Subarachnoid hemorrhage CT: Difference between revisions

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*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.
 
===Images===
===Images===
The following are the CT scans associated with diffuse subarachnoid hemorrhage.<ref name=radswiki> Rads wiki,  Images courtesy of RadsWiki [http://www.radswiki.net Images courtesy of RadsWiki]</ref>
The following are the CT scans associated with diffuse subarachnoid hemorrhage.<ref name=radswiki> Rads wiki,  Images courtesy of RadsWiki [http://www.radswiki.net Images courtesy of RadsWiki]</ref>

Revision as of 18:13, 12 December 2016

Subarachnoid Hemorrhage Microchapters

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Patient Information

Overview

Classification

Pathophysiology

Causes

Differentiating Subarachnoid Hemorrhage from other Diseases

Epidemiology and Demographics

Risk Factors

Screening

Natural History, Complications and Prognosis

Diagnosis

History and Symptoms

Physical Examination

Laboratory Findings

CT

MRI

Other Imaging Findings

Other Diagnostic Studies

Treatment

Medical Therapy

Surgery

Primary Prevention

Secondary Prevention

AHA/ASA Guidelines for the Management of Aneurysmal Subarachnoid Hemorrhage (2012)

Risk Factors/Prevention
Natural History/Outcome
Clinical Manifestations/Diagnosis
Medical Measures to Prevent Rebleeding
Surgical and Endovascular Methods
Hospital Characteristics/Systems of Care
Anesthetic Management
Cerebral Vasospasm and DCI
Hydrocephalus
Seizures Associated With aSAH
Medical Complications

Cost-Effectiveness of Therapy

Future or Investigational Therapies

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Case #1

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-In-Chief: Cafer Zorkun, M.D., Ph.D. [2]; Sara Mehrsefat, M.D. [3]

Overview

CT

The mainstay of diagnosis of suarachnoid hemorrhage is noncontrast head computed tomography (CT), with or without lumbar puncture.[1] The diagnosis of subarachnoid hemorrhage cannot be made on clinical grounds alone. Medical imaging is usually required to confirm or exclude bleeding.[2][3]

  • The modality of choice is computed tomography (CT/CAT) of the brain
  • The sensitivity of CT to the presence of subarachnoid blood is strongly influenced by both the amount of blood and the time since the hemorrhage[4]

The diagnosis is suspected when hyperattenuating material is seen filling the subarachnoid space. Most commonly this is apparent around

  • Circle of Willis (account of the majority of berry aneurysms)
  • Sylvian fissure

Small amounts of blood can sometimes be appreciated pooling in the interpeduncular fossa, appearing as a small hyperdense triangle, or within the occipital horns of the lateral ventricles.[5]

Subarachnoid haemorrhages are grouped into four categories according to the amount of blood by the Fisher Grade.[6]

Grading Amount of blood shown on initial CT scans
Grade 1
  • No hemorrhage evident
Grade 2
  • Subarachnoid hemorrhage less than 1 mm thick
  • No clots
Grade 3
  • Subarachnoid hemorrhage more than 1 mm thick
  • localised clots
Grade 4
  • Subarachnoid hemorrhage of any thickness with intra-ventricular hemorrhage (IVH) or parenchymal extension or absent blood in basal cisterns

Acute

  • The sensitivity of CT in the first 3 days after aSAH is very high (close to 100%)[7]
  • Acute Subarachnoid hemorrhage is typically 50-60 HU

Several days to weeks

  • 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.

Images

The following are the CT scans associated with diffuse subarachnoid hemorrhage.[8]

References

  1. van der Wee N, Rinkel GJ, Hasan D, van Gijn J (1995). "Detection of subarachnoid haemorrhage on early CT: is lumbar puncture still needed after a negative scan?". J Neurol Neurosurg Psychiatry. 58 (3): 357–9. PMC 1073376. PMID 7897421.
  2. Mayberg MR, Batjer HH, Dacey R, Diringer M, Haley EC, Heros RC, Sternau LL, Torner J, Adams HP Jr, Feinberg W, Thies W. Guidelines for the management of aneurysmal subarachnoid hemorrhage: a statement for healthcare professionals from a special writing group of the Stroke Council, American Heart Association. Circulation. 1994;90: 2592–2605.
  3. Bederson JB, Connolly ES Jr, Batjer HH, Dacey RG, Dion JE, Diringer MN, Duldner JE Jr, Harbaugh RE, Patel AB, Rosenwasser RH. Guidelines for the management of aneurysmal subarachnoid hemor- rhage: a statement for healthcare professionals from a special writing group of the Stroke Council, American Heart Association [published correction appears in Stroke. 2009;40:e518]. Stroke. 2009;40:994 –1025.
  4. Sames TA, Storrow AB, Finkelstein JA, Magoon MR (1996). "Sensitivity of new-generation computed tomography in subarachnoid hemorrhage". Acad Emerg Med. 3 (1): 16–20. PMID 8749962.
  5. Brant WE, Helms C. Fundamentals of Diagnostic Radiology. LWW. (2012) ISBN:1608319113
  6. Fisher C, Kistler J, Davis J (1980). "Relation of cerebral vasospasm to subarachnoid hemorrhage visualized by computerized tomographic scanning". Neurosurgery. 6 (1): 1–9. PMID 7354892.
  7. Perry JJ, Stiell IG, Sivilotti ML, Bullard MJ, Emond M, Symington C; et al. (2011). "Sensitivity of computed tomography performed within six hours of onset of headache for diagnosis of subarachnoid haemorrhage: prospective cohort study". BMJ. 343: d4277. doi:10.1136/bmj.d4277. PMC 3138338. PMID 21768192. Review in: Evid Based Med. 2012 Feb;17(1):27-8
  8. Rads wiki, Images courtesy of RadsWiki Images courtesy of RadsWiki

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