DR PRAVEEN K TRIPATHI

25 July 2016 1

Sella/suprasellar:

• Optic pathway/hypothalamic glioma

• Craniopharyngioma

• Pitutary tumors

• Germ cell tumours

Pineal region:

• Germ cell tumours

• Pinealblastoma(associated with retinoblastoma)

• Astrocytoma

• Ganglioglioma

• Epidermoid

Intraventricular:

• Ependymoma

• Choroid plexus papilloma/carcinoma

• Subependymal giant cell astrocytoma(associated with tuberous sclerosis )

• Lesions arising from suprasellar region may involve 3rd

ventricle

• Colloid cyst (3rd

ventricle, usually young adults)

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Schwannoma Meningioma Arachnoid cyst

Epidermoid Paraganglioma Metastasis

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Chordoma

Chondrosarcoma

Esthesioneuroblastoma

Sinonasalcarcinoma

Myeloma

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Best diagnostic clue

CT Finding: Partially Ca++, partially solid, cystic suprasellar mass in a child

MR Finding: High signal intensity suprasellar mass on pre-contrast Tl WI

CT

cysts near CSF density

typically large and a dominant feature

present 90 % of the time

solid component soft tissue density

enhancement in 90%

calcification seen in 90%

typically stippled and often peripheral in location

MRI

cysts: variable but ~80% are mostly or partly T2 hyperintense T1: iso- to hyperintense to brain (due to high protein content machinery oil cysts)

solid component T1 C+ (Gd): vivid enhancement

T2: variable or mixed

calcification difficult to appreciate on conventional imaging

susceptible sequences may better demonstrate calcification

MR angiography: may show displacement of the A1 segment of the anterior cerebral artery (ACA)25 July 2016 9

Unenhanced CT shows the calcifications more clearly.

After intravenous contrast the total extent of the lesion and its cystic

components are much evident.

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unenhanced and enhanced

T1weighted sagittal images, a

compressed pituitary gland can be

identified.

There is a large intrasellar and

suprasellar mass with cystic and

enhancing components as well as

calcifications.

These findings in a child are

virtually pathognomonic for

craniopharyngioma

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Axial MRI T1-image showing

cystic craniopharyngioma

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Axial MRI T1 gadolinium

image showing sphenoidal

craniopharyngioma

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Rathke cleft cyst (RCC)

Noncalcified, usually doesn't enhance, less heterogeneous, no solid components

Small RCC may be indistinguishable from the rare intra sellar CP

RCCs express cytokeratin 8,20 (CPs generally don't)

Suprasellar arachnoid cyst

No Ca++, enhancement

Hypothalamic/chiasmatic astrocytoma

Solid, or with small cystic/necrotic components

Ca++ rarei robust enhancement common

Pituitary adenoma

Rare in prepubescent children

Isointense with brain, enhances strongly

When cystic and hemorrhagic can mimic CP (Epi)dermoid tumors

Minimal/no enhancement25 July 2016 14

Imaging:

Pituitary macroadenomas are by definition >10 mm mass arising from the pituitary gland, and usually extending superiorly. Indentation at the diaphragma sellae can give a snowman or figure eight configuration .

Plain x-ray may show an enlarged sellaturcica;

CT

No contrast attenuation can vary depending on haemorrhagic, cystic and necrotic components.

Adenomas which are solid, without haemorrhage, typically have attenuation similar to brain (30-40 HU) and demonstrates moderate contrast enhancement; less marked than one typically sees in meningiomas. Calcification is rare.

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MRI

MRI is the preferred imaging modality

Exquisitely delineate the mass & clearly visualise the optic chiasm, anterior cerebral vessels and cavernous sinuses.

Overall signal characteristics can significantly vary depending on tumour components such as haemorrhage, cystic transformation or necrosis.

T1

typically isointense to grey matter

larger lesions are often heterogeneous and vary in signal due to areas of cystic change/necrosis/haemorrhage

T1 C+ (Gd)

solid components demonstrates moderate to bright enhancement

T2

typically isointense to grey matter

larger lesions are often heterogeneous and vary in signal due to areas of cystic change/necrosis/haemorrhage

T2* gradient echo

most sensitive for detecting any haemorrhagic components, which appear as areas of signal loss

calcification is rare, but should be excluded by reviewing CT scans

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PITUTARY MACROADENOMA

Pituitary macroadenoma there is suprasellar extension with elevation and compression

of the optic chiasm.

To distinguish between a pituitary macroadenoma and a meningioma.

1. Because they are soft tumors, they usually indent at the diaphragma sellae, giving

them a 'snowman' configuration

2. Enlargement of the sella turcica this generally only occurs with pituitary

macroadenomas that originate in the sella.25 July 2016 17

The lesion starts in the

sella, which is enlarged,

and extends into the

suprasellar cistern.

Note the classic

'snowman' configuration

caused by constriction by

the diaphragma sellae.

The bloodfluid level,

indicating hemorrhage.

PITUITARY ADENOMAS

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Coronal T1 c+ MR shows a macroadenoma that enhances strongly, invades the left cavernous sinus, and erodes the sellar floor. An area of lesser enhancement may represent cystic degeneration (arrow).

Coronal NECT shows

eroded sella caused by the

adenoma

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On the T2weighted images

The leaflets are displaced upwards by

tmacroadenoma which started in the

sella and is growing upwards.

A lesion originating above the sella and

growing downwards would push the

leaflets in the other direction (this can

be seen with meningiomas ).

Sometimes a meningioma can

give a similar appearance.

Note there is no diaphragmatic

constriction and there is

uniform enhancement after

the administration of

intravenous gadolinium

which is typical of

meningioma.25 July 2016 20

Another common pathway of extension is laterally into the cavernous sinus. Look for

1. If there more than 50% encirclement of the carotid artery? Note: meningiomas tend to constrict the carotid artery, macroadenomas do not.

2. Is there lateral displacement of the lateral wall of the cavernous sinus compared to the opposite side?

3. Is there an increased amount of tissue interposed between the carotid artery and the lateral wall of the cavernous sinus?

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Pitutary

macroadenoma27 Yr male

h/o progressive loss of vision rt > lt eye- 1month

Headache 1month

No signs symptom of hormonal impalance

Bitemporal hemianopia

PRL 5.5 ng/dl

Ncct–hyperdense lesion in sella

CECT brain – hetergenously

enhancing lesion in sellar

region with scalloping of

adjacent bone25 July 2016 22

Lobulated mass in sellar

and supra sellar region

Isointense on T1W &

T2W

Superior displacement of

optic chiasma

PITUITARY

MACROADENOMAS

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PITUTARY MACROADENOMA

Lobulated mass in sellar

and supra sellar region

Superior displacement of

optic chiasma

Moderate homogenous

enhancement with internal

hemorrhage

No extension in

cavernous sinus

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Classification of pineal tumors

Tumors of pineal parenchymal cells

(pinealomas) (about 25%)

• Pineoblastomas

• Pineocytomas

(ganglioglioma)

Germ cell tumors

• Germinomas (about 70%)

• Embryonal carcinoma (yolk sactumor)

• Endodermal sinus tumors

• Choriocarcinomas

• Teratomas (immature and mature)

Tumors of glial cell origin

• Astrocytoma

• Glioblastoma

Miscellanous tumors and cysts

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Imaging protocol

The pineal region is best imaged with MRI although CT, angiography and ultrasound (in

infants) also play a role.

A typical protocol would include:

sagittal T1 and T2 (high resolution)

pre and post contrast T1 axial and coronal

FLAIR

DWI

SWI/gradient echo (to assess for presence of calcification)

Normal appearance

The pineal gland is a small (~7 mm AP diameter) structure located at the posterior-most

aspect of the third ventricle

Calcification

No calcification before the age of 5 years of age.

Calcification larger than 1 cm in any one diameter, or any calcification before the age of 4

years considered pathological.

Pineal parenchymal tumours (e.g. pineocytoma or pineoblastoma) tend to peripherally

disperse calcification where as germ cell tumours tend to engulf the calcifications. An easy

way to remember this is that pineoblastomas tend to blast the calcifications appart.

Solid component

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Solid component

Cystic lesion, identification of a significant nodular component or of a thickened

(>2 mm) wall makes a pineal cyst unlikely and essentially excludes an arachnoid

cyst of cavum velum interpositum.

DWI is also helpful as densely cellular tumours

(e.g.pineoblastoma, meningioma and lymphoma) tend to demonstrate increased

restricted diffusion compared to normal brain parenchyma.

Local invasion

well circumscribed mass - pineal cyst, pineocytoma whereas more aggressive

masses can extend extensively into the adjacent brain and brainstem

e.g. pineoblastoma, some germ cell tumours.

CSF seeding

Some aggressive pineal region masses tend to seed the ventricular and

subarachnoid space (e.g.pineoblastoma).

Germinomas- multifocal disease involving not only the pineal gland but also the

floor of the third ventricle is relatively common25 July 2016 27

Facts:

Germ Cell Tumors

Causes Parinaud’s Syndrome

disorder characterized by fixed upward gaze

Location:

Commonly in Pineal Region (>50%)

Overlies tectum of midbrain

Presentation:

Obstructive Hydrocephalus due to aqueductalstenosis

On Imaging:

CT

Isodense or hyperdense

Enhances with contrast

MRI

Isointense or Hypointense on T1-weighted images

& enhance with gadolinium

Hyperintense on T2 images

T1 Images

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MRI of an asymptomatic pineal cyst in a 17-year-old girl

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MRI gadolinium images

of:

(A) Pineoblastoma,

(B) Pineal epidermoid,

(C) Pineal meningioma,

(D) Tectal glioma,

(E) oligodendroglioma

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Ependymoma

Subependymoma

Choroid plexus papilloma

Colloid cyst

Central neurocytoma

Meningioma

Gaint cell astrocytoma

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General Features

Best diagnostic clue-Heterogeneous signal, Soft or "plastic"

tumor: Squeezes out through 4th ventricle foramina into

cisterns.Indistinct interface with floor of 4th ventricle.

Radiographic Findings

Myelography: May be helpful in showing "drop"metastases

CT Findings

Infratentorial- 4th ventricle tumor, extends into CPA/cisterna

magna.Ca++ common (50%); +/- cysts, hemorrhage.

Hydrocephalus common.

Supratentorial-Large heterogeneous periventricular mass. Ca++

common (50%).Variable heterogeneous enhancement.

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MR Findings

T1WI-Heterogeneous, usually iso- to hypointense. Cystic foci

slightly hyperintense to CSF.

T2WI-Heterogeneous, usually iso-to hyperintense

Hyperintense cystic foci, Hypointense Ca++, blood products

T1C+: Mild to moderate, heterogeneous enhancement.

Axial NECT shows irregularly shaped 4th ventricular tumor with Ca++ and cyst (open arrow) extending laterally into right CPA (curved arrow). Classic ependymoma extending from 4th V into CPA cistern. 25 July 2016 33

On MRI, heterogeneous secondary to necrosis, hemorrhage and calcification.

Heterogenous contrast enhancement

Plasticity

Extension to the cerebellopontine angle is characteristic of ependymomas

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Sagittal graphic shows posterior fossa ependymoma extending out through 4th ventricle foramen.

Axial T1 C+ MR shows lobular enhancing mass extending out 4th ventricle through foramen of Luschka into left cerebellopontine angle, classic cellular ependymoma

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MRI gadolinium (A) sagittal, (B) axial images showing fourth ventricular ependymoma

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Rare, benign well-differentiated intraventricular ependymal

tumor

Presentation

Most asymptomatic. 40% become symptomatic

symptoms: Related to increased intracranial pressure,

hydrocephalus,Headache, gait ataxia, visual disturbance,

cranial neuropathy, nystagmus, vertigo, nausea, vomiting.

Age

Middle-aged/elderly adult, (typically 5th-6th decades)

Asymptomatic patients: Mean age = 60 years

Symptomatic patients: Mean age = 40 years

Location

Inferior fourth ventricle, frontal horns of lateral ventricle.25 July 2016 37

General Features

Best diagnostic clue: T2 hyperintense lobular,nonenhancingintraventricular mass.

CT Findings

Iso to hypodense intraventricular mass.Cysts or Ca++ may be seen in larger lesions.Rarely hemorrhage

No enhancement, mild enhancement (heterogenous)typical.

MR Findings

TlWI-Intraventricular mass, hypointense or isointense.

Typically homogeneous solid mass.

T2WI-Hyperintense intraventricular mass

Heterogeneity related to cystic changes, blood products or Ca++ may be seen in larger lesions

No edema seen in adjacent brain parenchyma

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Sagittal graphic shows a solid, well-circumscribed mass arising from the floor of the 4th ventricle with mild mass effect (arrow). Note lack of hydrocephalus, typical of subependymoma.

Sagittal T2WI MR shows a solid hyperintense mass along the inferior 4th ventricle (arrow). 43 year old male with headaches and trigeminal neuralgia.

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Axial NECT shows a calcified 4th ventricular mass in this 52 year old female. Calcification is more commonly seen in 4th Ventricular subependymomas.

Sagittal T1 C+ M R shows a classic nonenhancing 4th ventricular subependymoma (arrow). 4th

ventricular floor origin is typical.

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On Imaging:

CT:

Smooth, round lesions lesion hyperdense to brain tissue

Thin rim of enhancement after IV contrast

MRI:

T1-weighted hyperintenselesion due to proteinaceousnature.

T2-weighted shows hypointense lesion

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Ant 3rd ventricle

Neuroepithelial

cyst

Hypo to hyperI

on T1 & T2WI

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General Features

Best diagnostic clue: Child with strongly enhancing, lobulated

intraventricular mass.

Radiographic Findings

Increased cranial-to-facial ratio

Sutural diastasis due to hydrocephalus

CT Findings

Intraventricular bosselated mass

75% iso- or hyperattenuating. Ca++ in 25%, hydrocephalus

Intense, homogeneous enhancement

Heterogeneous enhancement suggests choroid plexus carcinoma

(CPCA).

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MR Findings

TlWI-Well delineated, lobulated mass. Iso- to hypointense

CSF trapped between papillae :-a mottled appearance

T2WI-Iso- to hyperintense. ± Internal linear and branching

vascular flow voids. Hydrocephalus

Foci of diminished signal representing Ca++

± Intratumoral hemorrhage.

T1 C+ :Robust homogeneous enhancement.

Ultrasonographic Findings

Hyperechoic mass with frond-like projections

Mass echogenicity similar to normal choroid plexus

Hydrocephalus

Color Doppler: Hypervascular mass with bidirectional flow.

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Axial CECT shows a vividly enhancing lobulated CPP arising from the trigone of left lateral ventricle. Note normal contralateral choroid plexus (arrow),"overproduction" hydrocephalus.

Axial CECT shows an obstructing, robustlyenhancing choroid plexus papillomaarising from roof of third ventricle. Note papillary surface projections

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Axial PD/Intermediate MR shows an expansile intraventricular choroid plexus papilloma with internal flow voids (arrow).

Sagittal T1C+ MR shows an enhancing mass with lobulatedmargins (arrow), obstructing fourth ventricular outlets.

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Neurocytoma

Magnetic resonance

image of central

neurocytoma. FLAIR

(A) and postcontrast T1-

weighted (B) axial

images of a central

neurocytoma projecting

from the septum

pellucidum into the

anterior body of the left

lateral ventricle.

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tumor location T2WI contrast

Central

neurocytoma

Lat, septum

pellucidum

Iso to GM dense

ependymoma lateral Heterogeneous heterogeneous

meningioma lateral Iso to GM dense

Choroid

plexus tumor

fourth heterogeneous dense

Colloid cyst third Hyper to GM none

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Cerebellar liponeuroc

ytoma

Metastasis 16%

Hemangioblastoma 7-

12%

Pilocyticastrocytoma

(2nd decade)

Brain stem glioma (1%

of adult tumor)

Choroid plexus tumor (<1%)

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Axial CT contrast image showing

multiple metastases

Axial T2 image showing SINGLE

metastases

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General Features Best diagnostic clue-Cystic cerebellar mass with enhancing

mural nodule Enlarged optic nerve/chiasm/tract with variable enhancement.CT Findings Discrete cystic/solid mass. May have little or no surrounding

edema. Solid component hypo- to isodense. Ca++ 20%, hemorrhage rare Often cause obstructive hydrocephalus. > 95% enhance (patterns vary).50% non enhancing cyst.

strongly enhancing mural nodule. 40% solid with necroticcenter, heterogeneous enhancement

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MR Findings T1WI- Solid portions iso/hypointense to GM. Cyst

contents iso- to slightly hyperintense to CSF T2WI-Solid portions hyperintense to GM. Cyst

contents hyperintense to CSF. T1 C+: Intense but heterogeneous enhancement of

solid portion or mural nodule. Cyst wall occasionallyenhances.

Ultrasonographic Findings Real Time-Solid components are hyperechoic relative

to brain parenchyma. Cysts may contain debris.

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•A large partially cystic mass in the right cerebellar hemisphere.

•The solid component only minimally enhances with a focal region demonstrating

more prominent ring enhancement.

•The fourth ventricle is effaced, and the lateral ventricles are enlarged.

•There is also marked effect on the brainstem with the prepontine and

perimesencephalic cisterns obliterated.25 July 2016 55

Axial T2W and T1C+ scans 25 July 2016 56

(A)MRI T1,

(B) MRI gadolinium

images showing

sellar pilocytic

astrocytoma,

(C) MRI T1,

(D) MRI gadolinium

images showing

cerebellar

pilocytic

astrocytoma

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CT

The mural nodule is isodense to brain on non-contrast scans with fluid density surrounding cyst

Bright enhancement of the nodule is demonstrated with contrast

The cyst walls do not usually enhance & calcification is not a feature

MRI T1

Hypointense to isointense mural nodule,

CSF signal cyst content

T1 C+ (Gd)

mural nodule vividly enhances BUT cyst wall does not enhance

T2

Hyperintense mural nodule

Flow voids due to enlarged vessels may be evident especially at the periphery of the cyst, seen in 60-

70% of cases

Fluid filled cyst, similar to CSF

MR perfusion imaging: high rCBV ratios

Angiography (DSA)

Enlarged feeding arteries and often dilated draining veins are demonstrated, with a dense tumour

blush centrally

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Coronal MRI gadolinium image showing

cystic hemangioblastoma with a mural

nodule

CT showing cystic hemangioblastoma

with a mural nodule

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Sagittal MRI gadolinium image showing a

cerebellar and spinal hemangioblastomas

Computed tomography angio showing

vascularity of left cerebellar

hemangioblastoma25 July 2016 60

CT

• mass arising from the vermis, resulting in effacement of the fourth ventricle / basal

cisterns and obstructive hydrocephalus.

•Usually hyperdense (90%) and cysts formation/necrosis is common (40-50%)

•Calcification is seen in 10-20% of cases .

•Enhancement is present in over 90% of cases and is usually prominent

MRI

T1

hypointense to grey matter

T1 C+ (Gd)

overall 90% enhance, often heterogeneously

T2/FLAIR

overall are iso to hyperintense to grey matter

heterogeneous due to calcification, necrosis and cyst formation

surrounding oedema is common

DWI/ADC- restricted diffusion (low ADC values)

MR spectroscopy

elevated choline

decreased NAA

may show a taurine peak61

Medulloblastoma

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(A) Contrast CT, (B) MRI T1, (C) MRI gadolinium images showing medulloblastoma

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• Imaging

– MRI is the method of choice to image these tumors (brainstem glioma appears isodenseon CR and can be missed);

– Appear isointense or hypointense on T1 images, hyperintense on T2, and inhanceuniformly and brightly with IV contrast;

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Magnetic resonance imaging axial sections showing: (A) “Diffuse infiltrating

type” as compared to. (B) “Expanding type” of brainstem glioma.

Schwannoma Meningioma Arachnoid cyst

Epidermoid Paraganglioma Metastasis

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CT

May show erosion and widening of the internal acoustic canal.

The density of these tumours on non-contrast imaging is variable, and often they are hard to see, especially on account of beam hardening and streak artefact form the adjacent petrous temporal bone.

Contrast enhancement is present, but can be underwhelming, especially in larger lesions with cystic components.

MRI

T1

slightly hypointense cf. adjacent brain (63%)

isointense cf. adjacent brain (37%)

may contain hypointense cystic areas

T2

heterogeneously hyperintense cf. to adjacent brain

cystic areas fluid intensity

may have associated peritumoural arachnoid cysts

T1 C+ (Gd)

contrast enhancement is vivid

but heterogeneous in larger tumours

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Epidermoid. A, Contrast-enhanced axial

T1-weighted image demonstrates right

cerebellopontine angle mass (arrow),

showing close to cerebrospinal fluid

(CSF) intensity signal on this sequence,

and no postcontrast enhancement.

B, Fluid-attenuated inversion recovery

(FLAIR) image, showing the same lesion

demonstrating signal intensity somewhat

higher than CSF.

C, On diffusion-weighted image, the

lesion is hyperintense, whereas on the

apparent diffusion coefficient map

calculated from the diffusion data

(D), the lesion (short arrow) is

significantly lower in intensity than is the

CSF in the fourth ventricle (long arrow).

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meningioma

• usually more homogeneous in appearance: significant signal heterogeneity with cystic or haemorrhagic areas is more typical of vestibular schwannoma than meningiomas(although cystic meningiomas do occur)

• meningiomas tend to have a broad duralbase

• usually lack trumpet IAM sign

• calcification more common

epidermoid

• no enhancing component

• very high signal on DWI

• does not widen the IAC

metastasis

• uncommon

• usually does not remodel the IAC as metastases are usually present for only a short time

ependymoma

• centered on the fourth ventricle

• does not extend into the IAC

• usually younger patients

Differential diagnosis

The most frequent differential to be considered are:

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Chordoma

Chondrosarcoma

Esthesioneuroblastoma

Sinonasalcarcinoma

Myeloma

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(A) Lateral radiograph; (B) Coronal MRI; (C) CT bone window images showing a

giant osteoma of anterior skull base

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On CT image- isointense on the non-contrast studies. There is irregular bone

destruction at its site of origin, which may be in the midline of the clivus or

eccentrically located.

The tumour may also show areas of calcification.

MRI

Lobulated masses arising from the clivus. They manifest low signal intensity

on T1-weighted images and have high signal intensity on T2-weighted images.

They do enhance with the administration of gadolinium, but this occurs to a

variable degree.

They can vary greatly in size and distribution.

They often extend intracranially as well as extracranially into adjacent

anatomical areas

Differentiating chordomas from chondrosarcomas is often difficult due to the

identical imaging appearance.

Chondrosarcomas usually arise eccentrically at the petroclival synchondrosis.

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MRI scan of 43-year-old man showing a enhancing large clival

chordoma at the skull base

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Age distribution

Tumor spread

• Intra- versus Extraaxial

• Midline crossing

• Multifocal disease

• Cortical based tumors

CT and MR Characteristics

• Fat - Calcification -Cyst - High density

• High on T1

• Low on T2

• Diffusion weighted imaging

• Perfusion Imaging

Enhancement

Differential diagnosis for specific anatomic area

• Skull base

• Sella/suprasellar

• Cerebello-pontineangle

• Pineal region

• Intraventricular

• 4th ventricle

Tumor Mimics

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Thank you