To compare the value of IETA conventional transvaginal ultrasound and contrast-enhanced ultrasound (CEUS) in evaluating the depth of muscular invasion and cervical invasion in patients with endometrial cancer (EC), and in predicting the pathological stage of EC.

A total of 83 EC patients who had been operated on at Shenzhen Hospital of Southern Medical University or the Seventh Affiliated Hospital of Sun Yat-sen University from January 2017 to December 2020 were enrolled in the study. All patients underwent conventional transvaginal ultrasound and CEUS examination within one month before surgery. The conventional ultrasound and CEUS images of all enrolled patients were analyzed by two sonographers with more than 10 years of experience in obstetrics and gynecology ultrasound, both of whom had been familiar with the specific contents of the consensus on endometrial lesions by the IETA expert group prior to the analysis. The diagnostic coincidence rate of conventional ultrasound and CEUS for EC pathological staging was compared by using pathological results as the reference, and the kappa value was used to test the consistency between ultrasound and pathological results. ROC curve was used to analyze the diagnostic efficacy of objective ultrasonic measurement methods for deep muscle invasion and cervical invasion in EC.

The endometrial thickness, endometrial echogenicity, endometrial midline appearance, endometrial-myometrial junction, absence of "bright edge" sign, and vascular pattern of endometrial lesions concluded by IETA experts had high specificity and consistency in EC with different pathological stages in this study, and they were good ultrasonic indicators for predicting EC. The CEUS subjective assessment (Kappa=0.873, P＜0.001), CEUS objective measurement (Kappa=0.842, P＜0.001), IETA conventional ultrasound subjective assessment (Kappa=0.811, P＜0.001), and IETA conventional ultrasound objective measurement (Kappa=0.764, P＜0.001) were in good agreement with pathological results. The diagnostic coincidence rate of CEUS for EC pathological stages was somewhat improved compared with that of conventional ultrasound. On conventional ultrasound or CEUS, the anterior and posterior diameter of the lesion, the volume of the lesion, and the ratio of the anterior and posterior diameter of the lesion to the uterine anterior and posterior diameter (AP ratio) all had good diagnostic efficacy in predicting deep muscular invasion (invasion depth ≥1/2) in EC, and the areas under the ROC curves (AUCs) were all ≥0.945; the minimum distance between the outer edge of the lesion and the serous layer had poor diagnostic efficiency, with AUCs of only 0.414 and 0.462, respectively; the distance between the lower edge of the lesion and the external cervical opening was not effective in predicting the presence of cervical invasion in EC, with AUCs of 0.521 and 0.559, respectively.

Both IETA routine transvaginal ultrasonography and CEUS have high diagnostic efficacy in the prediction of pathological stages of EC. The diagnostic efficiency of CEUS is somewhat improved compared with that of conventional transvaginal ultrasound, and it can better display the depth of lesion invasion to the muscular layer and the scope of cervical invasion. Combining CEUS with routine transvaginal ultrasound may help achieve the goal of early detection, accurate staging, and early treatment of EC.