Diagnostic Accuracy of Transabdominal and Transvaginal Ultrasound in Assessing Endometrial Pathologies in Women with Postmenopausal Bleeding: A Cross-sectional Study

Abstract

Introduction: Postmenopausal Bleeding (PMB) is defined as any spontaneous bleeding occurring after 12 consecutive months of amenorrhoea due to ovarian follicular inactivity. Timely evaluation of PMB is crucial to exclude potential underlying cervical or endometrial malignancies, which are significant causes of mortality. Although endometrial biopsy is considered the gold standard for diagnosis, it is invasive and can be painful. Therefore, a less invasive screening tool is needed, which is where the role of Ultrasound (USG) comes into play to identify candidates for endometrial biopsies. Aim: To evaluate and compare the diagnostic accuracy of Transabdominal Sonography (TAS) and Transvaginal Ultrasound (TVS) in detecting endometrial pathology in postmenopausal women with bleeding and to compare these findings with endometrial biopsy results. Materials and Methods: This cross-sectional study, conducted from November 2020 to October 2022 in the Department of Radiodiagnosis at Dr. Pinnamaneni Siddhartha Institute of Medical Sciences and Research Foundation Vijaywada, Andhra Pradesh, India, included 50 adult female patients of menopausal age with atleast 12 months of amenorrhoea. In these patients, endometrial thickness was measured using both TVS and TAS, after which they were referred to the Department of Gynaecology for endometrial biopsy. The patients were divided into two groups: those with endometrial pathology (40 patients) and those with other causes of PMB (10 patients). Quantitative, non normally distributed variables were analysed using the Wilcoxon’s Mann-Whitney U Test and the Kruskal-Wallis Test. Receiver Operating Characteristics (ROC) curve analysis with a >5 mm cut-off for endometrial thickness was performed. Statistical significance was set at p<0.05. Results: The mean age of the study participants was 59±7 years and the endometrial thickness measured using TAS was 4.46±3.05 mm, while the endometrial thickness measured using TVS was 5.28±3.83 mm. Significant differences were observed between the two groups (patients with and without endometrial pathology as a cause for PMB) regarding endometrial thickness, as measured by both TAS (W=446.000, p<0.001) and TVS (W=442.000, p<0.001). The endometrial pathologies identified in the study included endometrial atrophy (26 patients), endometrial hyperplasia (4 patients), endometrial carcinoma (7 patients), and endometrial polyps (3 patients). The strength of association, measured by Point-Biserial Correlation, was 0.69 for TAS and 0.70 for TVS, indicating a large effect size in both cases. Endometrial pathology was predicted with a sensitivity of 77% and specificity of 95% using TAS, and with a sensitivity of 85% and specificity of 89% using TVS. Conclusion: The present study emphasises that PMB is a prevalent concern in gynaecological practice, and ruling out endometrial cancer is critical due to its associated mortality. TVS remains a primary tool for identifying patients who require further evaluation through endometrial biopsy. Although TAS is initially performed for screening other pelvic pathologies and prior to conducting TVS, both modalities should be utilised.

Keywords

• endometrial atrophy
• endometrial carcinoma
• sensitivity
• specificity