Subarachnoid hemorrhage CT: Difference between revisions
No edit summary |
|||
| Line 6: | Line 6: | ||
==CT== | ==CT== | ||
The mainstay of diagnosis of suarachnoid hemorrhage is noncontrast head computed tomography (CT), with or without lumbar puncture. | The mainstay of diagnosis of suarachnoid hemorrhage is noncontrast head [[computed tomography|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. | The diagnosis of subarachnoid hemorrhage cannot be made on clinical grounds alone. [[Medical imaging]] is usually required to confirm or exclude bleeding. | ||
*The modality of choice is [[computed tomography]] (CT/CAT) of the brain | *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 (~30%) ref needed. | |||
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. | |||
The diagnosis is suspected when hyperattenuating material is seen filling the subarachnoid space. Most commonly this is apparent around | |||
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 | |||
Subarachnoid haemorrhages are grouped into four categories according to the amount of blood by the Fisher Grade.<ref>{{cite journal |author=Fisher C, Kistler J, Davis J |title=Relation of cerebral vasospasm to subarachnoid hemorrhage visualized by computerized tomographic scanning |journal=Neurosurgery |volume=6 |issue=1 |pages=1-9 |year=1980 |pmid=7354892}}</ref> | Subarachnoid haemorrhages are grouped into four categories according to the amount of blood by the Fisher Grade.<ref>{{cite journal |author=Fisher C, Kistler J, Davis J |title=Relation of cerebral vasospasm to subarachnoid hemorrhage visualized by computerized tomographic scanning |journal=Neurosurgery |volume=6 |issue=1 |pages=1-9 |year=1980 |pmid=7354892}}</ref> | ||
| Line 49: | Line 39: | ||
*Subarachnoid hemorrhage of any thickness with intra-ventricular hemorrhage (IVH) or parenchymal extension or absent blood in basal cisterns | *Subarachnoid hemorrhage of any thickness with intra-ventricular hemorrhage (IVH) or parenchymal extension or absent blood in basal cisterns | ||
|} | |} | ||
===Acute=== | |||
*The [[Sensitivity (tests)|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. | |||
[http://www.radswiki.net Images courtesy of RadsWiki] | [http://www.radswiki.net Images courtesy of RadsWiki] | ||
Revision as of 15:37, 12 December 2016
|
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.
- 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 (~30%) ref needed.
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.
Subarachnoid haemorrhages are grouped into four categories according to the amount of blood by the Fisher Grade.[1]
| 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.
-
CT: Diffuse subarachnoid hemorrhage -
CT: Diffuse subarachnoid hemorrhage -
CT: Diffuse subarachnoid hemorrhage -
CT: Diffuse subarachnoid hemorrhage
Once a subarachnoid hemorrhage is confirmed, the next question is about its origin. CT angiography (using radiocontrast) to identify aneurysms is generally the first step, as invasive angiography (injecting radiocontrast through a catheter advanced to the brain arteries) has a small rate of complications but is useful if there are plans to obliterate the source of bleeding, such as an aneurysm, at the same time.