ObjectivesThe primary aim is to evaluate interobserver agreement on International Endometrial Tumour Analysis (IETA) terminology and other ultrasound (US) features (“bridge sign”, lesion shape and "fan‐shaped shadowing") of polyps and fibroids. The secondary aim is to assess the relevance of these US features in the diagnosis of polyps and fibroids.MethodsFrom Leuven University Hospital Bleeding Clinic we selected stored 3D‐volumes of 113 non‐consecutive patients with a final pathologic diagnosis of fibroid or polyp. 3D‐volumes of unenhanced transvaginal US examinations on grayscale (GS) and with Doppler signal (DS) as well as fluid instillation sonography (FIS) in GS and adding DS (FIS&DS) were converted in video clips. Two experienced sonographers, blinded to pathology results, scored the clips for the presence of the US features and proposed a diagnosis. Interobserver agreement was determined using Cohen's kappa coefficient (k).ResultsThere were 71 polyps and 42 fibroids. Interobserver agreement was good for “circular flow”, both on DS (k = 0.66) and on FIS&DS (k = 0.62), moderate for the “bridge sign” on GS (k = 0.50), lesion shape on FIS (k = 0.44), “single dominant vessel” on FIS&DS (k = 0.57), “fan‐shaped shadowing” on FIS (k = 0.57) and for “multiple vessels with focal origin” on FIS&DS (k = 0.60). In polyps, sonographers reported an oval shape on FIS in 76‐77% (percentage for sonographer 1 and 2), a “single dominant vessel” on FIS&DS in 32‐37% and “multiple vessels with focal origin” on FIS&DS in 15‐20%. In fibroids, the sonographers reported the “bridge sign” on GS in 36‐45%, “fan‐shaped shadowing” on FIS in 38‐52% and “circular flow” on DS in 29‐52% and on FIS&DS in 38‐57%. Examiners agreed on the diagnosis in 82% of the cases (k = 0.69); 63% were polyps.ConclusionsInterobserver agreement for some of the US features is good to moderate. These may be selected in the differential diagnosis between polyps and intracavitary fibroids. Overall there was a good agreement on the diagnosis between both examiners.info:eu-repo/semantics/publishe