2D versus 3D transabdominal sonography for the measurement of lower uterine segment thickness in women with previous cesarean delivery

Objective: To evaluate the intermethod reliability of using 3D versus 2D transabdominal sonography in the measurement of lower uterine segment (LUS) thickness in women with previous cesarean delivery, in addition to determining the interobserver reliability of 2D and 3D transabdominal sonography in LUS measurement. Methods: Between February and July 2010 at Queen Mary Hospital, Hong Kong, 40 pregnant women with a history of previous cesarean delivery at 36-39 weeks of pregnancy underwent LUS measurement via 2D and 3D transabdominal sonography by 2 observers. The 3D examination was performed on the multiplanar display of the longitudinally acquired LOS volume. Inner myometrial thickness (MT) and full thickness (FT) were measured at the thinnest portion and perpendicular to the contour of the LUS. Results: The 2D and 3D LUS measurements obtained by the 2 observers were comparable (intraclass correlation coefficient [ICC]: MT, 0.81 and 0.98, respectively; FT, 0.76 and 0.98, respectively). For transabdominal LUS measurement, 2D MT provided the best interobserver reliability (ICC: 2D MT, 0.95; 2D FT, 0.91; 3D MT, 0.82; 3D FT, 0.77). Conclusion: Compared with the 2D approach, 3D transabdominal sonography does not seem to improve the reliability of LOS measurement. 20 measurement of MT seems to be most reliable between different observers. (C) 2011 International Federation of Gynecology and Obstetrics. Published by Elsevier Ireland Ltd. All rights reserved.