Subendometrial enhancement and peritumoral enhancement for assessing endometrial cancer on dynamic contrast enhanced MR imaging

• We have assessed the peritumoral enhancement (PTE), which mimics SEE on DCE.
• We evaluated the diagnostic accuracy of SEE for the myometrial invasion and the frequency of PTE.
• We assessed the relationship between these enhancements and important pathologic factors.
• PTE Type 1 is the main factor causing the overestimation of myometrial invasion using SEE on DCE.
• PTE Type 2 correlates the myometrial invasion and may play an important role in the diagnosis of LVSI.

ObjectivesTo evaluate the diagnostic accuracy of subendometrial enhancement (SEE) in assessing the myometrial invasion in endometrial cancer, the frequency and clinical significance of peritumoral enhancement (PTE) on dynamic contrast enhanced (DCE) imaging.Materials and methodsMR images of 147 patients with endometrial cancer were retrospectively analyzed for intact SEE and PTEs: Type 1, a focal early enhancement peritumorally, and Type 2, an irregular thin-layered early intense enhancement peritumorally. Two radiologists independently assessed intact SEE and PTEs on DCE imaging and compared the lesions by the presence and depth of myometrial invasion, grade, lymphovascular space involvement (LVSI), and lymph node metastasis. The relationship between SEE, PTEs, and each factor was analyzed using univariate and multivariate analyses. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and diagnostic accuracy were calculated for SEE.ResultsThe sensitivity, specificity, PPV, NPV and diagnostic accuracy for myometrial invasion based on SEE disruption on DCE were 96.6%, 32.1–46.4%, 85.8–88.5%, 69.2–76.5%, and 84.4–87.1%. According to multivariate analysis, SEE significantly predicted myometrial invasion (p < 0.0001). PTE Type 2 significantly predicted myometrial invasion presence (p < 0.05) and depth (p < 0.01).ConclusionDiagnosis of myometrial invasion only by using SEE might be difficult on DCE-MRI due to the overestimation by strong focal enhancement of PTE Type 1. PTE Type 2 correlates both with the presence and depth of myometrial invasion and also may play an important role in the diagnosis of LVSI.