Role of ¹⁸F-PSMA PET/MRI in Prostate Cancer Recurrence After Prostatectomy.

Abstract

¹⁸F-PSMA PET/CT and pelvic MRI are useful for assessing biochemical recurrence of prostate cancer after prostatectomy. We evaluated the role of ¹⁸F-PSMA PET/MRI in a 1-stop-shop protocol combining a single injection of ¹⁸F-PSMA, followed by pelvic PET/multiparametric MRI (mpMRI) and whole-body PET/CT acquisitions for the detection of recurrent disease. <b>Methods:</b> We evaluated 106 consecutive patients referred to our institute for biochemical recurrence after prostatectomy using a 1-stop-shop protocol comprising whole-body ¹⁸F-PSMA PET/CT and pelvic ¹⁸F-PSMA PET/mpMRI. Each imaging modality was reviewed in a blinded manner by 2 independent, experienced readers. ¹⁸F-PSMA PET/MRI, with positivity on either MRI or PSMA PET, served as the reference standard. <b>Results:</b> ¹⁸F-PSMA PET/MRI detected more local recurrences (<i>n</i> = 52, 49.06%) compared with ¹⁸F-PSMA PET/CT (<i>n</i> = 42, 39.62%) and mpMRI (<i>n</i> = 46, 43.00%). Discordant cases accounted for 18 patients (17%): 10% were positive only on MRI and 7% only on PSMA PET. Compared with ¹⁸F-PSMA PET/MRI, both mpMRI and ¹⁸F-PSMA PET demonstrated similar performance, with sensitivities of 88.5% and 78.8% and specificities of 100% and 98.1%, respectively. <b>Conclusion:</b> ¹⁸F-PSMA PET/MRI outperformed PET/CT and mpMRI in the detection of local recurrences of prostate cancer.