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بسم اهلل الرحمن الرحيم
Dr Ahmed Esawy
An Article By
Dr. Ahmed Esawy
MBBS M.Sc MD
Dr Ahmed Esawy
Dr Ahmed Esawy
Congenital cystic lesions
• 1-arachnoid cysts
• 2-porencephalic cyst,
• 4-multicystic encephalomalacia
• 3-hydranencephaly
• 5-holoprosencephaly
• 6-hydrocephalus (aqueduct stenosis)
• 7-periventricular leukomalacia (PVL),
• 8-septum pellucidum changes CSP CV CI
• 9-dandy walker malformation
• 10-dandy walker varaint
• 11-mega cisterna magna
• 12-schizencephaly
• 13-conatal cysts
• 14-subependymal cysts
Dr Ahmed Esawy
Post traumatic cystic lesion
)sequelae(late
• 15-encephalomalacia,
• 16-subarachnoid cyst
• 17-cystic lesions after brain surgery
and radiation injury to the brain.
• 18-Leptomeningeal cyst
• 19-Post traumatic porenencephally
Dr Ahmed Esawy
Inflammatory and infectious
cysts:
• 20-brain abscess
• 21-cysticercosis
• 22-hydatid cyst.
• 23-amoebic abscess
Dr Ahmed Esawy
VASCULAR
• 24-Aneurysm
• 25-Parenchymal Perianeurysmal Cystic
Changes in the Brain
• 26-Vein of Galen malformation
Dr Ahmed Esawy
Tumors and tumors like cysts
27-epidermoid cysts
28-dermoid cyst (cystic teratoma)
29-craniopharyngioma
30-cystic astrocytoma
31-cystic meningioma
32-cystic shwannoma
33-hemangioblastoma
34-cystic metastasis
35-cystic pituitary adenoma
36-Cystic degeneration / necrotic neoplasm Dr Ahmed Esawy
and Nonneoplastic
cystsinflammatory -non • 37-colloid cysts
• 38-Rathke’s cleft cysts,
• 39-neuroepithelial cysts
• 40-neuroenteric cysts
• 41-pineal cysts.
• 42-Choriod plexus cyst
• 43-CSF-Iike Choroidal Fissure and Parenchymal Cysts of the Brain
• 44-Trigonal cyst
• 45-Interhemispheric cyst
• 46-Dorsal cyst
• 47-Ependymal cysts
• 48-Enlarged VRS
• 49-Cystic trapped 4th ventricle
• 50-Diverticulation of 3rd , lateral ventricle Dr Ahmed Esawy
Dr Ahmed Esawy
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
Inflammatory and infectious
intracranial cysts
• 20-brain abscess
• 21-cysticercosis
• 22-hydatid cyst.
• 23-amoebic abscess
Dr Ahmed Esawy
Brain Abscess
Dr Ahmed Esawy
Brain abscess..
poorly defined area of posterior parietal brain edema (arrows). Early cerebritis
may not outline a focal mass clearly Dr Ahmed Esawy
Brain abscess.
a poorly defined pattern of mass effect and low attenuation in the left temporal lobe.
Of early cerebritis
Dr Ahmed Esawy
Brain abscess.
An area of ring like enhancement (yellow arrow) is noted within a much larger pattern of
edema (white arrow). The central core of the abscess (black arrow) does not enhance
(central necrosis) Dr Ahmed Esawy
temporal lobe abscess, extracranial, subdural, and intracerebral abscesses
Dr Ahmed Esawy
Brain abscess.
depressed skull fracture. The left parietal cranial injury an abscess of the subgaleal
space (SGA) the epidural space (EDA) the left cerebral hemisphere (CA).
Dr Ahmed Esawy
Brain abscess. Axial T1 +C ,T2-weighted MRI in a patient with a right frontal abscess.
Dr Ahmed Esawy
The right frontal lobe of the
brain is shifted across the
midline (double arrow) by an
intracranial abscess (single
black arrow) that has extended
upward from the medial right
orbit and medial ethmoid air
cells (curved dotted arrow).
T1-contras Brain abscess T1-contras
the enhancement within the right ethmoid
sinuses from which the infection arose.
The medial superior right maxillary sinus
has been destroyed (yellow arrow).
T1-contras
An abscess is noted within the medial inferior right orbit. The right maxillary sinus
(double white arrows) contains infected secretions and mucus Dr Ahmed Esawy
Brain abscess. (FLAIR) MRI
in a patient with abscess of the
cerebellar vermis (black arrow).
T2- MRI abscess of the midline
cerebellum. the large area of
increased signal, both within the
abscess and within the surrounding
cerebellum (black arrow).
Dr Ahmed Esawy
Brain abscess. T1-enhanced
central zone of enhancement
within the abscess, with a zone of
decreased brightness (edema,
white arrow). Brain abscess. T1enhanced
enhanced mass within the right medial
cerebellum (yellow arrow). The thick-
walled cystic mass was opened.
Dr Ahmed Esawy
CEREBRAL ABSCESS ON DW MRI
On trace DWI abscesses are typically hyperintense, indicating decreased diffusion of water.
– This is secondary to increased viscosity of pus
which contains, in addition to cellular debris and bacteria, large molecules such as fibrinogen, which bind water molecules and add to the effect of restricted diffusion.
– This can be confirmed with an apparent diffusion coefficient (ADC) map where abscesses are of low signal ,markedly reduced ADC
Dr Ahmed Esawy
Diffusion-weighted Imaging
ADC maps are of great value in
distinguishing neoplasms in ADC maps is
more often have facilitated diffusion,
Dr Ahmed Esawy
CEREBRAL THALAMIC ABSCESS ON MRI
Post-Gd T1WI: WI2T DWI
Dr Ahmed Esawy
Left and right frontal abscesses:
35-year-old male.
DWI ADC WI2T WI1T
Dr Ahmed Esawy
Pyogenic Abscess
T2 T1 T1/Gd DWI
bright on DWI
Dr Ahmed Esawy
Abscess (purulent) ADC decreased
dark on ADC map Dr Ahmed Esawy
7. 8.
DD : tumour
central hypointensity on diffusion-weighted image and hyperintensity on ADC
map, consistent with the diagnosis of tumor.
Dr Ahmed Esawy
7. 8. DD : tumour
Central hypointensity is seen on the diffusion-weighted image and hyperintensity
on the ADC map, consistent with the diagnosis of tumor.
Dr Ahmed Esawy
Brain abscess primary and secondary (daughter
Fluid and necrotic tissue (bright area) . edema surrounds
the abscess cavities (black arrows).
surrounding the abscess does not enhance
(white arrows).
DWI T1/Gd
Dr Ahmed Esawy
Brain abscess (FLAIR)
left occipital-parietal brain abscess.
Dr Ahmed Esawy
MRI Brain
abscess
T1/Gd
T2
well-defined hypointense
capsule
DWI
Dr Ahmed Esawy
MR Spectroscopy
• .Typical MR spectroscopic features of brain
abscesses include
• elevated peaks of amino acid, lactate,
alanine, acetate, pyruvate, and succinate
• absent signals of NAA, creatine, and choline.
Dr Ahmed Esawy
MR spectroscopy
• shed light on which organism is
responsible for the abscess
• because the presence of anaerobic
bacteria tends to cause elevated acetate
and succinate peaks.
Dr Ahmed Esawy
DD : NEOPLASM
• Elevation of choline and absence of signal from a variety of amino acids, acetate and succinate favours neoplastic process
Dr Ahmed Esawy
Dr Ahmed Esawy
Dr Ahmed Esawy
necrotic or cystic neoplasms Pyogenic brain abscesses
Elevated choline , decrease
NAA
elevated peaks of amino acid,
lactate, alanine, acetate,
pyruvate, and succinate
absent signals of NAA,
creatine, and choline
MRS
facilitate diffusion
dark
restricted diffusion
bright
DW
Bright on ADC map
The walls of necrotic or cystic
tumors have a lower ADC
value than of an abscess
markedly reduced ADC maps. ADC
wall of necrotic or cystic
neoplasms tends to have higher
rTBV
capsule of an abscess tends to
have lower rTBV
MR PERFUSION
Dr Ahmed Esawy
Signal volume MR spectra of
abscess
Short-echo MRS shows depression of the NAA, choline (Cho) and creatine (Cr) as well as elevation of the amino acid, lactate (Lac), acetate and succinate. Dr Ahmed Esawy
T2 T1+C
Single voxel MRS peaks representing
alanine, lactate and amino acids
DW hyperintense
signal in centre
ADC decrease signal
in centre
Brain abscess
Dr Ahmed Esawy
brain abscess
Dr Ahmed Esawy
Brain abscess in a 28-week gestation
preterm newborn
well-defined cystic structure with low-
level echoes (arrowheads) in the left
posterior parietal region
abscess has ring enhancement (arrowheads). Dr Ahmed Esawy
cysticercosis
Dr Ahmed Esawy
Cystercercus cellulosae - (3-20 mm)
regular round thin walled cyst,
produces only mild inflammation
larva in cyst
Dr Ahmed Esawy
Calcification in cysticercosis
• Calcification in burned out residues of cysticercosis
scattered throughout the brain in later stages Dr Ahmed Esawy
NEUROCYSTICERCOSIS
Multiple neurocysticercosis cysts of various sizes. Some contain visible scolices (arrows). MR image shows
T1 innumerable tiny low-signal-intensity
neurocyticercosis cysts in brain
parenchyma and subarachnoid spaces.
Most contain small “dot” that represents
the scolex (arrows Dr Ahmed Esawy
Intraparenchymal cysticercal cyst
Scolex within each cyst
Dr Ahmed Esawy
Differential Diagnosis
• abscess (T2-hypointense rim (
• Tuberculosis (profoundly hypointense on T2 ,meningitis)
• toxoplasmosis
• neoplasm primary or metastatic
• enlarged PVSs same appearance as CSF at all MR sequences and do not enhance)
• NEUROCYSTICERCOSIS characteristic “cyst with dot” appearance .
Dr Ahmed Esawy
multiloculated
amebic abscess
partially cystic mixed-signal-intensity
subcortical mass (arrow)T1 .
some enhancement around complex cystic
mass (arrow)T1+CONTRAST Dr Ahmed Esawy
Differential Diagnosis
• Complex conglomerated parasitic cysts of
any origin may mimic primary or
metastatic brain tumor .
Dr Ahmed Esawy
hydatid cyst
CT Unilocular cyst CSF density No edema no enhancement ± calcification
MRI low signal T1 , high signal T2 Dr Ahmed Esawy
hydatid cyst
T1+C
T1
T2
Dr Ahmed Esawy
HYDATID CYSTS
• 5 year child
very large nonenhancing cystic mass
without surrounding edema (arrows). Dr Ahmed Esawy
Differential Diagnosis
• arachnoid cyst
• epidermoid cyst
• neurocysticercosis
Dr Ahmed Esawy
Tuberculous abscesses
T1- multiple scattered ring-enhancing lesions
Dr Ahmed Esawy
MRS
• Tuberculous abscesses typically have high
lipid and lactate peaks.
• These abscesses have no peaks for amino
acids (leucine, isoleucine, and valine) at 0.9
ppm, succinate at 2.41 ppm, acetate at 1.92
ppm, and alanine at 1.48 ppm,
• in contrast to pyogenic abscesses, which
have peaks for all these metabolites.
Dr Ahmed Esawy
VASCULAR CYSTIC
INTRACRANIAL
LESION
Dr Ahmed Esawy
VASCULAR
• 24-Aneurysm
• 25-Parenchymal Perianeurysmal Cystic
Changes in the Brain
• 26-Vein of Galen malformation
Dr Ahmed Esawy
Vein of Galen malformations
(VOGMs)
• The aneurysm of the vein of Galen
represents a rare intracranial
arteriovenous malformation
Dr Ahmed Esawy
CT scan in a 3 month old child with vein of Galen malformation a: Plain axial CT
scan of the brain showing a rim of calcification located along the wall of the
venous sac Dr Ahmed Esawy
Fetal MRI imaging of aneurysm of vein of Galen
Dr Ahmed Esawy
CT scan with contrast medium. Note the enlarged lateral ventricles and the large well-defined globular mass in the pineal region. Contrast enhancement Dr Ahmed Esawy
MRI; midline sagittal projection. T1-weighted image shows the spheroidal lesion with a
signal void that is typical of a high flow arteriovenous malformation. The aneurysm
causes a mass-efect on the aqueductus of Silvius, the posterior part of the third ventricle
and the splenium of the corpus callosum. Dr Ahmed Esawy
MRI of a thrombosed vein of Galen mlaformation:
: Plain T2 weighted sagittal scan of the
brain revealing the characteristic
location of the lesion
Plain T1 weighted axial scan of the
brain revealing the presence of
thrombus at various st ages within the
venous sac
Dr Ahmed Esawy
Lateral MR venogram
Vein of Galen malformation.
T1-
The dilated vein of Galen communicates
with a persistent falcine sinus (arrow).
pericallosal branches (P).
Dr Ahmed Esawy
vein of Galen
malformation
neonate
Transcranial color Doppler ultrasonography
aneurysmal dilatation of the median
prosencephalic vein of Markowski (black
arrows). Dr Ahmed Esawy
Two year old Vein of Galen malformation.
Dr Ahmed Esawy
Plain radiograph of the skull showing calcification of the wall
of the venous sac of a vein of Galen malformation
Dr Ahmed Esawy
Differential diagnosis
midline cystic cerebral lesions • Arachnoid cysts
• Porencephalic cysts
• Choroid plexus cysts
• Choroid papilloma
• Intracranial teratomas
• Congenital dural arteriovenous fistula
Dr Ahmed Esawy
Parenchymal Perianeurysmal
Cystic Changes in the Brain
Dr Ahmed Esawy
large (2.0-cm-
diameter) right
posterior cerebral
artery aneurysm
(arrow) with an
adjacent cluster of
various sized cysts
(arrowheads).
Parenchymal Perianeurysmal Cystic
Changes in the Brain
Dr Ahmed Esawy
T2- perianeurysmal cysts in the left basal ganglia (arrowhead).
Coronal T1+C aneurysm of the left internal
carotid artery Several small cysts
(arrowheads) are seen superior to the
aneurysm(arrow)
Parenchymal Perianeurysmal Cystic
Changes in the Brain
Dr Ahmed Esawy
• T1 enhanced multiple small cysts (arrowheads) around the large (1.9-cm-diameter)
aneurysm (arrow) of the right posterior cerebral artery.
Parenchymal Perianeurysmal Cystic
Changes in the Brain
Dr Ahmed Esawy
right anterior cerebral artery aneurysm (arrow) as hyperintense. The
adjacent cyst (arrowhead) is unilocular and irregular in shape
Parenchymal Perianeurysmal Cystic
Changes in the Brain
Dr Ahmed Esawy
• CT scan shows a giant (4.0-cm-diameter) aneurysm (arrow) with prominent thrombosis and calcifications.
Perianeurysmal cyst (arrowhead) and edema are depicted in the left frontal lobe.
Parenchymal Perianeurysmal Cystic
Changes in the Brain
Dr Ahmed Esawy
blood within an arachnoid cyst at the tip of the left temporal lobe with a degree of
ventricular dilatation
Posterior communicating artery
aneurysm presenting with
haemorrhage into an arachnoid
cyst
Dr Ahmed Esawy
Nonneoplastic & noninflammatory
intracranial cysts
Dr Ahmed Esawy
and Nonneoplastic
cystsinflammatory -non • 37-colloid cysts
• 38-Rathke’s cleft cysts,
• 39-neuroepithelial cysts
• 40-neuroenteric cysts
• 41-pineal cysts.
• 42-Choriod plexus cyst
• 43-CSF-Iike Choroidal Fissure and Parenchymal Cysts of the Brain
• 44-Trigonal cyst
• 45-Interhemispheric cyst
• 46-Dorsal cyst
• 47-Ependymal cysts
• 48-Enlarged VRS
• 49-Cystic trapped 4th ventricle
• 50-Diverticulation of 3rd , lateral ventricle Dr Ahmed Esawy
Colloid cyst Colloid cyst
Dr Ahmed Esawy
• MRI appearance
• : variable signals depending on the contents
T1 hyperintense or hypo intense
T2 hyperintense or hypo intense
Colloid cyst Colloid cyst
Dr Ahmed Esawy
colloid cysts
Dr Ahmed Esawy
Colloid cyst
Characteristic site anterior 3rd ventricle
Characteristic contents
dense viscid mucoid material
(old blood, cholesterol crystals, CSF,various ions)
• CT: hyper dense midline lesion no enhancement
Dr Ahmed Esawy
Colloid cyst
Unenhanced CT. There is a dense, rounded mass in the region of the foramen of Monro causing
enlargement of the lateral ventricles, and indenting the anterior aspect of the third ventricle. Dr Ahmed Esawy
COLLOID CYSTS
• Transverse nonenhanced CT scan shows classic hyperattenuated colloid cyst at foramen of Monro (arrow ( Dr Ahmed Esawy
Differential Diagnosis
• CSF flow artifact (MR pseudocyst (
• neurocysticus cyst may occur at the foramen of Monro.
• Neoplasms such as subependymoma or choroid plexus papilloma
Dr Ahmed Esawy
Rathke cleft cyst T2
smoothly marginated cystic mass (arrows) within and projecting above the pituitary gland. The cyst appears slightly hyperintense relative to gray matter on both T1-weighting (B) and T2-weighting (A). There is no contrast enhancement of its contents or margins
T1 -c
Dr Ahmed Esawy
RATHKE CLEFT CYSTS
• Sagittal postcontrast
• cyst has moderately high protein content and is isointense with brain, not CSF. Location is typical for a Rathke cleft cyst , Dr Ahmed Esawy
Differential Diagnosis
• Craniopharyngioma
• cystic pituitary adenoma
• nonneoplastic cysts Unlike Rathke cleft cysts
Dr Ahmed Esawy
• Enhanced CT scan demonstrates an extra-axial cystic lesion over the left frontal
convexity with two small nodules of rim calcification. There is no contrast
enhancement of the cyst.
Intracranial laterally based
supratentorial neurenteric cyst
Dr Ahmed Esawy
Choroids Plexus Cysts
• Choroid plexus cysts are usually a few
millimeters in diameter and are commonly
located within the body of the plexus. Choroid
plexus cysts may be limited within the body itself
or may protrude into the ventricular cavity .
Isolated choroid plexus cysts occur in about 1%
of all pregnancies.
Dr Ahmed Esawy
Choroids Plexus Cyst
Dr Ahmed Esawy
Choroids Plexus Cyst
Dr Ahmed Esawy
Multiple small choroid plexus cysts in a normal infant..
Dr Ahmed Esawy
CHOROID
PLEXUS CYSTS
Transverse contrast-enhanced T1-weighted bilateral CPCs with peripheral and nodular enhancement (arrows) .
Most CPCs are actually degenerative
xanthogranulomas.
Dr Ahmed Esawy
Differential Diagnosis
• ependymal cyst do not enhance
• villous hyperplasia of the choroid plexus enhances strongly and relatively uniformly.
• Disturbed CSF flow and pseudolesions
• Colloid cysts should not be mistaken for CPCs
Dr Ahmed Esawy
T2 multiple bizarre-appearing cysts (arrows) in centrum semiovale and subcortical white matter of both hemispheres. The cysts vary in size and focally expand but otherwise spare the overlying cortex .
T1+C nonenhancing enlarged PVSs in
right basal ganglia
Enlarged PVSs, Virchow-Robin spaces
isointense to CSF at all pulse sequences
Dr Ahmed Esawy
Differential Diagnosis
• multiple lacunar infarcts
• cystic neoplasms
• infectious cysts (Neurocysticercosis cysts )
.
Dr Ahmed Esawy
EPENDYMAL CYSTS
• FLAIR MR
• enlarged atrium of the left lateral ventricle (open arrow). Signal intensity was isointense to
CSF at all pulse sequences. Note lateral displacement of choroid plexus (solid arrow) Dr Ahmed Esawy
Differential Diagnosis
• CPC
• arachnoid cyst
• neurocysticercosis
• asymmetric ventricles
Dr Ahmed Esawy
Neuroepithelial (ependymal) cyst
Intraventricular cysts 5-year-old male
T2- T2-
cyst within the
right lateral
ventricle with
signal intensity
isointense to
CSF in all
pulse
sequences
T2-
Dr Ahmed Esawy
NEUROGLIAL CYSTS
• neuroglial cyst (straight arrow) adjacent to left temporal horn .
• isointense to CSF at all sequences .
• neuroglial cyst in the choroid fissure (arrow .
AXIAL FLAIR MR
Dr Ahmed Esawy
Differential Diagnosis
• enlarged PVS
• infectious cyst
• porencephalic cyst
• arachnoid cyst
Dr Ahmed Esawy
PINEAL
CYSTS
postmortem slice
Sagittal contrast-enhanced T1
classic benign pineal cyst (straight arrows)
with rim enhancement and mild mass effect
(note slight compression, displacement of
tectal plate [curved arrow) .(]
Dr Ahmed Esawy
Differential Diagnosis
• benign pineal parenchymal neoplasm called a pineocytoma .
• Other cysts in the quadrigeminal cistern that mimic pineal cysts include arachnoid cysts (no calcium) and, rarely,epidermoid cysts
Dr Ahmed Esawy
NEURENTERIC CYSTS
• Sagittal T1
small well-delineated ovoid mass in front of pontomedullary junction (arrow). Mass is hyperintense
compared to CSF. Location and configuration are typical for a neurenteric cyst Dr Ahmed Esawy
Differential Diagnosis
• epidermoid cyst
• arachnoid cyst
• endodermal cysts (Rathke and colloid)
Dr Ahmed Esawy
The Virchow–Robin spaces (VRS) • perivascular compartments surrounding small blood
vessels as they penetrate the brain parenchyma
• Three types
IMAGING CHARACTER
• Characteristic site
• The content of the cysts is CSF-like.
• The adjacent brain parenchyma has normal signal intensity.
• No solid components are identified.
• no enhancement
• Enlarged cause pressure changes Dr Ahmed Esawy
Virchow-Robin Spaces TYPE 1
Proton density FALIR DWI ADC
Bilateral type I VR spaces in a 6-year-old boy
anterior perforated substance on both sides
The signal intensity of the surrounding brain parenchyma is normal
Dr Ahmed Esawy
Virchow-Robin Spaces TYPE 11
Proton density FALIR
Type II VR spaces in a 73-year-old woman hyperintense foci in the
centrum semiovale in both hemispheres
The signal intensity of the surrounding brain parenchyma is normal
FLAIR show old lacunar infarctions(arrow)
Dr Ahmed Esawy
Type II dilated VR spaces in a 6-year-old boy
FALIR T2
punctate hyperintense areas around the
occipital horns
Dr Ahmed Esawy
Type III VR spaces in a 68-year-old man
Proton density FALIR
T2
multiple punctate hyperintense areas in the brainstem ON T2 hypointenese on FLAIR
Dr Ahmed Esawy
Giant VR spaces in the mesencephalothalamic
region in a 19-year-old man.
T2
T1+C
multicystic lesion in the mesencephalothalamic region
Dr Ahmed Esawy
DIFFERENTIAL DIAGNOSIS
of VRS • Lacunar infarction
• Cystic periventricular leukomalacia
• Ovoid MS lesion of the centrum semiovale
• Parenchymal neurocysticercosis in the vesicular stage
• Hurler syndrome (mucopolysaccharidosis type I)
• Desmoplastic pilocytic astrocytoma
• Arachnoid cyst in the perisellar cistern area
• Neuroepithelial cyst of the thalamus
• Choroidal fissure cyst
Dr Ahmed Esawy
MR Imaging of CSF-Iike Choroidal
Fissure and Parenchymal Cysts of the Brain
Dr Ahmed Esawy
T1
T2
Left choroidal fissure
cyst (arrows) in 36-
year-old man
Dr Ahmed Esawy
T1
Right choroidal fissure cyst 31 y
right temporal lobe lesion (arrowheads)
Dr Ahmed Esawy
T2
T1
T1
Right choroidal fissure
cyst 31 y
right temporal lobe
lesion (arrowheads)
Dr Ahmed Esawy
• Left choroidal fissure cyst (arrows) • 13-year-old girl
• cyst between mesial temporal lobe and brainstem is seen on
T1 T2
Dr Ahmed Esawy
• Right choroidal fissure cyst in 74-year-old woman with cerebral atrophy
• Large cyst (arrows) medial to temporal tip of lateral ventricle (arrowheads) , no enhancement of lesion.
T1+C
T1
Dr Ahmed Esawy
T2
Right choroidal fissure cyst
(arrowheads) in 27-year-old man
Dr Ahmed Esawy
Left juxtasylvian cyst in 49-year-old woman loop of middle cerebral artery (small curved arrow) indenting cyst (large arrow). No enhancment
T2 T1+C
Dr Ahmed Esawy
T2
T1
T1
Right juxtasylvian cyst (arrows) in 54-year-old man
Note similarity in shape and location to Branch of middle cerebral artery indents
Dr Ahmed Esawy
T2
T1
T1
Right thalamic multiseptated cyst (arrows) in 66-year-old woman isointensity of cyst with CSF.
Dr Ahmed Esawy
Interhemispheric cysts associated with callosal agenesis
Dr Ahmed Esawy
Dr Ahmed Esawy
The most important condition that must be
distinguished from interhemispheric cysts is
the alobar form of holoprosencephaly
because to treat them as early as possible
in order to prevent gross developmental
deficits
Dr Ahmed Esawy
Tumors and tumors like
cysts intracranial
Dr Ahmed Esawy
ARACHNIOD VERSUS EPIDERMIOD
epidermiod Lower density than CSF
May show calcifications
invade structures
CT
LOWER THAN CSF MRI T1
HIGHER THAN CSF MRI T2
HIGH SIGNAL FLAIR
BRIGHT typical hyperintensity
T2 shine (restricted diffusion)
DIFFUSION
DARK lower than that of CSF and equal
to or higher than
that of brain parenchyma
ADC
Away from midlline CPA
, supra and parasellar region
middle cranial fossa and
cisterna magna
LOCATION
Dr Ahmed Esawy
T2
CT+no C CT+C
EPIDERMIOD AT CPA
Dr Ahmed Esawy
T2
T1+C
DIFFUSION
Epidermoid tumour
Dr Ahmed Esawy
Epidermoid, brain. CT+no C
, located in the middle cranial fossa with extension into the suprasellar cistern..
Dr Ahmed Esawy
Epidermoid, brain.
T2 T1+no C DIFFUSION
FLAIR
Dr Ahmed Esawy
epidermoid cysts
Dr Ahmed Esawy
EPIDERMOID
CYST
diffusion-shows markedly restricted diffusion (arrows .(
Dr Ahmed Esawy
T2WI T1WI
DWI ADC
End of images
EPIDERMOID
CYST
B 1000 ADC
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
Differential Diagnosis
• arachnoid cyst. Arachnoid cysts are isointense to CSF at all
sequences, including FLAIR. They displace rather than invade structures such as the epidermoid. Finally, arachnoid cysts do not restrict on diffusion-weighted image .
• Dermoid cysts are typically located along the midline and resemble fat, not CSF .
• Cystic neoplasms often enhance and do not resemble CSF .
• Neurocysticercosis cysts often enhance and demonstrate surrounding edema or gliosis .
Dr Ahmed Esawy
Dermoid cyst
location Midline plane, posterior fossa, suprasellar area and Intraventricular
MRI: high signal in T1 [ fat ]
Dr Ahmed Esawy
CT: fat density ± calcification, no
enhancement
Dermoid cyst
Dr Ahmed Esawy
Dermoid tumor 26-Y M
cystic lesion is present in the right temporal lobe+
peripheral marginal calcification in the lesion
partial marginal
enhancement
T1+C
multiple small foci of hyperintense signal are present along the sulci of the right temporal lobe. These represent fat droplets in the subarachnoid space from the focal rupture of the dermoid tumor.
T1+C
T1+NO C
Dr Ahmed Esawy
Rupture intraventricular or subarachnoid → fat /fluid level
Dr Ahmed Esawy
Dermoid tumor. The high signal intensity areas in the
subarachnoid space of the Sylvian fissures and ambient cisterns
represent lipid material from the tumor that has contaminated the CSF
Dr Ahmed Esawy
Suprasellar rupture dermoid tumours
T1W
Fat globules, which have spilled into the
subarachnoid space, are seen as high
signal foci in the left Sylvian fissure Dr Ahmed Esawy
posterior fossa lesion with posterior mural nodule
Unusual Imaging Appearance of an Intracranial Dermoid Cyst
Dr Ahmed Esawy
Ruptured dermoid cyst
• mixed-signal-intensity lesion in the pineal region (straight arrow) with multiple hyperintense droplets scattered through the subarachnoid space (curved arrows). Moderate hydrocephalus is present ..
T1+no C
Dr Ahmed Esawy
Differential Diagnosis
• Epidermoid (typically resemble CSF (not fat), lack dermal
appendages, and are usually located off midline)
• Craniopharyngioma (suprasellar, with a midline location, and demonstrate nodular calcification. craniopharyngiomas are strikingly hyperintense on T2 enhance strongly.
• teratoma
• lipoma .
Dr Ahmed Esawy
CT +no C
epidermiod tumour (inclusion cyst) of Quadrigeminal cistern
Quadrigeminal cistern cyst
Dr Ahmed Esawy
CT +C
epidermiod tumour (inclusion cyst) of Quadrigeminal cistern
displacment of choriod plexus and the body of lateral ventricle
Dr Ahmed Esawy
MRI T1+C
epidermiod tumour (inclusion cyst) of Quadrigeminal cistern
Compression of quadrigeminal plate and cereberal aqueduct
Dr Ahmed Esawy
MRI T2 Quadrigeminal cistern
Dr Ahmed Esawy
Differential Diagnosis
of Quadrigeminal cistern cyst
• Arachniod
• Teratoma
• Cystic pineal tumour
Dr Ahmed Esawy
craniopharyngioma
Dr Ahmed Esawy
CT+C large suprasellar cyst with several nodular calcifications of varying size (arrow) in the wall of the cyst
T1+C cystic intra-/suprasellar mass with strong contrast enhancement of the cyst wall (arrow). The cyst contents are isointense with gray matter, reflecting their high protein content.
T2-strongly hyperintense homogeneous cyst contents. The well circumscribed cyst (arrow) displaces the anterior cerebral arteries anteriorly and the middle cerebral arteries bilaterally
Craniopharyngioma in a child
Dr Ahmed Esawy
Craniopharyngioma in an adult T2
T1+C
Dr Ahmed Esawy
cystic astrocytoma
Dr Ahmed Esawy
hemangioblastoma
Dr Ahmed Esawy
postcontrast T1
facial schwannoma associated with large
arachnoid cyst )(open arrow .(
postcontrast T1
large pituitary macroadenoma with multiple
cysts (arrows) surrounding the suprasellar
component trapped PVSs
NEOPLASM-ASSOCIATED BENIGN
CYSTS
Dr Ahmed Esawy
cystic metastasis
NEOPLASM-ASSOCIATED BENIGN
CYSTS
Dr Ahmed Esawy
T1W post-contrast i dark DW bright on the ADC map
Cystic metastasis from CA breast
unrestricted diffusion in the center of the mass
Dr Ahmed Esawy
large right cerebellopontine angle tumour with a medial cystic component.
Cystic vestibular schawannoma T2W
Dr Ahmed Esawy
Cystic astrocytoma
Dr Ahmed Esawy
II- Magnetic resonance imaging:
• MRI emerged as the imaging
modality of choice for most
intracranial abnormalities. This is
especially true for lesions located in
the posterior fossa, where the
sensitivity of CT is limited by beam-
hardening artifacts from the petrous
bone.
Dr Ahmed Esawy
• If metastases are to be excluded,
heavily T1-weighted pre- and
post-contrast images can be
obtained. Intravenous contrast is
a routine for tumor and infection
investigation.
Dr Ahmed Esawy
• A potential drawback of SE images
is that they may not reliably show
the internal architecture or
morphology of cystic masses. If
the solid portion does not
enhances with contrast material, it
difficult to determine whether the
mass is simple cyst or a cyst with
solid component.
Dr Ahmed Esawy
• Fluid-attenuation inversion-recovery
(FLAIR) MRI belongs to a family of
inversion-recovery sequences, that
generates heavily T2-weighted
images with nulling/subtraction of
the CSF sign and enable improved
characterization of complex cystic
masses.
Dr Ahmed Esawy
Functional studies of cystic brain lesion
Dr Ahmed Esawy
N-acetylaspartate (NAA)
creatine-phosphocreatine(Cr)
choline (Cho).
amino acid, lactate, alanine, acetate,
pyruvate, and succinate
MR spectroscopy
Dr Ahmed Esawy
primary cystic neoplasm versus metastases
primary cystic neoplasm choline
Cystic metastases where no choline resonance
is seen
Dr Ahmed Esawy
necrotic or cystic neoplasms Pyogenic brain abscesses
Elevated choline , decrease
NAA
elevated peaks of amino acid,
lactate, alanine, acetate,
pyruvate, and succinate
absent signals of NAA,
creatine, and choline
MRS
facilitate diffusion
dark
restricted diffusion
bright
DW
Bright on ADC map
The walls of necrotic or cystic
tumors have a lower ADC
value than of an abscess
markedly reduced ADC maps. ADC
wall of necrotic or cystic
neoplasms tends to have higher
rTBV
capsule of an abscess tends to
have lower rTBV
MR PERFUSION
Dr Ahmed Esawy
CT and MR stereotactic biopsy:
Solid contrast enhancing areas are preferred for biopsy rather than cystic, necrotic, or hemorrhagic tumor regions.
Cystic brain lesion biopsy and treatment
Dr Ahmed Esawy
Image guided therapy:
CT and MRI have revolutionized the diagnosis and management of brain abscesses. If excisional neurosurgery is not immediately or otherwise indicated an attempt at abscess aspiration should be made usually guided by CT when the lesion is accessible. Also intraoperative imaging using MR allows for precise localization of the lesion and its relationship. Dr Ahmed Esawy
THANK YOU
Dr Ahmed Esawy
THANK YOU
Dr Ahmed Esawy
