Subarachnoid hemorrhage CT
|
Subarachnoid Hemorrhage Microchapters |
|
Diagnosis |
|---|
|
Treatment |
|
AHA/ASA Guidelines for the Management of Aneurysmal Subarachnoid Hemorrhage (2012)
|
|
Case Studies |
|
Subarachnoid hemorrhage CT On the Web |
|
American Roentgen Ray Society Images of Subarachnoid hemorrhage CT |
|
Risk calculators and risk factors for Subarachnoid hemorrhage CT |
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. The diagnosis of subarachnoid hemorrhage cannot be made on clinical grounds alone. Medical imaging is usually required to confirm or exclude bleeding.[1][2]
- 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
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.[3]
Subarachnoid haemorrhages are grouped into four categories according to the amount of blood by the Fisher Grade.[4]
| Grading | Amount of blood shown on initial CT scans |
|---|---|
| Grade 1 |
|
| Grade 2 |
|
| Grade 3 |
|
| Grade 4 |
|
Acute
- The sensitivity of CT in the first 3 days after aSAH is very high (close to 100%)
- 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.
The following are the CT scans associated with diffuse subarachnoid hemorrhage.[5]
References
- ↑ 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.
- ↑ 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.
- ↑ Brant WE, Helms C. Fundamentals of Diagnostic Radiology. LWW. (2012) ISBN:1608319113
- ↑ 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.
- ↑ Rads wiki, Images courtesy of RadsWiki Images courtesy of RadsWiki