Intracranial congenital cystic lesion Dr Ahmed Esawy CT MRI part 2
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Transcript of Intracranial congenital cystic lesion Dr Ahmed Esawy CT MRI part 2
Congenital cystic lesions
Dr Ahmed Esawy
•Arachnoid Cyst
Dr Ahmed Esawy
ARACHNIOD VERSUS EPIDERMIOD
arachniod CSF density
No calcification,no enhancment
displace structures
CT
Low signal like CSF MRI T1
high signal like CSF
MRI T2
Low signal like CSF
FLAIR
DARK hypointensity
(free diffusion)
DIFFUSION
BRIGHT marked
hyperintensity
like CSF
ADC
Retrocerebellar,CPA
Dr Ahmed Esawy
T2-weighted sagittal MRI image (see Image 2 for axial view) of the brain
in a 28-year-old woman with an incidental finding of a cisterna ambiens
arachnoid cyst (arrow).
28-year
Dr Ahmed Esawy
Unenhanced CT scan of the head in a 26-year-old man with a history of
seizures since childhood (same patient as Image 4). The scan shows a
large left frontoparietal cyst with a mass effect. Dr Ahmed Esawy
T1-weighted sagittal MRI image of the lumbosacral spine showing
an incidental sacral arachnoid cyst. Dr Ahmed Esawy
T2
DIFFUSION
autopsied brain
ARACHNOID CYSTS
Dr Ahmed Esawy
A)
B.
C.
D.
Arachnoid Cyst
T2-hyperintense mass in the left
cerebellopontine angle (arrow
T1-hypointense mass (arrow)
DW hypointensity in the mass (arrow) ADC map marked hyperintensity
(arrow) similar to that of the CSF Dr Ahmed Esawy
arachnoid cysts
Dr Ahmed Esawy
Arachnoid cyst with enlargement of the calvaria
T2 T1 Non contrast CT
Dr Ahmed Esawy
midline Arachnoid cyst
Causing dilated OH
Coronal gradient echo
FLAIR T1
DW
CT
Dr Ahmed Esawy
28-year-old woman
T2
superior cerebellar cistern arachnoid cyst
Dr Ahmed Esawy
26-year-old man
large left frontoparietal cyst Dr Ahmed Esawy
T2
ARACHNIOD CYST
T1 FLAIR
Dr Ahmed Esawy
• Prenatal coronal T1-left temporal fossa arachnoid cyst.
• post natal coronal T2-left temporal fossa arachnoid cyst.
• postnatal coronal T1-left temporal fossa arachnoid cyst. Dr Ahmed Esawy
Suprasellar arachnoid cyst in a patient with Mowat-Wilson syndrome (includes agenesis of the corpus callosum) and bradycardia from increased intracranial pressure.
The entire fluid collection represents the arachnoid cyst (C) and should not be confused with the third ventricle.
T2
Dr Ahmed Esawy
Differential Diagnosis
• epidermoid cyst
• Chronic subdural hematoma
• porencephalic cyst
Dr Ahmed Esawy
ARACHNIOD VERSUS EPIDERMIOD
epidermiod arachniod Lower density than CSF
May show calcifications
invade structures
CSF density
No calcification,no enhancment
displace structures
CT
LOWER THAN CSF Low signal like CSF MRI T1
HIGHER THAN CSF high signal like CSF
MRI T2
HIGH SIGNAL Low signal like CSF
FLAIR
BRIGHT typical hyperintensity
T2 shine (restricted diffusion)
DARK hypointensity
(free diffusion)
DIFFUSION
DARK lower than that of CSF and equal
to or higher than
that of brain parenchyma
BRIGHT marked
hyperintensity
like CSF
ADC
Away from midlline CPA
Retrocerebellar,CPA
Dr Ahmed Esawy
posterior fossa cystic malformation
destructive lesions
porencephalic cyst
hydranencephaly
multicystic encephalomalacia
Dr Ahmed Esawy
• The normal cisterna magna
characteristically measures 3–8 mm when
measurements are taken in the midsagittal
plane from the posterior lip of the foramen
magnum to the caudal margin of the
inferior vermis
Dr Ahmed Esawy
Isolated mega cisterna magna in a
patient with trisomy 21 transcranial
US /CT
Dr Ahmed Esawy
Dandy-Walker malformation
three criteria • (a) vermian hypoplasia with cephalad rotation of
the vermian remnant,
• (b) cystic dilatation of the posterior fossa communicating with the fourth ventricle, and
• (c) enlargement of the posterior fossa causing an abnormally high tentorium and torcular,
• the latter lying above the level of the lambdoid (ie,torcular-lambdoid inversion)
Dr Ahmed Esawy
Dandy-Walker malformation in a full-term 1-day-old neonate
retrocerebellar collection of CSF (arrowheads). Coronal US scan
shows vermian agenesis and a wide communication with a
"keyhole" appearance (arrowheads) between the cyst posteriorly
and the fourth ventricle (4) anteriorly . The cerebellar
hemispheres (C) are hypoplastic
Magnified transmastoid US scan Dr Ahmed Esawy
posterior fossa cystic malformation
Dandy Walker
Dr Ahmed Esawy
Dandy-Walker malformation in a full-term
1-day-old neonate
Coronal T2-weighted (d) and sagittal T1-weighted (e) MR images show the Dandy-Walker malformation.
Dr Ahmed Esawy
Sagittal T1-weighted image reveals a large posterior fossa fluid collection that extends to the upper
spinal canal. The foramen magnum is enlarged.
There is hypoplasia of the inferior vermis of the cerebellum. Superior vermis present in the midline.
There is significant decrease in the AP dimension of the medulla
Dandy-Walker Variant
with No Separate Fourth
Ventricle
Dr Ahmed Esawy
C. Coronal SPGR image shows asymmetry of the cerebellar
hemispheres; the right cerebellar hemisphere is hypoplastic
Sagittal T1-weighted image demonstrates a large posterior
fossa cyst that communicates with the fourth ventricle
elevating the cerebellar vermis and torcular Herophili
B. Axial T2-weighted
image shows a large CSF-
intensity fluid collection
that expands the posterior
fossa on the right and
communicates in the
midline with the fourth
ventricle (arrow)
Dandy-Walker Variant with Elevation of Torcula
Dr Ahmed Esawy
T1
Axial transmastoid US
T2
Arachnoid cyst
and complex
posterior fossa
malformations
in a full-term 1-
day-old
neonate
Dr Ahmed Esawy
Bilateral supraclinoid internal carotid artery occlusions with intact posterior circulation
Hydranencephaly in new born an extreme example of porencephaly
large cystic space involving the entire supratentorial area bilaterally
No cortical rim
Dr Ahmed Esawy
B. Axial T1-weighted image shows only
portions of temporal lobe and midbrain to
be present.Most of the cranium is filled
with fluid
Hydranencephaly with Microcephaly
A. Sagittal T1-weighted image
shows portions of frontal lobes,
midbrain and cerebellum to be
present Dr Ahmed Esawy
d
Hydranencephaly with increasing head size
A. Noncontrast CT through the
temporal lobes reveals normal-
appearing lower temporal lobes with
abnormal CSF collection frontally
B. CT image reveals that CSF replaces
the hemispheric brain tissue with a thin
residual midline and occipital lobe brain
C. Sagittal T1-weighted image
shows that the areas supplied by
posterior cerebral artery are
preserved
D. T2-weighted image shows normal
lower medial temporal and occipital
lobes. The thalami are not fuse
E. T2-weighted image shows
that CSF occupies most of the
space normally filled with brain
F. Coronal SPGR image shows also that areas
supplied by the posterior cerebral artery are
preserved. The falx (arrow) is partially normal
Dr Ahmed Esawy
B. Axial T2-weighted image shows the brainstem and cerebellum to be present
C. Axial T2-weighted image through the expected hemispheres shows a portion of
residual temporal lobe on the left
A. Sagittal T2-weighted image demonstrates
fluid filling most of the cranium in the
expected location of the cerebral
hemispheres. Only the cerebellum and part
of the thalami are present
Hydranencephaly with increasing head size
Dr Ahmed Esawy
PORENCEPHALIC CYSTS
• congenital or acquired cavities within the cerebral hemisphere
• cortical or subcortical
• unilateral or bilateral .
• The location often corresponds to territories supplied by the cerebral arteries .
• Congenital porencephalic cysts originate from a fetal or perinatal encephaloclastic process that results from intrauterine vascular or infectious injury .
• Acquired cysts are secondary to injury later in life and are usually secondary to trauma, surgery, ischemia, or infection
Dr Ahmed Esawy
Coronal T1-MR
enlarged left temporal horn (black arrow) that communicates with peripherally located porencephalic cyst (white arrows). Cyst extends to the brain surface
Dr Ahmed Esawy
Differential Diagnosis
• arachnoid cyst (extra-axial)
• schizencephaly
• (ependymal cyst) intraventricular with normal surrounding brain tissue (
• encephalomalacia
• hydranencephaly
Dr Ahmed Esawy
1-day-old term infant
Porencephaly (no communication with the ventricles)
CT no C
calcifications along the margins of the cavity (arrowheads). These are probably sequelae of a remote infarct in the distribution of the middle cerebral artery.
Dr Ahmed Esawy
Porencephaly in a 26-week gestation premature neonate
Dr Ahmed Esawy
CT scan at the age of 13 years showing the porencephalic
cyst in left cerebral hemisphere.
Dr Ahmed Esawy
• the midline cavities and their positions in the sagittal plane (top) and coronal plane (bottom).
• supratentorial cystic lesions in a periventricular location,
Dr Ahmed Esawy
28-week gestation neonate
Dr Ahmed Esawy
Cavum veli interpositium.
33 weeks of gestation
Dr Ahmed Esawy
Differential diagnosis Periventricular Location
• periventricular leukomalacia (PVL),
• connatal cyst (CC),
• subependymal cyst (SC)
• anatomic locations. Dr Ahmed Esawy
• Connatal cysts in a 30-week gestation preterm infant. just lateral to the frontal horn and body of the lateral ventricle.
connatal cysts are coarctation of the lateral ventricles and frontal horn cysts sequelae of ischemic insults
Dr Ahmed Esawy
Bilateral connatal cysts in a 3-week-old full-term neonate
along superolateral angles of the lateral ventricles (arrows).
Dr Ahmed Esawy
Subependymal Cysts
• acquired, posthemorrhagic cyst
• congenital and is related to germinolysis.
Dr Ahmed Esawy
Acquired subependymal cyst due to an
evolving subependymal hemorrhage
caudothalamic groove
T2 T1
Dr Ahmed Esawy
Open lip schizencephaly (type II)
T1
T2
T2
T2 FLAIR
Dr Ahmed Esawy
Periventricular Leukomalacia
• Periventricular leukomalacia (PVL) refers to white matter necrosis in a characteristic distribution.
• The distribution pattern is dorsal and lateral to the external angles of the lateral ventricles
• involves particularly the centrum semiovale and the optic (trigone and occipital horns) and acoustic (temporal horn) radiations .
• PVL most frequently occurs in premature infants of less than 32 weeks gestation due to the unique anatomic features of the brain at this age.
Dr Ahmed Esawy
• Extensive cystic PVL in a 29-week gestation premature neonate. extensive multiseptate cystic areas located superiorly to the frontal horns (arrows). There is ex vacuo dilatation of the ventricles secondary to white matter loss.
Dr Ahmed Esawy
Unilateral periventricular leukomalacia
Gray matter indents the ventricle wall (arrow)
due to severe white matter loss on right.
Corpus callosum is thin. The right hemisphere
is smaller than the left.
Typical undulation of ventricular wall is present
Dr Ahmed Esawy
B. DW image shows hypointensity
in right hemisphere cystic lesions
Multicystic Encephalomalacia
A.T1-weighted image shows a thin corpus callosum
Dr Ahmed Esawy
E. T2-weighted image
shows diffuse hyperintense
cysts throughout the right
hemisphere that is smaller
C. Axial FLAIR image
reveals small right
hemisphere and multiple
CSF containing spaces with
dilated lateral ventricle
D. Coronal FLAIR image confirms
the encephalo-malacia and ex
vacuo atrophy displacing the
midline to right
Multicystic Encephalomalacia
Dr Ahmed Esawy
Multicystic Encephalomalacia
F. T1-weighted image shows
hypointensity in the right cerebral
hemisphere. This is consistent with an
area of encephalomalacia and gliosis due
to a prior insult such as infarct or
infection. Minimal hyperintensity is noted
in the area of encephalomalacia
consistent with mineralization
H. CT at the age of 3years shows
multicystic encephalomalacia with
small right hemicranium
G. T1-FLAIR image shows multiple
CSF containing cysts. The thin cortex
is better appreciated in this sequence
Dr Ahmed Esawy
Schizencephaly with bilateral clefts in a 36-
week gestation preterm infant.
Dr Ahmed Esawy
Severe obstructive
hydrocephalus due to
aqueductal stenosis.
large fluid-filled space
posteriorly which
represents a markedly
dilated lateral ventricle
that simulates a large
cyst.
choroid plexus (CP) • thalami (T)
Dr Ahmed Esawy
Holoprosencephaly spectrum disorder in a newborn.
a) Midline sagittal US scan shows a large
monoventricle (arrows). The third and
fourth ventricles are normal
(b) Coronal US scan shows an absent septum pellucidum, the large monoventricle (arrows), and partially fused thalami (T).
Dr Ahmed Esawy
(b) Sagittal T2-weighted MR image shows
the shieldlike appearance of forebrain
structures and the monoventricle
(arrowheads).
A-Axial T2-weighted MR image shows
partial fusing (arrowheads) of the thalami
(T) and the large monoventricle posteriorly
Holoprosencephaly spectrum disorder in a newborn. Dr Ahmed Esawy
Sagittal T1-weighted image shows hypoplastic cerebellar hemisphere (arrow),
small brainstem and a large posterior CSF space. There is also a prominent CSF
space anterior to the pons. Corpus callosum is thin and splenium absent
Chiari III
Dr Ahmed Esawy
Holoprosencephaly/ aqueductal
stenosis
• The key is in the appearance of the thalami and
third ventricle: holoprosencephaly exhibits
fused thalami and an absent third
ventricle,while aqueductal stenosis will show
splayed thalami and a dilated third ventricle
Dr Ahmed Esawy
Left frontal intraparenchymal hematoma in a newborn with
increasing thrombocytopenia
T1
Spontaneous Intracranial Hematoma
Dr Ahmed Esawy
Spontaneous intracranial hematoma in a 2-month-old infant with an inherited thrombophilic disorder.
Dr Ahmed Esawy
Temporal lobe cysts and fetal
alcohol syndrome
Parasagittal T1-
T2-bitemporal intraparenchymal cysts
(arrows).
FLAIR
Dr Ahmed Esawy
Temporal lobe cysts and fetal
alcohol syndrome MRS
Dr Ahmed Esawy