A Novel Nomogram Based on 3-dimensional Transvaginal Ultrasound for Differential Diagnosis Between Severe and Mild-to-Moderate Intrauterine Adhesions

To develop and validate a nomogram for differentiating severe intrauterine adhesions (IUAs) from mild-to-moderate IUAs preoperatively on the basis of 3-dimensional transvaginal ultrasound (3D-TVUS).Retrospective observational study.University-affiliated hospital.A dataset of 413 patients who had undergone hysteroscopic adhesiolysis and 3D-TVUS examination before hysteroscopic adhesiolysis between March 2019 and December 2020.Not applicable.A total of 212 patients with mild-to-moderate IUAs and 201 patients with severe IUAs were enrolled. Intercornual distance, endometrial thickness, number of visible fallopian tubal ostia, echoes of the endometrial-myometrial junction zone, and endometrial blood flow grade differed significantly between the severe and mild-to-moderate IUAs groups. The area under the receiver operating characteristic curve of the nomogram was 0.880 (95% confidence interval, 0.843-0.918) in the training set and 0.878 (95% confidence interval, 0.818-0.939) in the validation set, revealing reliable discrimination. The calibration curve and Hosmer-Lemeshow test showed strong calibration, and decision curve analysis indicated that the nomogram had a high net benefit and a wide range of threshold probabilities.This nomogram, which was developed on the basis of 3D-TVUS, can accurately distinguish severe IUAs from mild-to-moderate IUAs preoperatively.