephrology
Also Included In: MRI / PET / Ultrasound;  Clinical Trials / Drug Trials
Article Date: 07 Aug 2007 - 0:00 PDT

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UroToday.com- Urothelial tumors of the upper tract are uncommon but represent a disproportionately high percentage of deaths from urothelial carcinomas. Early detection of such lesions is important and imaging of the upper tract is recommended for patients who present with hematuria. While such imaging has traditionally involved intravenous urography (IVU) followed by retrograde pyelogram (RPG) for equivocal cases the advent of CT urography (CTU) provides an opportunity to obtain additional information about the renal parenchyma and surrounding organs and is being increasingly used.

In this study, CTU and RUP were used to search for upper tract urothelial tumors in a selected series of patients presenting with hematuria who had equivocal or positive IVU findings and those with persistent hematuria but negative IVU and cystoscopy. In all, this retrospective study looked at 151 upper tracts in 106 patients. CTU was successfully performed in all while RPG was technically unsuccessful in 6 upper tracts including 4 with tumors. A total of 32 upper tract tumors were detected: 8 in the kidney, 9 in the renal pelvis, and 15 in the ureter using histopathology or tumor on clinical follow-up (over 24 months) as the 'gold standard'. After technical failures and technically successful but non-diagnostic studies were excluded from the analysis both CTU and RPG demonstrated similar sensitivity (0.97 and 0.96), specificity (0.93 and 0.97) as well as similar positive predictive value (0.79 and 0.87), and negative predictive value (0.99 and 0.97).

The results of this study suggest that RPG and CTU are comparable in their ability to rule out the presence of upper tract tumors in those patients with equivocal or positive IVU or those with persistent hematuria and a negative IVU. It would have been interesting if the authors had reported on CTU performed in comparison to IVU since this is the area where CTU might be most useful. Furthermore, since most urologists would perform ureteroscopy to visualize the urothelium in patients with a positive IVU the utility of a CTU in this population would be more to obtain staging information prior to instrumentation in cases with a high index of suspicion. Thus, while the data presented suggest that CTU is a viable alternative to RPG it remains to be seen if CTU can potentially replace both IVU and RPG for investigating hematuria in patients who are at high risk of harboring upper tract tumors. This is where the true utility of CTU may lie, since it would potentially shorten the delay in diagnosing upper tract urothelial tumors and reduce the number of diagnostic episodes.

Cowan NC, Turney BW, Taylor NJ, McCarthy CL, Crew JP.

BJU. 99(6):1363-70, June 2007
doi: 10.1111/j.1464-410X.2007.06766.x

Reported by UroToday.com Contributing Editor Ashish M. Kamat, MD

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