Subarachnoid FLAIR hyperintensity

Last revised by Rohit Sharma ◉ on 1 Dec 2024

Citation, DOI, disclosures and article data

Citation:

Radswiki T, Sharma R, Kogan J, et al. Subarachnoid FLAIR hyperintensity. Reference article, Radiopaedia.org (Accessed on 14 Mar 2025) https://doi.org/10.53347/rID-13419

DOI:

https://doi.org/10.53347/rID-13419

Permalink:

https://radiopaedia.org/articles/13419?embed_domain=hackmd.io%25252525252525252F%252525252525252540yipuafecsl2jsu8smr5njq%25252525252525252Fbnjhjgjghjghjgh

rID:

13419

Article created:

9 Apr 2011, The Radswiki ◉

Disclosures:

At the time the article was created The Radswiki had no recorded disclosures.

View The Radswiki's current disclosures

Last revised:

1 Dec 2024, Rohit Sharma ◉

Disclosures:

At the time the article was last revised Rohit Sharma had no financial relationships to ineligible companies to disclose.

View Rohit Sharma's current disclosures

Revisions:

21 times, by 15 contributors - see full revision history and disclosures

Systems:

Central Nervous System

Sections:

Gamuts

Synonyms:

Subarachnoid FLAIR high signal
Differential diagnosis for subarachnoid FLAIR hyperintensity

There are a wide range of causes for subarachnoid FLAIR hyperintensity, both pathological and artifactual.

Differential diagnosis

Pathological causes

subarachnoid hemorrhage
meningitis
leptomeningeal metastasis (e.g. carcinomatosis, lymphomatosis)
FLAIR vascular hyperintensities in acute stroke ^1,4,8
moyamoya disease
meningeal melanomatosis
meningeal melanocytosis
migraine
elevated blood pool to CSF ratio ¹
fat-containing lesions in subarachnoid space
- lipoma
- ruptured dermoid cyst
inflammatory cerebral amyloid angiopathy

Artifactual causes

hyperoxygenation therapy
- related to the paramagnetic effects of oxygen on the magnetic field
recent gadolinium contrast medium administration
- lasting ~2-24 hours, especially if there is adjacent pathology which involves disruption of the blood-brain barrier, or neovascularization ⁷
CSF flow artifact
vascular pulsation artifact
magnetic susceptibility artifact
motion artifact

References

1. Stuckey SL, Goh TD, Heffernan T et-al. Hyperintensity in the subarachnoid space on FLAIR MRI. AJR Am J Roentgenol. 2007;189 (4): 913-21. doi:10.2214/AJR.07.2424 - Pubmed citation
2. Noguchi K, Ogawa T, Seto H et-al. Subacute and chronic subarachnoid hemorrhage: diagnosis with fluid-attenuated inversion-recovery MR imaging. Radiology. 1997;203 (1): 257-62. Radiology (abstract) - Pubmed citation
3. Singh SK, Agris JM, Leeds NE et-al. Intracranial leptomeningeal metastases: comparison of depiction at FLAIR and contrast-enhanced MR imaging. Radiology. 2000;217 (1): 50-3. Radiology (full text) - Pubmed citation
4. Sanossian N, Saver JL, Alger JR et-al. Angiography reveals that fluid-attenuated inversion recovery vascular hyperintensities are due to slow flow, not thrombus. AJNR Am J Neuroradiol. 2009;30 (3): 564-8. doi:10.3174/ajnr.A1388 - Free text at pubmed - Pubmed citation
5. Kamran S, Bates V, Bakshi R et-al. Significance of hyperintense vessels on FLAIR MRI in acute stroke. Neurology. 2000;55 (2): 265-9. Neurology (full text) - Pubmed citation
6. Frigon C, Shaw DW, Heckbert SR et-al. Supplemental oxygen causes increased signal intensity in subarachnoid cerebrospinal fluid on brain FLAIR MR images obtained in children during general anesthesia. Radiology. 2004;233 (1): 51-5. doi:10.1148/radiol.2331031375 - Pubmed citation
7. Bozzao A, Floris R, Fasoli F et-al. Cerebrospinal fluid changes after intravenous injection of gadolinium chelate: assessment by FLAIR MR imaging. Eur Radiol. 2003;13 (3): 592-7. doi:10.1007/s00330-002-1546-4 - Pubmed citation
8. Mahdjoub E, Turc G, Legrand L, Benzakoun J, Edjlali M, Seners P, Charron S, Hassen WB, Naggara O, Meder JF, Mas JL, Baron JC, Oppenheim O. Do Fluid-Attenuated Inversion Recovery Vascular Hyperintensities Represent Good Collaterals before Reperfusion Therapy?. (2018) American Journal of Neuroradiology. 39 (1): 77. doi:10.3174/ajnr.A5431 - Pubmed
9. Panteleienko L, Banerjee G, Mallon D et al. Sulcal Hyperintensity as an Early Imaging Finding in Cerebral Amyloid Angiopathy–Related Inflammation. Neurology. 2024;103(12):e210084. doi:10.1212/wnl.0000000000210084 - Pubmed