Metabolic Volumetric Parameters in 11C-Choline PET/MR Are Superior PET Imaging Biomarkers for Primary High-Risk Prostate Cancer

Positron emission tomography/magnetic resonance imaging (PET/MRI) can facilitate the use of noninvasive imaging biomarkers in clinical prostate cancer staging. Although multiparametric MRI is a widely used technique, the clinical value of simultaneous PET imaging remains unclear. This study aimed at investigating this issue. Methods. Between January 2015 and December 2016, 31 high-risk prostate cancer patients underwent 11C-choline PET/MRI for staging purposes. Clinical characteristics and imaging parameters, including the standardized uptake value (SUV) and metabolic volumetric parameters from PET imaging; apparent dišusion coe›cient (ADC) values from diflusion-weighted imaging; and volume transfer rate constant (Ktrans), režux rate constant (Kep), and initial area under curve (iAUC) in 60 seconds from dynamic contrast-enhanced (DCE) MRI were analyzed. Results. 11C-Choline PET imaging parameters were signi¡cantly correlated with prostate-speci¡c antigen (PSA) levels, and metabolic volumetric parameters, including metabolic tumor volume (MTV) and uptake volume product (UVP), showed signi¡cant correlations with other MRI parameters. In our cohort analysis, the PET/MRI parameters UVP/minimal ADC value (ADCmin) and kurtosis of Kep (Kepkur)/ADCmin were signi¡cant predictors for progression-free survival (PFS) (HR = 1.01, 95% CI: 1.00–1.02, p = 0.031 and HR = 1.09, 95% CI: 1.02–1.16, p = 0.009, respectively) in multivariate Cox regression analysis. High UVP/ADCmin and Kepkur/ADCmin values were signi¡cantly associated with shorter PFS. Conclusions. Metabolic volumetric parameters such as MTV and UVP can be routinely used as PET imaging biomarkers to add prognostic value and show better correlations in combination with MR imaging parameters in high-risk prostate cancer patients undergoing 11C-choline PET/MRI.