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.