Diagnostic value of 18 F-prostate-specific membrane antigen-1007 PET/MRI versus 18 F-prostate-specific membrane antigen-1007 PET/computed tomography for biochemical recurrence of prostate cancer after radical prostatectomy.

Objective: To assess the diagnostic value of fluorine 18 ( 18 F)-labeled prostate-specific membrane antigen (PSMA)-1007 PET/MRI and compare with that of 18 F-PSMA-1007 PET/computed tomography (CT) for biochemical recurrence (BCR) of prostate cancer (PCa) after radical prostatectomy.

Materials and methods: We enrolled 40 patients who underwent 18 F-PSMA-1007 PET/CT and 18 F-PSMA-1007 PET/MRI for BCR after radical prostatectomy. Two readers independently assessed the images and determined their overall assessment of positive lesions on PET/MRI and PET/CT. The association between the patients' clinical characteristics and positive detection results on the PET/CT and PET/MRI was explored. The PET/CT and PET/MRI results were verified during a 24-month follow-up to calculate their diagnostic accuracy.

Results: The detection rate of positive patients on 18 F-PSMA-1007 PET/CT and PET/MRI were consistent, with a value of 77.50%. The positive detection results were moderately associated with the patients' prostate-specific antigen (PSA) levels at examination, and the detection rate increased significantly with values of 50.00%, 72.73%, 90.91%, and 100% for PSA levels <0.5, 0.5-<1.0, 1.0-<2.0, and ≥2.0 ng/ml, respectively. Conclusive follow-up for affirmation or refutation of PCa recurrence was available for 33 patients. Compared with the follow-up results, on the patient-based level, the diagnostic accuracies for PET/MRI and PET/CT were both 100%. On the lesion-based level, PET/MRI excluded a false positive of bone metastasis on PET/CT.

Conclusion: 18 F-PSMA-1007 PET/MRI and 18 F-PSMA-1007 PET/CT demonstrate almost equal diagnostic value in detecting BCR, but PET/MRI can provide more lesion information, facilitating diagnosis and treatment due to its superior soft tissue resolution.