11C-Acetate PET/CT in Bladder Urothelial Carcinoma: Intraindividual Comparison With 11C-Choline

OBJECTIVE:We present a first study of the use of C-acetate (ACET) positron emission tomography (PET)/computed tomography (CT) in bladder urothelial carcinoma (UC) and an intraindividual comparison with C- choline (CHOL) PET/CT. METHODS:Fourteen patients with biopsy-proven UC (11 T2, 3 T1 refractory to treatment) were prospectively evaluated before radical cystectomy and excision of pelvic lymph nodes (LNs), with ACET and CHOL PET/CT scans performed within 1 week. Image acquisition started 5 minutes after intravenous injection of 12 to 14 mCi for both tracers. Standardized uptake values (SUVs) and tumor-to-background ratios (TBR) were calculated for all tumor and nodal findings and correlated with histopathology and follow-up. RESULTS:ACET and CHOL were taken up in all UCs, involved LNs, and prostate pathology. SUVs were on average slightly, nonsignificantly higher for CHOL uptake (SUV) in UCs and significantly higher for ACET in LNs. TBR was nonsignificantly higher with CHOL for UC and significantly higher for LNs. CONCLUSIONS:In this preliminary series, C-ACET and C-CHOL PET/CT showed equivalent results in the preoperative evaluation of UC. Both tracers have the potential to contribute to selecting patients who would benefit from combined treatment—neoadjuvant chemotherapy and surgery—by identifying pathologic LNs or from surgery only, thanks to their high negative predictive value for LN involvement.