A standardized measurement technique may improve the reliability of measurements of endometrial thickness and volume

Objective To investigate whether standardization of the multiplanar view (SMV) when evaluating the uterus using three‐dimensional ultrasonography (3D‐US) improves intra‐ and interobserver reliability and agreement with regard to endometrial measurement. Methods Two‐dimensional (2D) and 3D‐US was used to measure endometrial thickness by two observers in 30 women undergoing assisted reproduction treatment. Endometrial volume was measured with Virtual Organ Computer‐aided AnaLysis (VOCAL™) in the longitudinal (A) and coronal (C) planes using an unmodified multiplanar view (UMV) and a standardized multiplanar view (SMV). Measurement reliability was evaluated by intraclass correlation coefficient (ICC) and agreement was examined using Bland–Altman plots with limits of agreement (LoA). The ease of outlining the endometrial–myometrial interface was compared between the A‐ and C‐planes using subjective assessment. Results Endometrial volume measurements using the SMV and A‐plane were more reliable (intra‐ and interobserver ICCs, 0.979 and 0.975, respectively) than were measurements of endometrial thickness using 2D‐US (intra‐ and interobserver ICCs, 0.742 and 0.702, respectively) or 3D‐US (intra‐ and interobserver ICCs, 0.890 and 0.784, respectively). The LoAs were narrower for SMV than for UMV. Reliability and agreement were not much different between the A‐ and C‐planes. However the observers agreed that delineating the endometrial–myometrial interface using the A‐plane was easier (first and second observer, 50.0 and 46.7%, respectively) or ‘comparable’ (50 and 53.3%, respectively), but never more difficult than using the C‐plane. Conclusions Endometrial volume measurements are more reliable than endometrial thickness measurements and are best performed using SMV and the A‐plane. Copyright © 2011 ISUOG. Published by John Wiley & Sons, Ltd.