Part2 infection and tumor Neuro Part2 infection and tumor

Infection Meningitis Cerebritis, encephalitis Brain abscess

Meningitis Most common CNS infection Adult: Pneumococci Routes of infection: - Hematogenous spread - Local extension from extracerebral infection - Direct implantation Hematogenous

Meningitis NCCT Normal (early stage) Increased density in subarachnoid space (exudate in CSF space) Dilatation of ventricular system (communicating + obstructive type hydrocephalus)

Meningitis CECT Leptomeningeal enhancement

CECT Leptomeningeal enhancement: sylvian,interpeduncular, folia of cerebellum

Meningitis Complication Hydrocephalus Subdural effusion / empyema Cerebritis / cerebral abscess Ependymitis Arterial / venous thrombosis

3 1 2 5 Hydrocephalus 4

precontrast Brain abscess Enhancing wall Post contrast

Tuberculous Infection Hematogenous spread (Lung) 1) Meningitis 2) Tuberculoma

TB meningitis Imaging: NCCT: Thick fibroexudate in basal cistern Impaired CSF absorption → hydrocephalus Imaging: NCCT: Obliteration of basal cistern by exudative content Ventricular system dilatation Hypodense areas of cerebral infarction (basal gg. and thalamus)

TB meningitis CECT: Leptomeningeal enhancement thick in cistern

Tuberculoma Associated with TB meningitis about 50% Solitary 70%, multiple 30-60% Location: - Adult: basal ganglia - Children: cerebellum - gray-white junction

Tuberculoma Findings: NCCT Iso-hyperdense lesion with edema CECT Nodular, ring or irregular enhancement

Chest: infiltration

TB meningitis with Tuberculoma NCCT CECT

TB meningitis with Tuberculoma CECT

Cerebritis/abscess Neonate, infant : occurs as complication from bacterial meningitis Location: - Corticomedullary junction - Frontal and parietal lobes are most common 4 stages: early-late cerebritis (0-2 wks) early-late abscess (2-4wks)

Imaging Cerebritis: NCCT Ill-define hypodensity area CECT Increase enhancement area or gyral enhancement

Imaging Abscess: Well-defined hypodensity (fluid density) with ring enhancement, surrounding vasogenic edema Ring enhancement of brain abscess Uniform thickness Thin wall

Ring enhancement Abscess Metastasis Primary tumor (anasplastic astro-GBM) Resolving hematoma Subacute infarction neurocysticercosis

Brain Tumor Is there a mass lesion? Is it intra-axial or extra-axial?

Extra-axial Vs Intra-axial

Imaging Intra-axial Extra-axial Round shaped Surrounding by parenchyma No bony change Vasogenic edema Extra-axial Broad- based Attachment to meninges, bone Adjacent bony changes Ipsilateral widening of CSF cleft Pushing mass effect Buckling gray-white matter

Broad-based lesion, Buckling, less edema Meningioma Extra-axial

Intra-axial Glioblastoma

Brain metastasis Parenchyma: corticomedullary junction Leptomeningeal skull

Brain metastasis NCCT Hypodense Hyperdense (GI tract, choriocarcinoma, melanoma, leukemia, lymphoma) Isodense (rare) Surrounding vasogenic edema Multiple lesions

Brain metastasis CECT Increased enhancement - nodular - ring enhancement (thick, irregular wall) Leptomeningeal enhancement

Parenchymal metastases NECT CECT Parenchymal metastases

Metastasis Leptomenigeal metastasis