Cranial UltrasoundPaul Iskander, MDAssistant Clinical ProfessorDepartment of RadiologyUCLA

Objectives

• Indications for Cranial Ultrasound• Normal Anatomy

• Differentiate between term and premature brains• Sonographic windows

• Hemorrhages• Grading

• Infarcts/Periventricular Leukomalacia• Pitfalls and Variants• Congenital abnormalities

Indications for Cranial Ultrasound

• Anything

• AIUM Practice Parameters for the Performance of Neurosonographyin Neonates and Infants

• Evaluation for hemorrhage or parenchymal abnormalities• Evaluation for hydrocephalus• Evaluation for possible or suspected hypoxic ischemic encephalopathy• Screening before surgical procedures• There are no contraindications to neurosonography

Normal anatomy using routine views

1 – Interhemispheric fissure 2 – Frontal lobe3 – Skull4 – Orbit

1 – Interhemispheric fissure 2 – Frontal lobe5 – Frontal horn of lateral ventricle6 – Caudate nucleus 7 – Basal ganglia8 – Temporal lobe9 – Sylvian fissure

2 – Frontal lobe5 – Frontal horn of lateral ventricle6 – Caudate nucleus 8 – Temporal lobe9 – Sylvian fissure10 – Corpus callosum11 – Cavum septum pellucidum12 – Third ventricle13 – Cingulate sulcus

1 – Interhemispheric fissure 8 – Temporal lobe9 – Sylvian fissure14 – Body of lateral ventricle15 – Choroid plexus (* plexus filling third ventricle)16 – Thalamus17 – Hippocampal fissure18 – Aqueduct of Sylvius19 – Brain stem20 – Parietal lobe

1 – Interhemispheric fissure 8 – Temporal lobe10 – Corpus callosum15 – Choroid plexus20 – Parietal lobe21 – Trigone of lateral ventricle22 – Cerebellum (a hemispheres, b vermis)23 – Tentorium24 – Mesencephalon

1 – Interhemispheric fissure 20 – Parietal lobe25 – Occipital lobe26 – Parieto-occipital fissure27 – Calcarine fissure

10 – Corpus callosum11 – Cavum septum pellucidum12 – Third ventricle13 – Cingulate sulcus16 – Thalamus22 – Cerebellum (a hemispheres, b vermis)24 – Mesencephalon28 – Pons29 – Medulla31 – Cisterna magna32 – Quadrigeminal cistern33 – Inderpeduncular fossa34 – Fornix

2 – Frontal lobe5 – Frontal horn of lateral ventricle6 – Caudate nucleus 8 – Temporal lobe14 – Body of lateral ventricle15 – Choroid plexus16 – Thalamus17 – Hippocampal fissure20 – Parietal lobe21 – Trigone of lateral ventricle22 – Cerebellum (a hemispheres, b vermis)25 – Occipital lobe36 – Occipital horn of lateral ventricle

2 – Frontal lobe8 – Temporal lobe9 – Sylvian fissure20 – Parietal lobe25 – Occipital lobe37 – Insula

Additional Views

Posterior fontanelle (coronal)

8 – Temporal lobe22 – Cerebellum (a hemispheres, b vermis)23 – Tentorium25 – Occipital lobe27 – Calcarine fissure 29 – Medulla36 – Occipital horn of lateral ventricle38 – Falx39 – Straight sinus

Posterior fontanelle (parasagittal)8 – Temporal lobe15 – Choroid plexus16 – Thalamus20 – Parietal lobe21 – Trigone of lateral ventricle22 – Cerebellum (a hemispheres, b vermis)25 – Occipital lobe27 – Calcarine fissure

Temporal window

1 – Interhemispheric fissure 8 – Temporal lobe12 – Third ventricle22 – Cerebellum (a hemispheres, b vermis)23 – Tentorium24 – Mesencephalon33 – Inderpeduncular fossa41 – Circle of Willis

Mastoid fontanelle

22 – Cerebellum (a hemispheres, b vermis)28 – Pons30 – Fourth ventricle31 – Cisterna magna

Prematurity

Extreme preterm (26 weeks)

Term

Premature Brain23 weeks –Sylvian fissure

27 weeks –cingulate gyrus, parieto-occipital sulcus

Preterm infant with “watery” brain, no myelinationBasal ganglia brighter than white matter on T1Small germinal matrix hemorrhage

Term infant with early myelination

Preterm infant – echogenic basal ganglia and wide CSF spaces

Term infant with bright basal ganglia???Anoxic brain injury

Arrow pointing to germinal matrix remnant(involutes at term)

Small germinal matrix hemorrhage

Germinal Matrix Hemorrhage

• Germinal matrix must be present• Premature babies – involutes by 36 weeks

• Weak walled blood vessels in the germinal matrix• Sensitive to stress and prone to rupture

• Additional risk factors• Low birthweight• Cyanotic congenital heart disease• Prolonged labor• Multifetal pregnancy

Germinal Matrix

Germinal Matrix

Image courtesy of A.Prof Frank Gaillard, Radiopaedia.org, rID: 8353

Grading System

• Volpe (1989)• Grade 1: Germinal matrix hemorrhage with no or minimal IVH (<10%

of ventricular area on parasagittal view)• Grade 2: Intraventricular hemorrhage (10-50% of ventricular area)• Grade 3: Intraventricular hemorrhage (>50%) and distends lateral

ventricle• Concomitant periventricular echodensity (IPE), periventricular

hemorrhagic infarct, venous infarct • Notated separately, in older literature classified as Grade 4

Grade 1 Hemorrhage

Grade I germinal matrix hemorrhage

Grade 2 Hemorrhage

Grade 2 Hemorrhage

Between Grade 2 and 3

Bilateral Grade 3 Hemorrhage

Bilateral intraventricular hemorrhage and right periventricular hemorrhagic infarct

Periventricular Leukomalacia

• White matter injury of prematurity• On a spectrum with hypoxic ischemic injury• Affects watershed areas – periventricular white matter

PVL Classification

• Grade 1: Transient periventricular echodensities persisting for 7 or more days

• Grade 2: Transient periventricular echogenicity evolving into small frontoparietal cysts

• Grade 3: Periventricular echodensities evolving to extensive periventricular cystic lesions

• Grade 4: Densities extending into the deep white matter and evolving into extensive cysts

Periventricular Flaring

Especially over trigone of lateral ventricle – this can be a normal variantIf persists greater than 1 week of life (longer for premature infant) – grade 1 PVL

Periventricular Flaring

Initial exam on left, 1 month followup on right shows normal white matter echogenicity

Grade 1 PVL

Sagittal image with increased periventricular echogenicityBrighter than choroid plexus

Grade 1 PVL

Grade 1-2 PVL

Grade 2 PVL

Increased periventricular echogenicitySmall cysts

1 month later

Grade 3 PVL

Grade 4 PVL

Variants and Pitfalls

Ventricle asymmetry

Dysmorphic choroid plexus

Normal variant – not to be confused with hemorrhage

Grade 1 hemorrhage

Periventricular halo artifact

Echogenic region (more echogenic than choroid) adjacent to the ventricular atria on sagittal view is a common pseudolesion – due to anisotropic effect

Periventricular cysts

Connatal Cysts Germinal Matrix Cyst Choroid Plexus Cyst

Lenticulostriate vasculopathy

• Associations with CMV, metabolic disorders, congenital heart disease, chromosomal abnormalities

• But often present with no identifiable cause

Congenital and Acquired Diseases

Agenesis of the Corpus Callosum

A B C D

Vein of Galen Malformation

Holoprosencephaly

Schizencephaly

Meningitis

Hypoxic-Ischemic Injury

CMV Encephalitis

Post Hemorrhagic Hydrocephalus

Thank you