Am J Perinatol 2012; 29(07): 503-508
DOI: 10.1055/s-0032-1310519
Original Article
Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Factors Influencing Visualization of the Intracranial Translucency during First-Trimester Screening for Aneuploidy

Carmen J. Beamon
1   Department of Obstetrics and Gynecology, Division of Maternal Fetal Medicine, University of North Carolina School of Medicine, Chapel Hill, North Carolina
,
Alison M. Stuebe
1   Department of Obstetrics and Gynecology, Division of Maternal Fetal Medicine, University of North Carolina School of Medicine, Chapel Hill, North Carolina
2   Department of Maternal and Child Health, Gillings Global School of Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
,
Honor M. Wolfe
3   Department of Obstetrics and Gynecology, University Hospitals/MacDonald Women's Hospital, Cleveland, Ohio
4   Department of Reproductive Biology, Case Western Reserve University School of Medicine, Cleveland, Ohio
› Author Affiliations
Further Information

Publication History

10 September 2011

09 January 2012

Publication Date:
11 April 2012 (online)

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Abstract

Objective Neural tube defects occur in 1/2000 live births. Imaging of the intracranial translucency (IT) during first-trimester screening has been proposed as an early screen for open neural tube defects (ONTD). This study evaluates visualization of the IT and factors influencing its visualization during first-trimester ultrasound screening for aneuploidy.

Methods Ultrasound images for patients undergoing first-trimester screening for aneuploidy from January 1, 2009, through July 31, 2009, were reviewed for IT visualization, defined as an intracranial translucency parallel to the nuchal translucency. Second-trimester ultrasounds and delivery records were reviewed for the presence of fetal ONTD.

Results The IT was visualized in 74.8% of 759 gestations studied at a mean gestational age of 12 weeks, 5 days. Among gestations where the IT was visualized, we found a larger crown-rump length, lower maternal weight, and more fetuses in the supine position (p < 0.0001). Predictive models for visualization of the IT were formulated based on these factors.

Conclusion The IT can be visualized in the majority of patients in the standard midsagittal plane used for measurement of the nuchal translucency. Visualization is significantly associated with crown-rump length, gestational age, maternal weight, and fetal position. Visualization of the IT is feasible.