Clinical value of 18F-PSMA-1007 PET/MRI in primary staging of patients with intermediate- to high-risk prostate cancer Ismail Ali1, Mahmoud Rezk2, Dalia Hamouda3, Omnia Talaat4, Yehia Omar5, Mohamed Abdel Tawab6, Ibrahim Nasr7. 1Radiology Department, Faculty of Human Medicine, Zagazig University. 2Radiology Department, National cancer Institute, Cairo University. 3Medical Oncology Department, Faculty of Human Medicine, Zagazig University. 4Radiation Oncology Department, National Cancer Institute, Cairo University. 5Director of PET/MRI unit, Misr Radiology Center, Cairo. 6Radiology Department, Faculty of Human Medicine, Alazhar University. 7Clinical Oncology and Nuclear Medicine Department, Faculty of Human Medicine, Zagazig University, Egypt . Journal: British Journal of Radiology Published at: Jan 2024 Abstract Objective: To assess the utility of 18F-PSMA-1007 PET/MRI in initial staging of intermediate- to high-risk prostate cancer (HRPCa). Methods: A total of 46 patients with pathologically verified intermediate and/or HRPCa who underwent 18F-PSMA-1007 PET/MRI with dedicated pelvic high-resolution multiparametric MRI (mpMRI) were included. Results: PET/MRI showed 100% sensitivity (SN), specificity (SP), positive predictive value (PPV), negative predictive value (NPV), and accuracy in detecting seminal vesicle (SV) and rectal invasion, versus 87.5%, 100%, 100% 93.8%, 95.7% and 50%, 100%,100%, 95.5%, and 95.7% for mpMRI respectively. However, PET/MRI had poor SN (40% and 0%) but high SP (94.4% and 100%) in detection of UB and neurovascular bundle (NV) invasion compared to 100% SN and SP for mpMRI. PET/MRI demonstrated stronger TNM staging agreement with the gold standard than mpMRI-WBMRI. It demonstrated concordance with T, N, and M stages in 40, 41, and 36 patients (k 0.84, 0.60, and 0.68, respectively) versus 29, 33, and 31 patients (k 0.54, 0.22, and 0.50) with accurate over all staging of 38/46 patients versus 30/46 patients (K 0.52 versus 0.22). Conclusion: 18F-PSMA-1007 PET/MRI is a promising imaging modality with high diagnostic accuracy in staging intermediate- and HRPCa; it improves local tumour evaluation and provides precise TNM staging.