OC21.02: *Endometrial assessment on ultrasound: why transvaginal scan alone is not good enough?

To evaluate the proportion of suboptimal assessments of endometrial thickness (ET) on transvaginal ultrasound (TVS) in women with abnormal uterine bleeding (AUB) and assess the efficacy of multimodal (MM) sonographic approach to ET measurement. This was a prospective observational study of consecutive women aged ≧45 years with AUB who underwent TVS assessment of ET between June-November 2022. If the endometrium could not be adequately visualised and measured on TVS using the double-layer measurement technique another method of endometrial assessment was immediately offered, including transabdominal, transrectal scan or saline infusion sonography. The relationship between TVS and MM ultrasound approach and quality of ET was assessed in both uni- and multivariate analysis models against clinical and demographic variables. A total of 387 women who initially underwent TVS to measure ET were included. In 245/387 (63%) ET measurement was optimal on TVS. However, ET assessment was suboptimal in the remaining 142/387 (37%) cases on TVS alone, which was successful in 118/142 (83%). The most common reason for suboptimal TVS was: adenomyosis 64/142 (45%), suboptimal angle 64/142 (45%) and submucosal fibroids 40/142 (28%). Median angle in suboptimal TVS cases was 33° [IQR 15,52], whereas with MM approach a median angle of 86° [IQR 78,90], (P < 0.0001) was reached to achieve optimal ET assessment. When TVS assessment was suboptimal, it was more likely to significantly overestimate ET by 1.26mm compared to MM approach (P < 0.0001). MM approach was more likely to result in optimal ET assessment in in patients of black ethnicity [OR 1.56 (95%CI 0.81 to 16.04) (P = 0.04)] or with adenomyosis [OR 1.17 (95% CI 0.3503 to 3.812) (P = 0.04)]. MM approach is a more effective way to assess ET than TVS alone in women presenting with AUB. MM approach is associated with a higher proportion of optimal ET assessment and significantly lower ET measurements, which could lead to reduction in unnecessary invasive interventions such as hysteroscopy or endometrial biopsy.