Fifteen (50) intracranial cystic lesion Dr Ahmed Esawy CT MRI main

‫الرحيم‬‫الرحمن‬‫اهلل‬‫بسم‬
Dr Ahmed Esawy

An Article By
Dr. Ahmed Esawy
MBBS M.Sc MD
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 cystsDr 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 neoplasmDr Ahmed Esawy

andNonneoplastic
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 ventricleDr 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 CSFMRI T1
high signal like CSFMRI T2
Low signal like CSFFLAIR
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

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
T2T1
Non contrast CT
Dr Ahmed Esawy

midline Arachnoid cyst
Causing dilated OH
Coronal gradient echo
FLAIRT1
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

epidermiodarachniod
Lower density than CSF
May show calcifications
invade structures
CSF density
No calcification,no enhancment
displace structures
CT
LOWER THAN CSFLow signal like CSFMRI T1
HIGHER THAN CSFhigh signal like CSFMRI T2
HIGH SIGNALLow signal like CSFFLAIR
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 CPARetrocerebellar,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 scanDr 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 posteriorfossa 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

Hydranencephaly with increasing head size
A. Noncontrast CT through the
emporal 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

• 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
Dr Ahmed Esawy

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..
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 mucusDr 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 ADCDr 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 ADCWI2TWI1T
Dr Ahmed Esawy

Pyogenic Abscess
T2 T1 T1/Gd DWI
bright on DWI
Dr Ahmed Esawy

Abscess (purulent)
ADC decreased
dark on ADC mapDr 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

necrotic or cystic neoplasmsPyogenic 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 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

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 stagesDr 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

• 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+CONTRASTDr Ahmed Esawy

• 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 T2Dr 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

• 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

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 enhancementDr 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
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)
Dr Ahmed Esawy

• T1 enhanced multiple small cysts (arrowheads) around the large (1.9-cm-diameter)
aneurysm (arrow) of the right posterior cerebral artery.
Dr Ahmed Esawy

right anterior cerebral artery aneurysm (arrow) as hyperintense. The
adjacent cyst (arrowhead) is unilocular and irregular in shape
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.
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

Colloid cystColloid cyst
Dr Ahmed Esawy

• MRI appearance
• : variable signals depending on the contents
T1 hyperintense or hypo intense
T2 hyperintense or hypo intense
Colloid cystColloid cyst
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

• 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

• 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

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

• 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

• 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

• 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

• 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

• 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

• 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
FALIRT2
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

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

epidermiod
Lower density than CSF
May show calcifications
invade structures
CT
LOWER THAN CSFMRI T1
HIGHER THAN CSFMRI T2
HIGH SIGNALFLAIR
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.
T2T1+no C
DIFFUSION
FLAIR
Dr Ahmed Esawy

epidermoid cysts
Dr Ahmed Esawy

EPIDERMOID
CYST
diffusion-shows markedly restricted diffusion (arrows.(
Dr Ahmed Esawy

T2WIT1WI
DWI ADC
End of images
EPIDERMOID
CYST
B 1000
ADC
Dr Ahmed Esawy

• 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

• 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
displacment of choriod plexus and the body of lateral ventricle
Dr Ahmed Esawy

MRI T1+C
Compression of quadrigeminal plate and cereberal aqueduct
Dr Ahmed Esawy

MRI T2 Quadrigeminal cistern
Dr Ahmed Esawy

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

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

Fifteen (50) intracranial cystic lesion Dr Ahmed Esawy CT MRI main

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