To compare the diagnostic performance of MRI and integrated PET/CT for the preoperative detection of peritoneal carcinomatosis arising from primary ovarian cancer.

Twenty-three patients with suspected ovarian tumors underwent a contrast-enhanced 1.5 Tesla MRI and a 18F-fluorodeoxyglucose (FDG) PET/CT prior to surgery. The peritoneal cavity was subdivided into six specific sites for a lesion-based analysis. The imaging findings were compared statistically with the histopathological findings using McNemar's test with Bonferroni's adjustment and generalized estimation equations.

The histopathological results of all 23 patients were confirmed for primary malignant epithelial ovarian cancer. Of the 23 patients, 19 had a total of 83 sites with peritoneal seedings throughout the abdomen and pelvis. The comparison of the patient- based sensitivity, specificity and accuracy of the use of MRI versus PET/CT for the detection of peritoneal carcinomatosis were 95% versus 84% (p < 0.05; N.S.), 50% versus 50% (p < 0.05; N.S.), and 87% versus 78% (p < 0.05; N.S.), respectively. Moreover, the comparison of the lesion-based sensitivity, specificity and accuracy of MRI versus integrated PET/CT were 86% and 75% (p = 0.004), 76% and 84% (p < 0.05; N.S.), and 82% and 78% (p < 0.05; N.S.), respectively.

We found that MRI was more sensitive than integrated PET/CT for the detection of preoperative peritoneal carcinomatosis arising from primary ovarian cancer.