Diagnostic efficiency of hybrid imaging using PSMA ligands, PET/CT, PET/MRI and MRI in identifying malignant prostate lesions

Objective The objective of this study was to assess the accuracy of 68 Ga-PSMA-11 PET/MRI, 18 F-PSMA-1007 PET/CT, 68 Ga-PSMA-11 PET/CT, and multiparametric (mp)MRI for the delineating of dominant intraprostatic lesions (IPL). Materials and methods 35 patients with organ-confined prostate cancer who were assigned to definitive radiotherapy (RT) were divided into three groups based on imaging techniques: 68 Ga-PSMA-PET/MRI ( n = 9), 18 F-PSMA-PET/CT ( n = 16) and 68 Ga-PSMA-PET/CT ( n = 10). All patients without PSMA-PET/MRI received an additional mpMRI. PSMA-PET-based automatic isocontours and manual contours of the dominant IPLs were generated for each modality. The biopsy results were then used to validate whether any of the prostate biopsies were positive in the marked lesion using Dice similarity coefficient (DSC), Youden index (YI), sensitivity and specificity . Factors that can predict the accuracy of IPLs contouring were analysed. Results Diagnostic performance was significantly superior both for manual and automatic IPLs contouring using 68 Ga-PSMA-PET/MRI (DSC/YI SUV 70% —0.62/0.51), 18 F-PSMA-PET/CT (DSC/YI SUV 70% —0.67/0.53) or 68 Ga-PSMA-PET/CT (DSC/YI SUV 70% —0.63/0.51) compared to mpMRI (DSC/YI—0.47/0.41; p