Intracranial congenital cystic lesion dr ahmed esawy ct mri part 2 • 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 • 15-encephalomalacia, • 16-subarachnoid cyst • 17-cystic lesions after brain surgery and radiation injury to the brain. • 18-Leptomeningeal cyst • 19-Post traumatic porenencephally • 20-brain abscess • 21-cysticercosis • 22-hydatid cyst. • 23-amoebic abscess • 24-Aneurysm • 25-Parenchymal Perianeurysmal Cystic Changes in the Brain • 26-Vein of Galen malformation • 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 • 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

1. Congenital cystic lesions
Dr Ahmed Esawy

2. •Arachnoid Cyst
Dr Ahmed Esawy

3. 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

4. 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

5. 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

6. T1-weighted sagittal MRI image of the lumbosacral spine showing
an incidental sacral arachnoid cyst.
Dr Ahmed Esawy

7. T2
DIFFUSION
autopsied brain
ARACHNOID CYSTS
Dr Ahmed Esawy

8. 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

9. arachnoid cysts
Dr Ahmed Esawy

10. Arachnoid cyst with enlargement of the calvaria
T2T1
Non contrast CT
Dr Ahmed Esawy

11. midline Arachnoid cyst
Causing dilated OH
Coronal gradient echo
FLAIRT1
DW
CT
Dr Ahmed Esawy

12. 28-year-old woman
T2
superior cerebellar cistern arachnoid cyst
Dr Ahmed Esawy

13. 26-year-old man
large left frontoparietal cyst
Dr Ahmed Esawy

14. T2
ARACHNIOD CYST
T1
FLAIR
Dr Ahmed Esawy

15. • 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

16. 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

17. Differential Diagnosis
• epidermoid cyst
• Chronic subdural hematoma
• porencephalic cyst
Dr Ahmed Esawy

18. 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

19. posterior fossa cystic malformation
destructive lesions
porencephalic cyst
hydranencephaly
multicystic encephalomalacia
Dr Ahmed Esawy

20. • 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

21. Isolated mega cisterna magna in a
patient with trisomy 21 transcranial
US /CT
Dr Ahmed Esawy

22. 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

23. 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

24. posterior fossa cystic malformation
Dandy Walker
Dr Ahmed Esawy

25. 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

26. 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

27. 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

28. T1
Axial transmastoid US
T2
Arachnoid cyst
and complex
posterior fossa
malformations
in a full-term 1-
day-old
neonate
Dr Ahmed Esawy

29. 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

30. 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

31. 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

32. 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

33. 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

34. 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

35. Differential Diagnosis
• arachnoid cyst (extra-axial)
• schizencephaly
• (ependymal cyst) intraventricular with normal
surrounding brain tissue (
• encephalomalacia
• hydranencephaly
Dr Ahmed Esawy

36. 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

37. Porencephaly in a 26-week gestation premature neonate
Dr Ahmed Esawy

38. CT scan at the age of 13 years showing the porencephalic
cyst in left cerebral hemisphere.
Dr Ahmed Esawy

39. • 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

40. 28-week gestation neonate
Dr Ahmed Esawy

41. Cavum veli interpositium.
33 weeks of gestation
Dr Ahmed Esawy

42. Differential diagnosis Periventricular Location
• periventricular leukomalacia (PVL),
• connatal cyst (CC),
• subependymal cyst (SC)
• anatomic locations. Dr Ahmed Esawy

43. • 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

44. Bilateral connatal cysts in a 3-week-old full-term neonate
along superolateral angles of the lateral ventricles (arrows).
Dr Ahmed Esawy

45. Subependymal Cysts
• acquired, posthemorrhagic cyst
• congenital and is related to germinolysis.
Dr Ahmed Esawy

46. Acquired subependymal cyst due to an
evolving subependymal hemorrhage
caudothalamic groove
T2
T1
Dr Ahmed Esawy

47. Open lip schizencephaly (type II)
T1
T2
T2
T2
FLAIR
Dr Ahmed Esawy

48. 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

49. • 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

50. 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

51. B. DW image shows hypointensity
in right hemisphere cystic lesions
Multicystic Encephalomalacia
A.T1-weighted image shows a thin corpus callosum
Dr Ahmed Esawy

52. 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

53. 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

54. Schizencephaly with bilateral clefts in a 36-
week gestation preterm infant.
Dr Ahmed Esawy

55. 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

56. 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

57. (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

58. 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

59. 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

60. Left frontal intraparenchymal hematoma in a newborn with
increasing thrombocytopenia
T1
Spontaneous Intracranial Hematoma
Dr Ahmed Esawy

61. Spontaneous intracranial hematoma
in a 2-month-old infant with an
inherited thrombophilic disorder.
Dr Ahmed Esawy

62. Temporal lobe cysts and fetal
alcohol syndrome
Parasagittal T1-
T2-bitemporal intraparenchymal cysts
(arrows).
FLAIR
Dr Ahmed Esawy

63. Temporal lobe cysts and fetal
alcohol syndrome MRS
Dr Ahmed Esawy