Abstract
PURPOSE: Prostate-specific membrane antigen (PSMA) Positron emission tomography/magnetic resonance imaging (PET/MRI) surpasses conventional MRI (cMRI) in prostate cancer (PCa) evaluation. Our objective is to evaluate correlation of quantitative parameters in PCa using Fluorine-18 (F-18) PSMA-1007 PET/MRI and their potential for predicting metastases. METHODS: This retrospective study included 51 PCa patients. Apparent diffusion coefficient (ADC), maximum standardized uptake value (SUVmax), PSMA total lesion uptake (PSMA-TLU), and PSMA total volume (PSMA-TV) were calculated in primary tumor. Correlation of ADC with other parameters was analyzed. Receiver Operating Characteristic curve analysis was conducted to determine optimal cut-off values for predicting metastases. RESULTS: ADC inversely correlated with SUVmax, PSMA-TLU, and PSMA-TV (p < 0.0001, < 0.0001, 0.0050, respectively). Lower ADC was associated with metastatic disease (p < 0.001). SUVmax, PSMA-TLU, PSMA-TV, SUVmax/ADC, PSMA-TLU/ADC, and PSMA-TV/ADC were higher in patients with metastases (p = 0.033 to < 0.001). PSMA-TLU/ADC and PSMA-TV/ADC best predicted metastases (sensitivity: 73.91% and 82.61%; specificity: 89.29% and 71.43%). PSMA-TLU, PSMA-TV, PSMA-TLU/ADC, and PSMA-TV/ADC were higher in patients with lymph node metastasis (p = 0.001 to 0.005). PSMA-TLU/ADC and PSMA-TV/ADC best predicted lymph node metastasis (sensitivity: 77.78% and 100%; specificity: 89.29% and 71.43%). SUVmax and SUVmax/ADC were higher in bone metastasis cases (p = 0.045), but their predictive value for bone metastasis was limited (Area under the curve (AUC): 0.634 and 0.652). CONCLUSION: F-18 PSMA-1007 PET/MRI may improve diagnostic accuracy for primary PCa lesions by utilizing the inverse relationship between ADC and other parameters. Moreover, a strong correlation between such parameters and presence of metastasis holds prognostic value of this modality.