Cerebrovascular diseae Flashcards
(232 cards)
Clinical term applies to any abrupt nontraumatic brain insult- literally a blow from an unseen hand
Stroke
2/3 of infarct are from
Thrombi
Normal brain metabolism is how many ml/100g tissue/min
55 ml/100g tissue/min
Oligemia is more common in the gray matter due to
Gray matter receives 3-4x more blood flow than white matter
Why are watershed zones more prone to infarction
They are served by penetrating end arteries and have no alternate route for perfusion
Mechanism of cytotoxic edema
Failure of membrane pumps permits efflux of K+ and simultaneous influx of Ca, Na and water, causing increased water content in the affected region
Cytotoxic edema peaks at how many days post infarction, and is maximum in what brain matter
3-7 days in gray matter
Vasogenic edema primarily affects what brain matter
White matter due to lose endothelial cell integrity
A subtle but important blurring of the gray white layers of the insula due to early edema. Can be seen in CT done within 6 hours of MCA occlusion
Insular ribbon sign
Hyperintense light bulb sign signal in DWI can be seen as early as how many minutes post infarction
15 minutes
T2 hyperintense signal from infarct will develop how many hours post ictus
6-12 hours post ictus
IV t-PA is frontline therapy for patients within how many hours of symptom onset
4.5 hours
endovascular thrombectomy can be done within how many hours of symptom onset
24 hours
ASPECTS score that can be a considered a candidate for thrombolysis
7 to 10
may be useful in identifying ischemic but still salvageable tissue (ischemic penumbra) to successfully guide selection of patients for stent retriever therapy beyong 4.5 hours
perfusion sensitive CT and MR techniques
this MRI sequence reflects “pure” diffusion behavior, free of underlying T2 contributions (“shine through” or “dark through”)
ADC
peak of edema in infarct as well encephalomalacic changes occur in what days
3-7 days
“fogging effect” may be encountered on CTs done during what week after infarction as edema and mass effect are subsiding
2nd week
edema that persists beyong __ month/s effectively rules out simple ischemia and should raise the possibility of recurrent infarction or an underlying tumor
1 month
pathophysiology of hemorrhagic transformation
reperfusion into infarcted capillary beds may secondarily lead to gross or microscopic hemorrhage, microscopic leakage of RBC (diapedesis), physical disruption of the capillary endothelial cells, loss of vascular autoregulation and anticoagulation or thrombolytic use
difference of hemorrhagic infarction from hemorrhagic transformation
hemorrhagic infarction is confined to the territory of the infarcted vessel, wheras primary hemorrhage does not necessarily respect vascular boundaries
true or false: IVH is uncommonly seen with hemorrhagic transformation and should raise the posibility of another process (such as hypertensive bleed or a ruptured AVM)
true
peak time of hemorrhagic transformation
1 to 2 weeks
appearance of hemorrhagic transformation
serpiginous line of petechial blood ff the gyral contours of the infarcted cortex. the dots are often patchy and discontinuous (petechial gyral pattern)