Detection of Open Spina Bifida in the First Trimester: Beyond Intracranial Translucency

Intracranial translucency (IT) has been used extensively as an indirect marker to exclude open spina bifida (OSB) in the first trimester. Like any sonographic sign, the use of IT is fraught with issues like non-visualization due to shadowing from bone, poor distinction from the adjacent hypoechoic brainstem, etc. In view of these challenges, researchers have come up with additional markers of OSB in the first trimester. The aim of this paper is to illustrate these sonographic clues so as to improve diagnostic accuracy in cases where obliteration of IT is equivocal.