Diagnostic value of [(18)F]FDG PET/MRI for staging in patients with ovarian cancer

PURPOSE: To evaluate the diagnostic potential of PET/MRI with 2-[(18)F]fluoro-2-deoxy-d-glucose ([(18)F]FDG) in ovarian cancer. MATERIALS AND METHODS: Participants comprised 103 patients with suspected ovarian cancer underwent pretreatment [(18)F]FDG PET/MRI, contrast-enhanced CT (ceCT) and pelvic dynamic contrast-enhanced MRI (ceMRI). Diagnostic performance of [(18)F]FDG PET/MRI and ceMRI for assessing the characterization and the extent of the primary tumor (T stage) and [(18)F]FDG PET/MRI and ceCT for assessing nodal (N stage) and distant (M stage) metastases was evaluated by two experienced readers. Histopathological and follow-up imaging results were used as the gold standard. The McNemar test was employed for statistical analysis. RESULTS: Accuracy for the characterization of suspected ovarian cancer was significantly better for [(18)F]FDG PET/MRI (92.5%) [95% confidence interval (CI) 0.84–0.95] than for ceMRI (80.6%) (95% CI 0.72–0.83) (p < 0.05). Accuracy for T status was 96.4% (95% CI 0.96–0.96) and 92.9% (95% CI 0.93–0.93) for [(18)F]FDG PET/MRI and ceMRI/ceCT, respectively. Patient-based accuracies for N and M status were 100% (95% CI 0.88–1.00) and 100% (95% CI 0.88–1.00) for [(18)F]FDG PET/MRI and 85.2% (95% CI 0.76–0.85) and 30.8% (95% CI 0.19–0.31) for ceCT and M staging representing significant differences (p < 0.01). Lesion-based sensitivity, specificity and accuracy for N status were 78.6% (95% CI 0.57–0.91), 95.7% (95% CI 0.93–0.97) and 93.9% (95% CI 0.89–0.97) for [(18)F]FDG PET/MRI and 42.9% (95% CI 0.24–0.58), 96.6% (95% CI 0.94–0.98) and 90.8% (95% CI 0.87–0.94) for ceCT. CONCLUSIONS: [(18)F]FDG PET/MRI offers better sensitivity and specificity for the characterization and M staging than ceMRI and ceCT, and diagnostic value for T and N staging equivalent to ceMRI and ceCT, suggesting that [(18)F]FDG PET/MRI might represent a useful diagnostic alternative to conventional imaging modalities in ovarian cancer.