Diagnostic Imaging of the Pituitary Gland

Mohamed Zaitoun
Assistant Lecturer-Diagnostic Radiology
Department , Zagazig University Hospitals
Egypt
FINR (Fellowship of Interventional
Neuroradiology)-Switzerland
zaitoun82@gmail.com

Knowing as much as
possible about your enemy
precedes successful battle
and learning about the
disease process precedes
successful management

Pituitary Gland
-The pituitary gland is formed from Rathke’s pouch
which is a superior invagination from the primitive
oral cavity
-The pituitary gland sits in the sella turcica, a cup-
shaped depression of the basisphenoid
-The pituitary is composed of anterior and posterior
lobes
-Rathke’s pouch closes off to form a vesicle that
involutes, sometimes, the involution is incomplete
and a cleft can be left behind which may give rise to
craniopharyngioma or Rathke’ cleft cyst

The mandibular nerve (V3) is the only segment of the trigeminal nerve that doesn’t
traverse the cavernous sinus , it exits inferiorly from Meckel’s cave through the
foramen ovale
The abducens nerve (VI) enters the petrous portion of the temporal bone through
Dorello’s canal and is the only nerve that travels in the medial venous sinusoids
The maxillary nerve (V2) is the only nerve of the cavernous sinus that doesn’t exit the
superior orbital fissure , instead , it exits the foramen rotundum

Small Pituitary Fossa
1-Normal Variant
2-Dystrophia Myotonica :
-Hereditary
-Usually starts in early adult life
-Cataracts , frontal baldness , testicular atrophy ,
thick skull and large frontal sinus
3-Radiotherapy as child
4-Hypopituitarism

Expanded Pituitary Fossa
a) Definition
b) Causes

a) Definition :
1-Size : Normal range is :
height 6.5-11 mm , length 9-16 mm , breadth 9-19
mm
2-Double floor : can be a normal variant
(asymmetrical development) but a tumor should
be suspected
3-Elevation / destruction of clinoid processes
4-Loss of lamina dura

b) Causes :
1-Parasellar / intrasellar mass
2-Raised intracranial pressure due to dilated
third ventricle
3-Empty sella
4-Nelson's syndrome : post-adrenalectomy for
Cushing's syndrome

J-Shaped Sella
a) Definition
b) Causes

a) Definition :
-Where the tuberculum sellae is flattened , thus
forming the straight edge of the "J“ , the
dorsum sellae remains rounded and forms the
loop of the "J“

Macrocephaly with J-shaped sella

Normal (1=tuberculum , 2=dorsum sella , 3=pituitary fossa) J-shaped sella

-Causes :
1. Normal : 5% of normal children
2. Optic chiasm glioma : if the chiasmatic sulcus is
markedly depressed (W- or omega-shaped sella) , the
tumor may be bilateral
3. Neurofibromatosis
4. Achondroplasia
5. Mucopolysaccharidoses
6.Chronic hydrocephalus : bone erosion occurs due to
the downward pressure of an enlarged third ventricle

Empty Sella
a) Incidence
b) Radiographic Features

a) Incidence :
-Relatively common incidental finding
-The hallmark of the finding is as the name suggests , a pituitary
fossa which is largely empty of tissue , replaced by CSF
-Empty sella is a component of the constellation of findings in
pseudotumor cerebri
-Pseudotumor cerebri also known as idiopathic (benign)
intracranial hypertension, is a syndrome associated with
elevated CSF pressure , visual changes and headaches that is
typically seen in obese black females
*Imaging findings include :
1-Empty sella
2-Flattening of posterior sclera of globes
3-Protruding optic nerve papilla
4-Tortous optic nerve with enlarged fluid-filled nerve sheath
5-The ventricles are normal in size or slightly reduced in caliber
6-The sigmoid or transverse sinus may be stenotic

Flattening of posterior sclera of globes , protruding optic nerve
papilla & tortuous optic nerve

b) Radiographic Features :
-MRI will shows the sella to be filled with CSF
and the infundibulum can be seen to traverse
the space , thereby excluding a cystic mass ,
this is known as the infundibulum sign

Post-Surgical Sella
-Small tumors are often removed via a
transsphenoidal approach (anterior wall of
sphenoid sinus → sella) , typically , sella and
sphenoid sinus are packed with Gelfoam ,
muscle and fat , postsurgical fluid may be seen
in the sphenoidal sinus

-Radiographic Features :
*Image sella soon after surgery (3-7 days) to
establish baseline imaging appearance for
further follow-up
-Gd-DTPA fat-suppression MRI techniques are
helpful to suppress bright signal from surgical
fat plug in the sella and to enhance pituitary
tissue

Ectopic Neurohypophysis
a) Incidence

a) Incidence :
-Ectopic posterior pituitary reflects an disruption
of normal embryogenesis and is one of the
more common causes of pituitary dwarfism
-May be associated with septo-optic dysplasia ,
optic nerve hypoplasia & agenesis of the
corpus callosum

-High T1 signal 3-8 mm tissue nodule at the
median eminence (floor of third ventricle)
-Absent normal posterior pituitary bright spot ,
it is important to note that a posterior
pituitary bright spot is not identified in 100%
of patients

T1 shows callosal dysgenesis with ectopic posterior pituitary

T1 shows ectopic posterior pituitary with septo-optic dysplasia

Intrasellar Masses
a) Neoplastic
b) Non-Neoplastic

Neoplastic
1-Pituitary microadenoma
2-Pituitary macroadenoma
3-Meningioma
4-Craniopharyngioma
5-Invasion by skull base
tumor
6-Pituitary metastases
Non-Neoplastic
1-Pituitary hyperplasia
2-Pituitary Apoplexy
3-Internal carotid artery
aneurysm
4-Ectatic carotid artery
5-Rathke’s cleft cyst
6-Infundibular Non-Neoplastic
Masses :
a) Sarcoidosis
b) Langerhans cell histiocytosis
c) Lymphocytic hypophysitis
7-Pituitary abscess

a) Neoplastic :
1-Pituitary microadenoma
3-Meningioma
4-Craniopharyngioma
5-Invasion by skull base tumour
6-Pituitary metastases

1-Pituitary Microadenoma :
a) Size
b) Types
c) Radiographic Features

a) Size :
-Adenomas < 10 mm
-75% are endocrinologically functional

b) Types :
1-Prolactinoma (most common : galactorrhea ,
amenorrhea , decreased libido(
2-Growth hormone (GH) (acromegaly , gigantism(
3-Adrenocorticotropic hormone (ACTH) (Cushing's
syndrome(
4-Gonadotroph (infertility or menstrual problems
in women , follicle-stimulating hormone(
5-Mixed (prolactin , GH , thyroid-stimulating
hormone least common(

c) Radiographic Features :
1-T1 noncontrast Appearance
2-Contrast enhancement (Gd-DTPA)

1-T1 Noncontrast Appearance :
-Microadenomas are hypointense / isointense
relative to pituitary
-Gland asymmetry
-Gland is convex superiorly (normal : flat or
concave)
-Stalk deviation
-Depression of sella floor

2-Contrast Enhancement (Gd-DTPA) :
-Dynamic imaging is required
-Low dose (0.05 mmol Gd/kg) : evaluation of
microadenomas
-Normal dose (0.1 mmol Gd/kg) : evaluation of
macroadenomas
-Adenoma enhances less rapidly than normal
pituitary

*N.B. : Dynamic Study :
-After a bolus injection of intravenous gadolinium ,
six consecutive sets of three images are obtained
in coronal plane every 10 seconds
-The enhancement occurs first in the pituitary
stalk , then in the pituitary tuft (the junction
point of the stalk and gland) and finally there is
centrifugal opacification of the entire anterior
lobe

-Within 30-60 seconds the entire gland shows
homogenous enhancement
-The maximum image contrast between the
normal pituitary tissue and microadenomas is
attained about 30-60 seconds after the bolus
injection of the intravenous contrast

High-resolution dynamic T1+C (at 60 seconds) shows a small nonenhancing
(dark) microadenoma (thin black arrow) lateralized to the right side of the
pituitary gland , the normal pituitary gland shows marked homogenous
enhancement and there is no deviation of pituitary stalk (thin white
arrow)

2-Pituitary Macroadenoma :
a) Size
c) Extension
d) Differential Diagnosis

a) Size :
-Adenomas > 10 mm
-Symptomatic because of their mass effect (e.g.
hypopituitarism , visual problems) rather than
endocrine dysfunction

-Heterogeneous appearance because of solid
and cystic components
-Enhancement : Intense but heterogeneous
-Intratumoral necrosis , hemorrhage (T1W
hyperintense)

Axial T2W (a) and T1W (b) images show a large inhomogeneous T1-
hypointense and T2-hyperintense pituitary mass (arrow) , which causes a
lateral displacement of bilateral internal carotid arteries (cavernous part) ,
on post contrast coronal (c) and sagittal (d) images , the lesion exhibits
marked but heterogeneous contrast enhancement

Axial T2W (a) and T1W (b) images demonstrate a large
inhomogeneous , T1-hypointense , T2- hyperintense pituitary mass
(arrow) which shows marked enhancement on post contrast
coronal (c) and sagittal (d) images

Axial T2 (a) and T1 (b) show a large inhomogeneous isointense pituitary mass (arrow)
encroaching bilateral cavernous sinus regions, on postcontrast coronal (c) and sagittal
(d) images, the lesion exhibits moderate contrast enhancement, left ICA (cavernous
part) appears to be displaced laterally by the mass while the right ICA is seen traversing
through the mass, thereby showing invasion of ipsilateral cavernous sinus, however,
both the arteries demonstrate normal contrast opacification with mild luminal
compromise

-Pituitary macroadenoma
-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
-Notice the blood-fluid
level, indicating
hemorrhage

Hemorrhagic pituitary macroadenoma T1

Hemorrhagic pituitary macroadenoma T2

Hemorrhagic pituitary macroadenoma T1+C

Coronal T1W (a) and Sagittal T2W (b) images reveal a pituitary mass (arrow) showing
intratumoral hemorrhage , on post contrast coronal (c) and sagittal (d) images ,
the lesion demonstrates mild enhancement with left cavernous sinus invasion

Pituitary apoplexy (pituitary macroadenoma with hemorrhage)
Axial T1W (a) , T2W (b) and GRE (c) images reveal a pituitary
mass with intratumoral hemorrhage (arrow)

c) Extension :
Large tumor extending beyond the confines of
the sella
1-Intrasellar expansion (ballooning of sella)
2-Extension into suprasellar cistern :
-Figure eight shape
-Thickening of cavernous sinus
-Encasement / narrowing of cavernous ICA flow
void , cavernous sinus involvement can be
difficult to determine unless tumor surrounds
the vessel / cavernous sinus

-Compression of optic chiasm
-Upward displacement of third ventricle
-Obstruction of foramen of Monro with
hydrocephalus , 10%
-Compression of frontal horn of lateral
ventricles
-Splaying of cerebral peduncles

T1+C showing a pituitary adenoma with elevation and compression of the optic
chiasm (arrow indicates area of optic chiasm)

Extension into sphenoid bone T1

Extension into sphenoid bone T2

Extension into sphenoid bone T1+C

Invasion of the base of the skull T1+C

d) Differential Diagnosis : From
Meningioma
-In Pituitary Macroadenoma :
-Because they are soft tumors , they usually
indent at the diaphragma sellae giving them
a (snowman or figure of 8 configuration )
-Enlargement of the sella turcica , this
generally only occurs with pituitary
macroadenomas that originate in the sella

-In Meningioma :
-There are dural tail usually visible
-Enhancement more vivid
-Hyperdense on non-contrast CT
-Typically narrow arteries which they encase
while macroadenoma doesn’t

-Pituitary macroadenoma
-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
-Notice the blood-fluid
level, indicating
hemorrhage

-In meningioma ,
there is no
diaphragmatic
constriction and
there is uniform
enhancement after
the administration
of intravenous
gadolinium

-On the coronal images (T1 and
T1-postcontrast) a compressed
pituitary gland can be
identified at the bottom of the
sella turcica
-Above it lies a large mass ,
partially intrasellar and
partially suprasellar
-Although the diaphragma
sellae can not be identified on
these images , it is probably a
suprasellar mass growing
downwards
-When pituitary
macroadenomas get this size
they usually have areas of
hemorrhage or necrosis , in
mengiomas this is less often

3-Meningioma :
-Tuberculum or diaphragma sellae meningioma
may extend into the sella (See Suprasellar
Masses)
-Purely intrasellar tumor rare
4-Craniopharyngioma :
-See (Suprasellar Masses)

5-Invasion by Skull Base Tumor :
Chordoma & Chondrosarcoma
1-Chordoma :
a) Incidence

a) Incidence :
-Occurs at any age but are usually seen in adults
(20-40 years)
-Expansile lytic mass arising from the central skull
base (clivus)
-Typically the mass projects in the mid-line
posteriorly indenting the pons , this characteristic
appearance has been termed the thumb sign

-The clivus is a combination of
two bones , the body of the
sphenoid and the anterior
aspect of the occipital bone
-Together they form a bony
slope anterior to the
brainstem which extends
from the dorsum sella to
the anterior aspect of the
foramen magnum

3D CT shows the sites of origin of intracranial
chordomas : the upper (yellow) , middle (red) and
lower (green) clivus

Sagittal T1-weighted MR images demonstrate
involvement of the upper clivus

involvement of the middle clivus

involvement of the lower clivus

1-CT
2-MRI
3-MRA
4-Conventional Angiography

1-CT :
-Centrally located well-circumscribed expansile
soft-tissue mass that arises from the clivus
with associated extensive lytic bone
destruction
-The bulk of the tumor is usually
hyperattenuating relative to the adjacent
neural axis

-Intratumoral calcifications appear irregular at
CT and are usually thought to represent
sequestra from bone destruction rather than
dystrophic calcifications in the tumor itself
-There is moderate to marked enhancement

Sagittal reformatted CT scan reveals bone sequestra at
the distal end of a lytic clival lesion (arrows)

Axial CT scan of the skull base demonstrates the lesion with a clival origin and
extension to the prepontine cistern with typical trabecular entrapment
(arrow) , dystrophic calcification is also seen (arrowhead)

CT scan shows a chondroid chordoma in the clivus with
intratumoral calcifications (arrow)

2-MRI :
*T1 :
-Intermediate to low signal intensity
-Small foci of hyperintensity (intratumoral
hemorrhage or a mucus pool)

Axial T1-weighted MR image shows a small hypointense mass in
the right side of the clivus (arrow)

Sagittal T1-weighted MR shows a large hypointense soft-tissue
mass that arises from the distal clivus with anterior extension
into the nasopharynx (arrows) and extradural extension into
the posterior fossa (arrowhead)

Sagittal T1-weighted MR image shows a retroclival mass
(arrows) that has a hyperintense rim and projects posteriorly ,
a finding that represents highly proteinaceous material or
blood products

*T2 :
-Most exhibit very high signal (reflects the high fluid
content of vacuolated cellular components )
-The intratumoral areas of calcification ,
hemorrhage and a highly proteinaceous mucus
pool usually demonstrate heterogeneous
hypointensity
-Low signal intensity septations that separate high
signal intensity lobules are commonly seen

Axial T2 shows an intracranial chordoma with diffuse
homogeneous hyperintensity

Axial T2 shows a multiseptate hyperintense mass with extension into the
sellar area and left cavernous sinus , the mass also exhibits areas of
hypointensity possibly secondary to calcification , hemorrhage or a mucus
collection

Axial T2 shows a septate tumor with a pseudoencapsulated appearance

-T1+C : Heterogeneous enhancement with a
honeycomb appearance corresponding to low
T1 signal areas within the tumor ,
occasionally , the enhancement is slight or
even absent , such a finding likely represents
necrosis and a large amount of mucinous
material in the tumor
-GE (gradient echo) : Confirms hemorrhage if
present with blooming

Axial unenhanced T1-weighted MR
image shows an isointense mass
along the right side of the clivus
and petrous apex
Axial contrast-enhanced T1-
weighted MR image shows the
mass with marked enhancement

Axial contrast-enhanced T1-weighted MR image shows a large midclival mass with
variable enhancement (honeycomb appearance) and extension to the sellar area
and adjacent cavernous sinuses , note the lateral displacement of the right
cavernous internal carotid artery (arrow)

Sagittal unenhanced T1-weighted
MR image shows a large
isointense soft tissue mass in the
distal clivus (arrows)
Sagittal T1+C , the mass exhibits little or
no enhancement (arrows)
Note the normal enhancement of the
nasal , nasopharyngeal and palatal
mucosa

3-MRA :
-Allows better evaluation of vascular
encasement and obviates cerebral
angiography which does not allow detection
of encasement without luminal narrowing or
occlusion
-Tumoral displacement or partial encasement of
intracranial arteries is common being
visualized in up to 80 % of intracranial
chordomas

Normal MRA
MRA shows posterior displacement of the
right PCA (arrowhead) and lateral
displacement of the right cavernous ICA
(arrow)

Sagittal T1-weighted MR image demonstrates posterior and superior
elevation of the right cavernous internal carotid artery (arrows)

Coronal T1-weighted MR shows a tumor with extension to the right
cavernous sinus and concomitant displacement and partial encasement of
the right cavernous internal carotid artery (arrow)

Sagittal T1+C shows a large irregularly enhancing mass (arrow) with
retroclival extension that encases the left ICA (arrowhead)

4-Conventional Angiography :
-Angiographic evaluation is reserved for cases in which
there is significant displacement , encasement or
narrowing of the ICA or vertebral artery at MRA
-Cerebral angiography can better demonstrate the
degree of luminal narrowing or occlusion and the
extent of collateral circulation
-Temporary balloon occlusion of the ICA is frequently
used to determine whether patients are at risk for
neurologic injury during surgery due to permanent
vessel occlusion

Left carotid arteriogram shows narrowing of the distal left ICA (arrow)
and upward displacement of the left MCA (arrowhead)

Sagittal T1-weighted MR image
shows a mass that involves the
posterior fossa (arrows) with
extracranial soft-tissue extension
to the face
Left ECA arteriogram demonstrates
recurrent tumor with vasculature
from the branches of the posterior
auricular artery (arrow) , note the
occlusion of the ICA (arrowhead)

2-Chondrosarcoma :
a) Incidence

a) Incidence :
-Paramedian arising from the petro-occipital
fissure and infiltrate the cavernous sinus

-Drawing of a sagittal
section through the
head depicts a large
chondrosarcoma
arising from the clivus
-The tumor is exerting
mass effect on the
pons and midbrain
without direct
invasion
Whitish areas within
the tumor represent
matrix mineralization

1-CT
2-MRI

1-CT :
-Shows a stippled and / or amorphous calcified
matrix

CT Showed peripheral Calcification

-MRI :
*T1 :
-The tumor shows variable signal intensity
-The areas of high T1 signal intensity may reflect
hemorrhage or mucin

*T2 :
-Characteristic high T2 signal intensity
-The heterogeneous T2 signal intensity may be
due to fibrocartilaginous foci or areas of
chondroid mineralization

T2 revealed a retroclival mass which was intensely
hyperintense , clival invasion was note

*T1+C :
-Enhancement is moderate to marked and
usually heterogeneous , though occasionally it
is homogeneous

Coronal T1+C of a chondrosarcoma , this is an enhancing mass involving the
left side of the sella and the cavernous sinus but arising from the skull
base just off midline

-A , Coronal T1+C shows a
large inhomogeneous-
appearing mass involving
the left CS , sella ,
suprasellar region ,
ipsilateral middle cranial
fossa and intratemporal
region , the mass has a
cystic lateral component
-B , Axial T2 shows that
the solid portion of the
mass is hyperintense , a
finding that is typical of
chondrosarcoma

6-Pituitary Metastases :
a) Incidence
b) Clinical Picture

a) Incidence :
-Rare (breast most common)
-May appear identical to pituitary adenomas
b) Clinical Picture :
Hormonal dysfunction and mass effect

-Although larger lesions are visible on CT ,
appearing as enhancing soft tissue masses ,
MRI is the modality of choice
for assessment of the pituitary region
-MRI : usually encountered in two pattern :
1-Sizeable mass arising from the pituitary fossa
(similar to a macroadenoma)
2-Infundibular lesion

1-Sizeable mass arising from the pituitary fossa
(similar to a macroadenoma) :
-These masses typically involve both the intra
and suprasellar compartments , as they are
usually rapidly growing they have a number of
features which are helpful in distinguishing
them from pituitary macroadenomas :

1-Relatively normal size fossa
2-Bony destruction rather than remodelling
3-Dural thickening
4-Dumb-bell shape as the diaphragma sella has
not had time to be stretched
5-Irregular edges

2-Infundibular Lesion :
-Involvement of the infundibulum typically
appears as nodular / irregular thickening and
enhancement , the posterior pituitary bright
spot may also be absent , either from
interruption of the normal transport of
neurosecretory granules down the
infundibulum or due to
concurrent infiltration of the posterior lobe

-Patient with lung cancer who
presented with a sixth cranial
nerve palsy
-The abnormality is in the
clivus which should have a
high signal intensity on this
sagittal T1-weighted
-A low signal intensity means
the normal fatty marrow has
been replaced by some other
tissue
-In this case by tumor
metastasis
-Also lymphomas , myelomas
or diffuse bone abnormalities
can give this appearance
-Therefore always take a
minute to look at the clivus

-T1 showing the
disappearance of the
characteristic high
signals of the
posterior pituitary and
increased size of the
pituitary stalk

- MRI T1+C showing
the nodular lesions
below the
hypothalamus region ,
the posterior pituitary
continued to lack the
characteristic high
signal

b) Non-Neoplastic :
1-Pituitary Hyperplasia
2-Pituitary Apoplexy
3-Internal Carotid Artery aneurysm
4-Ectatic Carotid Artery
5-Rathke’s cleft cyst
6-Infundibular Non-Neoplastic Masses :
a) Sarcoidosis
7-Pituitary Abscess

1-Pituitary Hyperplasia :
a) Definition
b) Etiology

a) Definition :
-Generalized homogeneous enlargement of the
gland
b) Etiology :
1-Pregnancy & Lactation
2-Nelson’s syndrome (infrequently develop
following total bilateral adrenalectomy (TBA) for
the treatment of Cushing's disease )

(a) Non-enhanced T1 shows normal pituitary gland (thin arrows) , (b) T1+C shows
pituitary hyperplasia (thick arrows) , the enlarged pituitary gland abuts the optic
chiasm superiorly (dotted arrows) , typical feature of physiologic enlargement is a
triangular shape to the gland with the apex pointing toward the optic apparatus

Coronal contrast-enhanced MRI shows the enlarged
gland without any visible adenoma

Sagittal contrast-enhanced MRI shows the enlarged
gland without any visible adenoma

2-Pituitary Apoplexy :
a) incidence
b) Causes

a) Incidence :
-Is an acute clinical syndrome caused by either
hemorrhage or infarction of the pituitary
gland
- An existing pituitary macroadenoma is usually
present (60-90%) but it can occur with healthy
glands in few isolated cases
-Manifests as acute onset of terrible headache ,
ptosis , vision changes , diplopia , nausea &
vomiting

b) Causes :
1-Acute onset of hemorrhage into pituitary
adenoma with necrosis and infarction of the
pituitary gland
2-Sheehan's syndrome : postpartum infarction
of anterior pituitary gland

-MRI typically demonstrates a pituitary region
mass
*T1 : hyperintense due to blood
*T2 : variable signal
*T1+C : enhancement variable and may be
difficult to identify due to intrinsic high T1
signal
*Diffusion : restricted diffusion may be present
in solid infarcted component

3-Internal Carotid Artery Aneurysm :
-Must not be mistaken for intrasellar tumor
(see Parasellar masses)

4-Ectatic Carotid Artery :
-Medially positioned ICAs may be bilateral and
produce (kissing carotids)

CTA 3D , intracranial intrasellar kissing carotids

5-Rathke’s Cleft Cyst :
a) Incidence
c) Differential Diagnosis

a) Incidence :
-Common in adult females
-Intrasellar , suprasellar or both
-Cystic or solid
-Arises from the embryologic remnants of
Rathke’s pouch in the pituitary gland (similar
to craniopharyngioma)

1-CT :
-Hyperdense on CT with rim enhancement
-No enhancement (may be rim enhancement) ,
No calcification unlike craniopharyngioma
which enhances and calcify

2-MRI :
*T1 :
-High T1W signal on MRI (the only two things that are this bright
on unenhanced T1-weighted images are either fluid ( blood or
proteinaceous fluid) or fat
-Small intracystic nodules with high signal intensity at T1 and low
signal intensity at T2 are present in approximately 45% of
cases and are considered a characteristic feature of Rathke
cleft cysts
*T2 :
-High signal intensity
*T1+C :
-Peripheral enhancement is sometimes noted (The claw sign
represents enhancing pituitary tissue completely wrapped
around the cyst)

T1 shows a well-marginated sellar mass , a Rathke cleft cyst , extending into
the suprasellar cistern , note that the mass has homogeneous high signal
intensity relative to the brain parenchyma

T2 shows the mass , a Rathke cleft cyst , is isointense relative to
the cortex

After contrast enhancement , no significant enhancement is seen in the
Rathke cleft cyst , note the normally enhancing pituitary infundibulum
dorsal to the mass

T1+C shows hypointense mass (yellow arrows) with faint peripheral rim
enhancement , the pituitary is displaced to the right and the optic chiasm
is displaced superiorly (red arrow)

The red arrow points to the cyst , the yellow to the compressed
and displaced pituitary stalk

Rathke cleft cyst in a 34 year old woman with a slightly elevated prolactin
level, (a) Coronal T1shows a high signal intensity spheroid lesion (arrow)
within the sella, (b) Coronal T2 shows a low signal intensity intracystic
nodule (arrowhead) within the spheroid lesion

c) Differential diagnosis :
From Craniopharyngioma
1-Enhancement of the wall of a cystic
craniopharyngioma on contrast-enhanced MR
images played an essential role in
differentiating it from Rathke cleft cyst
2-Craniopharyngioma is usually suprasellar or
have a suprasellar component
3-Craniopharyngioma tends to calcify

Craniopharyngioma ; suprasellar mass with rim enhancement

CT without contrast shows craniopharyngioma , suprasellar mass
with calcification

Craniopharyngioma with suprasellar location

a) Sarcoidosis

a) Sarcoidosis :
1-Incidence
2-Location
3-Clinical Picture
4-Radiographic Features

1-Incidence :
-Typically affecting patients 30-40 years of age
with a female predilection
-Sarcoidosis is a great mimic , enhancing lesions
may involve dura , leptomeninges , brain
parenchyma , hypothalamic pituitary axis and
cranial nerves

2-Location :
-Central nervous system involvement by
sarcoidosis is very variable with lesions
potentially involving the leptomeninges ,
pituitary and parenchyma of all parts of the
intracranial compartment

3-Clinical Picture :
-Variable and non-specific , it includes :
1-Signs and symptoms of raised ICP due to
hydrocephalus
2-Cranial nerve palsies :
-Optic nerve involvement (common)
-Facial Nerve palsy
4-Diabetes insipidus from pituitary involvement
5-Seizures

4-Radiographic Features :
a) CT :
-Plaque like dural thickening
-Often the only finding is hydrocephalus due to
unseen leptomeningeal disease
b) MRI :
*T1 :
-Iso or hypointense with respect to adjacent grey
matter

*T2 :
-Variable
-Most are hyperintense
*T1+C :
-Homogenous enhancement
- Enhancement involving the optic apparatus / floor
of the third ventricle and pituitary infundibulum
is particularly suggestive of sarcoidosis

Sagittal T1+C , shows a well-defined mass in the hypothalamic area
and a thickened pituitary stalk

(a) Sagittal and (b) coronal images of pituitary and hypothalamus Involvement , there is extensive
enhancement of the pituitary gland (arrow) and stalk (arrowhead) which is markedly
enlarged

T1+C , A : shows a well enhanced mass in the hypothalamic area , thickening of the
stalk and swelling of the pituitary gland , B : Shows improvement after treatment

Coronal T1+C , A : Shows an enhanced nodular lesions around the 3rd
ventricle ,
optic tract and decreased intensity of the posterior pituitary gland , B : Shows
disappearance of the nodular lesions after treatment

Leptomeningeal Involvement ( T1+C )

b) Lymphocytic Hypophysitis :
-Lymphocytic infiltration of the anterior pituitary
occurring in pregnancy / postpartum period
-Enlarged enhancing gland and infundibulum
-Responds to steroid therapy

T1+C shows diffuse enhancement of the pituitary gland (black arrow) , also
note the enlargement and enhancement of the infundibular stalk (white
arrow)

Postcontrast T1W coronal (a) and sagittal (b) images show slight enlargement
of pituitary gland and thickening of the infundibulum with minimal
enhancement (arrow) , the fossa is not enlarged , also note the absence of
posterior bright spot

c) Langerhans Cell Histiocytosis :
-Disease of children
-Commonest radiological presentation is a
thickened enhancing infundibulum with loss
of the normal posterior pituitary bright spot
-Parenchymal , cranial nerve , meningeal and
skull lesions also occur

T1+C shows remarkable thickening of the pituitary stalk resulting in slight
compression of optic chiasm

Loss of normal T1 high signal in the posterior pituitary

Normal high signal of post p Loss of normal signal

T1+C (a) coronal and (b) sagittal images show a contrast-enhancing
thickened pituitary stalk , an associated left frontal intradiploic skull
lesion is noted

A. T1 shows a uniformly thickened pituitary stalk (arrow) , the posterior lobe
no longer shows high signal intensity , B. T1+C shows strong enhancement
of the lesion (arrow)

7-Pituitary Abscess :
a) Incidence
b) Etiology
c) Clinical Picture
d) Radiographic Findings

a) Incidence :
-Rare , accounts for approximately 0.2-1% of all
pituitary lesions
b) Etiology :
-Caused by hematogenous seeding of the pituitary
gland or possibly by direct extension of an
adjacent infection such as meningitis , sphenoid
sinusitis , cavernous sinus thrombophlebitis or as
a result of a CSF fistula that has been
contaminated

c) Clinical Picture :
-The most common presenting symptoms are
headaches , visual problems and those of
pituitary insuffiency such as diabetes insipidus
d) Radiographic Findings :
-T1 : Typically show low intensity but may also
show marked T1 hyperintensity due to
purulent content

-T2 : Demonstrates increased intensity
-T1+C : Ring enhancement can be demonstrated
, which represents the abscess capsule
-DWI : Restricted diffusion within the abscess
cavity may be seen
-MRS : Lactate , aminoacid (valine , alanine and
leucine) and acetate peaks

T1 shows suprasellar mass with internal increased intensity

T2 coronal image shows suprasellar mass with increased
intensity and compression of the optic chiasm is seen

T1+C sagittal image shows peripheral enhancement of the suprasellar lesion

Suprasellar Masses
a) Neoplastic
b) Non-Neoplastic

a) Neoplastic
2-Suprasellar Meningioma
3-Craniopharyngioma
4-Optic pathway glioma
5-Hypothalamic
hamartoma
6-Lymhoma & Leukemia
7-Suprasellar Germ Cell
Tumors
8-Suprasellar Lipoma
9-Metastases
b) Non-Neoplastic
1-Aneurysm of ICA
2-Ectatic ICA
3-Arachnoid cyst
4-Epidermoid / Dermoid
5-Rathke's cleft cyst
6-Infundibular Non-
Neoplastic Masses :
a) Sarcoidosis
b) Langerhans cell
histiocytosis

a) Neoplastic :
-The most common suprasellar lesion in a child is
craniopharyngioma while the most common suprasellar
lesion in an adult is a pituitary macroadenoma that has
extended superiorly
1-Pituitary Macroadenoma
2-Suprasellar Meningioma
3-Craniopharyngioma
4-Chiasmatic Glioma
5-Infundibular Tumors
6-Hypothalamic Hamartoma
7-Suprasellar Germ Cell Tumors
8-Suprasellar Lipoma

1-Pituitary Macroadenoma : (See intrasellar
masses)
-Large tumors extend into the chiasmatic cistern
(suprasellar cistern) where they can compress the
optic apparatus
-Macroadenomas typically have a (cottage loaf or
figure of eight or snow man appearance )
-Hemorrhage , cyst formation and midline origin is
suggestive of macroadenoma rather than
meningioma

1-Suprasellar cistern
2-Pituitary gland
3-Pons
4- 3rd
ventricle
5-Corpus callosum

1-Suprasellar
cistern
2-Pituitary stalk
3-Cerebral
aqueduct
4-Hippocampus

1-Suprasellar
cistern
2-ACA
3-Lateral
ventricle
4-Caudate
nucleus

2-Suprasellar Meningioma :
a) Incidence
c) Differential Diagnosis

a) Incidence :
-Common in females (peak incidence 45 years of
age)
-2nd
most common tumor suprasellar tumor in
adults
-Arises from the anterior cranial fossa , sphenoid
wing or diaphragma sellae
-Typically presents with visual loss due to optic
pathway involvement

An autopsy specimen with the brain removed showing
a meningioma sitting on the diaphragma sellae

*CT :
-Unenhanced CT shows a mass which is hyperdense
to underlying parenchyma , however , it may be
iso or hypodense
-Contrast : Homogenous enhancement with dural
tail
-Calcification in circular or radial pattern
-Underlying parenchymal edema
-Hyperostosis

A: CT brain revealed a homogenous hyperdense globular mass at the
suprasellar region
B: The mass enhanced homogenously with intravenous contrast agent

A: CT brain showing hyperostosis of the sphenoid bony
B: CT brain of showing normal sphenoid bone thickness

*MRI :
-Isointense to grey matter on T1
-Variable intensity on T2 ranging from iso to hyperintense
-Enhancement is uniform
-Dural tail
-The pituitary gland should be identified separately (in
contrast to pituitary adenoma)
-Parenchymal edema
c) Differential Diagnosis :
-From pituitary macroadenoma (See before)

T1+C showed a nodular tumor with a tail of meningeal
enhancement (arrow) extended onto the cribriform plate

3-Craniopharyngioma :
a) Incidence
b) Clinical Picture
c) Radiographic Findings

a) Incidence :
-Benign tumor that arises from squamous
epithelial remnants along Rathke duct / pouch
-Most common tumor of the suprasellar cistern
of childhood
-Age: 1st to 2nd decade (>50%)
-Location: Combined suprasellar / intrasellar ,
completely intrasellar is rare (it is almost
always separate from the pituitary gland)

1-Growth retardation (compression of
hypothalamus)
2-Diabetes insipidus (pituitary compression)
3-Bitemporal hemianopsia (partial blindness
where vision is missing in the outer half of
both visual fields)
4-Headaches (most common)
5-Cranial nerve palsies (cavernous sinus
involvement)

c) Radiographic Findings :
1-CT :
-Midline cystic mass (90%) with mural nodule in suprasellar
location that extends superiorly and posteriorly
-Calcification in 90% (children) , less common in adults (50%) ,
typically stippled and often peripheral in location
-Enhancement of solid lesion rim , no enhancement of cystic
lesion (in contrast to Rathke’s cleft cyst , craniopharyngioma
almost always enhances , is almost always calcified and is
almost always separate from the pituitary
-Obstruction of foramen of Monro with hydrocephalus , 60%

Benign calcification Intermediate calcification

2-MRI :
-Variable signal intensity by MRI depending on cyst
content : high protein content , blood ,
cholesterol
*T1 :
-Hypointense (however , may be high signal on
T1W)
-The T1 hyperintensity observed in the cystic
components of craniopharyngioma is attributable
to the presence of protein , cholesterol granules
and methemoglobin

*T2 :
-Hyperintense
*T1+C :
-Rim like enhancement (avid enhancement of the
solid element and
*MRA :
-May demonstrate displacement of the A1 segment
of the anterior cerebral artery
*Angiography :
-Usually avascular

-In over 50% of cases
craniopharyngiomas have a
pathognomonic appearance
-On these unenhanced and
enhanced T1-weighted
sagittal , coronal & axial
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 (perhaps
with only a dermoid in the
differential diagnosis)

-Craniopharyngioma
in a 2 year old boy
-Sagittal T1 shows a
large mass (*) that
contains multiple high
signal intensity
components (arrows)

The yellow arrows point to the cyst , the red to the solid part of
the tumor and the blue to a dilated lateral ventricle
(hydrocephalus)

The yellow arrow points to the small solid part , the red
to the large cystic part

-N.B. :
-A suprasellar mass in a child or adolescent is
considered a craniopharyngioma until proven
otherwise
-The majority of craniopharyngiomas have cystic
components ; purely solid tumors are rare
-Clinical presentations of pediatric suprasellar region
lesions :
1-Diabetes insipidus most common with eosinophilic
granuloma of stalk
2-Precocious puberty most common with hypothalamic
hamartoma
3-Growth delay most common with craniopharyngioma

4-Optic Pathway Glioma :
-An astrocytoma involving the visual pathway (optic
nerve , optic chiasm and optic tract) is the 2nd
most
common suprasellar mass in children
(craniopharyngioma is the most common)
-Minority of patients with optic pathway glioma have
NF-1
-Tumors are isointense on T1 , hyperintense on T2 and
usually enhances

Optic pathway glioma , (a) T1 , (b) T1+C show a suprasellar mass that is
slightly hypointense relative to grey matter (yellow arrows) with diffuse
enlargement of the adjacent optic chiasm (red arrow) , the mass
demonstrates avid slightly heterogenous enhancement

T1 (a) , FLAIR (b) shows the lesion is hypointense on T1 and hyperintense on
FLAIR image , optic chiasma and left optic nerve are involved

5-Hypothalamic (Tuber Cinereum) Hamartoma:
a) Origin
b) Clinical Picture
c) Radiographic Findings

a) Origin :
-Sessile or pedunculated tumor lying between
the pituitary stalk and mamillary bodies
-Not a true neoplasm

-Left: Normal
infundibular recess
of the third
ventricle (blue
arrow) , mamillary
bodies (red arrow)
-Right: Tuber
cinereum
hamartoma
(curved arrow)

1-Tuber cinerum
2-Corpus
callosum
3-Fornix
4-Third ventricle
5-Cerebellum
6-Fourth
ventricle
7-Pons

1-Tuber cinerum
2-Cerebral
peduncle
3-Cerebral
aqueduct
4-Superior
colliculus

1-Tuber cinerum
2-Column of
fornix
3-Septum
pellucidum
4-Third ventricle

-Patients present with either :
1-Precocious puberty
2-Gelastic seizures (paroxysms of inappropriate
emotional outbursts , usually laughing)

c) Radiographic Findings :
*CT:
-Isodense
-No enhancement (in contrast with
hypothalamic gliomas)

Axial (a) and sagittal (b) post-contrast CT demonstrate a tiny
well-defined nonenhancing rounded suprasellar mass arising
from hypothalamus (arrow) , note , the lesion is isodense to
normal brain parenchyma

-CT images of a
hamartoma suspended
from the floor of the third
ventricle
-It does not enhance after
the administration of
intravenous contrast
-MR images of a similar
small nodule suspended
from the floor of the third
ventricle

-Note the enhancement
of the hypothalamic
glioma
-A : Unenhanced axial CT
scan reveals a
hyperdense mass
(arrow) that enhances
uniformly in the
suprasellar region
-B : CT+C reveals a
hyperdense mass that
enhances uniformly
(arrow) in the
suprasellar region

*MRI :
-T1W: similar signal intensity as GM
-T2W: hyperintense
-N.B. :
The floor of the third ventricle should be smooth
from infundibulum to mamillary bodies , any
nodularity should raise suspicion for a
hamartoma in the right clinical setting

-The best images to
see hamartoma on are
enhanced sagittal T1
-Here you can see the
non-enhancing
hamartoma attached
to the tuber cinereum
between the pituitary
stalk and mamillary
body
-Hamartoma (red
arrow) posterior to the
enhancing pituitary
gland and stalk

Sagittal T1+C of a hypothalamic hamartoma , this is seen as a pedunculated
mass hanging from the undersurface of the hypothalamus , it does not
enhance and has the same signal as the grey matter of the brain
parenchyma

(a) T1 , (b) FLAIR show a T1 isointense , FLAIR hyperintense suprasellar mass
(yellow arrows) projecting inferiorly from the hypothalamus , the optic
chiasm (red arrow) , anterior pituitary (blue arrow) and posterior pituitary
bright spot (green arrow) are normal

6-Lymhoma & Leukemia :
a) Lymphoma :
-May involve the pituitary gland , infundibulum
and hypothalamus
-Isointense on T1W with strong uniform
enhancement
-Coexistent disease may be visible in the
paranasal sinuses or orbit

b) Leukemia :
-Pituitary stalk involvement and thickening has
been reported with leukemia (chronic
myelogenous leukemia and acute
myelogenous leukemia)
-Clinically these patients have DI

7-Suprasellar Germ Cell Tumors :
-Germinoma & Dermoid , see (Pineal Region Masses)
-The most common intracranial germ cell tumor is a
germinoma , of which 80 % arise in the pineal region
and 20 % arise in the parasellar region
-Seen in children and adolescents
-Imaging shows a homogenous intensely enhancing
midline mass , the mass is hypointense on T2 and
dark on ADC due to hypercellularity

Sagittal T1+C of a germinoma with both a suprasellar and pineal
enhancing mass lesions

Coronal T2W FLAIR (a) and postcontrast T1W (b) images show a solid heterogeneous moderately
enhancing suprasellar mass in hypothalamic / infundibular region , multiple nonenhancing
hypointense intratumoral areas are present representing intratumoral hemorrhage or
calcification , postsurgical biopsy proved suprasellar germinoma

Suprasellar germinoma , sagittal T2 shows a solid mass with a cystic area (arrow) , the
tumor extends upward toward the infundibular recess

Suprasellar germinoma , sagittal T1+C with fat saturation shows a solid mass with
marked enhancement , the pituitary gland is compressed and flattened along the
sellar floor (arrows) , the tumor extends upward toward the infundibular recess

8-Suprasellar Lipoma :
a) Incidence

a) Incidence :
-Suprasellar cistern lipomas have an incidence of
approximately 0.4% account for
approximately 15% of all intracranial lipomas,
third in frequency after pericallosal lipomas
and quadrigeminal cistern lipomas

1-CT :
-Suprasellar lipomas appear as small fat density
regions in the suprasellar cistern with
matching negative density measurements (-30
to -100 HU)
-No calcification is present
2-MRI :
-High signal intensity on T1

Sagittal T1 of a suprasellar lipoma , the high signal mass containing fat is seen
lying on the undersurface of the hypothalamus in the interpeduncular
cistern

9-Metastases :
-Breast cancer is by far the most common lesion
to metastasize to the parasellar region

b) Non-Neoplastic :
1-Aneurysm of ICA
2-Ectatic ICA
3-Arachnoid cyst
4-Epidermoid / Dermoid
5-Rathke's cleft cyst
6-Infundibular non-neoplastic masses :
a) Sarcoidosis

1-Aneurysm of ICA : See Parasellar Masses
-A saccular supraclinoid ICA aneurysm may mimic a suprasellar
tumor
-Although parasellar aneurysms are relatively uncommon , it is
essential never to biopsy a mass that may represent an
aneurysm
-Pulsation artifact may be present on conventional MRI
sequences , CTA or MRA would be diagnostic
2-Ectatic ICA :
-See (Intrasellar masses)

(a) CT without contrast shows a large peripherally calcified mass in the
suprasellar region , it is hyperdense , (b) CTA of the circle of Willis shows a
giant peripherally calcified ACA/Acom aneurysm , it is mostly thrombosed
with a central lumen much smaller than the outer sac

(a) T1 , (b) T2 & (c) T1+C shows In the suprasellar region , anterior to the
pituitary is a 19 x 21 x 18mm rounded mass with heterogeneous
lamellated internal signal (predominantly high T1 and very low T2)
consistent with a thrombosed aneurysm , posterosuperiorly flow void is
noted consistent with a patent aneurysm 8 x 6 x 6mm arising from the
ACA / Acom complex

3-Arachnoid Cyst (Leptomeningeal Cyst) :
-See (Brain Tumors)

CT axial view showing suprasellar arachnoid cyst with
obstructive hydrocephalus with (Mickey-mouse) appearance

4-Epidermoid / Dermoid :
Epidermoid : See (CPA Masses)
-Occur most commonly in middle-aged adults in
the CPA but can be seen less commonly in the
paraellar region
Dermoid : See (Brain Tumors)

5-Rathke Cleft cyst :
6-Infundibular Non-Neoplastic masses : (See
Intrasellar Masses)
a) Sarcoidosis
b) Langerhans Cell Histiocytosis
c) Lymphocytic Hypophysitis

Cavernous Sinus / Parasellar Masses
a) Neoplastic
b) Non-Neoplastic

a) Neoplastic
1-Schwannoma
2-Meningioma
3-Pituitary adenoma
4-Metastasis
5-Lymphoma & Leukemia
6-Invasion by skull base
tumor
7-Nasopharyngeal
carcinoma
8-Juvenile Angiofibroma
b) Non-Neoplastic
1-Aneurysm of ICA
2-Ectatic ICA
3-Cavernous sinus thrombosis
4-Carotid-cavernous fistula
5-Invasive sinusitis
6-Dermoid /Epidermoid
7-Tolosa-Hunt syndrome
8-Infundibular Non-Neoplastic
masses :
a) Sarcoidosis

a) Neoplastic :
1-Schwannoma
2-Meningioma
3-Pituitary adenoma
4-Metastasis
5-Lymphoma & Leukemia
6-Invasion by skull base tumor
7-Nasopharyngeal carcinoma
8-Juvenile Angiofibroma

1-Schwannoma :
-See (Cerebellopontine angle masses)
2-Meningioma :
-See (Cerebellopontine angle masses)
3-Pituitary Adenoma :
-Direct local invasion from the sella

4-Metastasis :
-Metastases to the CS can be hematogenous or
perineural in nature
a) Hematogenous Spread :
-Distant tumors with hematogenous spread to the
CS are generally renal , gastric , thyroid , lung and
breast cancers
-MR imaging shows CS enlargement , outward
bowing of its lateral wall and replacement of the
Meckel cave with soft tissue that homogeneously
enhances

-Axial T1+C shows an
enhancing mass
(from primary breast
carcinoma) in the
Meckel cave
(arrowhead)
-In the absence of
primary tumor
elsewhere ,
schwannoma needs
to be considered in
the differential
diagnosis

Coronal T1+C shows a classic "winking Meckel cave sign“ , the normal (left) Meckel
cave is CSF-filled , hypointense (blue arrow) , the right side is filled with an
enhancing mass that fills and expands the Meckel cave (red arrow) , patient had a
history of multiple brain metastases from a lung cell carcinoma

b) Perineural Spread :
-Perineural tumor spread is commonly seen along
branches of cranial nerve V
-Perineural spread is most commonly seen with
adenoid cystic or squamous cell carcinoma but
may also be seen with lymphoma , melanoma ,
basal cell carcinoma , rhabdomyosarcoma ,
neurogenic tumors and juvenile angiofibroma
-MR imaging features of perineural tumor spread
include nerve enlargement and enhancement
and foraminal enlargement and destruction

Trigeminal nerve (Normal anatomy)

(a) Coronal T1+C shows a thick enhancing third division (arrows) of the right
trigeminal nerve in a patient with a small adenoid cystic carcinoma in the
nasopharynx , (b) slightly posterior to (a) , the tumor has invaded the
Gasserian ganglion and fills the Meckel cave (arrow)

5-Lymphoma & Leukemia :
-As with metastases , lymphoma and leukemia
reach the CS by direct extension from a primary
lesion or from hematogenous spread
-MR imaging may show infiltrative lesions of the
skull base invading the CS without arterial
narrowing
-Lymphoma and leukemia may also appear as
diffuse enlargement and enhancement of the CS
similar to the appearance of metastases

-Although they tend to be T2 hypointense , most
have no specific MR imaging findings but the
diagnosis may be suggested because of the
clinical results
-Nowadays , most patients with known
lymphoma/leukemia who have been treated
will have clinical evidence of relapse by the
time MR imaging depicts the new lesions

T1 shows a parasellar mass lesion which is isointense

T2 shows a parasellar mass lesion which is isointense to hypointense

T1+C shows a parasellar mass lesion which is inhomogeneously enhanced

6-Invasion by Skull Base Tumors :
Chordoma and chondrosarcoma
-See (Intrasellar Masses)

T2 shows a lobulated , hyperintense lesion (arrow heads) arising from the dorsum
sellae and invading the Meckel's cave and the cavernous sinus on the right side

(a) Coronal T1+C shows a large inhomogeneous-appearing mass involving the
left CS , sella , suprasellar region , ipsilateral middle cranial fossa &
intratemporal region , the mass has a cystic lateral component , (b) Axial
T2 shows that the solid portion of the mass is hyperintense , a finding that
is typical of chondrosarcoma

7-Nasopharyngeal Carcinoma :
-The most common primary malignant extracranial
neoplasm to invade the CS
-Intracranial extension may occur directly via the
skull base erosion or by perineural spread along
branches of the trigeminal nerve
-Tumor can extend through the petro-occipital
synchondrosis and foramen lacerum into the
inferior CS or via the carotid canal to gain access
to the CS without destroying bone

-Once the CS is invaded , bulky masses are
present in the nasopharynx
-The tumor is generally hypointense to iso-
intense (relative to muscles) on T1-weighted
images and T2 hypointense and shows
moderate-to-intense contrast enhancement

-Axial T2-weighted
image shows a
relatively
hypointense mass
involving the left CS
and sella , extending
into the posterior
ethmoid air cells
-Invasive T2
hypointense masses
are generally either
neoplasias or fungal
infections

8-Juvenile Angiofibroma :
-Is a highly vascular tumor that affects mostly
adolescent boys
-It can extend into the central skull base and to the
anterior part of the CS through the foramen
rotundum , vidian canal or foramen lacerum
-The tumor can invade the CS directly by erosion of
the pterygoid bone
-The characteristic signal intensity voids on MR
imaging representing large vascular structures
are typical of this tumor

-Axial postcontrast T1-
weighted image shows
a very large tumor
involving both CSs and
surrounding the ICAs
(arrows)
-The mass extends
into the sella ,
paranasal sinuses ,
right middle cranial
fossa and both orbits
-Note flow voids
(arrowheads) due to
enlarged blood vessels

b) Non-Neoplastic : ICA & Cavernous Sinus
1-Aneurysm of ICA
2-Ectatic ICA
3-Cavernous sinus thrombosis
4-Carotid-cavernous fistula
5-Invasive sinusitis
6-Dermoid /Epidermoid
7-Tolosa-Hunt syndrome
a) Sarcoidosis

1-Aneurysm of ICA :
a) Incidence
b) Clinical Picture

a) Incidence :
-Cavernous carotid aneurysms compose 5% of giant
aneurysms (>2.5 cm in diameter)
They may produce CS syndrome by virtue of mass
effect , inflammation or rupture into the CS with
subsequent development of a CCF
-Most are idiopathic but they may occasionally be
traumatic or mycotic in nature

-A patent aneurysm shows signal intensity void on
spin-echo MR imaging sequences
-Partially thrombosed giant aneurysms show mixed
signal intensities representing various stages of
clot in their walls (due to chronic dissections) or
within their lumen
-Flowing blood through the patent portion of the
lumen appears as a signal intensity void on spin-
echo images and high signal intensity on gradient
techniques

(a) Axial T2 shows a left intracavernous ICA (A) aneurysm , note flow artifacts
(arrow) confirming the pulsatile nature of the lesions
(b) Coronal post contrast maximum-intensity image from a CTA in the same
patient shows the left intracavernous aneurysm

T2 shows a large aneurysm characterized by flow void is seen in the right cavernous
sinus

2-Ectatic ICA :

3-Cavernous Sinus Thrombosis :
a) Etiology
b) Radiographic features

a) Etiology :
-Most commonly results from contiguous spread
of infection from the sinuses or middle third
of the face or less commonly dental abscess or
orbital cellulitis
-Staphylococcus aureus is the most common
infectious microbe found in 50 - 60% of the
cases

b) Radiographic features :
-MR imaging signs of CS thrombosis include
changes in signal intensity and / or in the size
and contour of the CS , MRI with contrast is
the modality of choice
-Although subacute thrombus exhibits high
signal intensity on all pulse sequences and is
easy to recognize , acute thrombosis may be
isointense and difficult to diagnose

-Enhancement of the peripheral margins of an
enlarged CS may suggest a clot within it
-Indirect signs that help to suggest the diagnosis
are dilation of the superior ophthalmic veins ,
exophthalmos and increased dural
enhancement along the lateral border of CS
and ipsilateral tentorium
-The presence of sinusitis and appropriate
clinical symptoms confirm the diagnosis

T1+C shows meningeal enhancement consistent with meningitis (White
arrow) , swollen non-enhancing cavernous sinus . i.e. cavernous sinus
thrombosis (open arrows) , narrowed ICA (green arrows)

(a) Coronal T1+C shows an enlarged and inhomogeneous appearing right CS
that contains areas of low signal intensity (arrow) compatible with clot
(b) Coronal T1+C in a different patient shows a large nonenhancing clot
expanding the left CS , the ipsilateral ICA is slightly narrowed

4-Caroticocavernous fistula :
a) Definition
b) Etiology
c) Clinical Picture
d) Classification
e) Radiographic Features

a) Definition :
-Represent abnormal communication between
the carotid circulation and the cavernous
sinus

b) Etiology :
-Direct CCFs are often secondary to trauma ,
most commonly seen in the young male
patients , presentation is acute and symptoms
develop rapidly
-In contrast , indirect CCFs have a predilection
for the postmenopausal female patient and
the onset of symptoms is often insidious

c) Clinical Picture :
1-Pulsatile exophthalmos / proptosis : 75 %
2-Chemosis and subconjunctival haemorrhage
3-Progressive visual loss : 25-32 %
4-Pulsatile tinnitus ( usually objective )
5-Raised intracranial pressure
6-subarachnoid haemorrhage, intracerebral
hemorrhage , otorrhagia, epistaxis : 2.5-8.5 %

d) Classification :
-It can be broadly classified into two main types
1-Direct : Direct communication between intra-
cavernous ICA and cavernous sinus
2-Indirect : Communication exists via branches
of the carotid circulation ( ICA or ECA )

-Another method is to classify according to four
main types :
Type A : Direct connection between the
intracavernous ICA and CS
Type B : Dural shunt between intracavernous
branches of the ICA and CS
-Type C : Dural shunt between meningeal
branches of the ECA and CS
-Type D : B + C

Direct : type A
-A direct fistula is due to a direct communication
between the intracavernous ICA and the
cavernous sinus
-There are a number of causes , however
aneurysm rupture and trauma are by far the
most common

Indirect : types B , C & D
-Indirect fistulas are due to communication by
multiple branches between the ICA / ECA and CS
-The are most frequent are type C , with meningeal
branches of the ECA forming the fistula
-They are postulated to occur secondary to
cavernous sinus thrombosis with
revascularization
-Other predisposing factors appear to be pregnancy
, surgical procedures in the region , sinusitis

e) Radiographic Features :
1-CT
2-MRI
3-Catheter Angiography

1-CT :
-Proptosis
-Enlargement of cavernous sinus , enlarged
superior ophthalmic veins
-Extra ocular muscles may be enlarged
-Orbital edema
-May show SAH / ICH from ruptured cortical
vein

2-MRI :
-Findings of CCFs include a dilated CS with multiple
signal intensity void structures that are
associated with proptosis and an enlarged
superior ophthalmic vein
-On gradient-echo images , these flow voids shows
high signal intensity , the presence of flow-
related enhancement in the CS on MR
angiography suggests the diagnosis in the right
clinical setting

-Other supporting findings are a dirty
appearance of the retro-orbital fat and
enlargement of the extraocular muscles , due
to the presence of intracavernous
communications , very high-flow fistulas may
result in enlargement of both CSs

3-Catheter Angiography :
-Rapid shunting from ICA to CS
-Enlarged draining veins
-Retrograde flow from CS , most commonly into the
ophthalmic veins

ICA to a CS fistula , axial source image from an MRA shows flow-
related enhancement in the medial (arrow) left CS from a direct-
type fistula

MRA shows an enlarged superior ophthalmic vein (arrow)

MRA shows a right carotid cavernous fistula (arrow)

5-Invasive Sinusitis :
-Invasive aspergillosis may affect the sphenoid sinus
in immunocompromised patients and may
extend intracranially with invasion of the CS
-This infection shows low signal intensity on both
T1 and T2 which is attributed to the presence of
ferromagnetic elements and calcium in the fungal
and mucous concretions
-It exhibits intense inhomogeneous contrast
enhancement

(a) Coronal T1+C shows involvement by aspergillosis of the mucosa in the left sphenoid sinus
(white arrow) which extends laterally and has resulted in thrombosis of the adjacent CS
(black arrow) , the intracavernous ICA (arrowhead) is narrowed and its walls are significantly
thickened
(b) In a different patient , an axial T1+C shows enhancing mucosa in the right sphenoid sinus with
enhancing soft tissues in the ipsilateral CS (including the Meckel cave) , with narrowing of the
ICA and significant thickening of its walls

6-Epidermoid / Dermoid :
-See Suprasellar Masses

(a) Axial T1+C shows a large mass (E) epidermoid cyst inside the right the Meckel
cave , the mass does not enhance and is nearly isointense to CSF
(b) Axial T2 shows that the mass (E) is nearly as bright as CSF

(a) T1 shows a heterogenous T1 hyperintense lesion (arrows) in Meckel’s cave and the cavernous
sinus , note the presence of T1 hyperintense droplets (arrow heads) on the cerebellar folia ,
(b) Axial fat saturated T1+C shows the signal of the mass is suppressed and no enhancement
is seen (arrows) , ruptured dermoid cyst

7-Tolosa-Hunt syndrome :
-Is a term applied to a retro-orbital
pseudotumor extending to the CS
-Its clinical triad includes unilateral
ophthalmoplegia (pain) , cranial nerve palsies
and a dramatic response to systemic
corticosteroids
-The process is usually unilateral but may be
bilateral (5%)

-MR imaging findings include an enlarged CS
containing abnormal soft tissues that are
isointense to muscle on T1-weighted images
and dark or bright on T2-weighted images and
display contrast enhancement with focal
narrowing of the ICA

(a) Axial T2 shows hypointense soft tissue throughout the right CS and
extending into the superior orbital fissure
(b) Coronal T1+C shows that the abnormal soft tissue enhances prominently
and diffusely and involves the Meckel cave

a) Sarcoidosis

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