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computed_tomography_angiography_for_subarachnoid_hemorrhage

Computed tomography angiography for subarachnoid hemorrhage

Computed tomography angiography is slowly replacing digital subtraction angiography as the first-line technique for the diagnosis and treatment planning of cerebral aneurysms, but digital subtraction angiography is still required in patients with diffuse SAH and negative initial computed tomography angiography.

Computed tomography angiography (CTA) is increasingly used for the detection, characterization, and follow-up of intracranial aneurysms.

A lower threshold to request a CT angiogram may render a patient population that differs from previous studies primarily evaluated with conventional angiography.


All CTA studies performed over a 10-year period at a large neurovascular referral center were reviewed for the presence of an intracranial aneurysm. Patient demographics, mortality, CTA indication, aneurysm location, size, and rupture status were recorded.

2927 patients with aneurysms were identified among 29 003 CTAs. 17% of the aneurysms were ruptured at the time of imaging, 24% of aneurysms were incidentally identified, and multiple aneurysms were identified in 34% of patients. Aneurysms most commonly arose from the supraclinoid internal carotid artery (22%), the middle cerebral artery (18%), and the anterior communicating artery (13%). Male sex, age <50 years, aneurysms >6 mm, and aneurysms arising from the anterior communicating artery, posterior communicating artery, or the posterior circulation were independent predictors of aneurysm rupture. Independent mortality predictors included male sex, posterior circulation aneurysms, intraventricular hemorrhage, and intraparenchymal hemorrhage.

These results indicate that aneurysms detected on CTA that arise from the anterior communicating artery, posterior communicating artery, or the posterior circulation, measure >6 mm in size, occur in men, and in patients aged <50 years are associated with rupture.

CT angiography (CTA) is increasingly used for the detection, characterization, and follow-up of intracranial aneurysms. A lower threshold to request a CT angiogram may render a patient population that differs from previous studies primarily evaluated with conventional angiography.

All CTA studies performed over a 10-year period at a large neurovascular referral center were reviewed for the presence of an intracranial aneurysm. Patient demographics, mortality, CTA indication, aneurysm location, size, and rupture status were recorded.

2927 patients with aneurysms were identified among 29 003 CTAs. 17% of the aneurysms were ruptured at the time of imaging, 24% of aneurysms were incidentally identified, and multiple aneurysms were identified in 34% of patients. Aneurysms most commonly arose from the supraclinoid internal carotid artery (22%), the middle cerebral artery (18%), and the anterior communicating artery (13%). Male sex, age <50 years, aneurysms >6 mm, and aneurysms arising from the anterior communicating artery, posterior communicating artery, or the posterior circulation were independent predictors of aneurysm rupture. Independent mortality predictors included male sex, posterior circulation aneurysms, intraventricular hemorrhage, and intraparenchymal hemorrhage.

These results indicate that aneurysms detected on CTA that arise from the anterior communicating artery, posterior communicating artery, or the posterior circulation, measure >6 mm in size, occur in men, and in patients aged <50 years are associated with rupture 1).

DSA identifies vascular pathology in 13% of patients with CTA-negative SAH. Aneurysms or pseudoaneurysms are identified in an additional 4% of patients by repeat DSA following an initially negative DSA. All patients with CT-negative SAH should be considered for DSA. The pattern of SAH may suggest the cause of hemorrhage, and aneurysms should specifically be sought with diffuse or perimesencephalic subarachnoid hemorrhage 2).

Bone-subtraction CTA is as accurate as DSA in detecting cerebral aneurysms after SAH, provides similar information about aneurysm configuration and measures, and reduces the average effective radiation dose for vascular diagnostics by 65%. Diagnostic equivalence in association with dose reduction suggests replacing DSA with bone-subtraction CTA in the diagnostic work-up of spontaneous SAH 3).


In view of the aggressive natural history of posterior circulation traumatic intracranial aneurysm (TICA), deSouza et al., recommend that CTA of the head and neck vessels be performed for cases presenting with post-traumatic disproportionate cisternal and or third ventricle or fourth ventricle SAH. In the event of initial CTA being negative, repeat CTA and if negative DSA should be performed between 5 to 7 days, with a low threshold for further repeat at 10 days if a traumatic dissection is still suspected. Close monitoring for hydrocephalus and vasospasm is required during hospital admission and significant therapy input is likely to be required post discharge from acute care 4).

1)
Heit JJ, Gonzalez RG, Sabbag D, Brouwers HB, Ordonez Rubiano EG, Schaefer PW, Hirsch JA, Romero JM. Detection and characterization of intracranial aneurysms: a 10-year multidetector CT angiography experience in a large center. J Neurointerv Surg. 2015 Nov 9. pii: neurintsurg-2015-012082. doi: 10.1136/neurintsurg-2015-012082. [Epub ahead of print] PubMed PMID: 26553878.
2)
Heit JJ, Pastena GT, Nogueira RG, Yoo AJ, Leslie-Mazwi TM, Hirsch JA, Rabinov JD. Cerebral Angiography for Evaluation of Patients with CT Angiogram-Negative Subarachnoid Hemorrhage: An 11-Year Experience. AJNR Am J Neuroradiol. 2015 Sep 3. [Epub ahead of print] PubMed PMID: 26338924.
3)
Aulbach P, Mucha D, Engellandt K, Hädrich K, Kuhn M, von Kummer R. Diagnostic Impact of Bone-Subtraction CT Angiography for Patients with Acute Subarachnoid Hemorrhage. AJNR Am J Neuroradiol. 2015 Oct 8. [Epub ahead of print] PubMed PMID: 26450538.
4)
deSouza RM, Shah M, Koumellis P, Foroughi M. Subarachnoid haemorrhage secondary to traumatic intracranial aneurysm of the posterior cerebral circulation: case series and literature review. Acta Neurochir (Wien). 2016 Sep;158(9):1731-40. doi: 10.1007/s00701-016-2865-6. Epub 2016 Jun 30. Review. PubMed PMID: 27364895; PubMed Central PMCID: PMC4980416.
computed_tomography_angiography_for_subarachnoid_hemorrhage.txt · Last modified: 2016/09/09 18:42 (external edit)