Multiparametric [11C]Acetate positron emission tomography-magnetic resonance imaging in the assessment and staging of prostate cancer

BACKGROUND The aim of this study was to evaluate whether MP [11C]Acetate PET-MRI enables an accurate differentiation of benign and malignant prostate tumors as well as local and distant staging. MATERIALS AND METHODS Fifty-six consecutive patients fulfilling the following criteria were included in this IRB-approved prospective study: elevated PSA levels or suspicious findings at digital rectal examination or TRUS; and histopathological verification. All patients underwent MP [11C]Acetate PET-MRI of the prostate performed on separate scanners with PET/CT using [11C]Acetate and 3T MP MR imaging. Appropriate statistical tests were used to determine diagnostic accuracy, local and distant staging. RESULTS MP imaging with two MRI parameters (T2w and DWI) achieved the highest sensitivity, specificity, and diagnostic accuracy of 95%, 68.8%, and 88%, with an AUC of 0.82 for primary PCa detection. Neither assessments with a single parameter (AUC, 0.54-0.79), nor different combinations with up to five parameters (AUC, 0.67-0.79) achieved equally good results. MP [11C]Acetate PET-MRI improved local staging with a sensitivity, specificity, and diagnostic accuracy of 100%, 96%, and 97% compared to MRI alone with 72.2%, 100%, and 95.5%. MP [11C]Acetate PET-MRI correctly detected osseous and liver metastases in five patients. CONCLUSIONS MP [11C]Acetate PET-MRI merges morphologic with functional information, and allows insights into tumor biology. MP [11C]Acetate PET-MRI with two MRI-derived parameters (T2 and DWI) yields the highest diagnostic accuracy. The addition of more parameters does not improve diagnostic accuracy of primary PCa detection. MP [11C]Acetate PET-MRI facilitates improved local and distant staging, providing "one-stop" staging in patients with primary PCa, and therefore has the potential to improve therapy. PATIENT SUMMARY In this report we investigated MP [11C]Acetate PET-MRI for detection, local and distant staging of prostate cancer. We demonstrate that MP [11C]Acetate PET-MRI with two MRI-derived parameters (T2 and DWI) achieves the best diagnostic accuracy for primary prostate cancer detection and that MP [11C]Acetate PET-MRI enables an improved local and distant staging.