Contribution of 18F-FDG PET/MR Imaging in Detection of Peritoneal Carcinomatosis in Patients with Ovarian Cancer

Abstract

Abstract Purpose: Presence of peritoneal metastasis in ovarian cancer is one of the most important factors affecting the prognosis of the disease. In this study, it was aimed to compare the diagnostic performances of 18F-FDG PET/CT and 18F-FDG PET/MR imaging for the detection of peritoneal recurrence in patients with ovarian cancer. Material-Methods: 66 images of 45 patients with ovarian cancer who had elevated serum Ca-125 levels at post-operative follow-up and were referred to 18F-FDG PET/CT for restaging of disease were prospectively recruited in the study. All patients underwent whole body 18F-FDG PET/CT followed by whole abdomen PET/MRI. The peritoneal carcinomatosis index (PCI) was calculated for each patient in both imaging modalities. PET/CT and PET/MRI were evaluated for the presence and localization of peritoneal recurrences for each modality. Results: In study-based analysis; PET/MRI was positive in 49 studies (74%), while PET/CT was positive in 34 studies (51%) (p=0.001). The total number of regions with peritoneal uptake was 144 in PET/CT and 243 in PET/MRI (p<0.001). The median PCI was 1.5 in PET/CT and 4 in PET/MRI (p<0.001). In the evaluation of liver-spleen capsule metastases, the detection rate was 17/66 (26%) for PET/CT and 30/66 (45%) for PET/MRI (p=0.008). Distant organ metastases were detected on PET/MR in 3 studies where PET/CT was negative. In our study, additional findings obtained from PET/MRI changed the treatment strategy in 15 patients. Conclusion: Peritoneal metastasis detection rate is higher in PET/MRI than PET/CT in patients with recurrent ovarian cancer with elevated Ca-125 levels. In addition, PET/MRI is useful in the evaluation of the liver-spleen capsule metastases. PET/MRI findings can help to selection of appropriate treatment strategy in recurrent ovarian cancer patients.