INTRACRANIAL NEOPLASMS - Oregon Health Science University：颅内肿瘤-俄勒冈健康与科学大学.pptVIP

PRIMARY INTRACRANIAL NEOPLASMS Monika Arora, MS 4 Lyudmila Morozova, MS 4 Imaging for Brain Tumors1 Skull X-rays: Rarely necessary. Useful in demonstrating calcification, erosion, or hyperostosis CT: Most widely used for diagnosis of brain tumors Will detect 90% of tumors, but might miss: Small Tumors (0.5 cm) Tumors Adjacent to bone (pituitary adenomas, clival tumors, and vestibular schwannomas) Brain Stem Tumors Low Grade Astrocytomas More sensitive than MRI for detecting acute hemorrhage, calcification, and bony involvement MRI: Preferred for follow-up of most brain tumors More sensitive than CT scans Can detect small tumors Provides much greater anatomic detail Especially useful for visualizing skull base, brain stem, posterior fossa tumors Infratentorial vs Supratentorial Tumors SUPRATENTORIAL TUMORS3 Meningiomas Gliomas Astrocytomas Glioblastoma Multiforme Oligodendrogliomas Germinomas Colloid Cysts of Third Ventricle MENINGIOMA1,2,3 Epi: 2nd most common primary brain tumor after gliomas, incidence of ~ 6/100,000 Usual age 40-70 FM Facts: Arise from arachnoidal cap cell type from the arachnoid membrane Usually non-invasive Associated with NF-2 Location: Parasagittal region Sphenoid wing Parasellar region Presentation: Asymptomatic Symptomatic: focal or generalized seizure or gradually worsening neurologic deficit MENINGIOMA1 On Imaging CT: isodense or hypodense, homogenous extra-axial mass with smooth or lobulated, clearly demarcated contours which enhance homogenously and densely with contrast Frequently have areas of calcification and produce hyperostosis of adjacent bone. GLIOMAS Arise from Glial Cells Astrocytomas Astocytomas fall on a gradient that ranges from benign to malignant Oligodendrogliomas ASTROCYTOMA1,2,3: Diffuse Low Grade Astrocytoma Epi: 15% of Astrocytomas Young Adults Facts: Widely Infiltrate surrounding tissue Location: Frontal Region Subcortical white matter Presentation: Seizures Headache Slowly progressive ne