Abstract
1474
Objectives: To quantitatively characterize clinically significant intra-prostatic cancer (IPC) by prostate specific membrane antigen (PSMA) expression and cell density on PSMA-11 positron emission tomography/magnetic resonance (PET/MR).
Methods: Retrospective study approved by the institutional review board with informed written consent obtained. Patients with a solitary, biopsy-proven prostate cancer, Gleason score (GS) ≥7, presenting for initial evaluation by positron emission tomography/computerized tomography (PET/CT), underwent early prostate PET/MR immediately after PSMA-11 tracer injection. PET/MR (MRAC) and PET/CT (CTAC) maximal standardized uptake value (SUVmax) and minimal apparent diffusion coefficient (ADCmin) in normal prostatic tissue (NPT) were compared to IPC area. The relationship between SUVmax and ADCmin measurements was obtained.
Results: Twenty-two patients (mean age 69.5±5.0 years) were included in the analysis. 44 prostate areas were evaluated (22 IPC and 22 NPT). Median MRAC SUVmax of NPT was significantly lower than median MRAC SUVmax of IPC (p<0.0001). Median ADCmin of NPT was significantly higher than median ADCmin of IPC (p<0.0001). A very good correlation was found between MRAC SUVmax with CTAC SUVmax (rho=-0.843, p<0.0001). Good inverse relationship was found between MRAC SUVmax and CTAC SUVmax with ADCmin (rho=-0.717, p<0.0001 and -0.740, p<0.0001; respectively; Z=0.22, p=0.82, NS.) Conclusions: PET/MR SUVmax and ADCmin are distinct biomarkers able to differentiate between IPC and NPT in naïve prostate cancer patients with GS≥7.