Diagnostic Value of Integrated PET/MRI for Detection and Localization of Prostate Cancer: Comparative Study of Multiparametric MRI and PET/CT

Purpose: To evaluate the diagnostic value of integrated positron emission tomography/magnetic resonance imaging (PET/MRI) compared with conventional multiparametric MRI and PET/computed tomography (CT) for the detailed and accurate segmental detection/localization of prostate cancer. Materials and Methods: Thirty-one patients who underwent integrated PET/MRI using F-18-choline and F-18-FDG with an integrated PET/MRI scanner followed by radical prostatectomy were included. The prostate was divided into six segments (sextants) according to anatomical landmarks. Three radiologists noted the presence and location of cancer in each sextant on four different image interpretation modalities in consensus (1, multiparametric MRI; 2, integrated F-18-FDG PET/MRI; 3, integrated F-18-choline PET/MRI; and 4, combined interpretation of 1 and F-18-FDG PET/CT). Sensitivity, specificity, accuracy, positive and negative predictive values, likelihood ratios, and diagnostic performance based on the DOR (diagnostic odds ratio) and NNM (number needed to misdiagnose) were evaluated for each interpretation modality, using the pathologic result as the reference standard. Detection rates of seminal vesicle invasion and extracapsular invasion were also evaluated. Results: Integrated F-18-choline PET/MRI showed significantly higher sensitivity than did multiparametric MRI alone in high Gleason score patients (77.0% and 66.2%, P=0.011), low Gleason score patients (66.7% and 47.4%, P=0.007), and total patients (72.5% and 58.0%, P=0.008) groups. Integrated F-18-choline PET/MRI and F-18-FDG PET/MRI showed similar sensitivity and specificity to combined interpretation of multiparametric MRI and F-18-FDG PET/CT (for sensitivity, 58.0%, 63.4%, 72.5%, and 68.7%, respectively, and for specificity, 87.3%, 80.0%, 81.8%, 72.7%, respectively, in total patient group). However, integrated F-18-choline PET/MRI showed the best diagnostic performance (as DOR, 11.875 in total patients, 27.941 in high Gleason score patients, 5.714 in low Gleason score groups) among the imaging modalities, regardless of Gleason score. Integrated F-18-choline PET/MRI showed higher sensitivity and diagnostic performance than did integrated F-18-FDG PET/MRI (as DOR, 6.917 in total patients, 15.143 in high Gleason score patients, 3.175 in low Gleason score groups) in all three patient groups. Conclusion: Integrated PET/MRI carried out using a dedicated integrated PET/MRI scanner provides better sensitivity, accuracy, and diagnostic value for detection/localization of prostate cancer compared to multiparametric MRI. Generally, integrated F-18-choline PET/MRI shows better sensitivity, accuracy, and diagnostic performance than does integrated F-18-FDG PET/MRI as well as combined interpretation of multiparametric MRI with F-18-FDG PET/CT.