Transitional cell carcinoma of the upper urinary tract: optimizing image interpretation with 3D reconstructions.

Purpose: This article reviews the pathophysiology of transitional cell carcinoma (TCC), CT urography (CTU) protocols, different possible 3D reconstruction techniques, and the importance of 3D reconstructions for appropriate interpretation.

Results/conclusion: CTU has largely replaced conventional IV pyelography in the evaluation of the upper urinary tract for TCC. The majority of large lesions can be easily seen on standard axial images with multiplanar reformats. However, it is imperative to also use 3D reconstructions when interpreting these studies, as subtle lesions can be difficult to visualize on the more traditional images. In this pictorial essay, we present multiple cases of upper urinary tract TCC which illustrate the value of 3D reconstructions for increasing the conspicuity of lesions, particularly at the junction of the infundibulum and calyx and in the ureters. As these cases demonstrate, each of the three possible 3D reconstruction techniques (maximum intensity projection, volume rendering, and volume rendered "virtual ureteroscopy") has its own distinct advantages, although the pitfalls of each technique must also be kept in mind.