Hematuria in the ER patient: optimizing detection of upper tract urothelial cancer - A pictorial essay.

Upper tract urothelial carcinoma (UTUC) is a rare and challenging subset of the more frequently encountered urothelial carcinomas (UCs), comprising roughly 5-7% of all UCs and less than 10% of all renal tumors. Hematuria is a common presenting symptom in the emergency setting, often prompting imaging to rule out serious etiologies, with UTUC especially posing as a diagnostic challenge. These UTUC lesions of the kidney and ureter are often small, mimicking other pathologies, and are more aggressive than typical UC of the bladder, emphasizing the importance of timely and accurate diagnosis. Multidetector computed tomography urography (CTU) is the standard imaging modality for diagnosis, tumor staging, and surgical planning. Various postprocessing techniques like multiplanar reconstructions, maximal intensity projection (MIP) images, and 3D volumetric rendering technique (VRT) are crucial for accurate detection. In addition, 3D cinematic rendering (CR) is a novel technique that employs advanced illumination models, producing images with realistic shadows and increased surface detail, outperforming traditional VRT. We will review the distinctive imaging features between UTUC and infiltrating mimicking lesions on CTU in patients who presented with hematuria, in conjunction with advanced postprocessing techniques, ultimately improving diagnostic confidence and preoperative planning in the emergency context.