The MIBC-PET study is a prospective, single-center study of 60 patients with newly diagnosed, histologically confirmed, high-grade muscle-invasive bladder cancer (MIBC). Patients will undergo baseline staging using 18F-FDG PET/CT and contrast-enhanced CT of the chest, abdomen, and pelvis, as well as repeat examinations after two cycles of neoadjuvant therapy. 18F-FDG PET/CT incorporates standard delayed imaging and early dynamic pelvic acquisition to overcome urinary interference. The primary objectives are to compare the diagnostic accuracy of 18F-FDG PET/CT versus contrast-enhanced CT in baseline staging and to predict pathologic response to neoadjuvant chemotherapy. Secondary endpoints include validation of dynamic 18F-FDG PET/CT for local staging and radiomics/AI models. The study is approved by the ethics committee (CE-AVEC 109-2024-Oss-AOUFe, principal investigator Dr. Luca Urso) and the results should inform the integration of 18F-FDG PET/CT in the diagnosis of MIBC.