Evaluating the Diagnostic Performance of PET/MR Versus CECT in Determining Resectability in Ovarian Cancer

Objective: This study aimed to compare the diagnostic accuracy of whole-body PET/MR imaging and contrast-enhanced CT for detecting metastatic disease in patients undergoing surgical resection, using pathology as the reference standard. Materials and Methods: Nineteen patients with suspected metastatic involvement (including four who received neoadjuvant therapy before surgery) underwent both FDG PET/MR and contrast-enhanced CT scans. Imaging was reviewed for metastases at defined sites (e.g., perihepatic region, hepatic parenchyma, mesentery, bowel serosa, colon surface, and nodal basins). Findings on each modality were compared to surgical pathology results per site. Sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) were calculated for PET/MR and CT, with pathology as the reference standard. Results: Overall, PET/MR achieved approximately 55.5% sensitivity, 89.5% specificity, 82.5% accuracy, 57.6% positive predictive value (PPV), and 88.6% negative predictive value (NPV). In contrast, CT demonstrated 75.0% sensitivity, 72.3% specificity, 72.9% accuracy, 42% PPV, and 91.5% NPV. No significant correlations were observed between semi-quantitative PET/MR measures, such as SUV or MR ADC values, and patient survival outcomes; therefore, these metrics were excluded from further analysis. Notably, PET/MR imaging findings changed clinical management in 3/6 chemotherapy patients. PET/MR demonstrated greater sensitivity in detecting nodal metastases, 75% compared to CT (25%), and identified small bowel serosal lesions in 1 of 1 case (100% sensitivity) versus none with CT. CT showed slightly higher specificity (81%) for colon serosal involvement than PET/MR (75%). Conclusions: CT demonstrates higher sensitivity, whereas PET/MR offers greater specificity and negative predictive value. When used together, the two modalities may provide a more reliable and comprehensive assessment of metastatic disease.