Ver el código de «CT brain interpretation»

==Mnemonic==
[[File:Brainlobes.png|thumb|Lobes of the brain.]]
[[File:Cranial bones en.png|thumb|Bones of the cranium.]]
[[File:Computed tomography of human brain - large.png|thumb|Example of a normal head CT with IV contrast.]]
''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 with injury to middle meningeal artery
***Low mortality if treated prior to unconsciousness (<20% morbidity/mortality)
**[[SDH|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 with major shift (secondary to 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 increased ICP (squished shut)
**Suprasellar
**Quadrigeminal
***"W" shaped
***Second cistern to show increased 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 increased ICP)
*Findings
**[[brain tumor|Tumor]]
***May see increased hypodensity ([[cerebral edema in brain cancer|edema]])
***80% visible without contrast
**Atrophy 
**[[brain abscess|Abscess]]
**Hemorrhagic contusion
**Mass effect
**[[Stroke]]
**Intracranial air ([[skull fracture]])
**Hyperdense middle cerebral artery or basilar artery sign
***Suggests thrombosis of vessel
**Suggestive of [[Cerebral venous thrombosis]] :
***Empty delta sign: dense triangle in superior sagittal sinus
***Cord sign: hyperattenuated, homogeneous linear or round foci in cerebral sinus <ref>Ram K. P. Vijay. "The Cord Sign."Radiology. 2006; 240:299-300.</ref>
***Vein Sign: hypoattenuated foci in the deep vein  <ref>Linn J, Pfefferkorn T. "Noncontrast CT in Deep Cerebral Venous Thrombosis and Sinus Thrombosis: Comparison of Its Diagnostic Value for Both Entities."AJNR Am J Neuroradiology. 2010; 30: 728-735. </ref>

==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 increased pressure versus atrophy: 
***Are the gyri effaced? If yes suggestive of increased pressure

==Bone==
*Inspect petrous ridges for [[basilar skull fracture|skull base fracture]]
*Look at mastoid air cells full of fluid (blood) for indirect evidence of fracture

==Examples==
<gallery mode="packed">
File:Intracerebral heamorrage.jpg|[[Hemorrhagic stroke]] (spontaneous intracranial hemorrhage)
File:Epidural Hematoma.jpg|[[Epidural hemorrhage]]
File:Subduralandherniation.png|[[Subdural hemorrhage]]
File:SubarachnoidP.png|[[Subarachnoid hemorrhage]]
File:Hydrocephalus (cropped).jpg|[[Hydrocephalus]]
File:PMC4857327 10.1177 2050313X15591314-fig3.png|[[Brain abscess]]
File:StrokeMCA overlay.png|[[Ischemic stroke]]
</gallery>

==See Also==
*[[Head CT (Clinical Decision Rules)]]
*[[CT Before Lumbar Puncture]]
*[[Intracerebral Hemorrhage (ICH)]]
*[[X-ray interpretation (main)]]

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

[[Category:Neurology]]
[[Category:Radiology]]