Term
| General radiographic analysis tips |
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Definition
each slice must be evaluate separately, systematically.
--Check symmetry,
--quality of brain tissue (distinct margins b/w grey/white)
--CSF spaces: ventricles, sulci, etc
--Blood presence shown by increased density
--skull fx?
--Windows |
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Definition
--residual radiation striking detector, assigned "gray value"
--faster than MRI (8 minutes)
--Set windows for bone, blood, brain tissue |
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Term
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Definition
skull is radiopaque
fat is radiolucent
ventricles (water) is dark
calcified choroid plexus radiolucent
vascular supply needs contrast added |
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Term
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Definition
classical crescent shape
doesn't cross midline
usually not associated with skull Fx
brain edema causes mass effect |
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Definition
classical biconvex (lens) shape
may cross midline
rapid accumulation of blood, significant mass effect (is an emergency!)
associated often with skull fx |
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Definition
CT normal for first day, edema becomes visible after 6 hours (way past therapeutic window)
--once visible, wedge shape of low density (edema) |
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Term
| types of radioimaging for strokes |
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Definition
CT: ischemic stroke won't be visible on CT for first 6 hours, past therapeutic window. but is useful in ruling out hemorrhagic stroke!
MRI will show ischemic stroke well |
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Term
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Definition
| big hyperdense blood, with hypodense edema surrounding |
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Definition
CT good for first 12 hours of bleeding
see blood mixed with CSF |
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Definition
T1: dark water, bright fat
T2: dark fat, bright water |
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Definition
T1 shows solid phase of brain tumor
T2 shows associated vasogenic edema, liquid phase
*T2 good to look at nucleus pulposa |
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Term
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Definition
| radioactive material used, shows functional brain activity |
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