CT urogram is performed in 3 phases - noncontrast, renal cortical phase (aka nephrographic phase) and a urographic (aka excretory) phase in which the ureters and bladder are opacified with excretecontrast. MR urography protocols rely on pre-contrast T1 and T2 images and post-contrast images to provide similar information.
Today's case is an example of a bladder cancer detected at CT urography in a patient who presented with hematuria. Non-contrat phase is shown in the top left, axial and coronal renal cortical phase (2 right panels) show an enhancing mass, ruling out hematoma and calculus. Finally, the urographic phase on the bottom left shows the mass again as a filling defect. The bladder and ureters should be scrutinized for the presence of multifocal disease. This was a papillary urothelial carcinoma.
Case courtesy of Mohammadtaghi Niknejad, Radiopaedia.org, rID: 93120