OptiCross HD IVUS for Assessing Invasion Depth in Upper Tract Urothelial Carcinoma

Upper tract urothelial carcinoma (UTUC) is difficult to stage accurately because cross-sectional imaging and ureteroscopic biopsy may not reliably demonstrate muscular or periureteral invasion. This exploratory study evaluates whether a 60-MHz OptiCross HD intravascular ultrasound (IVUS) catheter can be safely introduced into the renal pelvis or ureter during planned surgery and provide intraluminal images that correspond to the final pathologic T stage. Fifteen adults with suspected or confirmed UTUC who are already scheduled for radical nephroureterectomy (RNU) will undergo one IVUS examination immediately before surgery. The IVUS result will not alter the planned treatment. Three independent reviewers who are blinded to clinical and pathologic information will assess invasion depth and image quality. IVUS-based T stage will be compared with postoperative pathology. Technical success, visualization of ureteral wall layers and lesion boundaries, and adverse events will also be evaluated through 3 months after surgery.