Neuroradiology Flashcards
Imaging techniques that can be used
Xray
CT - emergencies
MRI - better tissue contrast
US - via fontanelle in neonates
CT
Axial slices
With/without contrast
5-10mins in total - 30s scan
Can monitor patients closely when anesthetised/unconscious
White - dense
Black - air
MRI
Imaging water and fat With/without contrast Tissue contrast is more sensitive -cerebral edema - acute inflammation -gliosis - scarring -encephalitis -demyelination -acute infarcts
Limited availability
Bone is black
T1 - fat is bright
T2 - water is bright
Proton density, FLAIR (T2 like with dark CSF)
CI
- claustrophobia
- metallic implants
Cerebral angiography
Can be done under LA in IR
-contrast catheter via femoral
Risk of stroke - dislodging atheroma
When would you image
Headache - new onset/changed pattern
-acute headache => meningitis, encephalitis, cerebral abscess, SAH, brain tumour?
TIA, stroke Epilepsy, fits MS Coma Trauma
Meningitis headache
- findings in meningitis
- findings in complications of meningits
Generally nothing found but done to assess for high ICP before LP
Complications of meningitis which can be found
- hydrocephalus
- empyema (found with contrast)
Encephalitis headache
Most common cause - herpes simplex
CT normal in 1st few days
MRI more sensitive
-edema, swelling in temporal (with HSV)
-hermorrhage
Cerebral abscess
- sources of infection
- findings on CT
From
- direct extension from sinus, mastoid, OM, trauma
- haematogenous in IVDU, suppurative lung disease
Mass lesion at grey white interface due to narrowing of blood vessels here - enhanced with contrast
SAH
- most common causes
- findings on CT
Rupture of berry aneurysm from CofW
AVM - abnormal tangled connection between the arteries and veins
trauma
CT findings
- high density in cisterns
- communicating hydrocephalus
- if CT -ve => LP (xanthochroma)
Initial management - cerebral angio within first 24hrs
-nimodipine given to reduce risk of vasospasm limiting blood supply to brain
Brain tumour
- most common types
- presentations
MRI
Most common
Glioma (most common type = astrocytoma)
-high grade - more visible
-low grade - less visible
Meningiomas - benign
-well defined, avid enhancement
Mets - from breast, lung
-ring enhancing at grey white interface, edema
Headache + neuro deficit/seizures
TIA, stroke
TIA - ischemic events that resolve
Investigations - assess for cause
- carotid doppler US
- MRI
- echo
CT ASAP
- infarction CT may initially be normal
- 1 day - swelling, mass effect
- 3wks - swelling reduces, gliosis (low density)
Lacunar infarct - lenticulostriate vessels supply deep brain structures
-in HTN => LS vessels thicken and occlude
Epilepsy and fits
Most patients with epilepsy have normal CT
Intractable seizures - MRI hippoocampal sclerosis
Additional features can suggest the possible cause of the seizures
MS
Clinical diagnosis
MRI - periventricular white matter (inflammation around the course of the vessels in the brain
Coma
CT dictated by history
- hypoglycemia, uremia
- trauma
- massive stroke
Trauma
CT Absolute indications -decreased consciousness -focal neuro signs -seizures -depressed, open, basal skull fractures
Relative indications
- persistent/severe headache
- vomiting
- TLOC
- amnesia
Complications
- acute EDH (lentil), SDH (bright banana)
- chronic SDH (dark banana)
- cerebral contusion
