OC12.04: *Applicability of morphological uterus sonographic assessment features associated with adenomyosis among experts and refinements of definitions

To assess the inter-observer agreement on the Morphological Uterus Sonographic Assessment (MUSA) features among experts and provide improved definitions of the features to facilitate diagnosing adenomyosis. A modified Delphi procedure among experts was planned. In the first round, 15 video recordings of morphological variations of adenomyosis and normal uteri were presented in a web-based survey. In the second round, the results of the first round were shared with the experts before they were asked to assess a set of 2D/3D still images and provide feedback for revised definitions. An expert meeting was organised to distill the results from the two preceding rounds into constructive improvements of the MUSA features associated with adenomyosis and discuss these until consensus was reached. Consensus was predefined as a level of agreement of at least 70% in each recording. 15 out of 18 invited experts agreed to participate. Eleven completed the first assessment round and reached consensus about the presence of the MUSA features in most videos. Uncertainty was highest for irregular and interrupted junctional zone (JZ). The experts wanted more detailed definitions of globular uterus and myometrial cysts and recommended adding 3D sonography to optimise visualisation of subendometrial lines, buds, irregular and interrupted JZ. In the second round, fifteen experts joined the survey and reached consensus for all criteria in most still images. Consensus was reached for revised definitions except for subendometrial lines, buds and the interrupted JZ. Thirteen experts joined the face-to-face meeting and consented on improvements of the definitions and tips to improve understanding of the MUSA features. Myometrial cysts, hyperechogenic islands and subendometrial lines and buds were identified as primary features of adenomyosis. Consensus between adenomyosis experts was achieved regarding ultrasound description of adenomyosis using the MUSA criteria, and revised definitions and guidance for assessment were provided.