Objective
To identify if synchronous reading of multiparametric MRI (mpMRI) and 68Ga-PSMA-11 PET/CT (PSMA-PET) images can improve diagnostic performance and certainty against mpMRI/PSMA-PET reported independently and synthesized, while also assessing concordance between imaging modalities and agreement with histopathology.
Methods
This is a retrospective analysis of 100 men randomly selected from the PRIMARY trial, a prospective phase II multi-centre imaging trial. Three dual trained radiologist/nuclear medicine physicians re-reported the mpMRI, PSMA PET both independently and synchronously for the same patients in random order blinded to previous results. Diagnostic performance was assessed for mpMRI/PSMA-PET images read synchronously or independently and then synthesized. Agreement between imaging results and histopathology was examined. Concordance between imaging modalities was defined as overlapping lesions. Reporting certainty was evaluated by the individual reporters for each modality.
Results
ISUP grade group ≥2 cancer was present in 60% of men on biopsy. Synchronous reading of mpMRI/PSMA-PET increased sensitivity compared to mpMRI or PSMA-PET alone (93% vs 80% vs 88% respectively), although specificity was not improved (63% vs 58% vs 78% respectively). No significant difference in diagnostic performance was noted between PSMA-PET/MRI read synchronously or if reported independently and then synthesized. Most patients had concordant imaging (60%), while others had discordant lesions only (28%) or a mixture (concordant and discordant lesions; 12%). When mpMRI/PSMA-PET findings were concordant and positive, 95% had csPCa. When PSMA-PET alone was compared to synchronous PSMA-PET/MRI reads, there was an improvement in reader certainty in 20% of scans.
Conclusion
Synchronous mpMRI/PSMA-PET reading improves reader certainty and sensitivity for csPCa compared to mpMRI or PSMA-PET alone. However, synthesizing the results of independently read PSMA-PET and mpMRI reports provided similar diagnostic performance to synchronous PSMA-PET/MRI reads. This may provide greater flexibility for urologists in terms of referral patterns, reduce healthcare system costs and improve efficiencies in prostate cancer diagnosis.