Presentation1.pptx, ultrasound examination of the neonatal head.
1. Dr/ ABD ALLAH NAZEER. MD.
Ultrasound examination of the neonatal head.
2. ULTRASOUND OF THE NEONATAL HEAD PROTOCOL
INDICATIONS
Prematurity:
Some people discriminate between the terms preterm and premature.
Preterm refers to delivering prior to 37weeks whilst a premature infant is
one that has not yet reached the level of fetal development that generally
allows life outside the womb.
The fine network of vessels (the germinal matrix) on the floor of the
anterior horn of the lateral ventricles (the ependyma) are extremely fragile.
If there is any hypoxic episode, the reactive increase in blood pressure can
result in a hemorrhage of these vessels.
Usually assessed at day 1 and again at day 7.
Increased head circumference
Persisting large fontanelle
Craniosynostosis (premature closure of sutures)
Trauma
Known hypoxia
Follow up of known pathology
Failure to thrive
Suspected intracranial mass or infection
3. LIMITATIONS
If the anterior fontanel is very small or closed your visibility will be reduced or
completely obscured. Even with a large fontanelle, the peripheral extremes of
the brain are obscured from view.
EQUIPMENT SELECTION AND TECHNIQUE
Probes:
Primarily a small footprint, wide sector, mid.-frequency probe is essential.
Ideally a specific 5-8MHz vector probe however a trans-vaginal probe also
provides excellent imaging. (A TV probe can be ergonomically difficult to use
for some operators and awkward to ft in a humidicrib.)
You may also require a high frequency linear array to assess superficial
structures and a curvilinear probe for axial trans-temporal images.
Environment:
A warm room with warm gel.
If still in high oxygen environment, this should be maintained as much as
possible.
Patient position:
If still in a humidicrib as a high oxygen environment, the baby must be
scanned there. You may need to place a cloth under and/or beside the baby's
head to support and immobilize it for the scan.
4. SCANNING TECHNIQUE
Use sufficient gel to not require too much transducer pressure.
Approach is generally via the anterior fontanel. The posterior
fontanel can also be used.
Using the small footprint sector or TV probe:
Begin in a coronal plane slowly sweeping from the anterior
to the posterior.
Rotate 90o to perform sagittal and para-sagittal views.
Using the high frequency linear probe:
Gently scan through the anterior fontanelle in transverse.
You should assess the superior sagittal sinus for patency,
and the sub-arachnoid space.
You will usually be able to scan as deep as the 3rd ventricle.
Using the 5mHz curvilinear probe: scan through the temple in
an axial plane, particularly assessing the opposite subdural
region.
5. WHAT TO LOOK FOR:
A solid grasp of the intracranial anatomy is vital.
Also, a thorough understanding of the developmental evolution of the neonatal
brain and how it changes between 28weeks and term.
Essentially, the normal 10week premature brain is relatively smooth,
homogenous & devoid of sulci/gyrae.
SAGITTAL
Midline (must include corpus callosum the 3rd and 4th ventricles and
cerebellum).
Parasagittal to show caudothalamic notch and detail of lateral venticles
Far lateral to show periventricular white matter.
CORONAL
frontal
caudate region
series of images caudate to trigone of lateral ventricles
occipital region
MEASUREMENTS
Coronal: frontal horn of lateral ventricles at the foramen of Monroe (caudate
nucleus)
Sagittal: trigone of lateral ventricles
6. ULTRASOUND OF THE NEONATAL HEAD - Normal
Normal sagittal at the 3rd
and 4th ventricles.
Normal anterior coronal neonatal brain. Scan,
angling forward of this point as far as possible
to the 'bulls-horns' of the sphenoid bone.
7. Normal parasagittal at the lateral ventricles. Normal mid-anterior coronal at
the sylvian fissures and 3rd ventricle.
9. Normal coronal view of the lateral
ventricles and caudao-thalamic groove.
Normal posterior coronal using a linear array
transducer. Zoomed at the level of the trigone
of the lateral venticles, visualizing the body of
the choroid plexii.
10. The superior sagittal sinus and other
vascular channels can be readily
assessed with power Doppler. Normal far-posterior coronal.
11. Coronal images for neonatal brain, C (caudate), T (thalamus),F (foramen of Monro),
m (midbrain), 3 (third ventricle), q(quadrigeminal plate cistern), CB(cerebellar hemispheres.
14. Germinal Matrix Hemorrhage
Germinal matrix hemorrhage (GMH) is also known as periventricular
hemorrhage or preterm caudothalamic hemorrhage.
These germinal matrix hemorrhages occur in the highly vascular but also
stress sensitive germinal matrix, which is located in the caudothalamic
groove. This is the subependymal region between the caudate nucleus and
thalamus.
The germinal matrix is only transiently present as a region of thin-walled
vessels, migrating neuronal components and vessel precursors
It has matured by 34 weeks gestation, such that hemorrhage becomes very
unlikely after this age.
Most GMHs occur in the first week of life
Most common in infants
These hemorrhages start in the caudothalamic groove and may extend into
the lateral ventricle and periventricular brain parenchyma.
Most infants are asymptomatic or demonstrate subtle signs that are easily
overlooked.
These hemorrhages are subsequently found on surveillance sonography.
15.
16. Grade 1 intracranial hemorrhage, Sagittal and coronal US of subependymal
hemorrhage located in the groove between the thalamus and the nucleus caudatus.
27. Peri Ventricular Leukomalacia (PVL)
PVL is also known as Hypoxic-Ischemic Encephalopathy (HIE) of the
preterm.
It is a white matter disease that affects the periventricular zones.
In prematures this white matter zone is a watershed zone between deep
and superficial vessels.
Until recently ischemia was thought to be the single cause of PVL, but
probably other causes (infection, vasculitis) play an additional role.
PVL presents as areas of increased periventricular echogenicity.
Normally the echogenicity of the periventricular white matter should be
less than the echogenicity of the choroid plexus.
PVL occurs most commonly in premature infants born at less than 33
weeks gestation (38% PVL) and less than 1500 g birth weight (45% PVL).
Detection of PVL is important because a significant percentage of surviving
premature infants with PVL develop cerebral palsy, intellectual
impairment or visual disturbances.
More than 50% of infants with PVL or grade III hemorrhage develop
cerebral palsy.
38. Gray-scale and Doppler coronal USG demonstrating a cystic midline structure in
the region of posterior third ventricle with mass effect. (A) Typical swirl effect is
noted on Doppler (B). Findings are highly suggestive of aneurysmal malformation
of the vein of Galen. The corresponding axial and sagittal T2W images of MR
examination confirming large aneurysmal dilatation of the vein of Galen (C and D)
39.
40.
41. Coronal section - Absent corpus callosum,
widely separated frontal horns of lateral
ventricles, dilation and posterosuperior
displacement of third ventricle. Partial agenesis corpus callosum.
42.
43.
44.
45.
46. Coronal section - Dandy - Walker malformation - dilation of the
fourth ventricle (blue star), hypoplastic cerebellar hemispheres.
47.
48. Porencephalic cyst: Large foci of intraventricular/intraparenchymal bleed
could lead to a cavitating destructive lesion in the brain parenchyma. After
resolution and evacuation of the hematoma, the cavity of the lesion
communicates with the ventricular system, leading to the formation of a
porencephalic cyst. Porencephalic cysts, which are, often, a sequel of grade 4
hemorrhages are usually associated with higher neurodevelopmental defects .
Coronal USG and the high-resolution parasagittal view demonstrating a large
porencephalic cyst communicating with the left lateral ventricular cavity.
53. Midline cystic structures.
Communicate with each other.
Do not communicate with ventricular system or subarachnoid spaces.
Obliterated from posterior to anterior.
57. Connatal Cysts.
Normal variant: incidence = 0.7%.
Superolateral to frontal horns.
Anterior to Foramen of Monroe.
String of pearls.
Resolve spontaneously.
61. Benign Hygroma of infancy.
Children 6 months to 2 years.
Head circumference > 97th percentile
Cause unknown, ? Familial.
Subarachnoid spaces > 3.3 mm
+/_ slight ventricular enlargement
63. Hydrocephalus.
Obstructive: non-communicating).
Most common.
CSF cannot enter subarachnoid space
Aqueductal stenosis, Chiari Malformation, Dandy-Walker.
Non-obstructive: communicating).
Impaired CSF resorption.
Infection, hemorrhage, congenital absence arachnoid villi.
Ex Vacuo:
Loss of brain parenchyma lead to increase CSF spaces.
68. Coronal and parasagittal USG demonstrating colpocephaly in a patient with agenesis of
corpus callosum. Also, there is hypoplasia of the cerebellum, mainly involving the right lobe
69. Holoprosencephaly:
Ultrasound may also show a snake under the skull sign in some situations.
Holoprosencephaly is a rare congenital brain malformation resulting from
incomplete separation of the two hemispheres.
Alobar holoprosencephaly
In alobar holoprosencephaly, the thalami are fused and there is a single large
posteriorly located ventricle. Most commonly associated with facial abnormalities
such as cyclopia, ethmocephaly, cebocephaly, and median cleft lip.
For more details see the article on alobar holoprosencephaly
Semilobar holoprosencephaly
Here the basic structure of the cerebral lobes are present, but are fused most
commonly anteriorly and at the thalami. The olfactory tracts and bulbs are usually
not present, and there is agenesis or hypoplasia of the corpus callosum.
For more details see the article on semilobar holoprosencephaly
Lobar holoprosencephaly
This is the least affected subtype. Patients demonstrate more subtle areas of
midline abnormalities such as fusion of the cingulate gyrus and thalami. The
olfactory tracts are absent or hypoplastic. There may be hypoplasia or absence of
the corpus callosum.
72. Coronal section - Alobar holoprosencephaly - large, horseshoe-shaped
single ventricular cavity (blue arrow) and fused thalami (pink star).
73.
74.
75. Hydranencephaly is a rare encephalopathy that occurs in-utero. It
is characterised by destruction of the cerebral hemispheres with
transformation of the same into a membranous sac containing
cerebrospinal fluid and the remnants of cortex and white matter .
Hydranencephaly.
77. Anencephaly is the most severe form of cranial neural tube defect
(NTD) and is characterised by absence of cortical tissue (although
brainstem and cerebellum may be variably present) as well as absence
of the cranial vault. Morphological spectrum within anencephaly
ranges from holocrania (severest form) to merocrania (mildest form)
Antenatal ultrasound
Anencephaly may be sonographically detectable as early as 11 weeks.
Ultrasound can be a non invasive, cost effective and fast method to detect
anencephaly and has an accuracy of approximating 100% at 14 weeks
no parenchymal tissue is seen above the orbits and calvarium is absent:
parts of the occipital bone and mid brain may be present
if a small amount of neural tissue is present, it is then termed exencephaly
this may be seen at an earlier stage
less than expected value for crown rump length (CRL)
a "frog eye" or "mickey mouse" appearance may be seen when seen in
the coronal plane due to absent cranial bone/brain and bulging orbits.
may show evidence of polyhydramnios: due to impaired swallowing
79. Encephalocele (also known as
meningoencephalocele) are a type of
cephalocoele where brain tissue herniates
out through a defect in the cranium.
Antenatal ultrasound
An encephalocoele may be seen as a purely cystic
mass or may contain echoes from herniated brain
tissue. if the mass appears cystic, the meningocele
component predominates, while a solid mass
indicates predominantly an encephalocele. Larger
encephalocoeles may show accompanying
microcephaly.
81. Coronal section - periventricular calcifications
(white arrows) in a patient with CMV infection
Sagittal and coronal views - Tuberous
sclerosis - marked echogenous
intracerebral foci.
82. Fetal intracranial hemorrhage may occur either within the cerebral
ventricles, subdural space or infratentorial fossa.
Antenatal ultrasound
The sonographic appearance of fetal intracranial hemorrhage is extremely
variable, depending on its location and age of the hemorrhage. A massive
intraparenchymal hemorrhage can sometimes be seen as an irregular hyperechoic
mass. As the hemorrhage matures, porencephalic cyst formation or fetal
intracranial calcification may be seen.
83. USG images demonstrating a grade 4 left intracranial hemorrhage. Note extensive ill-defined
intraparenchymal component with relatively less mass effect, indicating hemorrhagic venous infarct
84. Large right tempo-occipital and cerebellar hemorrhage, shown as
the hyperechoic area in the coronal and parasagittal images
85. Acute ischemia: Evaluation of diffuse brain edema is technically challenging on
neurosonography. As the size of the ventricles varies considerably, ventricular size is unreliable
as a parameter in assessing the mass effect. The usual observation in the cases of ischemia is a
combination of diffuse increase in the echogenicity of ganglionic areas with associated
obliteration of cisterns and small capacity of the ventricles. CT and/or magnetic resonance
imaging (MRI) still remain as superior techniques in assessing diffuse intracranial ischemia Serial
Doppler examination of the intracranial vessels and circle of Willis is helpful in evaluating the
severity of intracranial ischemia. Diastolic flow, reflected in Resistive Index (RI) is a measure that
will indicate the hemodynamic status of intracranial flow.
Coronal USG at two levels demonstrating the subtle increase in the cerebral parenchymal echoes in a patient with acute
ischemia (secondary to meconium aspiration). Note the small-capacity ventricles and obliterated cisternal spaces
89. High-resolution images of the subarachnoid spaces; normal high-convexity subarachnoid
space is demonstrated (yellow arrows). (B) Shows a dilated subarachnoid space with
internal echoes in a patient with pyogenic meningitis (black arrows)