3. A-Genu of the
Corpus Callosum
B-Anterior Horn of
the Lateral Ventricle
C-Internal Capsule
D-Thalamus
E-Pineal Gland
F-Choroid Plexus
G-Straight Sinus
9. 1-Benign Cyst :
a) Incidence
b) Radiographic Features
c) Differential Diagnosis
10. a) Incidence :
20-30 years of age, more in women
-Simple cystic structure within the gland
measuring < 1.5 cm
-Unlikely to be significant when no mass effect
and when there are no relevant symptoms
11.
12. b) Radiographic Features :
*CT :
-Well circumscribed fluid density lesions with
thin rim calcification seen in 25%
-Some peripheral enhancement is also often
seen
-The internal cerebral veins are elevated and
splayed by the cyst
13.
14. *MRI :
-Slightly higher signal than CSF on all sequences
-A common incidental finding on MRI studies
*T1 :
-Typically iso to low signal compared to brain
parenchyma
-55 to 60% are somewhat hyperintense when
compared to CSF
-Generally homogenous signal
15.
16.
17.
18.
19. *T1+CApproximately 60% of lesions enhance
-Enhancement is usually thin (< 2mm) and
confined to the rim (either complete or
incomplete)
-It is important to note that if post contrast
imaging is delayed (60 - 90min), gadolinium
may diffuse into the cyst fluid and may lead
to the mass appearing solid
:
-
20.
21.
22. c) Differential Diagnosis :
-A differential consideration is Pineocytoma
which would shows internal enhancement and
may have cystic component, however a truly
cystic Pineocytoma is considered very rare
23. 2-Germ Cell Tumors :
a) Germinoma (most common)
b) Teratoma
c) Embryonal Cell Carcinoma
d) Choriocarcinoma
24. a) Germinoma :
1 Incidence
2Radiographic Features
3-Tumor Markers
25. 1-Incidence :
-Most common pineal germ cell tumor (equivalent to
seminoma in testes and dysgerminoma in ovary)
-Males predominate (10:1), age 10 to 30 years
-In females, more commonly located in suprasellar location
-Serum markers (alpha-fetoprotein) may also be
positive
26. 2-Radiographic Features :
a) CT
-Well defined slightly hyperdense mass that
engulfs a prominent calcified pineal gland
-Homogeneous intense enhancement
-Central calcification due to pineal engulfment
(rare)
27.
28.
29.
30.
31. b) MRI
-T1 : isointense or slightly hyperintense to adjacent
brain
-T2 : isointense or slightly hyperintense to adjacent
brain, may have areas of cyst formation, central
calcification appears low signal (engulfed pineal
gland)
-T1+C : vivid and homogeneous
38. 1-Incidence :
-Second most common pineal germ cell tumor
-Almost exclusively in male children
-The most common congenital intracranial
tumor and are usually diagnosed prenatally
-Presence of fat and calcification is
diagnostically helpful with little to no
enhancement
39. 2-Radiographic Features :
*CT :
-Demonstrates at least some fat and some
calcification which is usually solid / clump like
-They usually have cystic and solid components,
contributing to an irregular outline, solid
components demonstrate variable
enhancement
40.
41. CT+C , there is relatively homogeneous enhancement of the non-calcified
solid portions of the tumor , the cystic region doesn’t enhance
42. *MRI :
-T1 :
-Hyperintense components due to fat and
proteinaceous / lipid rich fluid
-Intermediate components of soft tissue
-Hypointense components due to calcification and
blood products
-T2 :
-Mixed signal from differing components
-T1+C :
-Little or no enhancement
-Solid soft tissue components show enhancement
46. 3-Choriocarcinoma, Yolk Sac Tumors and
Embryonal Carcinoma :
-Are rare neoplasms
-These neoplasms may have imaging findings
similar to those of other germ cell neoplasms or
primary pineal neoplasms
-Evaluation of tumor markers assists in making the
appropriate diagnosis
-These lesions may also hemorrhage - resulting in
T1 shortening
47. a)Sagittal T1 weighted MR
image shows an
heterogeneous pineal region
mass with foci of T1
shortening due to
hemorrhage , note the
associated hydrocephalus
b)Axial postcontrast T1-
weighted MR image shows
that the pineal region mass
also has an heterogeneous
enhancement with foci of
necrosis/cyst , involvement of
the tectal plate and both
thalami are also present (not
shown) , evaluation of serum
oncoproteins demonstrated
high level of b-hCG , biopsy of
the lesion revealed that it
corresponds to
Choriocarcinoma
50. a) Pineocytoma :
-No male predilection
-Older age group, mean age 35 years
-Slow growing, dissemination is uncommon
-No helpful imaging features, cannot be
distinguished by imaging features from a
Pineoblastoma
51.
52. CT+C shows homogenous enhancement of the mass which assumes a
triangular shape as it conforms to the contours of the pulvinar of
the thalami and velum interpositum
56. b) Pineoblastoma :
-Highly malignant PNET (Primitive Neuroectodermal
Tumors)
-In patients with trilateral retinoblastoma, Pineoblastoma
may develop in patients with familial and or bilateral
retinoblastoma
-(Exploded calcifications) along outside of mass
(peripherally), unlike germinoma which engulfs and
induces calcification of the pineal gland
-Dense enhancement
-Larger, more heterogeneous with much greater
propensity for local invasion and CNS dissemination
57.
58.
59.
60. Axial nonenhanced CT shows a large pineal region mass with resultant hydrocephalus ,
the pineal calcifications are exploded toward the periphery (arrows)
64. b) Extrinsic Pineal Mass :
1 Gliomas
2Vein of Galen Aneurysm
3-Meningioma
4-Quadrigeminal Plate Lipoma
65. 1-Gliomas :
-Gliomas (most commonly astrocytomas) of
varying grade may occur in adjacent intra-axial
structures such as the tectum, midbrain or
splenium of the corpus callosum
Tectal Glioma :
a) Incidence
b) Radiographic Features
66.
67. a) Incidence :
-Tectal plate gliomas are encountered in
children and adolescents
-Usually low grade tectal tumor causing
aqueduct stenosis
-Typically low grade astrocytoma with good
prognosis
68. b) Radiographic Features :
-CT :
-Typical CT finding is homogenous expansion of
tectal plate, isodense to grey matter with
minimal enhancement in postcontrast image
71. -MRI :
-Typically the tumors demonstrate expansion of the
tectal plate by a solid nodule of tissue
*T1 :
-Iso to slightly hypointense to grey matter
*T2 :
-Hyperintense to grey matter
*T1+C :
-Usually no enhancement
-Higher grade tumors tend to be larger and tend to
enhance more vividly
73. T2 FLAIR shows a tectal mass leading to obliteration of the
cerebral aqueduct
74. T1+C shows a slightly hypointense tectal mass which does not
enhance , the mass obstructs the aqueduct and is stable over
8 years
75. 2-Vein of Galen Aneurysm :
-Despite the name, a vein of Galen aneurysm
isn’t a true aneurysm, instead, it represents
dilatation of the vein of Galen due to an
arteriovenous fistula between the anterior or
posterior circulation and the venous plexus
leading to the vein of Galen
76.
77. 3-Meningioma :
-The tentorial apex, adjacent to the pineal gland,
is a characteristic location for meningioma
-The tentorial meningioma tends to depress the
internal cerebral veins, in contrast to a pineal-
based mass which typically elevates the
internal cerebral veins
78.
79. 4-Quadrigeminal Plate Lipoma :
-At CT, lipomas have low attenuation, consistent
with fat
-At MR imaging, they have the same signal
characteristics as fat (hyperintense on T1 with
saturation on fat-saturated images)
-No enhancement is seen on postcontrast
images
80. Quadrigeminal plate lipoma , (a) axial T1 , (b) sagittal T1 show a lobulated ,
hyperintense mass of the quadrigeminal plate , note the associated
thinning of the posterior body (arrow) and splenium of the corpus
callosum
