Mark Elwood Lockhart MD, Presenter: Nothing to Disclose

To assess the reproducibility of bony and soft-tissue pelvimetry measurements obtained from dynamic MRI studies in primiparous women across multiple centers.

Standardized dynamic pelvic 1.5T MR imaging (multiplanar T2-weighted) was performed at 6 clinical sites for the Childbirth and Pelvic Symptoms Imaging Study. Three groups of primiparous women were studied 6-12 months postpartum: (1) vaginal delivery with obstetrical anal sphincter tear; (2) vaginal delivery without anal sphincter tear; and (3) cesarean delivery without labor. After initial standardized training, 9 bony and 11 soft tissue pelvimetry parameters were measured by blinded readers at the acquisition sites and a blinded central reader. At 18 months after the initial readings, three of the readers underwent additional standardized training, and re-read 20 MRI studies to evaluate whether additional training reduced measurement variability. Variability was assessed by intraclass correlation.

On initial readings of 198 subjects (mean age 27 ± 6.2 years), only 6 of 20 MRI parameters showed good agreement (intraclass correlation (ICC) range 0.71-0.93) between the site and central expert reader. The remaining parameters had neutral or poor agreement (ICC range 0.10-0.69). Additional training reduced measurement variability: 11 of the 20 parameters had good agreement (ICC range 0.70-0.92). Correlations were greater for bony measurements [ICC (5/9 & 8/9 variables ≥0.70, initial reads and re-reads, respectively] than for soft tissue measures (1/11 & 3/11).

Even with standardized centralized training, there is high variability of pelvic MRI measurements among readers, particularly of soft tissue structures, which improves slightly with additional training. This measurement variability affects the utility of many MRI measurements for multi-center pelvic floor disorder research. Grant Number 2U01 HD41249, 2U10 HD41250, 2U10 HD41261, 2U10 HD41267, 1U10 HD41248, 1U10 HD41263, 1U10 HD41268, 1U10 HD41269

Despite increasing clinical use, the research utility of MRI pelvimetry parameters may be limited by high measurement variability among readers at different institutions despite standardized training.

Lockhart, M, Reproducibility of Dynamic MRI Pelvic Measures: A Multisite Study.  Radiological Society of North America 2007 Scientific Assembly and Annual Meeting, November 25 - November 30, 2007 ,Chicago IL. http://archive.rsna.org/2007/5001516.html