MIBC-PET is a prospective, monocentric, no-profit study with paired imaging comparison enrolling 60 patients with newly diagnosed, histologically confirmed high-grade MIBC. All patients undergo baseline staging with \[18F\]FDG PET/CT and contrast-enhanced CT (ceCT) of chest, abdomen, and pelvis. A second \[18F\]FDG PET/CT and CT are performed after two cycles of neoadjuvant therapy. \[18F\]FDG PET/CT includes both standard delayed imaging and an early dynamic pelvic acquisition to overcome urinary tracer interference. The primary endpoints are (1) diagnostic accuracy of \[18F\]FDG PET/CT versus ceCT for baseline staging, and (2) accuracy of \[18F\]FDG PET/CT in predicting pathological response to neoadjuvant chemotherapy. Secondary endpoints include validation of early dynamic \[18F\]FDG PET/CT for local staging and radiomic/AI-based predictive modeling.