Which structure's maximum normal size is most commonly used to assess hydrocephalus during prenatal ultrasound?

Which structure's maximum normal size is most commonly used to assess hydrocephalus during prenatal ultrasound?

• A. Lateral Ventricle Atrial Width
• B. Cerebellum Diameter
• C. Fetal Abdomen Diameter
• D. Placental Thickness

Answer: (A)

Hydrocephalus in the fetus is evaluated by measuring the width of the lateral ventricle at its widest point—the atrium. This maximum normal size is about 10 mm; a measurement above that indicates ventriculomegaly, which suggests hydrocephalus. The measurement is done in the axial view with the head in a neutral position, ensuring you capture the widest part of the atrium without including other spaces. The other structures listed aren’t used to assess hydrocephalus because they reflect different anatomy or growth parameters: the cerebellum diameter relates to the posterior fossa and not ventricular dilation; fetal abdomen diameter and placental thickness pertain to overall fetal growth and placental status rather than ventricular size.

Hydrocephalus in the fetus is evaluated by measuring the width of the lateral ventricle at its widest point—the atrium. This maximum normal size is about 10 mm; a measurement above that indicates ventriculomegaly, which suggests hydrocephalus. The measurement is done in the axial view with the head in a neutral position, ensuring you capture the widest part of the atrium without including other spaces.

The other structures listed aren’t used to assess hydrocephalus because they reflect different anatomy or growth parameters: the cerebellum diameter relates to the posterior fossa and not ventricular dilation; fetal abdomen diameter and placental thickness pertain to overall fetal growth and placental status rather than ventricular size.