This document discusses various types of intraventricular lesions that can be seen on different imaging modalities like CT and MRI. It describes the typical appearance and characteristics of common intraventricular masses like choroid plexus papilloma, astrocytoma, subependymal giant cell astrocytoma, ependymoma, meningioma, metastases and others. It also discusses vascular malformations, cysts and other rare lesions that can involve the lateral, third or fourth ventricles. Imaging findings for each type of lesion are provided along with examples of relevant images.

1. Intraventricular Lesions
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Jnmc wardha

2. IMAGING MODALITIES
• 1. Plain skull radiographs–May demonstrate calcification and
evidence of raised intracranial tension.
• 2. Plain and contrast enhanced CT–May help in characterization of
the lesion confirming the presence of calcification. MDCT may help
in better localization through its multiplanar capability with the help
volumetric data acquisition.
• 3. Conventional ventriculography/CT ventriculography – It has
become obsolete with the advent of MRI.
• 4. MRI – It has transformed the way we look at intracranial lesions
with its exquisite resolution and multiplanar capability.
• 5. Angiography – Indicated in vascular malformations and for
angioembolization

5. Lateral Ventricular Masses
• About half of these in adults and one-fourth in
children are found in the lateral ventricles
• In children, intraventricular neoplasms occur
more often in the trigone, primarily because
certain tumor types that favour the trigonal
region have a predilection for occurring in
children

6. Choroid Plexus Papilloma (CPP)
• It is the most common tumor occurring in the
lateral ventricles in the first decade
• In children, they occur more commonly in the
atrium of the lateral ventricles in contrast to
adults, where these are more frequently seen
in the fourth ventricle

7. • On CT the tumor is seen as a well defined, frond
like mass which is iso or mildly hyperdense to
brain.
• There is usually homogenous and intense
enhancement following contrast administration
though heterogenous enhancement is seen in
adults and in tumors with carcinomatous change
• Diffuse hydrocephalus involving dilatation of all
the ventricles occurs which is usually attributed
to the overproduction of CSF

8. • MR the tumor is hypo to isointense on T1WI
and iso to hyperintense to T2WI.
• There is homogenousand bright enhancement
after gadolinium injection though
heterogenous enhancement can also be seen
when tumor outgrows its blood supply

9. Right lateral ventricular mass centered on the choroid plexus
and display hyper intense signal on T1, hyperintense signal
on T2 with avid enhancement on post contrast study. There is
associated unilateral transependymal CSF permeation.

10. Astrocytoma
• It usually arises in the tissues around the
ventricle and invades the lateral ventricle
secondarily
• The most common site is the thalamus where
it can develop into a large mass within the
lateral ventricle.

11. • On CT, the low grade astrocytoma is seen as a
poorly marginated low density mass. There is
usually minimal mass effect or edema around
the lesion.
• It shows little or no contrast enhancement.
• The anaplastic astrocytoma and glioblastoma
have heterogenous appearance due to areas
of hemorrhage, necrosis or cyst formation

12. • MRI is helpful in the evalua-tion of degree of
differentiation of the astrocytoma.
• The low grade astrocytoma has a signal
pattern lower than normal brain parenchyma.
The high grade gliomas and glioblastomas
show varied signal intensity with areas of
necrosis, hemorrhage and cyst formation.

13. Astrocytoma: contrast CT show
intensely enhancing heterogenous mass with
dense calcification
occupying the frontal horn and body of right
lateral ventricle

14. Subependymal Giant Cell Astrocytoma
(SGCA)
• SGCA is a circumscribed tumor which occurs
almost exclusively in patients with tuberous
sclerosis (TS).
• It is a slow growing tumor and is discovered
either during the course of routine studies in
patients with TS or because it causes
hydrocephalus
• It arises usually in the region of foramen of
Monro but can occur anywhere in the ventricles

15. • On CT SGCA appears as a well-defined mass
which is iso to hyperdense to cerebral
parenchyma and enhance sharply following
contrast injection.
• Foci of calcification are common.
• On MRI the mass is hypointense on T1WI and
hyperintense on T2WI with prominent
enhancement after IV gadolinium injection

16. There is an intraventricular mass in the
foramem of Monro area, on the left, with
contrast enhancement and irregular
calcifications. Multiple subependymal calcified
nodules are also seem.

17. Ependymoma
• This is commonly seen in children in the
posterior fossa with a predilection for males
and is less common than astrocytoma.
• Supratentorial ependymomas are seen in 30-
40 percent cases and are usually
extraventricular (75-80%). When
intraventricular they usually arise in the
trigone of lateral ventricle

18. • On CT ependymomas show cystic component
(70%) and calcification (50%). The solid
component is isodense to brain parenchyma
with bright enhancement with contrast

19. • On MRI, the tumor is iso to hypointense on
T1WI and hyperintense on T2WI. There is
usually heterogeneity due to areas of
hemorrhage, necrosis and calcification . With
gadolinium administration there is usually
moderate to intense enhancement.
• Although ependymoma is a benign tumor, it
has a high recurrence rate and can spread
through CSF pathways

20. Ependymoma: Axial T1 (A) and T2 (B) MR
images show tumor having solid (small arrow)
and cystic (large arrow) component
in the trigone of right lateral ventricle with
pariventricular edema and hydrocephalus

21. Meningioma
• Intraventricular meningioma is an uncommon
tumor and constitutes 0.5 to 3 percent of all
intracranial tumors.
• It is more common in adult females. Although
rare, the meningiomas in children are more
frequently intraventricular and malignant
• show equal incidence in both sexes and are
usually associated with neurofibromatosis

22. • meningioma appears as a sharply defined, globular
mass, iso- to hyperdense to brain parenchyma.
• Calcification is seen in 45 percent cases.
• It shows diffuse intense enhancement with contrast
• On MRI it is isointense (60%) or hypointense (40%) on
T1WI and isointense (50%) or hyperintense (50%) on
T2WI .
• There is homogenous and strong enhancement with IV
gadolinium administration .
• Proton MR spectroscopy may reveal alanine peak with
reduced NAA.

24. Metastases
• Intraventricular metastases can be due to
blood borne dissemination or by
paraventricular spread.
• The blood borne metastasis most often
involves the choroid plexus in the ventricles.
• The common primary tumors with
intraventricular metastases are bronchogenic
carcinoma, carcinoma of breast and
melanoma

25. • On CT or MRI the choroid plexus metastasis
shows expansion of choroid plexus with marked
contrast enhancement
• The paraventricular spread of tumor can occur
along CSF pathways to ventricular ependymal
lining and leptomeninges or, infiltration in the
subependymal space as a sheet of tumor cells.
• Malignant astrocytomas are the commonest
tumor to show CSF spread followed by
ependymomas, medulloblastomas, pineal tumors
and choroid plexus papillomas

26. • On CT, these lesions are seen as discrete, iso
to hyperdense nodule or sheet like
subependymal rim surrounding a part or all of
the ventricle .
• On MRI they appear hypointense on T1WI and
hyperintense on T2WI. Melanoma metastasis
differs in being hyperintense on T1WI and
isointense on T2WI

27. Metastasis: CECT shows diffuse ependymal
enhancement and
hyperdense nodule in the left paraventricular
region with edema in patient
of carcinoma thyroid

28. Central Neurocytoma
• It is a well-differentiated benign
intraventricular tumor of neuroepithelial
origin
• The site of origin is usually at or near the
midline at the base of the septum pellucidum
and usually in close proximity to foramen of
Monro. It is quite large at presentation and
usually presents due to obstructive
hydrocephalus.

29. • On CT, it appears as iso to slightly hyperdense
mass with cystic changes and foci of
calcification.
• Mild to moderate enhancement with contrast
is seen.
• On MRI, the tumor show heterogenous
pattern and there is variable enhancement
following IV gadolinium administration

30. • The differential diagnosis is mainly
ependymoma, subependymoma and
oligodendrogliomas which are most often
hyperintense.
• Heterotopic grey matter neither shows
enhancement nor calcification.
• Meningioma is usually located posteriorly in
the atrium of lateral ventricle as are choroid
plexus tumors

32. Vascular Malformations
• AVMs and cavernous angiomas can have some
part actually within the ventricle
• Lateral ventricle is the most common to be
involved but they can occur in any part of the
ventricular system

33. • On CT these lesions are seen as heterogenous areas,
with or without calcifications.
• On contrast administration, abnormal vessels are seen
as tortuous high density structures.
• MRI is superior to CT in demonstrating the feeding
vessels the nidus and the serpiginous draining veins
which appear as flow voids both on T1WI and T2WI.
• Angiography is the confirmatory study which shows all
aspects of the vascular malformations
• There can occur intraventricular fluid-fluid level seen in
cases of intraventricular hemorrhage

34. Intraventricular hemorrhage: NCCT brain
shows presence of
hemorrhage in the left cerebral hemisphere
extending into the ipsilateral
lateral ventricle due to AVM rupture

35. Choroid Plexus Cysts and
Xanthogranulomas
• Xanthogranulomas are usually discovered
incidentally
• They are symptomatic only when they cause
obstruction at foramen of Monro

36. • Cysts show low density on CT and show signal
characteristics similar to CSF on MRI.
• They lack contrast enhancement and show
diffusion restriction on DWI.
• Xanthogranulomas are dense on CT and may
show flecks of calcification. The center is often of
low attenuation due to fat content.
• On MRI, these are well defined partially cystic
masses that appear hypo or isointense on T1WI
and iso to hyperintense on T2WI and show
contrast enhancement

37. CECT shows choroid plexsus cyst well-defined
cystic lesion in the
trigone of left lateral ventricle with anteriorly
displaced choroid plexus
(arrow

38. Third Ventricular Masses
• In children, hydrocephalus is the most
common feature of 3rd ventricular masses
• In adults mental and behavioral changes,
particularly increasing apathy, are common.
Depending on the parts of the ventricle
involved these tumors can be further
categorized as anterior or posterior 3rd
ventricular masses

39. Anterior Third Ventricular Masses
Colloid cyst
• It arises from the roof of the 3rd ventricle at
the level of foramen of Monro.
• They are round to oval lesions and vary in size
from few millimeters to several centimeters in
diameter
• Symptoms of intermittent obstruction are
common and sudden death due to acute
obstruction has been reported.

40. • On CT, colloid cysts are well encapsulated,
homogeneously hyperdense masses which show little
or no contrast enhancement .
• Calcification is not a feature.
• On MR, the signal characteristics of colloid cysts vary
widely. The most common appearance is a mass that is
hyperintense on T1WI and hypointense on T2WI
though it can be isointense on both T1 and T2 WI
• Rim enhancement following contrast can be observed.
CSF flow artifacts at foramen of Monro can mimic
colloid cysts (pseudotumor)

42. Germinoma
• The tumor that occurs solely in the 3rd
ventricle is called “ectopic pinealoma” and
rarely occurs in association with the posterior
third ventricular germinoma.
• The tumor has the potential to spread via CSF
pathways and therefore CSF analysis for tumor
cells can be helpful in obtaining diagnosis in
some patients

43. • On non-contrast CT, the germinoma appears
as an iso to hyperdense mass with indistinct
tumor boundaries.
• Calcification is rare.
• It shows uniform enhancement on contrast
injection.
• The tumor shows similar characters on MRI
with homogenous enhancement following IV
gadolinium administration.

44. Germinoma:A large enhancing mass is
centered on the pineal region. It is
heterogeneous with areas of cystic change.
There is marked compression of the tectum
with resulting obstructive hydrocephalus. A
little surrounding oedema is also present

45. Craniopharyngioma
• Primary third ventricular craniopharyngioma is
extremely rare and is almost always an
extension of the craniopharyngioma from the
sellar supra sellar region.
• There are two peaks of occurrence; the first in
young children less than 15 years and the
second in the 5th to 6th decades.

46. • On CT the tumor shows solid and cystic
components in majority of patients . The solid
component shows contrast enhancement
particularly in children
• Calcification is seen in almost all patients in
childhood while it is seen in up to 50 percent
of cases in adults.

47. Craniopharyngioma: CECT shows isolated
anterior third
ventricular cystic lesion which was proven to
be craniopharyngioma on
surgery. Note dystrophic parenchymal
calcification (arrow)

48. Epidermoid and Dermoids
• These are uncommon tumors encountered in the
anterior 3rd ventricle. They usually present due to
obstructive hydrocephalus.
• On CT the epidermoid appears as hypodense
lesion which does not enhance with contrast
administration. Dermoid usually shows the
presence of fat and calcification.
• On MRI, the epidermoid shows signal characters
similar to CSF while the dermoid shows
hyperintense foci of fat and areas of signal loss
due to calcification on T1WI.

50. Cysticercosis
• Intraventricular cysticercosis presents with
repeated attacks of meningitis in children and
with hydrocephalus in adults
• It is seen in 20-25 percent of all
neurocysticercosis, most commonly in 4th
ventricle, foramen of Monro and lateral
ventricle

51. • It can be difficult to diagnose on CT because it
shows similar attenuation like CSF. MR is the best
imaging modality and T2WI clearly shows the
hyperintense cyst in the ventricular wall.
• It can be of the racemose variety at times and is
not readily differentiated from a tuberculoma.
Unilocular cystic forms may often show an
eccentric hypointense nodule suggestive of scolex
within the cyst on thin T2 weighted sequences

52. A well defined thin walled cystic lesion is noted
within the third ventricle causing its expansion.
It is hypointense on T1, hyperintense on T2
and suppressed on FLAIR images. An eccentric
enhancing nodule is seen within this lesion,
findings are suggestive of intraventricular
cysticercosis.
Mild to moderate dilatation of bilateral lateral
ventricles with periventricular ooze is noted

53. Posterior Third Ventricular Masses
• A variety of structures in and around the posterior
third ventricle including the pineal gland can be the
origin of these tumors.
• The tumors can be astrocytomas of all grades,
ependymomas, germinomas, meningiomas, vascular
malformations, pineal tumors, metastasis or primary
lymphomas.
• Regardless of the origin, these masses cause
obstructive hydrocephalus due to compression of the
posterior third ventricle or aqueduct and abnormal eye
movements from pressure on, or infiltration of the
pretectal area

54. • Glial Tumors Astrocytomas comprise 25 percent
of the mass lesions in the posterior third
ventricle.
• Other gliomas like ependymomas,
oligodendrogliomas, or glioblastomas can also
occur in this area.
• There are no significant age or sex predilection.
• The imaging features are similar to those
occurring in other areas of brain

55. Germinoma
• Germinoma is more common in posterior than anterior 3rd
ventricle.
• It is common in young males and causes precocious
puberty
• It may lead to Parinaud’s syndrome and hydrocephalus.
• On CT and MRI, it appears as well demarcated,
homogenous soft tissue mass and shows uniform
enhancement after IV contrast administration.
• There is no calcification within the tumor.
• The tumor spreads through CSF pathway and responds to
radiotherapy. Therefore after obtaining tissue diagnosis
(either by stereotactic or open biopsy) the entire neuroaxis
should be irradiated.

56. large lobulated mass is centered on the pineal
gland, engulfing the pineal calcifiation. It is
somewhat hyperdense compared to adjacent
brain. A further smaller mass is seen in the
floor of the third ventricle. The midbrain is
distorted, compressed and demonstrates low
density suggestive of oedema. Obstructive
hydrocephalus is present.

57. Teratoma
• Mature teratomata are well-differentiated benign
tumors with a malignant potential.
• They are well encapsulated and show no
evidence of infiltration of surrounding structures.
• On CT teratomas show areas of fat attenuation
and calcification/ossification.
• The solid portion can show some degree of
contrast enhancement.
• OnT1WI the fat in the teratoma appears
hyperintense. Signal loss due to calcific foci can
be seen on both T1WI and T2W.

58. Pineoblastoma
• It resembles other PNETs (e.g.
Medulloblastoma) histologically.
• It is an infiltrative tumor and presents with
obstructive hydrocephalus or Parinauds’
syndrome.

59. • On CT, it appears hyderdense and enhances
homogenously and brightly following IV contrast
injection .
• On MRI, it is hypo or iso intense on T1WI and
hyperintense on T2WI. Small areas of necrosis,
hemorrhage, cyst formation or calcification can be
seen.
• There is typically brilliant enhancement on gadolinium
injection.
• It also shows spread along CSF pathways like
germinoma and therefore the entire craniospinal axis
should be imaged in such patients

60. A large mass ( * ) centred on the pineal region elvates, splays and
partially engulfs the internal cerebral veins (blue arrows). Pineal
calcifications (red arrows) are best seen on CT and are located at
the periphery of the mass.
Enhancing soft tissue is also seen filling the floor of the third
ventricle (green arrows) and in the lateral ventricles (best seen in
the left forntal horn - yellow arrow)

61. Fourth Ventricular Masses
• Primary fourth ventricular neoplasms are common in
children but rare in adults. The pediatric tumors are
cerebellar astrocytoma, medulloblastoma,
ependymoma and choroid plexus papilloma.
• In adults, metastases are the most common fourth
ventricular neoplasm. Other tumors such as choroid
plexus papilloma, epidermoid, dermoid are rare
• masses like arachnoid cysts, vascular malformation,
cysticercosis,minflammatory cysts are occasionally
seen within the fourth ventricle

62. Cerebellar astrocytoma
• It is the most common posterior fossa
neoplasm and constitutes 25 percent of all
fourth ventricular neoplasms in children.29
Histologically majority of the tumors are of
pilocytic type
• It usually originates from the vermis and
extends anteriorly into the fourth ventricle.
Rarely, the tumor arises primarily within the
ventricle itself.

63. • On CT, the tumor appears as a large lesion
with solid (40%) or cystic (60%) components.
The cystic mass shows a mural nodule. The
nodule is always solitary and isodense with
cerebellum on non contrast scans. The nodule
may or may not be calcified.
• On contrast administration the nodule shows
intense, homogenous enhancement which
does not extent beyond the contor of the cyst

64. • On MRI, the appearance is similar with cystic
component being hypo- to isointense on T1WI
and hyperintense on T2WI. The
• mural nodule shows intense enhancement
with IV gadolinium

65. Pilocytic Astrocytoma: MRI brain showing a
large posterior fossa cystic mass with
enhancing mural nodule

66. Medulloblastoma
• This primitive neuro-ectodermal tumor (PNET) is
the second most common posterior fossa tumor
constituting one-fourth of all posterior fossa
tumors in children
• The tumor shows dissemination along the CSF
pathways
• Spinal cord metastases are also common (12-
40%). Dorsal and lumbosacral region is seeded
most commonly and the deposits are often
multiple

67. • On CT medulloblastoma is usually seen as a large,
mildly hyperdense, midline solid mass arising
from the inferior vermis.
• The tumor bulges anteriorly into the fourth
ventricle and may extend into adjacent cisterns.
• Rarely, calcification, hemorrhage and necrosis are
seen.
• On contrast, it shows moderate degree of
homogenous enhancement.

68. • On MR, the typical medulloblastoma fills the fourth
ventricle and extends inferiorly through foramen of
Magendie into the cistern magna.
• It appears hypointense on T1WI and shows variable
signal pattern on T2WI.
• Moderate enhancement is typical after IV gadolinium
injection . Due to high tumor cellularity it may show
diffusion restriction with low ADC values.
• Other fourth ventricular tumors like ependymoma and
astrocytomas can often be differentiated from it on
MRI based on this findings

70. Ependymoma
• It is the third most common fourth ventricular
tumor in children. Nearly 50 percent of
posterior fossa ependymomas are located in
the fourth ventricle
• On CT, the mass is midline and situated within
an expanded fourth ventricle and often shows
calcification (50%). There is usually moderate
enhancement on contrast administration

71. • The mass typically extends outwards into
cerebellopontine cisterns or into the cisterna
magna through the fourth ventricular exit
foramina (Figs 19.19 B and C).
• Hydrocephalus is nearly always seen. The tumor
exhibits similar morphology on MRI as hypo to
isointense signal on T1WI and intermediate to
hyperintense signal on T2WI with heterogenous
post contrast enhancement

72. Ependymoma: CECT (A) showing an illdefined
heterogeneously enhancing fourth ventricular
tumor with presence of calcification.

73. Thank you