CT as is very good at showing fresh blood as bright and allows us to rule out a haemorrhage
First imaging modality for anyone suspected of a brain bleed and why?
Because haemorrhagic stroke is managed with no tpa as opposed infarct stroke
Why do we care so much about haemorrhage v infarct and thus use CT?
Whether bleed is extra-axial/parenchymal means it is around the blood and usually comes from large vessel rupture/aneurysm as opposed to intra which is bleed into brain itself usually from small vessel disease/HTN
Difference in location of brain bleeds and how they differ from casue?
Will get bright bleeds often on basal side of brain around circle of willis or inbetween sulci, enough pressure can bleed into brain itself/ventricles
Where/how does blood from subarachnoid bleed typically show on CT? How can it develop?
CT angiogram to find source of bleed/aneurysm, catheter angiogram
Key to follow up once haemorrhage is found?
Trauma as will have bleed at coup and cotra-coup positions
What can create a weird/multi-pattern of subarachnoid bleeds?
Will often see now change mainly just looking for no haemorrhage, bright visible vessel due to occlusion causing backlog
How will a fresh stroke often appear on CT? Although we can get waht?
What is going on here?
Flow analysis CT to see movement of fluid sort of like a doppler, will have an area with low flow and a gradient of increasing flow around it
New era method for quickly analysising stroke area on CT?
Angiogram to find occlusion and use stent/clot retrieval, follow up to ensure flow is returned
Key to follow up once stroke is found/suspected post CT? What we do?
Stroke that has begun to infarct and thus have lost grey-white matter differentiation, will get darker and darker until liquefactive necrosis leaves a small dark area
What is going on here? How will it change as it develops?
May get enough edema to cause hydrocephalus and even midline shift that requires craniotomy to reduce pressure
Although the infarcted area eventually shrinsk on CT post infarct how can a currently necrosising area affect the brain?
MRI on DWI that makes edematous change extremely obvious
What is this imaging modality as an alternative to CT for stroke?
Pineal gland and ventricles
Two common areas on CT to appear bright due to calficification not bleeding?
Posterior fossa and basal ganglia esp thalamus just lateral of third ventricle
TWo very common spots for haemorrhagic stroke to occur secondary to HTN?
Minimal hemiplegia more cerebellar ataxia and dysarthria from temporal lobe effects
How do posterior fossa strokes change in presentation?
Bleed into ventricles and thus secondary hydrocephalus
Common problem with lacunar infarcts?
Basilar artery clot
Is this a normal CT, so what is this bright vessel?
Will have a lot of perpindicular (from the ventricles) bright plaques and also some in the spinal cord
How MS/demyelination appears on MRI?
Use a special sequence to see high activity and thus active lesion or contrast enhancing plaques are typically active
Two ways to visualise number of active plaques as opposed to inactive?