Endometrial carcinoma: Evaluation using diffusion-tensor imaging and its correlation with histopathologic findings

Although the prognosis of endometrial carcinoma (EMC) patients strictly depends on tumor invasion depth and its histologic grade, accurate preoperative assessment of these prognostic factors is often difficult.

To determine the usefulness of diffusion-tensor imaging (DTI) as a noninvasive method for evaluating tumor invasion depth and its histologic grade in patients with EMC.

Prospective.

Twenty-five consecutive patients with histologically confirmed EMC who were surgically treated at our institution.

DTI was performed with a 1.5T MRI system using a single-shot echo-planar imaging sequence with b values of 0 and 1000 s/mm² and motion-probing gradients in nine noncollinear directions.

Fractional anisotropy (FA), mean diffusivity (MD), and axial diffusivity (AD) maps were analyzed by three observers and compared with histopathologic findings.

Dunnett's test, Spearman's rank correlation coefficient, and receiver operating characteristic (ROC) curve analyses.

FA maps from all patients distinctly identified the junctional zone as a high-FA zone (0.864 ± 0.037) that was significantly different from the endometrium and outer myometrium (0.251 ± 0.030 and 0.471 ± 0.091, respectively; P < 0.001). All EMCs were clearly depicted as hypointense areas on all DTI maps. AD maps provided the best tumor-to-uterus contrast, and EMCs (0.977 ± 0.120 × 10^-3 mm² /s) had significantly lower AD values than all other layers of the normal uterine wall (2.166 ± 0.408, 2.010 ± 0.289, and 2.655 ± 0.203 × 10^-3 mm² /s, respectively; P < 0.001). EMCs were clearly demarcated from the normal uterine wall, and DTI maps and histopathologic data yielded identical findings regarding tumor invasion depth. FA values showed a significant inverse correlation (r = -0.818; P < 0.001) with histologic grades 1, 2, and 3 of endometrioid adenocarcinomas.

In patients with EMC, DTI may be useful for evaluating tumor invasion depth and its histologic grade.

1 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019;50:250-260.