Value of Fused18F-Choline-PET/MRI to Evaluate Prostate Cancer Relapse in Patients Showing Biochemical Recurrence after EBRT: Preliminary Results

Abstract

Purpose. We compared the accuracy of18F-Choline-PET/MRI with that of multiparametric MRI (mMRI),18F-Choline-PET/CT,18F-Fluoride-PET/CT, and contrast-enhanced CT (CeCT) in detecting relapse in patients with suspected relapse of prostate cancer (PC) after external beam radiotherapy (EBRT). We assessed the association between standard uptake value (SUV) and apparent diffusion coefficient (ADC).Methods. We evaluated 21 patients with biochemical relapse after EBRT. Patients underwent18F-Choline-PET/contrast-enhanced (Ce)CT,18F-Fluoride-PET/CT, and mMRI. Imaging coregistration of PET and mMRI was performed.Results.18F-Choline-PET/MRI was positive in 18/21 patients, with a detection rate (DR) of 86%. DRs of18F-Choline-PET/CT, CeCT, and mMRI were 76%, 43%, and 81%, respectively. In terms of DR the only significant difference was between18F-Choline-PET/MRI and CeCT. On lesion-based analysis, the accuracy of18F-Choline-PET/MRI,18F-Choline-PET/CT, CeCT, and mMRI was 99%, 95%, 70%, and 85%, respectively. Accuracy, sensitivity, and NPV of18F-Choline-PET/MRI were significantly higher than those of both mMRI and CeCT. On whole-body assessment of bone metastases, the sensitivity of18F-Choline-PET/CT and18F-Fluoride-PET/CT was significantly higher than that of CeCT. Regarding local and lymph node relapse, we found a significant inverse correlation between ADC and SUV-max.Conclusion.18F-Choline-PET/MRI is a promising technique in detecting PC relapse.