F-18 Fluorocholine Dynamic Time-of-Flight PET/MR Imaging in Patients with Newly Diagnosed Intermediate- to High-Risk Prostate Cancer: Initial Clinical-Pathologic Comparisons

Abstract

Purpose: To investigate the initial clinical value of fluorine 18 (18F) fluorocholine (FCH) dynamic positron emission tomography (PET)/ magnetic resonance (MR) imaging by comparing its parameters with clinical-pathologic findings in patients with newly diagnosed intermediate-to high-risk prostate cancer (PCa) who plan to undergo radical prostatectomy. Materials and Methods: The institutional review board approved the study protocol, and informed written consent was obtained from all subjects for this HIPAA-compliant study. Twelve men (mean age 6 standard deviation, 61.7 years +/- 8.4; range, 46-74 years) with untreated intermediate-to high-risk PCa characterized according to Cancer of the Prostate Risk Assessment (CAPRA) underwent preoperative FCH dynamic PET/MR imaging followed by radical prostatectomy between April and November 2015. PET/ MR imaging parameters including average and maximum K1 (delivery rate constant) and standardized uptake values (SUVs) and Prostate Imaging Reporting and Data System (PI-RADS) version 2 scores were measured and compared with clinicalpathologic characteristics. For statistical analysis, the Spearman rank correlation and Mann-Whitney U tests were performed. Results: Of the PET parameters, maximum SUV of primary tumors showed significant correlations with several clinical-pathologic parameters including serum prostate-specific antigen level (rho = 0.71, P =.01), pathologic stage (rho = 0.59, P =.043), and postsurgical CAPRA score (rho = 0.72, P =.008). The overall PI-RADS score showed significant correlations with pathologic tumor volume (rho = 0.81, P< .001), percentage of tumor cells with Gleason scores greater than 3 (rho = 0.59, P =.02), and postsurgical CAPRA score (rho = 0.58, P =.046). The high-risk postsurgical CAPRA score patient group had a significantly higher maximum SUV than did the intermediate-risk group. Combined PET and MR imaging showed improved sensitivity (88%) for prediction of pathologic extraprostatic extension compared with that with MR imaging (50%) and PET (75%) performed separately. Conclusion: Maximum SUVs and PI-RADS scores from FCH PET/MR imaging show good correlation with clinical-pathologic characteristics, such as postsurgical CAPRA score, which are related to prognosis in patients with newly diagnosed intermediate-to high-risk PCa. (C) RSNA, 2016