The value of T2 mapping for evaluating the pathological type, grade and depth of myometrial invasion in endometrial carcinoma

Abstract

Objective: To investigate the value of T2 map and synthetic T2WI generated by T2 mapping in evaluating the histological type, pathological classification and depth of myometrial invasion of endometrial carcinoma (EC). Methods: Seventy-three patients with pathologically proven EC diagnosed at the First Affiliated Hospital of Zhengzhou University from December 2019 to December 2021 and 42 healthy volunteers were enrolled in the study. All subjects underwent conventional MRI, diffusion weighted imaging (DWI) and T2 mapping sequence for the pelvic cavity to test the T2 values and the apparent diffusion coefficient (ADC) of the focus nidus of the patients and the normal endometrium of the volunteers. The T2 and ADC values of EC vs normal endometrium, and those of different histological types and pathological grades were compared. The receiver operating characteristic (ROC) curves were constructed to evaluate the diagnostic performance of T2 and ADC values in determining the pathological type and classification of EC. In addition, two radiologists used synthetic T2WI combined with T2 map and conventional T2WI combined with DWI, respectively, to evaluate the depth of myometrial invasion, and compared the imaging results with the results of pathological diagnosis to evaluate the diagnostic efficacy of the two methods in determining the depth of myometrial invasion. Results: The T2 and ADC values of endometrial carcinoma were 85.0 (80.8, 92.5) ms and 0.71 (0.64, 0.77) ×10(-3) mm(2)/s, respectively, which were significantly lower than those of normal endometrium [147.4 (123.4, 176.7) ms and 1.46 (1.26, 1.76)×10(-3) mm(2)/s, respectively; both P<0.05]. The T2 values of endometrioid carcinoma (EA) [84.1 (79.5, 88.7) ms] were significantly lower than those of non-EA [98.8 (92.1, 102.8) ms; P<0.05]. There was no significant difference in ADC values between EA and non-EA (P=0.075). The T2 values of G1, G2 and G3 groups in EA were 89.1 (84.4, 94.4) ms, 83.6 (80.9, 86.2) ms, and 76.5 (71.4, 80.3) ms, respectively. There were significant differences in the T2 values between G1 vs G2, G1 vs G3, and G2 vs G3 groups, respectively (all P<0.017). Significant difference was also found in the ADC values between the G1 and G3 groups (P<0.017). The area under the ROC curve (AUC) of T2 values in distinguishing EA from non-EA was 0.867. The AUC of T2 values, ADC values and their combination in predicting high-grade EA was 0.888, 0.730 and 0.895, respectively. The accuracy of synthetic T2WI+ T2 map and conventional T2WI+ DWI in the diagnosis of deep myometrial invasion was 78.1% and 79.5%, respectively, with no significant difference (P>0.05). Conclusions: T2 mapping has great potential in preoperative evaluation of EC. The quantitative T2 value can be used in the diagnosis, pathological classification and grading of EC. The combination of synthetic T2WI and T2 map may be helpful to determine the depth of myometrial invasion.