Neonatal Echoencephalography

1
Neonatal Echoencephalography

• Tanya Nolan

2
Embryology

• At the end of the 4th week after conception, the
  cranial end of the neural tube differentiates
  into 3 primary brain vesicles
• Prosencephalon (Forebrain)
• Diencephalon
• Thalmus
• Hypothalmus
• Posterior Pituitary
• Telencephalon
• Cerebral hemispheres
• Cortex Medullary Center
• Corpus Striatum
• Olfactory System
• Mesencephalon (midbrain)
• Cerebral Aqueduct
• Superior and inferior colliculi (quadrigeminal
  body)
• Rhombencephalon (hindbrain)
• Myelencephalon

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Anatomy of the Neonatal BrainCerebrum

• 2 Hemispheres (Gray and White Matter)
• Lobes of the Brain
• Frontal
• Parietal
• Occipital
• Temporal
• Gyrus and Sulcus
• Gyrus convulutions of the brain surface causing
  infolding of the cortex
• Sulcus Groove or depression separating gyri.

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Anatomy of the Neonatal BrainCerebrum

• Fissures
• Interhemispheric
• Area of Falx Cerebri
• Sylvian
• Most lateral aspect of brain
• Location of middle cerebral artery
• Quadrigeminal
• Posterior and inferior from the cavum vergae
• Vein of Galen posterior to fissure
• Falx Cerebri
• Fibrous structure separating the 2 cerebral
  hemispheres
• Tentorium Cerebelli
• V shaped echogenic extension of the falx
  cerebri separating the cerebrum and the
  cerebellum

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Cerebrum

• Basal Ganglia
• collection of gray matter
• Caudate Nucleus Lentiform Nucleus
• Largest basal ganglia
• Relay station between the thalmus and cerebral
  cortex
• Germinal Matrix includes periventricular tissue
  and caudate nucleus
• Thalmus
• 2 ovoid brain structures
• Located on either side of the 3rd ventricle
  superior to the brainstem
• Connects through middle of the 3rd ventricle
  through massa intermedia
• Hypothalmus
• Floor of 3rd Ventricle
• Pituitary Gland is connected to the hypothalmus
  by the infundibulum

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Anatomy of the Neonatal Brain

• Meninges
• Dura Mater
• Arachnoid
• Pia Mater
• Cerebral Spinal Fluid (CSF)
• Surrounds and protects brain and spinal cord.
• 40 formed by ventricles, 60 extracellular fluid
  from circulation.

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Ventricular System

• Lateral Ventricles Largest of the CSF cavities.
• Frontal Horn
• Body
• Occipital Horn
• Temporal Horn
• Trigone Atrium
• Foramen of Monro
• 3rd Ventricle
• Aqueduct of Sylvius
• 4th Ventricle
• Foramen of Luschka
• Foramen of Megendie
• Cisterns
• Cisterna Magna
• Spaces at the base of the skull where the
  arachnoid is widely separated from the pia mater.

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Anatomy of the Neonatal Brain
Choroid Plexus
Cavum Septum Pellucidum

• Corpus Callosum
• Broad band of connective fibers between cerebral
  hemispheres.
• The roof of the lateral ventricles.
• Cavum Septum Pellucidum
• Thin, triangular space filled with CSF
• Lies between the anterior horn of the lateral
  ventricles.
• Floor of the corpus callosum
• Choroid Plexus
• Mass of specialized cells that regulate IV
  pressure by secretion/absorption of CSF
• Within atrium of the lateral ventricles

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Anatomy of the Neonatal BrainBrain Stem

• Midbrain
• Pons
• Medulla Oblongata

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Anatomy of the Neonatal BrainCerebellum

• Posterior cranial fossa
• 2 Hemispheres connected by Vermis
• 3 Pairs of Nerve Tracts
• Superior Cerebellar Peduncles
• Middle Cerebellar Peduncles
• Inferior Cerebellar Peduncles

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Cerebrovascular System

• Internal Cerebral Arteries
• Vertebral Arteries
• Circle of Willis
• Middle Cerebral Artery
• Longest branch in Circle of Willis that provides
  80 of blood to the cerebral hemispheres

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Anatomy of the Neonatal Skull

• Fontanelles (Soft Spots)
• Spaces between bones of the skull

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Function and Physiology

• Cerebellum
• Controls Skeletal Muscle Movement
• Cerebral Hemispheres
• Frontal
• Voluntary muscles, speech, emotions, personality,
  morality, and intellect
• Parietal
• Pain, temperature, and spatial ability
• Occipital
• Vision
• Temporal
• Auditory and Olfactory

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Indications for Sonographic Exam

• Cranial abnormality found on pre-natal sonogram
• Increasing head circumference with or without
  increasing intracranial pressure
• Acquired or Congenital inflammatory disease
• Prematurity
• Diagnosis of hypoxia, hypertension, hypercapnia,
  hypernaturemia, acidosis, pneumothorax, asphyxia,
  apnea, seizures, coagulation defects, patent
  ductus arteriosus, or elevated blood pressure
• History of birth trauma or surgery
• Suctioning of infant
• Genetic syndromes and malformations

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Sonographic Technique

• What anatomy do you scan?
• Supratentorial Compartment
• Both cerebral hemispheres
• Basal Ganglia
• Lateral 3rd Ventricle
• Interhemispheric fissure
• Subarachnoid space
• Views
• Coronal
• Modified Coronal (anterior fontanelle)
• Sagittal (anterior fontanelle)
• Parasagittal (anterior fontanelle)
• Infratentorial Compartment
• Cerebellum
• Brain Stem
• 4th Ventricle
• Basal Cisterns
• Views
• Coronal (mastoid fontanelle and occipitotemporal
  area)

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Coronal Scan

• Transducer placed in anterior fontanelle with
  scanning plane following coronal suture.
• Transducer angled from anterior to posterior
• CRITICAL images must be symmetric!

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Coronal Scan

• Anterior
• Orbits, anterior horns, and lateral ventricles

• Anterior
• Orbits
• Anterior horns of lateral ventricles

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Coronal Scan

• Middle
• Lateral Ventricles
• (Asymmetry in the size of the lateral ventricles
  can be a common normal variant)
• Choroid Plexus
• Cavum Septum Pellucidum
• 3rd Ventricle
• Corpus Callosum

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Coronal Scan

• Posterior
• Cisterna magna
• Choroids
• Glomus of Choroids
• Occipital Lobe

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Coronal Scan (Anterior)

• Cavum Septum Pellucidum
• Midline hypoechoic/cystic structure separating
  the bodies and frontal horns of the lateral
  ventricles.
• Anterior to corpus callosum
• Caudate Nucleus
• Inferior and lateral walls of ventricles at the
  body and frontal horns
• Higher echogenicity in premature infants in
  comparison to brain parenchyma
• Frontal Horns
• Midline Slit-like hypoechoic/cystic formations
• Posterior comma-like
• Size increase from 2mm at the frontal lobe to 3-6
  mm at the choroid plexus region.

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Coronal Scan (Midline)

• Choroid Plexus
• Frontal and occipital horns devoid of choroid
  plexus
• Becomes enlarged at the level of the atria
  almost fills the cavity
• Very echogenic structure inside ventricular
  cavities surrounding the thalmac nuclei
• Becomes smaller with increased gestational age

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Coronal Scan (Posterior)

• Coronal studies through the Posterior Fontanelle
  provides an alternate window to visualize the
  choroid plexus and lateral ventricles.

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Modified Coronal Scan

• Transducer positioned over anterior fontanelle
  with an angle of approximately 30-40 degrees
  between the scanning plane and the surface of the
  fontanelle.
• Demonstrates body of lateral ventricles, 3rd
  ventricle, and posterior fossa (infratentorial
  compartment 4th ventricle, cerebellar
  hemispheres, and cisterna magna)
• 3rd Ventricle
• Not visualized in normal conditions. Prominent in
  premature infants less than 32 wks
• Thin and very echogenic formation seen in midline
  immediately below the septum pellucidum
  corresponding with the choroid plexus and
  extending into the 3rd ventricle.

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Sagittal and Bilateral Parasagittal Scan

• Provides most extensive visualization of the
  brain.
• Transducer positioned over anterior fontanelle in
  sagittal plane and angled medial and lateral.

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Sagittal Scan (Midline)

• Cavum Septum Pellucidum
• Anechoic structure immediately below corpus
  callosum
• Corpus Callosum
• 2 thin parallel lines separated by a thin
  echogenic space
• 3rd Ventricle
• Anechoic structure inferior to the septum
• Cerebellum (Tentorium)
• Vermis appears echo dense
• Cisterna Magna
• Anechoic space next to vermis
• 4th Ventricle
• Small v oriented posteriorly inside the
  echogenic vermis.

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Sagittal Scan (Midline)

• Supratentorial Structures
• Choroid plexus (CP)
• Corpus callosum (CC)
• Septum pellucidum(SP)
• Third ventricle (3V)
• Infratentorial Structures
• Brain stem (BS)
• Cerebellar vermis (V)
• Cisterna magna (CM)
• Fourth ventricle (4V)

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Parasagittal Scan (Right)

• Close to Midline
• Caudo-thalmic groove
• important because subependymal hemorrhages begin
  in the germinal matrix at the level of these
  ganglia
• Slightly more lateral
• anechoic frontal horns and bodies of lateral
  ventricles
• echogenic choroid plexus (2-3 mm height)

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Parasagittal Scan (Right)

• External to Lateral Ventricles
• White Matter
• Important in studying intraparenchymal
  hemorrhages, porencephaly, and periventricular
  leukomalacia
• Most Lateral Aspect
• Sylvian Fissure
• Middle Cerebral Artery
• Insula

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Parasagittal Scan (Right)

• Close to Midline
• Caudo-thalmic groove
• important because subependymal hemorrhages begin
  in the germinal matrix at the level of these
  ganglia
• Slightly more lateral
• anechoic frontal horns and bodies of lateral
  ventricles
• echogenic choroid plexus (2-3 mm height)
• External to Lateral Ventricles
• White Matter
• Important in studying intraparenchymal
  hemorrhages, porencephaly, and periventricular
  leukomalacia
• Most Lateral Aspect
• Sylvian Fissure
• Middle Cerebral Artery
• Insula

C
T
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Parasagittal Scan\ Repeat process on the Left
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Doppler

• Typical transcranial Doppler with imaging scan
  and recording from middle cerebral artery (MCA).
• Doppler image shows circle of Willis.
• A anterior cerebral artery
• M middle cerebral artery
• P posterior cerebral artery
• RI resistive index
• Demonstrates
• Decreased blood flow/ischemia/infarction
• Vascular abnormalities
• Cerebral Edema
• Hydrocephalus
• Intracranial Tumors
• Near-field structures

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Pathology
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Chiari Malformation

• Downward displacement of the cerebellar tonsils
  and the medulla through the foramen magnum.
• Arnold-Chiari malformation shows a small
  displaced cerebellum, absence of the cisterna
  magna, malposition of the fourth ventricle,
  absence of the septum pellucidum, and widening of
  the third ventricle
• Commonly related
• to meningomyelocele

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Chiari Malformation

• Sonographic Features
• Small posterior fossa
• Small, displaced Cerebellum
• Possible Myelomeningocele
• Widened 3rd Ventricle
• Cerebellum herniated through enlarged foramen
  magnum
• 4th ventricle elongated
• Posterior horns enlarged
• Cavum Septum pellucidum absent
• Interhemispheric Fissure widened
• Tentorium low and hypoplastic

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Holoprosencephaly

• Common large central ventricle because
  prosencephalon failed to cleave into separate
  cerebral hemispheres.
• Alobar Holoprosencephaly (Most Severe)
• Fused thalami anteriorly to a fused choroid
  plexus
• Single midline ventricle
• No falx cerebrum, corpus callosum,
  interhemispheric fissure, or 3rd ventricle
• Semilobar Holoprosencephaly
• Single ventricle
• Presents with portions of the falx and
  interhemispheric fissure
• Thalmi partially separated
• 3rd Ventricle is rudimentary
• Mild facial anomalies
• Lobar Holoprosencephaly (Least Severe)
• Near complete separation of hemipsheres only
  anterior horns fused
• Full development of falx and interhemispheric
  fissure

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Holoprosencephaly

• Alobar Holoprosencephaly Semilobar
  Holoprosencephaly

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Dandy-Walker Malformation

• Congenital anomaly of the roof of the 4th
  ventricle with occlusion of the aqueduct of
  Sylvius and foramina of Magendie and Luschka
• A huge 4th ventricle cyst occupies the area where
  the cerebellum usually lies with secondary
  dilation of the 3rd ventricle absent cerebellar
  vermis

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Dandy-Walker Malformation
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Agenesis of the Corpus Callosum

• Complete or partial absence of the connection
  tissue between cerebral hemispheres
• Narrow frontal horns
• Marked separation of lateral ventricles
• Widening of occipital horns and 3rd Ventricle
• Vampire Wings

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Agenesis of the Corpus Callosum
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Ventriculmegaly

• Enlargement of the ventricles without increased
  head circumference
• Communicating
• Non-communicating
• Resut of cerebral atrophy
• Sonographic Findings
• Ventricles greater than normal size first noted
  in the trigone and occipital horn areas
• Visualization of the 3rd and possibly 4th
  ventricles
• Choroid plexus appears to dangle within the
  ventricular trium
• Thinned brain mantle in case of cerebral atrophy

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Hydrocephalus

• Enlargement of ventricles with increased head
  circumference
• Communicating
• Non-communicating
• Sonographic Findings
• Blunted lateral angles of enlarged lateral
  ventricles
• Possible intrahemispheric fissure rupture
• Thinned brain mantle
• Aqueductal Stenosis
• Most common cause of congenital hydrocephalus
• Aqueduct of Sylvius is narrowed or is a small
  channel with blind ends occasionally caused by
  extrinsic lesions posterior to the brain stem
• Sonographic Findings
• Widening of lateral and 3rd ventricles
• Normal 4th ventricle

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Hydrancephaly

• Occlusion of internal carotid arteries resulting
  in necrosis of cerebral hemispheres
• Absence of both cerebral hemispheres with
  presence of the falx, thalmus, cerebellum, brain
  stem, and postions of the occipital and temporal
  lobes
• Sonographic findings
• Fluid filled cranial vault
• Intact cerebellum and midbrain

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Cephalocele

• Herniation of a portion of the neural tube
  through a defect in the skull
• Sonographic Findings
• Sac/pouch containing brain tissue and/or CSF and
  meninges
• Lateral Ventricle Enlargement

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Subarachnoid Cysts

• Cysts lined with arachnoid tissue and containing
  CSF
• Causes
• Entrapment during embryogenesis
• Residual subdural hematoma
• Fluid extravasation sectondary to meningeal tear
  or ventricular rupture

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Hemorrhagic Pathology

• Subependymal-Intraventricular Hemorrhage
  (SEH-IVH)
• Caused by capillary bleeding in the germinal
  matrix
• Most frequent location is the thalamic-caudate
  groove
• Continued subependymal (SEH) bleeding pushes into
  the ventricular cavity (IVH) continues to
  follow CSF pathways causing obstruction
• Treatment Ventriculoperitoneal Shunt
• Since 70 of hemorrhages are asymptomatic, it is
  necessary to scan babies routinely
• Small IVHs may not be seen from the anterior
  fontanelle because blood tends to settle out in
  the posterior horns
• Risk Factors
• Pre term infants
• Less than 1500 grams birth weight

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Hemorrhagic Pathology

• Grades
• Based on the extension of the hemorrhage
• Ventricular measurement
• Mild dilation 3-10 mm
• Moderate dilation 11-14 mm
• Large dilation greater than 14mm
• Grade I
• Without ventricular enlargement
• Grade II
• Minimal ventricular enlargement
• Grade III
• Moderate or large ventricular enlargement
• Grade IV
• Intraparenchymal hemorrhage

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Hemorrhagic Pathology

• Grade I

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Hemorrhagic Pathology

• Grade II

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Hemorrhagic Pathology

• Grade III

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Hemorrhagic Pathology

• Grade IV

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Intraparenchymal Hemorrhage

• Brain parenchyma destroyed
• Originally considered an extension of IVH, but
  may actually be a primary infarction of the
  periventricular and subcortical white matter with
  destruction of the lateral wall of the ventricle.
• Sonographic Finding
• Zones of increased echogenicity in white matter
  adjacent to lateral ventricles

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Intracerebellar Hemorrhage

• Types
• Primary
• Venous Infarction
• Traumatic Laceration
• Extension from IVH
• Sonographic Findings
• Areas of increased echogenicity within cerebellar
  parenchyma
• Coronal views through mastoid fontanelle may be
  essential to differentiate from large IVH in the
  cisterna magna

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Epidural Hemorrhages and Subdural Collections

• Best diagnosed with CT because the lesions are
  located peripherally along the surface of the
  brain.

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Ischemic-Hypoxic Lesions

• Hypoxia Lack of adequate oxygen to the brain
• Ischemia lack of adequate blood flow to the
  brain
• Types
• Selective neuronal necrosis
• Status marmoratus
• Parasagittal cerebral injury
• Periventricular leukomalacia (PVL), white matter
  necrosis (WMN), or cerebral edema
• Focal brain lesions (occurs when lesions are
  distributed within large arteries)
• Sonographic Findings
• Areas of increased echogenicity in subcortical
  and deep white matter in the basal ganglia

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Ischemic-Hypoxic LesionsPeriventricular
Leukomalacia (PVL) or White Matter Necrosis (WMN)

• Most important cause of abnormal neurodevelopment
  in preterm infants
• Early chronic stage
• Multiple cavities develop in necrotic white
  matter adjacent to frontal horns
• Middle chronic Stage
• Cavities resolve and leave gliotic scars and
  diffuse cerebral atrophy
• Increased Echogenicity
• Late chronic stage
• Echolucencies develop in the echolucent lesions
  corresponding to the cavitary lesions in the
  white matter (cysts)

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PVL or WMN
2
1
4
3
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ECMOExtracorporeal Membrane Oxygenation

• Used for pulmonary and Circulatory Support in
  many neonates to allow additional time for lung
  development
• Cannula inserted into R internal jugular vein and
  carotid artery
• Hemorrhage and ischemia are common in children on
  ECMO

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Brain Infections

• Common infections referred to by TORCH
• T Toxoplasma Gondii
• O Other (Syphilis)
• R Rubella Virus
• C Cytomegalovirus
• H Herpes Simplex Type 2
• Consequences
• Mortality
• Mental Retardation
• Developmental Delay

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Ependymitis and Ventriculitis

• Ependymitis
• Irritation from hemorrhage within the ventricle
• Occurs earlier than ventriculitis
• Sonographic Features
• Thickened, hypoechoic ependyma (epithelial lining
  of the ventricles)
• Ventriculitis
• Common complication of purulent meningitis
• Sonographic Findings
• Thin septations extending from the walls of the
  lateral ventricles.