CT brain interpretation: Difference between revisions

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==Mnemonic==
==Mnemonic==
Blood Can Be Very Bad
Blood Can Be Very Bad
#Blood
*Blood
#Cisterns
*Cisterns
#Brain
*Brain
#Ventricles
*Ventricles
#Bone
*Bone


==Blood==
==Blood==
#Questions
*Questions
##Is blood present?
**Is blood present?
##If so, where is it?
**If so, where is it?
##If so, what effect is it having?
**If so, what effect is it having?
#Physiology
*Physiology
##Acute blood is bright white (once it clots)
**Acute blood is bright white (once it clots)
##Blood becomes isodense at 1wk (exact time depends on size of clot)
**Blood becomes isodense at 1wk (exact time depends on size of clot)
##Blood becomes hypodense at 2wks (exact time depends on size of clot)
**Blood becomes hypodense at 2wks (exact time depends on size of clot)
#Findings
*Findings
##Epidural Hematoma (blood problem)
**Epidural Hematoma (blood problem)
###Lens shaped
***Lens shaped
###Does not cross sutures
***Does not cross sutures
###Classically described w/ injury to middle meningeal artery
***Classically described w/ injury to middle meningeal artery
###Low mortality if treated prior to unconsciousness (<20% morbidity/mortality)
***Low mortality if treated prior to unconsciousness (<20% morbidity/mortality)
##Subdural (brain problem)
**Subdural (brain problem)
###Sickle shaped
***Sickle shaped
###Crosses sutures but not midline
***Crosses sutures but not midline
###Marker for severe head injury (mortality approaches 80%)
***Marker for severe head injury (mortality approaches 80%)
####Small amount of bleed can be associated w/ major shift (2/2 brain injury/oozing)  
****Small amount of bleed can be associated w/ major shift (2/2 brain injury/oozing)  
##[[SAH]]
**[[SAH]]
###Blood in the cisterns/cortical gyral surface/interhemispheric fissure
***Blood in the cisterns/cortical gyral surface/interhemispheric fissure
####Suprasellar cistern is first place see SAH (location adjacent to circle of willis)
****Suprasellar cistern is first place see SAH (location adjacent to circle of willis)
###Aneurysm: 80%
***Aneurysm: 80%
###AVM: 5%
***AVM: 5%
##Intraventricular/Intraparenchymal Hemorrhage
**Intraventricular/Intraparenchymal Hemorrhage
###Typically obvious findings
***Typically obvious findings
###Unimportant if intraventricular ruptured into parenchyma or vice-versa
***Unimportant if intraventricular ruptured into parenchyma or vice-versa


==Cisterns==
==Cisterns==
#4 key cisterns:
*4 key cisterns:
##Circummesencephalic
**Circummesencephalic
###First cistern to show incr ICP (squished shut)
***First cistern to show incr ICP (squished shut)
##Suprasellar
**Suprasellar
##Quadrigeminal
**Quadrigeminal
###"W" shaped
***"W" shaped
###Second cistern to show incr ICP
***Second cistern to show incr ICP
##Sylvian
**Sylvian
###May see isloated distal MCA bleed
***May see isloated distal MCA bleed
#2 questions:
*2 questions:
##Is there blood?
**Is there blood?
##Are the cisterns open?
**Are the cisterns open?


==Brain==
==Brain==
#Compare side to side
*Compare side to side
#Look for grey-white differentiation
*Look for grey-white differentiation
##Grey is denser so appears lighter on CT
**Grey is denser so appears lighter on CT
#Look at gyral pattern all the way around (gyri effacement indicator of incr ICP)
*Look at gyral pattern all the way around (gyri effacement indicator of incr ICP)
#Findings
*Findings
##Tumor
**Tumor
###May see increased hypodensity (edema)
***May see increased hypodensity (edema)
###80% visisble w/o contrast
***80% visisble w/o contrast
##Atrophy  
**Atrophy  
##Abscess
**Abscess
##Hemorrhagic contusion
**Hemorrhagic contusion
##Mass effect
**Mass effect
##Stroke
**Stroke
##Intracranial air (skull fx)
**Intracranial air (skull fx)
##Hyperdense middle cerebral artery or basilar artery sign
**Hyperdense middle cerebral artery or basilar artery sign
###Suggests thrombosis of vessel
***Suggests thrombosis of vessel


==Ventricles==
==Ventricles==
#Check all 4 for size and for hemorrhage
*Check all 4 for size and for hemorrhage
##Temporal tips (comma-shaped) of lateral ventricle first place to show hydrocephalus  
**Temporal tips (comma-shaped) of lateral ventricle first place to show hydrocephalus  
##If enlarged must differentiate between hydrocephalus from incr pressure versus atrophy:  
**If enlarged must differentiate between hydrocephalus from incr pressure versus atrophy:  
###Are the gyri effaced? If yes suggestive of incr pressure
***Are the gyri effaced? If yes suggestive of incr pressure


==Bone==
==Bone==
#Inspect petrous ridges for skull base fx
*Inspect petrous ridges for skull base fx
#Look at mastoid air cells full of fluid (blood) for indirect e/o fracture
*Look at mastoid air cells full of fluid (blood) for indirect e/o fracture


==See Also==
==See Also==
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*[[X-ray interpretation (main)]]
*[[X-ray interpretation (main)]]


==Source==
==References==
*Blood Can Be Very Bad: CT Interpretation Course Guide
*Blood Can Be Very Bad: CT Interpretation Course Guide
*www.uic.edu/com/ferne/pdf/acep2005_spring/perron_acep2005_spring_bcbvb_course.pdf
*www.uic.edu/com/ferne/pdf/acep2005_spring/perron_acep2005_spring_bcbvb_course.pdf

Revision as of 14:40, 1 June 2015

Mnemonic

Blood Can Be Very Bad

  • Blood
  • Cisterns
  • Brain
  • Ventricles
  • Bone

Blood

  • Questions
    • Is blood present?
    • If so, where is it?
    • If so, what effect is it having?
  • Physiology
    • Acute blood is bright white (once it clots)
    • Blood becomes isodense at 1wk (exact time depends on size of clot)
    • Blood becomes hypodense at 2wks (exact time depends on size of clot)
  • Findings
    • Epidural Hematoma (blood problem)
      • Lens shaped
      • Does not cross sutures
      • Classically described w/ injury to middle meningeal artery
      • Low mortality if treated prior to unconsciousness (<20% morbidity/mortality)
    • Subdural (brain problem)
      • Sickle shaped
      • Crosses sutures but not midline
      • Marker for severe head injury (mortality approaches 80%)
        • Small amount of bleed can be associated w/ major shift (2/2 brain injury/oozing)
    • SAH
      • Blood in the cisterns/cortical gyral surface/interhemispheric fissure
        • Suprasellar cistern is first place see SAH (location adjacent to circle of willis)
      • Aneurysm: 80%
      • AVM: 5%
    • Intraventricular/Intraparenchymal Hemorrhage
      • Typically obvious findings
      • Unimportant if intraventricular ruptured into parenchyma or vice-versa

Cisterns

  • 4 key cisterns:
    • Circummesencephalic
      • First cistern to show incr ICP (squished shut)
    • Suprasellar
    • Quadrigeminal
      • "W" shaped
      • Second cistern to show incr ICP
    • Sylvian
      • May see isloated distal MCA bleed
  • 2 questions:
    • Is there blood?
    • Are the cisterns open?

Brain

  • Compare side to side
  • Look for grey-white differentiation
    • Grey is denser so appears lighter on CT
  • Look at gyral pattern all the way around (gyri effacement indicator of incr ICP)
  • Findings
    • Tumor
      • May see increased hypodensity (edema)
      • 80% visisble w/o contrast
    • Atrophy
    • Abscess
    • Hemorrhagic contusion
    • Mass effect
    • Stroke
    • Intracranial air (skull fx)
    • Hyperdense middle cerebral artery or basilar artery sign
      • Suggests thrombosis of vessel

Ventricles

  • Check all 4 for size and for hemorrhage
    • Temporal tips (comma-shaped) of lateral ventricle first place to show hydrocephalus
    • If enlarged must differentiate between hydrocephalus from incr pressure versus atrophy:
      • Are the gyri effaced? If yes suggestive of incr pressure

Bone

  • Inspect petrous ridges for skull base fx
  • Look at mastoid air cells full of fluid (blood) for indirect e/o fracture

See Also

References

  • Blood Can Be Very Bad: CT Interpretation Course Guide
  • www.uic.edu/com/ferne/pdf/acep2005_spring/perron_acep2005_spring_bcbvb_course.pdf
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