5. 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
13. 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
14. 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
15. 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
16. T1-weighted sagittal MRI image of the lumbosacral spine showing
an incidental sacral arachnoid cyst.Dr Ahmed Esawy
18. 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
25. • 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
26. 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
28. ARACHNIOD VERSUS EPIDERMIOD
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
29. posterior fossa cystic malformation
destructive lesions
porencephalic cyst
hydranencephaly
multicystic encephalomalacia
Dr Ahmed Esawy
30. • 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
31. Isolated mega cisterna magna in a
patient with trisomy 21 transcranial
US /CT
Dr Ahmed Esawy
32. 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
33. 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
35. 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
36. 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
37. 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
39. 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
40. 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
41. 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
42. 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
43. 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
44. 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
45. Differential Diagnosis
• arachnoid cyst (extra-axial)
• schizencephaly
• (ependymal cyst) intraventricular with normal
surrounding brain tissue (
• encephalomalacia
• hydranencephaly
Dr Ahmed Esawy
46. 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
47. Porencephaly in a 26-week gestation premature neonate
Dr Ahmed Esawy
48. CT scan at the age of 13 years showing the porencephalic
cyst in left cerebral hemisphere.
Dr Ahmed Esawy
49. • 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
53. • 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
54. Bilateral connatal cysts in a 3-week-old full-term neonate
along superolateral angles of the lateral ventricles (arrows).
Dr Ahmed Esawy
58. 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
59. • 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
60. 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
61. B. DW image shows hypointensity
in right hemisphere cystic lesions
Multicystic Encephalomalacia
A.T1-weighted image shows a thin corpus callosum
Dr Ahmed Esawy
62. 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
63. 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
65. 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
66. 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
67. (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
68. 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
69. 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
70. Left frontal intraparenchymal hematoma in a newborn with
increasing thrombocytopenia
T1
Spontaneous Intracranial Hematoma
Dr Ahmed Esawy
76. Brain abscess..
poorly defined area of posterior parietal brain edema (arrows). Early cerebritis
may not outline a focal mass clearly
Dr Ahmed Esawy
77. Brain abscess.
a poorly defined pattern of mass effect and low attenuation in the left temporal lobe.
Of early cerebritis
Dr Ahmed Esawy
78. 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
79. temporal lobe abscess, extracranial, subdural, and intracerebral abscesses
Dr Ahmed Esawy
80. 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
81. Brain abscess. Axial T1 +C ,T2-weighted MRI in a patient with a right frontal abscess.
Dr Ahmed Esawy
82. 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
83. 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
84. 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
85. 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
86. Diffusion-weighted Imaging
ADC maps are of great value in
distinguishing neoplasms in ADC maps is
more often have facilitated diffusion,
Dr Ahmed Esawy
91. 7. 8.
DD : tumour
central hypointensity on diffusion-weighted image and hyperintensity on ADC
map, consistent with the diagnosis of tumor.
Dr Ahmed Esawy
92. 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
93. 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
96. 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
97. 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
98. DD : NEOPLASM
• Elevation of choline and absence of
signal from a variety of amino acids,
acetate and succinate favours
neoplastic process
Dr Ahmed Esawy
101. 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
102. 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
103. 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
105. 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
107. Cystercercus cellulosae - (3-20 mm)
regular round thin walled cyst,
produces only mild inflammation
larva in cyst
Dr Ahmed Esawy
108. Calcification in cysticercosis
• Calcification in burned out residues of cysticercosis
scattered throughout the brain in later stagesDr Ahmed Esawy
109. 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
111. 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
119. 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
122. Vein of Galen malformations
(VOGMs)
• The aneurysm of the vein of Galen
represents a rare intracranial
arteriovenous malformation
Dr Ahmed Esawy
123. 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
125. 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
126. 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
127. 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
128. 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
134. 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
135. 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
136. • 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
137. 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
138. • 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
139. 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
143. • MRI appearance
• : variable signals depending on the contents
T1 hyperintense or hypo intense
T2 hyperintense or hypo intense
Colloid cystColloid cyst
Dr Ahmed Esawy
145. 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
146. 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
147. COLLOID CYSTS
• Transverse nonenhanced CT scan shows classic hyperattenuated
colloid cyst at foramen of Monro (arrow (Dr Ahmed Esawy
148. 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
149. 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
150. 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
152. • 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
153. 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
157. 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
158. 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
159. 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
160. Differential Diagnosis
• multiple lacunar infarcts
• cystic neoplasms
• infectious cysts (Neurocysticercosis cysts )
.
Dr Ahmed Esawy
161. 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
163. 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
164. 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
166. 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
167. 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
168. 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
170. 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
171. 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
172. 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
173. Type II dilated VR spaces in a 6-year-old boy
FALIRT2
punctate hyperintense areas around the
occipital horns
Dr Ahmed Esawy
174. 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
175. 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
176. 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
177. MR Imaging of CSF-Iike Choroidal
Fissure and Parenchymal Cysts of the Brain
Dr Ahmed Esawy
181. • Left choroidal fissure cyst (arrows)
• 13-year-old girl
• cyst between mesial temporal lobe and brainstem is seen on
T1
T2
Dr Ahmed Esawy
182. • 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
184. 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
185. 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
189. 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
191. ARACHNIOD VERSUS EPIDERMIOD
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
199. ARACHNIOD VERSUS EPIDERMIOD
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
200. 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
201. Dermoid cyst
location Midline plane, posterior fossa,
suprasellar area and Intraventricular
MRI: high signal in T1 [ fat ]
Dr Ahmed Esawy
202. CT: fat density ± calcification, no
enhancement
Dermoid cyst
Dr Ahmed Esawy
203. 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
205. 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
206. 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
207. posterior fossa lesion with posterior mural nodule
Unusual Imaging Appearance of an Intracranial Dermoid Cyst
Dr Ahmed Esawy
208. 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
209. 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
210. CT +no C
epidermiod tumour (inclusion cyst) of Quadrigeminal cistern
Quadrigeminal cistern cyst
Dr Ahmed Esawy
211. CT +C
epidermiod tumour (inclusion cyst) of Quadrigeminal cistern
displacment of choriod plexus and the body of lateral ventricle
Dr Ahmed Esawy
212. MRI T1+C
epidermiod tumour (inclusion cyst) of Quadrigeminal cistern
Compression of quadrigeminal plate and cereberal aqueduct
Dr Ahmed Esawy
216. 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
220. 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
222. 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
223. large right cerebellopontine angle tumour with a medial cystic component.
Cystic vestibular schawannoma T2W
Dr Ahmed Esawy
225. 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
226. • 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
227. • 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
228. • 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
231. primary cystic neoplasm versus metastases
primary cystic neoplasm choline
Cystic metastases where no choline resonance
is seen
Dr Ahmed Esawy
232. 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
233. 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
234. 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