Pregnancy

Are there secondary intracranial signs of open spina bifida on Ultrasound? Most cases of open spina bifida are associated with posterior fossa abnormalities (Chiari II malformations) in utero due to downward traction of the spinal cord. This includes downward-curved “C shaped” herniation of the cerebellum (the “banana” sign), effacement of the cisterna magna, flattening of …

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Can Ultrasound differentiate spina bifida in utero? During routine second trimester US, the fetal spine is screened for any open or closed spinal defect. Open spina bifida containing only herniated meninges is a meningocele. If the herniated contents also include spinal cord elements, it is a myelomeningocele. On US, these defects usually appear as cystic …

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What is the purpose of evaluating the fetal lips on Ultrasound? Evaluation of the fetal lips at the time of routine second trimester US can detect a cleft lip, the most common facial anomaly. A cleft lip can be unilateral or bilateral and is associated with a cleft palate in up to 80% of cases. …

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Ultrasound features of anencephaly Anencephaly is one of the most common neural tube defects with a frequency of 1 in 1000. The fetal skull and cerebral cortex are absent while the skull base, brainstem, and orbits remain. US can depict absence of the calvarium and brain above the orbits as early as 8 weeks gestation, …

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What is the importance of the fetal cisterna magna measurement during routine second trimester Ultrasound? A normal fetal cisterna magna diameter is <10 mm (usually 2 to 8 mm). Effacement of the cisterna magna suggests a possible Chiari II malformation with a meningocele or myelomeningocele. Enlargement of the cisterna magna can be seen with a Dandy Walker …

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How many vessels are in the umbilical cord? Normally, the umbilical cord is comprised of three vessels (two arteries and one vein). A two-vessel cord (one artery and one vein) in isolation does not always imply a fetal abnormality, and in multiple gestations is a more common normal variant. However, detection of a two-vessel umbilical …

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Why is the diameter of the fetal lateral ventricle measured during routine second trimester Ultrasound? Measurement of the width of the lateral ventricle at the atrium is a standard second trimester fetal measurement used to detect hydrocephalus. Normally, the lateral ventricle diameter is <10 mm (usually 4 to 8 mm). A lateral ventricle measurement >10 mm is indicative …

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