Central nervous system
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Central nervous system. Central nervous system Radiology college Guanghui Yu. DWI. A B. Normal tissue Brown's movement or diffusion Movement of hydrones at random. Cytotoxic edema

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Central nervous system
Central nervous system

Central nervous system

Radiology college

Guanghui Yu


DWI

A B

Normal tissue

Brown's movementor diffusion

Movement of hydrones at random

Cytotoxic edema

Brown's movement of hydrones

restricted

hydrone

Cell


Tumor
Tumor

Tumor


Brain neoplasm
Brain Neoplasm

  • Neural

    tissue

Neoplasm

Neuron

permanentcell

rare

Astrocyte

Oligodendrocyte

Ependymal cell

astrocytoma

Glial cell

oligodendroglioma

ependymoma


Brain neoplasm1
Brain Neoplasm

Brain Neoplasm

  • About 80~85% of all intracranial tumors occur in adults

  • the majority are situated in the supratentorial compartment

  • the most common intra-axial supratentorial neoplasm is the glioblastoma, while metastasis is the most common intra-axial tumor of the posterior fossa


Brain neoplasm2
Brain Neoplasm

  • Primary cerebral gliomas account for 40~45% of all intracranial tumors

  • Adult gliomas are mainly supratentorial in location, whereas in children 70~80% are infratentorial

  • MRI is superior to CT in terms of both tumor detection and delineation

  • Enhancement after contrast injection is better evaluated by MR owing to its superior sensitivity


Brain neoplasm3
Brain Neoplasm

Astrocytoma

  • According to haemorrhage, calcification, edema around tumor, degree of enhancement, astrocytomas are divided into grade I-IV


Brain neoplasm4
Brain Neoplasm

grade I-II

Axial CT without and with intravenous injection of contrast medium. Nonenhancing, hypodense space-occupying lesion infiltrates part of the temporal lobe and insula on the right side. Two arrows indicate the compressed and displaced middle cerebral artery branches within the insular portion of the sylvian cistern


Brain neoplasm5
Brain Neoplasm

grade I-II

axial T2WI. Marked hyperintensity of the tumor due to the high water content of the neoplastic cells. coronal T1WI The tumor is markedly hypointense. Arrowheads point on the right side at the elevated sylvian fissure by the enlarged temporal lobe.


Brain neoplasm6
Brain Neoplasm

grade I-II

axial T2WI Left cerebellar hemispheric pilocytic astrocytoma, partially cystic.The nodular component is isointense. The tumor grows toward the cerebellopontine angle cistern. coronal T1WI. and with isointense nodular components. coronal T1WI following contrast injection. Enhancement of the nodular components




Grade iii iv1
grade III-IV

Infiltrating astrocytomas with ill-defined margin


Meningioma

  • Meningioma arise from specialized meningothelial cells mainly in arachnoid granulations

  • These tumors mostly affect adults with a strong female predilection (2:1 over males) and are rare in childhood

  • Gross pathology shows two basic configurations: an oval or lobulated mass with a broad-based attachment to the dura ; or a flattened, linear lesion extending along the dura

  • Several factors produce tumor heterogeneity: tumoral vascularity, cystic foci and calcifications


  • Ninety percent are supratentorial

  • frequently cause hyperostosis of the inner table and can extensively penetrate the skull, causing marked thickening of the bone and osteoblastic reaction ;bone erosion is rare

  • Brain oedema develops in approximately 50% of meningiomas

  • Their preferential locations are as follows: parasagittal or attached to the sagittal sinus (25%); the convexity (20%); sphenoid wings (15~20%); parasellar (5~10%); olfactory grooves (2~10%) ; Ten percent are infratentorial and arise from the petrous bone in the cerebellopontine angle, the clivus, the tentorium ; Rarely meningiomas are intraventricular, or arise from the optic nerve sheath



hyperdense to the dura at an obtuse angle. Most lesions are homogeneously hyperdense, some isodense and a few hypodense


Marked homogeneous enhancement to the dura at an obtuse angle. Most lesions are homogeneously hyperdense, some isodense and a few hypodense


MRI to the dura at an obtuse angle. Most lesions are homogeneously hyperdense, some isodense and a few hypodense

  • Isointensity on both T1WI and T2WI

  • Sixty percent of meningiomas have a "dural tail" of enhancement

  • Marked homogeneous enhancement


Axial T2 to the dura at an obtuse angle. Most lesions are homogeneously hyperdense, some isodense and a few hypodense WI. Frontoparietal extra-axial space-occupying lesion attached to the falx and the dura of the convexity, on the right side, reaching the midline. The paracentral lobule as well as the most cranial portion of the motor and sensory convolutions are compressed. No significant peritumoral oedema


Dural tail to the dura at an obtuse angle. Most lesions are homogeneously hyperdense, some isodense and a few hypodense

MR T1-weighted sagittal image, following intravenous injection of contrast. Marked homogeneous enhancement of the lesion.


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