Reproducibility of Dynamic MR Imaging Pelvic Measurements: A Multi-institutional Study

doi:10.1148/radiol.2492072009

HOME

HELP

FEEDBACK

SUBSCRIPTIONS

Genitourinary Imaging

Reproducibility of Dynamic MR Imaging Pelvic Measurements: A Multi-institutional Study¹

Mark E. Lockhart, MD, MPH, Julia R. Fielding, MD, Holly E. Richter, MD, PhD, Linda Brubaker, MD, Caryl G. Salomon, MD, Wen Ye, MD, Christiane M. Hakim, MD, Clifford Y. Wai, MD, Alan H. Stolpen, MD, and Anne M. Weber, MD

¹ From the Departments of Radiology (M.E.L.) and Obstetrics and Gynecology (H.E.R.), University of Alabama at Birmingham, 625 19th St South, JTN Room 363, Birmingham, AL 35249; Department of Radiology, University of North Carolina, Chapel Hill, NC (J.R.F.); Departments of Obstetrics & Gynecology and Urology (L.B.) and Radiology (C.G.S.), Loyola University, Chicago, Ill; Department of Biostatistics, University of Michigan, Ann Arbor, Mich (W.Y.); Department of Radiology, University of Pittsburgh, Pittsburgh, Pa (C.M.H.); Department of Obstetrics and Gynecology, University of Texas–Southwestern, Dallas, Tex (C.Y.W.); Department of Radiology, University of Iowa, Iowa City, Iowa (A.H.S.); Edward Hines, Jr., VA Hospital, Hines, Ill (C.G.S.); and National Institute of Child Health and Human Development, Bethesda, Md (A.M.W.). Received November 16, 2007; revision requested January 15, 2008; revision received May 19; accepted May 30; final version accepted June 16. Supported in part by National Institute of Child Health and Human Development grants 2U10 HD41249, 2U10 HD41250, 2U10 HD41261, 2U10 HD41267, 1U10 HD41248, 1U10 HD41263, 1U10 HD41268, and 1U10 HD41269. Address correspondence to M.E.L. (e-mail: mlockhart{at}uabmc.edu).

Purpose: To assess the reproducibility of bone and soft-tissue pelvimetrymeasurements obtained from dynamic magnetic resonance (MR) imagingstudies in primiparous women across multiple centers.

Materials and Methods: All subjects prospectively gave consent forparticipation in this institutional review board–approved,HIPAA-compliant study. At six clinical sites, standardized dynamicpelvic 1.5-T multiplanar T2-weighted MR imaging was performed inthree groups of primiparous women at 6–12 months after birth:Group 1, vaginal delivery with anal sphincter tear (n = 93); group2, vaginal delivery without anal sphincter tear (n = 79); and group3, cesarean delivery without labor (n = 26). After standardized centraltraining, blinded readers at separate clinical sites and a blindedexpert central reader measured nine bone and 10 soft-tissue pelvimetryparameters. Subsequently, three readers underwent additional standardizedtraining, and reread 20 MR imaging studies. Measurement variabilitywas assessed by using intraclass correlation for agreement betweenthe clinical site and central readers. Acceptable agreement was definedas an intraclass correlation coefficient (ICC) of at least 0.7.

Results: There was acceptable agreement (ICC range, 0.71–0.93)for eight of 19 MR imaging parameters at initial readings of 198subjects. The remaining parameters had an ICC range of 0.13–0.66.Additional training reduced measurement variability: Twelve of 19parameters had acceptable agreement (ICC range, 0.70–0.92).Correlations were greater for bone (ICC, $≥$ 0.70 in five [initial readings]and eight of nine [rereadings] variables) than for soft-tissue measurements(ICC, $≥$ 0.70 in three [initial readings] of 10 and four [rereadings]of 10 readings, respectively).

Conclusion: Despite standardized central training, there is highvariability of pelvic MR imaging measurements among readers, particularlyfor soft-tissue structures. Although slightly improved with additionaltraining, measurement variability adversely affects the utility ofmany MR imaging measurements for multicenter pelvic floor disorderresearch.