Background
Acute aneurysmal subarachnoid hemorrhage (SAH) is a medical and neurosurgical emergency
from ruptured brain aneurysm. Aneurysmal SAH is identified on brain computed tomography
(CT) as increased density of basal cisterns and subarachnoid spaces from acute blood
products. Aneurysmal SAH-like pattern on CT appears as an optical illusion effect
of hypodense brain parenchyma and/or hyperdense surrounding cerebral cisterns and
blood vessels termed as “pseudo-subarachnoid hemorrhage” (pseudo-SAH).
Methods
We reviewed clinical, laboratory, and radiographic data of all SAH diagnoses between
January 2013 and January 2018, and found subsets of nonaneurysmal SAH, originally
suspected to be aneurysmal in origin. We performed a National Library of Medicine
search methodology using terms “subarachnoid hemorrhage,” “pseudo,” and “non-aneurysmal
subarachnoid hemorrhage” singly and in combination to understand the sensitivity,
specificity, and precision of pseudo-SAH.
Results
Over 5 years, 230 SAH cases were referred to our tertiary academic center and only
7 (3%) met the definition of pseudo-SAH. Searching the National Library of Medicine
using subarachnoid hemorrhage yielded 27,402 results. When subarachnoid hemorrhage and pseudo were combined, this yielded 70 results and sensitivity was 50% (n = 35). Similarly,
search precision was relatively low (26%) as only 18 results fit the clinical description
similar to the 7 cases discussed in our series.
Conclusions
Aneurysmal SAH pattern on CT is distinct from nonaneurysmal and pseudo-SAH patterns.
The origin of pseudo-SAH terminology appears mostly tied to comatose cardiac arrest
patients with diffuse dark brain Hounsfield units and cerebral edema, and is a potential
imaging pitfall in acute medical decision-making.
Key Words
To read this article in full you will need to make a payment
Purchase one-time access:
Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online accessOne-time access price info
- For academic or personal research use, select 'Academic and Personal'
- For corporate R&D use, select 'Corporate R&D Professionals'
Subscribe:
Subscribe to Journal of Stroke and Cerebrovascular DiseasesAlready a print subscriber? Claim online access
Already an online subscriber? Sign in
Register: Create an account
Institutional Access: Sign in to ScienceDirect
References
- Management of aneurysmal subarachnoid hemorrhage.Handb Clin Neurol. 2017; 140: 195-228
- Subarachnoid haemorrhage: diagnosis, causes and management.Brain. 2001; 124: 249-278
- Sensitivity of computed tomography performed within six hours of onset of headache for diagnosis of subarachnoid haemorrhage: prospective cohort study.BMJ. 2011; 343: d4277
- Atypical causes of nontraumatic intracranial subarachnoid hemorrhage.Clin Neurol Neurosurg. 2009; 111: 354-358
- Subarachnoid hemorrhage: beyond aneurysms.AJR Am J Roentgenol. 2014; 202: 25-37
- Increased density of tentorium and falx: a false positive CT sign of subarachnoid hemorrhage.Can Assoc Radiol J. 1986; 37: 243-247
- CT diagnosis of non-traumatic subarachnoid haemorrhage in patients with brain edema.Eur J Radiol. 1998; 28: 222-225
- Pseudo-subarachnoid hemorrhage: a rare neuroimaging pitfall.Can J Neurol Sci. 1999; 26: 57-59
- Pseudo-subarachnoid hemorrhage of the head diagnosed by computerized axial tomography: a postmortem study of ten medical examiner cases.J Forensic Sci. 2002; 47: 360-365
- False subarachnoid hemorrhage in anoxic encephalopathy with brain swelling.J Neuroimaging. 2000; 10: 236-238
- Pseudosubarachnoid haemorrhage on CT brain scan: an unusual presentation of diffuse hypoxic brain injury.Intensive Care Med. 2007; 33: 2038-2040
- Pseudo-subarachnoid hemorrhage found in patients with postresuscitation encephalopathy: characteristics of CT findings and clinical importance.AJNR Am J Neuroradiol. 2008; 29: 1544-1549
- The framing of decisions and the psychology of choice.Science. 1981; 211: 453-458
- Developing optimal search strategies for detecting clinically sound studies in MEDLINE.J Am Med Inform Assoc. 1994; 1: 447-458
- Pseudo-subarachnoid hemorrhage: a potential imaging pitfall.Can Assoc Radiol J. 2014; 65: 225-231
- Pseudo-subarachnoid hemorrhage.Am J Emerg Med. 2008; 26: e1-e2
- Pseudo-subarachnoid haemorrhage due to chronic hypoxaemia: case report and review of the literature.BMC Neurol. 2014; 14: 219
- Subarachnoid contrast enhancement after spinal angiography mimicking diffuse subarachnoid hemorrhage.AJR Am J Roentgenol. 1998; 170: 503-505
- Pseudo-subarachnoid hemorrhage: a potential imaging pitfall associated with diffuse cerebral edema.AJNR Am J Neuroradiol. 2003; 24: 254-256
- Images from headache: spontaneous intracranial hypotension presenting as “pseudo” subarachnoid hemorrhage.Headache. 2008; 48: 614-615
- Pseudo-subarachnoid hemorrhage: a CT-finding in spontaneous intracranial hypotension.Neurology. 2005; 65: 135-137
- Acute purulent leptomeningitis mimicking subarachnoid hemorrhage on CT.J Comput Assist Tomogr. 1994; 18: 126-128
- [Spontaneous hyperdense intracranial vessels seen on CT scan in polycythemia cases].J Radiol. 2003; 84: 605-608
- The diffuse hyperdense intracranial circulation sign.Neurohospitalist. 2011; 1: 137
- Role of Hounsfield units to distinguish pseudo-subarachnoid hemorrhage.Clin Toxicol (Phila). 2011; 49: 948
- “Pseudo-subarachnoid hemorrhage sign” on early brain computed tomography in out-of-hospital cardiac arrest survivors receiving targeted temperature management.J Crit Care. 2017; 40: 36-40
- Pseudo-subarachnoid hemorrhage and cortical visual impairment as the presenting sign of gliomatosis cerebri.Semin Ophthalmol. 2004; 19: 78-80
- Image in toxicology: Pseudo-subarachnoid hemorrhage in a case of severe valproic acid poisoning.Clin Toxicol (Phila). 2011; 49: 699-700
- Ehrlichia meningitis mimicking aneurysmal subarachnoid hemorrhage: a case study for medical decision-making heuristics.Neurohospitalist. 2016; 6: 76-79
Article info
Publication history
Published online: June 05, 2018
Accepted:
April 12,
2018
Received in revised form:
April 5,
2018
Received:
February 19,
2018
Identification
DOI: https://doi.org/10.1016/j.jstrokecerebrovasdis.2018.04.016
Copyright
© 2018 National Stroke Association. Published by Elsevier Inc. All rights reserved.
