Neonatal head ultrasound is a specialized skill often performed at the bedside in the NICU. The premature brain is fragile and at high risk for hemorrhage and ischemic injury. Your images directly guide decisions about management and prognosis in some of the most vulnerable patients.

When Is Neonatal Head Ultrasound Performed?

Routine screening: All infants ≤ 30 weeks gestational age — typically at 7–14 days of life and 36–40 weeks corrected gestational age
Symptomatic infants: Apnea, seizure, acute neurologic deterioration, drop in hematocrit
Follow-up: After documented IVH — monitor for progression, hydrocephalus, cystic evolution

Why Ultrasound (Not CT)?

No radiation (critical for the developing brain)
Portable — comes to the NICU bedside
The fontanelles provide acoustic windows that CT cannot exploit
Highly sensitive for hemorrhage and ventricular size in this age group

Anatomy and Acoustic Windows

Anterior Fontanelle (Primary Window)

The anterior fontanelle (bregma) is the main acoustic window. It's located at the junction of the coronal and sagittal sutures — the diamond-shaped soft spot at the top of the head. It closes between 9–18 months.

Probe: 5–8 MHz sector/curved probe (small footprint). Some labs use a high-frequency linear probe for supplemental views.

Posterior Fontanelle (Secondary Window)

The posterior fontanelle (lambda) is smaller, at the junction of the sagittal and lambdoid sutures. It closes by 2–3 months. Useful for:

Posterior fossa evaluation (cerebellum)
Supplemental views of occipital lobes

Mastoid Fontanelle

Lateral window — useful for posterior fossa and temporal lobe views when available.

Scanning Protocol

Coronal Planes (Anterior Fontanelle)

From the anterior fontanelle, angle the probe forward (toward the face) to backward (toward the occiput) to obtain a series of coronal planes.

Standard coronal planes (6 views):

Frontal — anterior to the frontal horns: frontal lobes, interhemispheric fissure
Frontal horns — through the frontal horns of the lateral ventricles: caudothalamic groove (where IVH begins), frontal horns, corpus callosum
Foramen of Monro — third ventricle, thalami, choroid plexus
Trigones / atria — body and atria of lateral ventricles, choroid plexus, periventricular white matter
Posterior horns — occipital horns, periventricular regions
Parieto-occipital — far posterior, occipital lobes

Sagittal Planes (Anterior Fontanelle)

Rotate the probe 90° for sagittal views. Angle left and right to sweep through the brain.

Standard sagittal planes:

Midline sagittal — corpus callosum, third ventricle, cerebral aqueduct, fourth ventricle, cerebellar vermis, cavum septi pellucidi
Right parasagittal — body of lateral ventricle, caudothalamic groove, choroid plexus, caudate nucleus
Left parasagittal — same for left side
Right temporal — temporal horn, Sylvian fissure
Left temporal — same for left side

Posterior Fontanelle / Mastoid Views

Posterior coronal views of the cerebellum, fourth ventricle, posterior fossa.

Normal Neonatal Brain Landmarks

Germinal matrix: Present only in premature infants — the subependymal zone at the caudothalamic groove (junction of caudate nucleus and thalamus, adjacent to the floor of the frontal horn). This is where IVH originates. It appears as a small echogenic nub at the caudothalamic groove.

Choroid plexus: Fills the lateral ventricles posteriorly — highly echogenic, irregular, "cauliflower" appearance in the trigones. Extends into the roof of the third ventricle.

Corpus callosum: Thin echogenic band spanning the midline on sagittal view.

Cavum septi pellucidi: Normal fluid-filled space between the leaves of the septum pellucidum — present in premature infants (usually closes by 6 months).

Periventricular white matter: Should be homogeneous, slightly echogenic relative to cortex.

Intraventricular Hemorrhage (IVH) — Grading

The Papile grading system (modified) is the standard:

Grade	Description
Grade I	Subependymal hemorrhage (germinal matrix) — does NOT extend into ventricle
Grade II	IVH without ventricular dilation — blood in ventricle, no hydrocephalus
Grade III	IVH WITH ventricular dilation (hydrocephalus)
Grade IV	Periventricular hemorrhagic infarction (PVHI) — parenchymal involvement; formerly called "Grade IV IVH" but now recognized as infarction, not extension of IVH

Sonographic appearance of IVH:

Subependymal: echogenic nub at the caudothalamic groove, larger than the normal germinal matrix remnant
Intraventricular: echogenic material filling the ventricle (acute blood is brightly echogenic)
Dilated ventricles: measure ventricular index (frontal horn width at level of foramen of Monro)

Ventricular index (VI) measurement: Width of the lateral ventricle measured from the midline to the lateral wall at the level of the foramen of Monro on the coronal view. Normal values are gestational-age-dependent (Levene's nomogram).

Grade I is benign — nearly all resolve without sequelae. Grade III–IV carries higher risk of neurodevelopmental impairment; PVHI has the worst prognosis.

Periventricular Leukomalacia (PVL)

PVL is ischemic white matter injury in the premature brain — injury to periventricular white matter due to hypoxia-ischemia.

Acute phase (0–1 week):

Increased echogenicity in periventricular white matter (bilateral, usually symmetric)
Compare to normal: white matter should be less echogenic than choroid plexus
A common pitfall: normal periventricular "blush" can mimic PVL — look for abnormal echogenicity that persists and is ≥ choroid plexus brightness

Subacute / chronic phase (2–6 weeks):

Echogenicity may transiently normalize
Later: cystic PVL develops — periventricular cysts (anechoic, non-vascular) in the white matter
Cystic PVL = strong predictor of cerebral palsy (particularly spastic diplegia)

Hydrocephalus: Monitoring

Serial measurements of the ventricular index track progressive dilation after IVH.

Levene's ventricular index:

Measure at the level of the foramen of Monro in the coronal plane
Compare to age-corrected nomogram
Progressive dilation > 97th percentile warrants neurosurgical consultation

Also document:

Third ventricle width (normal < 3 mm in term)
Torcular-choroid plexus distance in occipital horn

Key Images to Capture

Coronal: 6 standard planes as described above Sagittal: Midline, bilateral parasagittal, temporal views Posterior fontanelle: Posterior fossa views

Always measure:

Ventricular index bilaterally (coronal, at foramen of Monro)
Any focal lesion — size, location, echogenicity

Reporting Language

Normal: "Anterior fontanelle scan: normal brain parenchyma with homogeneous echogenicity. Germinal matrix within expected limits. No subependymal or intraventricular hemorrhage identified. Lateral, third, and fourth ventricles are of normal size for gestational age. Corpus callosum intact. No periventricular cystic change."

Grade III IVH: "Bilateral intraventricular hemorrhage with associated ventricular dilation. Echogenic blood fills the frontal horns and bodies of the lateral ventricles bilaterally. Ventricular index: right 15.2 mm, left 15.6 mm (above 97th percentile for corrected gestational age of 30 weeks). No periventricular extension. Grade III IVH bilaterally. Neurosurgical consultation recommended. Repeat imaging in 1 week."

SonoBuddy's pediatric protocols include neonatal head, pyloric stenosis, and hip dysplasia guides.

Neonatal Head Ultrasound: IVH Grading, Fontanelle Windows, and Technique