MR assessment of myometrial invasion in women with endometrial cancer: discrepancy between T2-weighted imaging and contrast-enhanced T1-weighted imaging

PURPOSE: The purpose of the study was to investigate how frequently discrepant imaging findings are encountered between T2-weighted imaging and contrast-enhanced T1-weighted imaging in the preoperative magnetic resonance (MR) assessment of myometrial invasion in women with endometrial cancer. METHODS: Seventy-one consecutive women (mean age, 59 years; age range 35-86 years) with endometrial cancer who underwent preoperative MR imaging were included in this single-institution, retrospective study. Depth of myometrial invasion was separately assessed on T2-weighted imaging and contrast-enhanced T1-weighted imaging, and the assessment was considered discrepant, when the two imaging sequences did not match each other. The image analysis also included potential pitfalls responsible for discrepant imaging findings, including the absence of the junctional zone, disruption of the junctional zone, extension to the uterine cornu, presence of leiomyoma and presence of adenomyosis. The results were correlated with histopathologic findings. RESULTS: Of the 71 women, 19 (26.8%) showed discrepant imaging findings between T2-weighted imaging and contrast-enhanced T1-weighted imaging. Histopathologic findings revealed that contrast-enhanced T1-weighted imaging correctly depicted endometrial cancers in all women with discrepant MR imaging findings. Among the analyzed potential pitfalls, only disruption of the junctional zone showed a significant difference between women with concordant MR imaging findings (29.5%, 13/44) and women with discordant MR imaging findings (93.8%, 15/16) (p = 0.000). CONCLUSION: In the preoperative MR assessment of myometrial invasion in women with endometrial cancer, discrepant imaging findings between T2-weighted imaging and contrast-enhanced T1-weighted imaging are frequently encountered, especially when the junctional zone is disrupted.