Intracranial translucency (IT) is the ultrasound appearance of the fourth ventricle in mid-sagittal plane as seen on 11-13 week antenatal scan. It is used as a marker for neural tube defects. Its absence is reported in open spina bifida 1.
Radiographic features
Technique
the fetus must be in the mid-sagittal plane, the same plane for measurement of nuchal translucency and nasal bone, where the brainstem, fourth ventricle, and cisterna magna are identified
-
the anteroposterior diameter of the fourth ventricle is measured between two echogenic lines:
posterior border of the brainstem anteriorly
choroid plexus of the fourth ventricle posteriorly
The median value of intracranial translucency is between 1.5 mm to 2.5 mm for crown rump length (CRL) 45 mm to 84 mm respectively 2.
Unable to process the form. Check for errors and try again.