Inter‐ and intraobserver variability in three‐dimensional ultrasound assessment of the endometrial–myometrial junction and factors affecting its visualization

Abstract

To assess the inter- and intraobserver variability of three-dimensional (3D) ultrasound assessment of the endometrial-myometrial junction (EMJ), and to assess demographic and physiological factors that affect the quality of its imaging. Women attending our gynecology clinic, who were deemed to have normal uteri on transvaginal ultrasound examination, were enrolled in this prospective study. They underwent 3D volume acquisition of the entire uterus in order to acquire a coronal view of the organ. Visualization of EMJs was classified as optimal, satisfactory or unsatisfactory. In order to assess the intra- and interobserver variabilities of the classification system, the volumes were classified by two independent observers on two separate occasions. The same classification system was then used to evaluate the EMJs of 101 women who were deemed to have normal uteri on transvaginal ultrasound examination. The results were correlated with age, parity, stage of cycle, menopausal status and endometrial thickness in order to assess whether any of these factors affect visualization of the EMJ. A total of 30 uterine volumes were examined in the first analysis. Both the inter- and intraobserver variability were good (kappa values of 0.77 and 0.83). Of the 101 EMJs assessed in the second analysis, 47 were classified as optimal, 42 as satisfactory and 12 as unsatisfactory. Endometrial thickness was positively associated with EMJ visualization and parity was negatively associated with EMJ visualization. Assessment of EMJ visualization has both good inter- and intraobserver variability in women with normal uteri. Parity and endometrial thickness have contrasting, statistically significant, effects on visualization of the EMJ.