Intracranial hemorrhage CT: Difference between revisions

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CAT scan ([[computed axial tomography]]) is the definitive tool for accurate diagnosis of an intracranial hemorrhage.
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{{Intracranial hemorrhage}}
{{CMG}}
==CT==
CT scan ([[computed axial tomography]]) is the definitive tool for accurate diagnosis of an intracranial hemorrhage.


{|
| [[Image:Posterior fossa hemorrhage.jpg|thumb|CT scan showing hemorrhage in the [[posterior fossa]]]]
| [[Image:Intracerebral hemorrhage.jpg|thumb|Spontaneous ICH with [[hydrocephalus]] on CT scan]]
|}
===Cerebral Amyloid Angiopathy <small><ref>Christine P. Chao, Amy L. Kotsenas, and Daniel F. Broderick. [http://radiographics.rsnajnls.org/cgi/content/abstract/26/5/1517 Cerebral Amyloid Angiopathy: CT and MR Imaging Findings.] RadioGraphics 2006 26: 1517-1531.</ref></small>===
===Cerebral Amyloid Angiopathy <small><ref>Christine P. Chao, Amy L. Kotsenas, and Daniel F. Broderick. [http://radiographics.rsnajnls.org/cgi/content/abstract/26/5/1517 Cerebral Amyloid Angiopathy: CT and MR Imaging Findings.] RadioGraphics 2006 26: 1517-1531.</ref></small>===


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*CT allows rapid establishment of the presence or absence of an ICH and exclusion of an [[Cerebrovascular accident | acute cerebral infarction]].  
*CT allows rapid establishment of the presence or absence of an ICH and exclusion of an [[Cerebrovascular accident | acute cerebral infarction]].  
*Non-enhanced head CT is the preferred imaging modality for initial work-up as it provides crucial information regarding the characteristics of the ICH, including size, location, shape, and extension to the extraaxial spaces  
*Non-enhanced head CT is the preferred imaging modality for initial work-up as it provides crucial information regarding the characteristics of the ICH, including size, location, shape, and extension to the extra-axial spaces.
*If an ICH is present in a cortical-subcortical location suspicious for Cerebral amyloid angiopathy, the patient should undergo additional evaluation with MR imaging.  
*If an ICH is present in a cortical-subcortical location suspicious for cerebral amyloid angiopathy, the patient should undergo additional evaluation with MR imaging.  
*GRE is currently the most sensitive MR imaging sequence for detection of the chronic cortical-subcortical microhemorrhage.
*GRE is currently the most sensitive MR imaging sequence for detection of the chronic cortical-subcortical microhemorrhage.


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*Subarachnoid hemorrhage appears as a high-attenuating, amorphous substance that fills the normally dark CSF-filled subarachnoid spaces.  
*Subarachnoid hemorrhage appears as a high-attenuating, amorphous substance that fills the normally dark CSF-filled subarachnoid spaces.  
*These findings are most evident in the largest subarachnoid spaces, such as the suprasellar cistern and Sylvian fissures.
*These findings are most evident in the largest subarachnoid spaces, such as the suprasellar cistern and Sylvian fissures.
*Acute Subarachnoid hemorrhage is typically 50-60 HU.  
*Acute subarachnoid hemorrhage is typically 50-60 HU.  
*When CT scanning is performed several days to weeks after the initial bleed, the findings are more subtle.  
*When CT scanning is performed several days to weeks after the initial bleed, the findings are more subtle.  
**The initial high-attenuation of blood and clot tend to decrease, and these appear as intermediate gray.  
**The initial high-attenuation of blood and clot tend to decrease, and these appear as intermediate gray.  
**These findings can be isointense relative to normal brain parenchyma.  
**These findings can be isointense relative to normal brain parenchyma.  
*In addition to detecting Subarachnoid hemorrhage, CT is useful in localizing the source of bleeding.
*In addition to detecting subarachnoid hemorrhage, CT is useful in localizing the source of bleeding.


[http://www.radswiki.net Images courtesy of RadsWiki]
[http://www.radswiki.net Images courtesy of RadsWiki]
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Image:Subarachnoid hemorrhage 004.jpg|CT: Diffuse subarachnoid hemorrhage
Image:Subarachnoid hemorrhage 004.jpg|CT: Diffuse subarachnoid hemorrhage
</gallery>
</gallery>
====MRI====
*Fluid-attenuated inversion recovery (FLAIR) is the most sensitive MRI pulse sequence for the detection of SAH. '''SAH appears as high-intensity signal in normally low signal CSF spaces.'''
*T2- and T2*-weighted images can potentially demonstrate SAH as low signal intensity in normally high-signal subarachnoid spaces.
*On T1-weighted images, acute SAH may appear as intermediate- or high-intensity signal in the subarachnoid space.
*MR angiography may be useful in the evaluation of aneurysms and other vascular lesions that cause SAH.


===Subdural Hemorrhage===
===Subdural Hemorrhage===
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**They do not cross the midline because of the meningeal reflections.
**They do not cross the midline because of the meningeal reflections.


*In the '''acute''' phase, 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.  
*In the acute phase, 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.  
*The attenuation changes as the hematoma ages.
*The attenuation changes as the hematoma ages.


*'''Subacute''' subdural hematomas may be difficult to detect because they may have isoattenuation compared with adjacent gray matter  
*Subacute subdural hematomas may be difficult to detect because they may have isoattenuation compared with adjacent gray matter  


*'''Chronic''' subdural hematomas have isoattenuation relative to the cerebrospinal fluid.  
*Chronic subdural hematomas have isoattenuation relative to the cerebrospinal fluid.  


*Rebleeding into subdural hematomas also may occur and is depicted as a layer of high-attenuation hemorrhage within a lower attenuation hematoma.
*Rebleeding into subdural hematomas also may occur and is depicted as a layer of high-attenuation hemorrhage within a lower attenuation hematoma.
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Image:Subdural-hematoma-003.jpg|CT: Subdural hemorrhage
Image:Subdural-hematoma-003.jpg|CT: Subdural hemorrhage
</gallery>
</gallery>
====MRI====
*MRI is more sensitive than CT scanning in the detection of subdural hematomas because the multiplanar and superior tissue differentiation of MRI makes detection easier.
*The shape of the subdural hematoma on axial images is the same crescent-shaped pattern seen on CT scan images.
*The signal depends on the age of the hemorrhage and follows the signal pattern of intraparenchymal hematomas in acute and subacute cases.
*Chronic subdural hematomas, which appear as isoattenuation relative to CSF on CT scans, often demonstrate increased signal intensity on T1-weighted images because of the presence of free methemoglobin, though the intensity decreases over time.


===Perimesencephalic Hemorrhage <small><ref>Schievink, Wouter I., Wijdicks, Eelco F.M., Spetzler, Robert F. [http://www.ajnr.org/cgi/content/abstract/21/3/521 Diffuse Vasospasm after Pretruncal Nonaneurysmal Subarachnoid Hemorrhage.] AJNR Am J Neuroradiol 2000 21: 521-523</ref></small>===
===Perimesencephalic Hemorrhage <small><ref>Schievink, Wouter I., Wijdicks, Eelco F.M., Spetzler, Robert F. [http://www.ajnr.org/cgi/content/abstract/21/3/521 Diffuse Vasospasm after Pretruncal Nonaneurysmal Subarachnoid Hemorrhage.] AJNR Am J Neuroradiol 2000 21: 521-523</ref></small>===
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Image:Perimesencephalic-hemorrhage-003.jpg|CT: Perimesencephalic hemorrhage
Image:Perimesencephalic-hemorrhage-003.jpg|CT: Perimesencephalic hemorrhage
</gallery>
</gallery>
==References==
{{Reflist|2}}
[[Category:Needs overview]]
[[Category:Neurology]]
[[Category:Emergency medicine]]
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{{WikiDoc Sources}}

Latest revision as of 18:38, 13 March 2013

Intracranial hemorrhage Microchapters

Patient Information

Overview

Classification

Subdural hematoma
Epidural hematoma
Subarachnoid hemorrhage
Intraventricular hemorrhage
Intraparenchymal hemorrhage

Causes

Differential Diagnosis

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

CT

CT scan (computed axial tomography) is the definitive tool for accurate diagnosis of an intracranial hemorrhage.

CT scan showing hemorrhage in the posterior fossa
Spontaneous ICH with hydrocephalus on CT scan

Cerebral Amyloid Angiopathy [1]

  • Cerebral amyloid angiopathy manifests radiologically as part or all of a constellation of findings including:
    • Acute or chronic ICHs in a distinctive cortical-subcortical distribution
    • Leukoencephalopathy
    • Atrophy
  • CT allows rapid establishment of the presence or absence of an ICH and exclusion of an acute cerebral infarction.
  • Non-enhanced head CT is the preferred imaging modality for initial work-up as it provides crucial information regarding the characteristics of the ICH, including size, location, shape, and extension to the extra-axial spaces.
  • If an ICH is present in a cortical-subcortical location suspicious for cerebral amyloid angiopathy, the patient should undergo additional evaluation with MR imaging.
  • GRE is currently the most sensitive MR imaging sequence for detection of the chronic cortical-subcortical microhemorrhage.

Epidural Hematoma

  • Typical appearance is a biconvex, elliptical, extra-axial fluid collections.
  • Acute EDH may contain both a hyperattenuating clot and a swirling lucency (believed to represent a mixture of active bleeding and the serum remaining after previous clot formation).
  • Subacute EDH becomes homogeneously hyperattenuating.
  • Chronic EDH is at least partly hypoattenuating as the clot undergoes breakdown and resorption.

Images courtesy of RadsWiki

  • CT: Epidural hematoma

    CT: Epidural hematoma

  • CT: Epidural hematoma

    CT: Epidural hematoma

  • CT: Epidural hematoma

    CT: Epidural hematoma

  • CT: Epidural hematoma

    CT: Epidural hematoma

Intracerebral Parenchymal Hemorrhage

Images courtesy of RadsWiki

  • CT: Intracerebral parenchymal hemorrhage

    CT: Intracerebral parenchymal hemorrhage

  • CT: Intracerebral parenchymal hemorrhage

    CT: Intracerebral parenchymal hemorrhage

  • CT: Intracerebral parenchymal hemorrhage

    CT: Intracerebral parenchymal hemorrhage

  • CT: Intracerebral parenchymal hemorrhage

    CT: Intracerebral parenchymal hemorrhage

Intraventricular Hemorrhage

Images courtesy of RadsWiki

  • CT: Intraventricular hemorrhage

    CT: Intraventricular hemorrhage

  • CT: Intraventricular hemorrhage

    CT: Intraventricular hemorrhage

Subarachnoid Hemorrhage

Computed Tomography

  • Subarachnoid hemorrhage appears as a high-attenuating, amorphous substance that fills the normally dark CSF-filled subarachnoid spaces.
  • These findings are most evident in the largest subarachnoid spaces, such as the suprasellar cistern and Sylvian fissures.
  • Acute subarachnoid hemorrhage is typically 50-60 HU.
  • When CT scanning is performed several days to weeks after the initial bleed, the findings are more subtle.
    • The initial high-attenuation of blood and clot tend to decrease, and these appear as intermediate gray.
    • These findings can be isointense relative to normal brain parenchyma.
  • In addition to detecting subarachnoid hemorrhage, CT is useful in localizing the source of bleeding.

Images courtesy of RadsWiki

  • CT: Diffuse subarachnoid hemorrhage

    CT: Diffuse subarachnoid hemorrhage

  • CT: Diffuse subarachnoid hemorrhage

    CT: Diffuse subarachnoid hemorrhage

  • CT: Diffuse subarachnoid hemorrhage

    CT: Diffuse subarachnoid hemorrhage

  • CT: Diffuse subarachnoid hemorrhage

    CT: Diffuse subarachnoid hemorrhage

Subdural Hemorrhage

Computed Tomography

  • Unlike epidural hematomas, subdural hematomas are not restricted by dural tethering at the cranial sutures.
    • They can cross suture lines and continue along the falx and tentorium.
    • They do not cross the midline because of the meningeal reflections.
  • In the acute phase, 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.
  • The attenuation changes as the hematoma ages.
  • Subacute subdural hematomas may be difficult to detect because they may have isoattenuation compared with adjacent gray matter
  • Chronic subdural hematomas have isoattenuation relative to the cerebrospinal fluid.
  • Rebleeding into subdural hematomas also may occur and is depicted as a layer of high-attenuation hemorrhage within a lower attenuation hematoma.

Images courtesy of RadsWiki

  • CT: Subdural hemorrhage

    CT: Subdural hemorrhage

  • CT: Subdural hemorrhage

    CT: Subdural hemorrhage


  • CT: Subdural hemorrhage

    CT: Subdural hemorrhage

  • CT: Subdural hemorrhage

    CT: Subdural hemorrhage

  • CT: Subdural hemorrhage

    CT: Subdural hemorrhage

Perimesencephalic Hemorrhage [2]

Images courtesy of RadsWiki

  • CT: Perimesencephalic hemorrhage

    CT: Perimesencephalic hemorrhage

  • CT: Perimesencephalic hemorrhage

    CT: Perimesencephalic hemorrhage

  • CT: Perimesencephalic hemorrhage

    CT: Perimesencephalic hemorrhage

References

  1. ↑ Christine P. Chao, Amy L. Kotsenas, and Daniel F. Broderick. Cerebral Amyloid Angiopathy: CT and MR Imaging Findings. RadioGraphics 2006 26: 1517-1531.
  2. ↑ Schievink, Wouter I., Wijdicks, Eelco F.M., Spetzler, Robert F. Diffuse Vasospasm after Pretruncal Nonaneurysmal Subarachnoid Hemorrhage. AJNR Am J Neuroradiol 2000 21: 521-523


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