Myometrial invasion in endometrial cancer: diagnostic performance of diffusion-weighted MR imaging at 1.5-T

Objective: To determine the diagnostic accuracy of diffusionweighted (DW) magnetic resonance (MR) imaging in the preoperative assessment of myometrial invasion by endometrial cancer. Materials and methods: In this prospective study, 47 patients with histologically confirmed endometrial cancer underwent preoperative MR imaging and total hysterectomy. The MR protocol included spin-echo multishot T2- weighted, dynamic T1-weighted and DW images acquired with b-values of 0 and 500 s/mm2. Myometrial tumour spread was classified as superficial (<50%) or deep (≥50% myometrial thickness). Postoperative histopathological findings served as a reference standard. Indices of diagnostic performance were assessed for each sequence. Results: At histopathological examination, superficial myometrial invasion was found in 34 patients and deep myometrial invasion in 13. In the assessment of tumour invasion, sensitivity, specificity, positive and negative predictive values of T2-weighted images were 92. %, 76.5%, 60.0% and 96.3%, respectively. The corresponding values for dynamic images were 69.2%, 61.8%, 40.9% and 84.0%, and for DW images 84.6%, 70.6%, 52.4% and 92.3%. T2-weighted and DW imaging proved to be the most accurate techniques for tumour spread determination. Conclusion: DW imaging proved to be accurate in assessing myometrial invasion, and it could replace dynamic imaging as an adjunct to routine T2-weighted imaging for preoperative evaluation of endometrial cancer.