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157 Cards in this Set
- Front
- Back
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What are 7 things to look for on CT of the brain.
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Ventricular size and cortical sucli enlargement
Mass and mass effect Change in attenuation Intra and extra-axial collection |
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What bony areas should be looked at
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cranium, paranasal sinuses, orbit
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What is a common type of artifact on CT
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beam hardening artifact
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What is another type of artifact?
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partial volume averaging
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What type of edema is seen with stroke?
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cytotoxic
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What type of edema is finger like
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vasogenic
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What are some causes of vasogenic edema?
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tumor, infection and late infarct
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How do you describe an old infarct
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chronic infarct
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How do you describe an infarct at the top of the brain in the grey matter
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convexity infarct
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In addition to looking for venticular dilation what other age related things should you look for
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cerebral atrophy. "there is no enlargement of cortical sulci"
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How do you say there is no stroke
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there is no acute hemorrhage or acute territorial infarct.
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How do you say there is no subdural/epidural hematoma
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there is no extra-axial fluid collection.
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How do you say there is no change from the prior exam
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there is no significant interval change
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How do you descibe decreased attenuation next to a brain hemoorhage
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adjacent edema.
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What is craniotomy
When is a craniectomy done |
bone is back in place
skull is removed to allow brain to swell. |
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How do you refer to post surgical changes
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the bony location and type of surgical procedure
s/p left occipital craniotomy and then mention post surgical changes to "what ever part of the brain" ex s/p left occipital craniectomy with post surgical |
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What is a smart sounding way of updating progress
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"interval" resolution or "interval" worsening
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What is a smart way of saying no infarct
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'there is no acute territorial infarct"
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How do you describe sinus disease
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if there is just some peripheral thinking.." there is mild mucosal thickening involving the maxillary
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What is a subdural hematoma
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subdural hematomas appear as a crescent-shaped extra-axial collection with increased attenuation that, when large enough, causes effacement of the adjacent sulci and midline shift.
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What is the shape of a subdural hematoma
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cresent shaped
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Describe the blood spread of SDH
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subdural hematomas are not restricted by dural tethering at the cranial sutures; they can cross suture lines and continue along the falx and tentorium
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Do subural hematomas cross the midline
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no
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What is a subdural hematoma
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subdural hematomas appear as a crescent-shaped extra-axial collection with increased attenuation that, when large enough, causes effacement of the adjacent sulci and midline shift.
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What is the shape of a subdural hematoma
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cresent shaped
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Describe the blood spread of SDH
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subdural hematomas are not restricted by dural tethering at the cranial sutures; they can cross suture lines and continue along the falx and tentorium
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Do subural hematomas cross the midline
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no
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What is the shape of a SDH
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Crescent with a concave
surface away from the skull |
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What is the shape of an epidural hematoma
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biconvex
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What are some causes of aliasing artifact or streak
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metallic objects
insufficient penetration of normal tissue |
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What does beam aliasing artifact or streak occur with
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motion artifact
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What does aliasing artifact or streak look like
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dark lines which radiate around sharp corners
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What is partial volume averaging
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blurring around sharp corners
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What causes partial volume averaging
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two areas of different density. For example bone and cartilage
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What is the actual computerized problem that causes partial volume averaging
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The processor tries to average out the two densities or structures, and information is lost.
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Who is partial volume avering overcome
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using thinner slices
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What does beam hardening artifact look like
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gives a "cupped appearance".
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When does beam hardening artifact occur
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It occurs when there is more attenuation in the center of the object than around the edge.
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How is beam hardening artifact corrected
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This is easily corrected by filtration and software.
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What is the best way to analyze brain parenchyma
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Use the brain’s natural symmetry to help you
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What is the attenuation of the brain in neonates
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In neonates, the brain is usually diffusely hypodense due to lack of myelination.
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In the elderly what are some degenerative changes that happen to the brain
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small vessel disease commonly results in diffuse brain atrophy, in the periventricular white matter being hypodense due to gliosis, and in lacune infarcts within the basal ganglia.
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What are 2 causes of hyperdensity of the brain parenchyma
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Hyperdensity within the parchenchyma is either due to hematoma (hemorrhage) or calcification.
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When does beam hardening artifact occur
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Linear segments of hyperdensity along the cerebral cortex are usually artifactual due to adjacent bone (beam hardening).
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What is sucal effacement
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Sulcal effacement. The sulci along the cerebral convexity on the involved side will appear smaller than the other side.
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If you are unable to visualize the basal cistern what should you be concerned for
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Poor visualization of the basal cisterns should raise concern for increased intracranial pressure and possibly brain herniation.
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What does hyperdensity within the dependent portion of the ventricles indicate
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Hyperdensity within the subarachnoid spaces and the dependent portions of the ventricles usually indicates hemorrhage
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How should you check for subdural hemorrhage
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Always check the subdural windows to check for subdural hemorrhage, especially along the edges of the intracranial cavity.
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Is the falx and the tentorium ever calcified
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the falx, and to a lesser the tentorium, is often calcified in the elderly
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How do you differentiate calcificaton of the falx and the tentorium from sdh
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suspicious of subdural hemorrhage if the density is symmetrically thicker on one side of the falx or tentorium than the other side.
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What can clue you into a fx on a ct brain
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STS, fluid within sinus or mastoid aircells always raises suspicion for fracture of the adjacent bone.
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What should you always check in trauma
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Check the sulci, basal cisterns and ventricles for subarachnoid hemorrhage.
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How does beam hardening artifact appear
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beam hardening artifact appears as linear streaks
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What are signs of acute infarct
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Dense MCA, Edema of the basal ganglia and/or insular cortex, Sulcal effacement
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What should you look for if pt has a headache
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SAH, and sinus disease
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What should you look for in mental status change
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SDH, infarct, mass
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What should you look for in seziures
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infarct, mass
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Where is a SAH seen
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, subarachnoid hemorrhage (SAH) appears as a high-attenuating, amorphous substance that fills the normally dark, CSF-filled subarachnoid spaces around brain
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Can the sulci fill with blood in SAH
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yes
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Can the sylvian fissure fill with blood
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yes
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Can the ventricles fill with blood in a SAH
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yes
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What are 4 things to know about pineal gland calcification
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usually in the form of a cluster of amorphous, irregular densities
may be solitary the size of calcification: usually 3-5 mm if greater than 1 cm, suspect pinealoma, AV malformation, etc. |
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cisterns
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http://books.google.com/books?id=9c3W5Cy6-R4C&pg=PA242&lpg=PA242&dq=ambient+cistern+fourth+ventricle&source=bl&ots=0hlKp7092t&sig=Q4SOW27LenWyvBd4oAQs_Y9cTyI&hl=en#v=onepage&q=ambient%20cistern%20fourth%20ventricle&f=false
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What is the relation of the jugular vein to the common carotid
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the jugular vein is lateral
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When do the transverse foramen begin
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C6
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If you see prominent temporal horns what should be suspected
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hydrocephalus
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What is a good window to look for disc herniation
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40/400
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What is a good window for looking for pathology in angiography
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100/800
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Where is a common area to look if you suspect brain herniation
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the quadrigeminal plate
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If there is blood in the interhemispheric fissure what type of brain bleed is it
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a SDH
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How long does contrast stay with in the brain
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residual may be in the brain for hours
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When is thrombolytic therapy appropiate
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less than 3 hrs from onset of symptoms
no contraindication to TPA there is not too much involvement of the brain |
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Why is having more than 1/3 of the brain involved a contraindication
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too much risk of hemorrhage
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What percent of stroke are ischemic
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80
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what percent of stroke are hemorrahgic
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20
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How long must neurologic symptoms persist to be considered a stroke
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greater than 24h
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What percent of pt with ischemic stroke have a normal ct brainin frist 6h
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60%
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What is the first 4 intial signs seen in acute ischemic stroke
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vague hypodensity
insular ribon sign (loss of grey-white interface) sulcal effacement from slight swelling basal ganglia (loss of grey white interface) |
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How does an ischemic stroke appear after 24h on ct
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well circumscribed hypodensity
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when does peak mass effect occur
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3-5 days
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When does mass effect go away
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2-4 wkss
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What are 2 long term sequela of infarct
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ex vacuo dilation of ventircles
encephalomalacia in infarcted area |
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What does the insular ribbon sign look like
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a subtle hypodensity around the insular cortex with loss of grey white differentiation
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What is a density seen sometimes in an acute mca
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dense mca sign
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What is a basilar artery thrombus that is equivalent to mca sign
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dense basilar artery sign
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what type of edema is associated with acute infarction
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cytotoxic
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What is the shape of cytotoxic edema
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wedge
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What are some causes of vasogenic edema
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infection, x-ray, tumor
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What does vasogenic edema look like
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finger like
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When does enhancement of an infarcted area begin
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3 days
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Is IV contrast given for a perfusion scan
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yes
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What percent of strokes are not form causes amenable to tpa
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40
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How long does DWI take to perform
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2 minutes
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Is DWI sensitive for acute ischema
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yes
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What are the contraindications for MRI
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pacer, AICD , aneurysm clip
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How do acute strokes appear on T1
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normal or low signal
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How do acute strokes appear on t2
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high signal
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How do strokes appear on flair
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High
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How do strokes appear on dwi
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high
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What sequences are most sensitive for acute stroke
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dwi and flair
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How long does an area take to become bright on DWI after ischemia
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30 minutes
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How long does an area take to become bright on t2 and t1 sequence
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8 hrs
16 hrs |
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How long does an infarcted area remain bright on t2
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forever
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What happens to the t1 signal as encephalomalacia of an infarcted area occurs
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progressively darker until matches density of CSF
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What how long does DWI stay bright following a stroke
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10-14 days
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What does an area with encephalomalacia look like on DWI
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low signal
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What sequence becomes progresively brighter compared with DWI
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T2
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When does DWI/T2 cross over occur
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3-7 days
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What are some false positives of DWI
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hemorrhage
MS Abscess lymphoma and other tumors |
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Is DWI sensitive for stroke
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yes
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Is DWI specific for stroke
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no
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What is the appearance of a subacute stroke on T1/T2/flair and DWI
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dark on T1
bright on T2 bright on flair very bright on DWI |
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Is an MRA good for seeing small intracerebral vessels
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no
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When are MRAs commonly ordered
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if there is going to be an intervention
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What are same vasculopathies that will predispose to chronic ischemic change
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diabetes
htn temporal arteritis takayasu arteritis PAN sarcoid SLE wegners |
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What are some infection etiologies of ischemic damage
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symphilis
tb herpes |
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What are two large vessel cause of ischemic damage
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moyamoya
fibromuscular dysplasia |
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What is the normal attenuation of white matter and grey matter
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30-34 -wm
37-41-gm |
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What is more dense clotted blood or acutely extravasting blood
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clotted blood is more dense than acute extravasated blood (which is bright on CT)
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What are 5 possible locations of blood in the brain
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intraparenchymal
intraventricular subarachnoid subdural epidural |
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What is an instance where an acute bleed may be difficult to see
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an anemic pt
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When does the highest clot density of blood occur
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at 72h
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When does high density clot start to disappear
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several weeks
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What is the hct when non-clotted blood may be isodense with the brain
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less than 30%
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What are 4 locations where hypertensive intraparenchymal hemorrhage will occur 80% of the time
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basal ganglia
thalamus pons cerebrum |
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What is potential confused with a basal ganglia bleed
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calcification (usually symmentric)
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what are causes of atypical locations of hemisphere hemorrhage
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AVM, aneurysm, trauma, amyloid angiopathy, tumor, vasculitis, drugs, anticoagulatin, bleeding diathesis
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What are 2 causes of aneurysms
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berry and mycotic
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What are drugs which can cause intraparencymal hemorrhage
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cocaine and amphetamine
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What are 2 causes of SAH
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berry aneurysm and trauma
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What are causes of berry aneurysm
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familial vs sporadic
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What % of SAH are caused by berry aneurysms
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80-90%
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What are some congenital causes of berry aneurysm
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APKD
marfans ehlers danlos fibromuscular dysplasia |
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What percent of pt with ADPD
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have berry aneurysm 10
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What percent of pt that have one berry aneurysm have multiple
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15-20
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When do berry aneurysm bleed most often after intial rupture
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1st day
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What percent of berry aneurysm will rupture in the 1st 6 months
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50%
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Why is it important to get an MRA or CTA soon after a SAH from a berry aneursym occurs
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because vasospasm may occur leading to infarction
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Can an EDH and SDH cause life threatening herniation and mass effect
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yes
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What are 3 causes of IVH
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trauma, htn, aneurysm
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What is the progression of blood products
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oxyhemoglobin-->deoxyhemoglobin-->methmegobin
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Are standard T1 and T2 images sensitive for small acute hemorrhage
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no (need CT first)
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What does a subacute SDH look like on CT
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isodense
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What does a subacute SDH look like on T1 and T2
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bright on both
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What does a hygroma look like on T1 and T2
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T1 dark
T2 bright (like fluid) |
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What does an old stroke look like on MRI
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water signal on T1 and T2 and dark on DWI
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What is the mc cause of stroke in an older pt
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atherosclerotic disease
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What is the cause of stroke in atherosclerotic disease`
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thrombotic event or embolic event
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What % atherosclerotic disease of the carotid artery is considered critical and needs to be treated
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greater than 70%
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What is a primary intraventricular hemorrhage
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definition varies by author
within intraparenchymal hemorrhage with in 15mm and vessels in the wall or vessels in the wall |
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What are causes of vessels in the wall of the ventricles causing hemorrhage
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vascular malformations (MC if not including iph within 15mm)
intraventricular tumor intraventricular aneurysm moyamoya (rare) pituitary apoplexy (rare) vasculitis (rare) |
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What vessel aneurysms tend to cause intraventricular hemorrhage
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distal lenticulostriate or choroidal arteries
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can the circle of willis vessels cause intraventricular hemorrhage without SAH
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yes, but very rare
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What is hyperostosis frontalis interna
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this is benign bilateral symmetric overgrowth of the frontal bones inner table
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Can blood layering on the tentorium and falx be subarachnoid
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yes, but usually its subdural. If the pt has a ruptured aneurysm then it will be a SAH.
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If blood is in the cortical sulci is it always SAH
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yes
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What is called when the defect caused by a craniectomy is repaired
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status post cranioplasty
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