Assessment of Transvaginal Ultrasound Cervical Length Image Quality : Obstetrics & Gynecology

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Contents: Original Research

Assessment of Transvaginal Ultrasound Cervical Length Image Quality

Boelig, Rupsa C. MD; Feltovich, Helen MD; Spitz, Jean Lea MPH, RDMS; Toland, Gregory MS; Berghella, Vincenzo MD; Iams, Jay D. MD;  on Behalf of the Perinatal Quality Foundation

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Obstetrics & Gynecology 129(3):p 536-541, March 2017. | DOI: 10.1097/AOG.0000000000001820


To use data from the Cervical Length Education and Review program to evaluate the quality of transvaginal cervical length ultrasonography by trained imagers (ie, ultrasonographers, radiologists, perinatologists).


This is a retrospective observational study of data from the Cervical Length Education and Review program. Candidates underwent an online lecture series, examination, and submitted a batch of images for review. For a candidate’s batch of images to pass, all images must meet at least seven of the nine criteria assessed, the overall batch score needs to be 80% or greater, correct caliper placement must be met for all images, and the same criterion cannot be consistently missed. We also examined a subset of these criteria-appropriate image acquisitions, defined as an image that demonstrated both internal and external os and visualization of the entire endocervical canal. Primary outcome was the overall initial candidate pass rate; secondary outcomes included distribution of criteria missed in images and percentage of images that was inadequately acquired.


Six hundred eighty-seven candidates submitted 3,748 images between June 10, 2012, and August 18, 2016. Eighty-five percent of candidates were ultrasonographers. Of the 687 initial batches submitted, 105 (15%) did not pass. Eight hundred thirty-seven images (22%) of all images failed at least one criterion; the most common image deficiencies were in “anterior width of cervix equals the posterior width” (33%), “failure to visualize” the internal or external os (29%), “cervix occupies 75% of image and bladder area visible” (33%), and incorrect caliper placement (24%). Two hundred fifty-six (7%) of all images failed to meet our criteria for adequate image acquisition.


Fifteen percent of trained imagers failed to obtain appropriate cervical length imaging. This highlights the importance of a standardized cervical length training and certification program.

© 2017 by The American College of Obstetricians and Gynecologists. Published by Wolters Kluwer Health, Inc. All rights reserved.

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