Clinical brain tumor of MRI Clinical brain tumor of MRI

放射診斷科孫柏齡 2007.04.202007.04.20

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Case 1Case 1

Clinical History:Clinical History: 17-year-old female with a clinical suspicion 17-year-old female with a clinical suspicion

of cerebellar mass.of cerebellar mass.

Your diagnosis isYour diagnosis is

Radiologic Findings:Radiologic Findings: A T1W image (Fig. 1) shows a hypointense, approximateA T1W image (Fig. 1) shows a hypointense, approximate

ly 7cm x 4cm mass in the right cerebellar hemisphere, wily 7cm x 4cm mass in the right cerebellar hemisphere, with a moderate amount of mass effect on the 4th ventricle th a moderate amount of mass effect on the 4th ventricle and cerebellum. and cerebellum.

The mass is hyperintense on the T2W image (Fig. 3). The mass is hyperintense on the T2W image (Fig. 3). The cystic portion of the mass has signal intensity similar The cystic portion of the mass has signal intensity similar

to CSF on the T1W images and T2W images, but is hypto CSF on the T1W images and T2W images, but is hyperintense to CSF on the proton density weighted image erintense to CSF on the proton density weighted image (Fig. 2) due to increased protein content. (Fig. 2) due to increased protein content.

Following Gadolinium administration, T1W images (Fig. Following Gadolinium administration, T1W images (Fig. 4-6) show intense homogeneous enhancement of a mur4-6) show intense homogeneous enhancement of a mural nodule in the superior aspect of the mass. al nodule in the superior aspect of the mass.

Although septations within the mass show faint enhanceAlthough septations within the mass show faint enhancement, the cystic portion of the mass does not show enhament, the cystic portion of the mass does not show enhancement. ncement.

Diagnosis:Diagnosis:

Juvenile pilocytic astrocytoma. Juvenile pilocytic astrocytoma.

Discussion:Discussion:

Cerebellar juvenile pilocytic astrocytomas are the most cCerebellar juvenile pilocytic astrocytomas are the most common infratentorial neoplasm in the pediatric age grouommon infratentorial neoplasm in the pediatric age group. p.

Although they commonly form well-defined lobular massAlthough they commonly form well-defined lobular masses which contain cysts and a vascular mural nodule, they es which contain cysts and a vascular mural nodule, they may occasionally present a solid mass without a cystic cmay occasionally present a solid mass without a cystic component and may simulate other pediatric posterior fosomponent and may simulate other pediatric posterior fossa masses. sa masses.

They have an increased incidence in type I neurofibromaThey have an increased incidence in type I neurofibromatosis. tosis.

They have an excellent prognosis following complete resThey have an excellent prognosis following complete resection. ection.

The differential diagnosis includes medulloblastoma and The differential diagnosis includes medulloblastoma and ependymoma in a child. ependymoma in a child.

Case 2Case 2

Clinical History:Clinical History:3-year-old presents with headache and ata3-year-old presents with headache and ata

xia.xia.

Your Diagnosis is?Your Diagnosis is?

Diagnosis:Diagnosis:

Ependymoma. Ependymoma.

Findings:Findings: Axial CT image demonstrates a right cerebellar and fourtAxial CT image demonstrates a right cerebellar and fourt

h ventricle mass which is somewhat higher in attenuation h ventricle mass which is somewhat higher in attenuation than the remaining brain parenchyma. than the remaining brain parenchyma.

In addition, there is marked dilatation of the temporal horIn addition, there is marked dilatation of the temporal horns indicating hydrocephalus. ns indicating hydrocephalus.

Axial T1 and T2 weighted images as well as a sagittal imAxial T1 and T2 weighted images as well as a sagittal image following the intravenous administration of contrast dage following the intravenous administration of contrast demonstrates an approximately 4 cm fourth ventricular maemonstrates an approximately 4 cm fourth ventricular mass with probable extension toward the outlets of the fourtss with probable extension toward the outlets of the fourth ventricle. h ventricle.

There is very little enhancement following the intravenouThere is very little enhancement following the intravenous administration of contrast. s administration of contrast.

Discussion:Discussion: Ependymomas are the third most common brain tumor in children aEpendymomas are the third most common brain tumor in children a

nd account for approximately 15% of posterior fossa malignancies. nd account for approximately 15% of posterior fossa malignancies. They classically arise from ependymal cells lining the fourth ventriclThey classically arise from ependymal cells lining the fourth ventricl

e. Commonly, the tumor expands the fourth ventricle and extends the. Commonly, the tumor expands the fourth ventricle and extends through the foramen of Magendie and through the foramina of Luschkrough the foramen of Magendie and through the foramina of Luschka. a.

The tumors are often calcified and may demonstrate a large cystic cThe tumors are often calcified and may demonstrate a large cystic component. omponent.

Inhomogeneous enhancement is usually seen. Because of their locaInhomogeneous enhancement is usually seen. Because of their location, seeding throughout the subarachnoid space can be seen. tion, seeding throughout the subarachnoid space can be seen.

Supratentorial ependymomas, however, are usually more aggressivSupratentorial ependymomas, however, are usually more aggressive and have a poorer prognosis. e and have a poorer prognosis.

As stated above, ependyomomas are the third most common posterAs stated above, ependyomomas are the third most common posterior fossa tumor in childhood behind juvenile pilocytic astrocytomas aior fossa tumor in childhood behind juvenile pilocytic astrocytomas and medulloblastomas.nd medulloblastomas.

Case 3Case 3

History:History:10-year-old presented with 10 days of vom10-year-old presented with 10 days of vom

iting, unsteady gait, slurred speech, headaiting, unsteady gait, slurred speech, headache, and diplopia.che, and diplopia.

Your diagnosis isYour diagnosis is

Diagnosis: Diagnosis:

Medulloblastoma (PNET).Medulloblastoma (PNET).

Findings: Findings: A sagittal noncontrast T1W image (Image 1) reveals a miA sagittal noncontrast T1W image (Image 1) reveals a mi

ldly hypointense mass arising in the 4th ventricle with exldly hypointense mass arising in the 4th ventricle with expansion posteriorly to displace and distort the vermis. pansion posteriorly to displace and distort the vermis.

An axial T1-weighted image after contrast (Image 2) demAn axial T1-weighted image after contrast (Image 2) demonstrates the loss of definition of the peripheral borders oonstrates the loss of definition of the peripheral borders of the enhancing 4th ventricular mass. f the enhancing 4th ventricular mass.

No additional abnormalities in the periventricular or subarNo additional abnormalities in the periventricular or subarachnoid space are identified. achnoid space are identified.

The mass is hyperintense to gray and white matter on an The mass is hyperintense to gray and white matter on an axial T2-weighted image (Image 3). There is a shunt undaxial T2-weighted image (Image 3). There is a shunt under the right occipitotemporal scalp.er the right occipitotemporal scalp.

Discussion: Discussion: Medulloblastoma represents about 25% of childhood intrMedulloblastoma represents about 25% of childhood intr

acranial tumors, with approximately 50% presenting in thacranial tumors, with approximately 50% presenting in the first decade. e first decade.

Medulloblastoma occurs only in the posterior fossa, althoMedulloblastoma occurs only in the posterior fossa, although it has been grouped with histologically similar tumors ugh it has been grouped with histologically similar tumors arising elsewhere as a primitive neuroectodermal tumor arising elsewhere as a primitive neuroectodermal tumor (PNET).(PNET).

Medulloblastoma generally involves the 4th ventricle and Medulloblastoma generally involves the 4th ventricle and vermis, with a lateral location more common in the desmvermis, with a lateral location more common in the desmoplastic variant and in older patients. oplastic variant and in older patients.

On MR, medulloblastoma involves the 4th ventricle and vOn MR, medulloblastoma involves the 4th ventricle and vermis, although eccentric extension to involve the cerebeermis, although eccentric extension to involve the cerebellar hemispheres is not rare. llar hemispheres is not rare.

It is nonspecifically hypo- to isointense on T1W images aIt is nonspecifically hypo- to isointense on T1W images and hyperintense on T2W images. nd hyperintense on T2W images.

MedulloblastomaMedulloblastoma EpendymomaEpendymoma AstrocytomaAstrocytoma

Unenhanced CTUnenhanced CT HyperHyper IsoIso HypoHypo

EnhancementEnhancement ModerateModerate MininalMininal Nodule enhance, cyst Nodule enhance, cyst dose notdose not

CalificationCalification UncommonUncommon commoncommon UncommonUncommon

OriginOrigin VermisVermis 4th ventricle epend4th ventricle ependyomayoma

HemisphericHemispheric

T2WIT2WI IntermediateIntermediate IntermediateIntermediate BrightBright

AgeAge 5-125-12 2-102-10 10-2010-20

Cyst formationCyst formation 10-20%10-20% 15%15% 60-80%60-80%

Foraminal spreaForaminal spreadd

NoNo Yes(Luschka, MagYes(Luschka, Magendie)endie)

NoNo

TESTTEST

What is the most common infratentorial neWhat is the most common infratentorial neoplasm in the pediatric age group? oplasm in the pediatric age group?

Q&AQ&A

1.請問Medulloblastoma、 Ependymoma、 Astrocytoma在 CT上表現特徵差異為何 ?

答 : Medulloblastoma由於密度比較高，所以 CT表象比較亮