MR imaging in endometrial carcinoma as a diagnostic tool for the absence of myometrial invasion

Objective.To evaluate whether magnetic resonance imaging (MRI) is a reliable modality for verifying preoperative diagnosis of stage IA endometrial carcinoma.Methods.One hundred sixteen patients with endometrial carcinoma underwent preoperative pelvic non-contrast T2-weighted or dynamic MRI. We compared the interpretations of the MRI results with the histological findings of the resected uterus.Results.In assessing the depth of myometrial invasion, the accuracy of MRI was 62.1%. As to the presence of cancerous myometrial invasion, the positive predictive value was 94.4% as high as previously reported by other institutions. However, the negative predictive value, the probability of the absence of myometrial invasion, was only 42.2%. Even when dynamic study was applied to the patient, the value only improved up to 60.0%.Conclusion.MRI has a definite advantage in evaluating deep myometrial invasion, but not the absence of invasion. We should take precautions against the risk of under-diagnosis when selecting stage IA endometrial carcinoma with use of MRI to preserve fertility or to eliminate lymphadenectomy.