Stroke (Cerebrovascular Disease) Flashcards
What might be a general issue with imaging to determine stroke?
It takes time, and may have difficult distinguishing new lesions from old ones.
What does the FAST acronym mean for strokes?
Face - does one side droop?
Arms - does one arm drift downward
Speech - is it slurred or strange
Time - if you see any of these signs, time is of the essence
What are the four levels of clinical evidence?
- Randomized controlled trial - double blind + placebo
- Non-randomized controlled trial
- Observational studies with control
- Observational studies without control
- Case studies
What level of blood flow defines an infarcation of the brain?
<10 mL / 100 g / min
What is the majority of strokes and what causes them?
70-80% of strokes are ischemic strokes, up to 25% are due to clots / plaques from other areas
What is a TIA?
Transient ischemic attack - ministroke, symptoms disappear in less than 24 hours and most last less than 30 minutes. Increases your risk of future strokes
What is a hemorrhagic transformation?
When an ischemic stroke becomes a hemorrhagic stroke due to pressure buildup.
What causes hemorrhagic stroke and who is it common in?
Accounts for 20-30% of strokes, more common in children. Greatest predisposing factor is hypertension.
What is a thunderclap headache?
Sudden, severe headache “worst headache of your life” caused by hemorrhagic bleeding into the subarachnoid space
What type of aneurysm typically occurs at the anterior communicating artery?
saccular / berry
What is a fusiform aneurysm?
aneurysm characterized by bulges on all sides
What is a false aneurysm vs dissecting aneurysm? What can these cause?
False - bulge in blood vessel but no true rupture of intima
Dissecting - tunica intima is torn, leading to blood in the vessel wall
Both can cause an ischemic stroke
What type of stroke do AV malformations cause? What structure is associated with them?
Hemorrhagic stroke, due to buildup of pressure
An AVM nidus is associated with them
Where is central venous thrombosis most common, and what is the most common genetic cause?
Common in superior sagittal sinus. Common in genetic mutations to clotting factors
What percentage of patients have a patent foramen ovale and why is this a stroke risk factor?
25% of patients, it is a risk factor because systemic venous clots will be able to get into the arterial system through the foramen ovale
What are other common causes of emboli from the heart?
Causes 15-20% of strokes
Atrial fibrillation, endocarditis, or MI
When is the penumbra?
Part of the brain which can potentially be rescued, surrounding the infarcted area. Delayed necrosis + apoptosis of cells
What are the risk factors for stroke?
Hypertension Heart disease, atrial fibrillation and especially rheumatic (from strep throat) Diabetes Smoking Dyslipidemia Previous stroke
What is non-contrast CT good for?
Hemorrhagic but not early ischemic stroke
What is perfusion CT good for?
Ischemic stroke and revealing penumbra
What is CT angiography good for?
Uses contrast, reveals flow in blood vessels
How do white matter, gray matter, and CSF appear on T1-weighted imaging?
White matter: light
Gray matter: Dark
CSF: Black
How do white matter, gray matter, and CSF appear on T2-weighted imaging?
White matter: dark
Gray matter: light
CSF: white
What is perfusion-weighted imaging good for? What sequence is it based off?
T2 - perfusion of tissue
What is diffusion-weighted imaging good for? What sequence is it based off?
T2 - Early detection of ischemic stroke