Evaluating Myometrial Invasion in Endometrial Cancer: Comparison of Reduced Field-of-view Diffusion-weighted Imaging and Dynamic Contrast-enhanced MR Imaging

PURPOSE: To compare the diagnostic ability of reduced FOV diffusion-weighted (DW) MR imaging with that of 3D dynamic contrast-enhanced (DCE) MR imaging in evaluating the depth of myometrial invasion in patients with endometrial cancer. METHODS: Three tesla MR images including T(2)-weighted imaging, reduced FOV DW imaging and 3D DCE MR imaging in sagittal and oblique axial (short axis) planes in 25 women with surgically proven endometrial cancer were retrospectively evaluated. The depth of myometrial invasion (stage S: < 50% vs stage D: ≥ 50%) on MR imaging was correlated with surgical pathology results. RESULTS: The 25 endometrial cancers included 16 stage S and 9 stage D tumors. The depth of myometrial invasion could be accurately evaluated in 68% of the cases for T(2)-weighted imaging, 92% for 3D DCE MR imaging, and 96% for reduced FOV DW imaging. In two patients with coexisting adenomyosis, both T(2)-weighted imaging and 3D DCE MR imaging failed to reveal the deep myometrial invasion, and reduced FOV DW imaging clearly demonstrated the tumor margin in the cases. Combination of reduced FOV DW imaging reading together with T(2)-weighted imaging improved the assessment of myometrial invasion with a diagnostic accuracy of up to 100%. CONCLUSIONS: Addition of reduced FOV DW imaging may improve the staging accuracy of MR imaging for endometrial cancer in assessing the depth of myometrial invasion. Especially, reduced FOV DW imaging has an advantage in assessing the depth of myometrial invasion for patients with coexisting adenomyosis. Reduced FOV DW imaging can be an alternative to 3D DCE MR imaging in evaluating myometrial invasion of endometrial cancer without the use of contrast medium.