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Original Paper
Assessment of intracranial translucency (IT) in the detection of spina bifida at the 11–13-week scan
Article first published online: 24 AUG 2009
DOI: 10.1002/uog.7329
Copyright © 2009 ISUOG. Published by John Wiley & Sons, Ltd.
Additional Information
How to Cite
Chaoui, R., Benoit, B., Mitkowska-Wozniak, H., Heling, K. S. and Nicolaides, K. H. (2009), Assessment of intracranial translucency (IT) in the detection of spina bifida at the 11–13-week scan. Ultrasound in Obstetrics & Gynecology, 34: 249–252. doi: 10.1002/uog.7329
Publication History
- Issue published online: 24 AUG 2009
- Article first published online: 24 AUG 2009
- Manuscript Accepted: 20 JUL 2009
- Abstract
- Article
- References
- Cited By
Keywords:
- first trimester;
- nuchal translucency;
- prenatal diagnosis;
- spina bifida;
- ultrasound
Abstract
Objective
Prenatal diagnosis of open spina bifida is carried out by ultrasound examination in the second trimester of pregnancy. The diagnosis is suspected by the presence of a ‘lemon-shaped’ head and a ‘banana-shaped’ cerebellum, thought to be consequences of caudal displacement of the hindbrain. The aim of the study was to determine whether in fetuses with spina bifida this displacement of the brain is evident from the first trimester of pregnancy.
Methods
In women undergoing routine ultrasound examination at 11–13 weeks' gestation as part of screening for chromosomal abnormalities, a mid-sagittal view of the fetal face was obtained to measure nuchal translucency thickness and assess the nasal bone. In this view the fourth ventricle, which presents as an intracranial translucency (IT) between the brain stem and choroid plexus, is easily visible. We measured the anteroposterior diameter of the fourth ventricle in 200 normal fetuses and in four fetuses with spina bifida.
Results
In the normal fetuses the fourth ventricle was always visible and the median anteroposterior diameter increased from 1.5 mm at a crown–rump length (CRL) of 45 mm to 2.5 mm at a CRL of 84 mm. In the four fetuses with spina bifida the ventricle was compressed by the caudally displaced hindbrain and no IT could be seen.
Conclusion
The mid-sagittal view of the face as routinely used in screening for chromosomal defects can also be used for early detection of open spina bifida. Copyright © 2009 ISUOG. Published by John Wiley & Sons, Ltd.