Linking To And Embedding Radiopaedia’s “Acute Basilar Artery Occlusion”

Posted on July 16, 2026 by Tom Wade MD

Today, I review, link to, and embed Radiopaedia’s Acute Basilar Artery Occlusion.* Last revised by Joachim Feger on 27 Nov 2025.

*Citation:D’Souza D, Sharma R, Agazzi G, et al. Acute basilar artery occlusion. Reference article, Radiopaedia.org (Accessed on 16 Jul 2026) https://doi.org/10.53347/rID-971

DOI:
https://doi.org/10.53347/rID-971
Permalink:
https://radiopaedia.org/articles/acute-basilar-artery-occlusion
rID:
Article (rID 971, “Acute basilar artery occlusion”)

All that follows is from the above resource.

Acute basilar artery occlusion is a cause of infarction of the posterior circulation, including vital structures such as the brainstem and/or thalami. It is a true neurointerventional emergency, and if not treated early, it can result in rapid neurological deterioration and even death. Even with maximal treatment, mortality and morbidity are high.

Although occlusions of the posterior circulation arteries comprise about a fifth of all strokes, basilar artery occlusion is relatively rare, accounting for only ~1% of all strokes, and ~10% of large vessel occlusions 2,9.

Patients with acute occlusion of the basilar artery may present with sudden and dramatic neurological impairment, the exact characteristics of which will depend on the site of occlusion. Clinical features include:

  • sudden death/loss of consciousness
  • top of the basilar syndrome 14
    • visual and oculomotor deficits
    • behavioral abnormalities
    • somnolence, hallucinations, and dream-like behavior
    • motor dysfunction is often absent
  • proximal and mid portions of the basilar artery (pons) can result in patients being “locked in” 7,8
    • complete loss of movement (quadriparesis and lower cranial dysfunction) and respiratory muscle paralysis
    • preserved consciousness
    • preserved ocular movements (often only vertical gaze) 8, as the oculomotor nerve is not affected

Acute occlusion of the basilar artery may have a number of etiological mechanisms, most commonly either thromboembolism, atherosclerosis, or propagation of intracranial dissection 13. Although these pathologies may occur anywhere, each of these has a predilection for different segments of the basilar artery:

  • proximal: vertebrobasilar junction 13
    • thromboembolism (e.g. cardioembolic)
    • atherosclerosis with thrombosis
    • propagation of vertebral arterial dissection (rare)
  • middle: midsegment 13
    • atherosclerosis with thrombosis
  • distal: distal third or basilar tip (most common site of occlusion) 13

For general and detailed features of ischemic stroke, please see that article.

Transcranial Doppler ultrasound findings include 12:

  • absent (or reduced) signal in the basilar artery
  • indirect signs such as abnormal waveforms in the vertebral arteries and collateral flow

Transcranial Doppler ultrasound may also have a role in assessing recanalization at the bedside 12.

  • non-contrast CT
    • hyperdense vessel sign of the basilar artery (the basilar artery equivalent of the hyperdense MCA sign), present in ~65% 9
    • a high index of suspicion is needed in the correct clinical setting, as the diagnosis can easily be missed (often only present on 1 or 2 slices); additionally, it is well recognized that acute clots are of lower attenuation than chronic clots 5,6
    • hypoattenuation delineates tissue with ischemic damage (beam-hardening artifacts limit visualization of the brainstem on CT)
  • contrast-enhanced CT

Angiography remains the gold standard for the diagnosis of basilar artery occlusion. However, in practice, DSA is used only after non-invasive imaging during endovascular clot retrieval for therapeutic recanalization 9. Images demonstrate a filling defect within the basilar artery.

  • DWI/ADC
    • restricted diffusion within infarcted tissue
  • T2/FLAIR
    • hyperintense signal within infarcted tissue
    • loss of flow void within the basilar artery

Management is essentially the same as that for ischemic stroke due to large vessel occlusions of other arteries. As such, acute treatments include intravenous thrombolysis and endovascular clot retrieval 1,2.

Notably, compared to evidence supporting endovascular clot retrieval in the anterior circulation, outcomes in randomized control trials in the posterior circulation have been more heterogeneous 1, with positive landmark trials including the ATTENTION and BAOCHE trials 3,4. There is no consensus regarding the advantage of direct aspiration thrombectomy vs stent retriever for basilar artery occlusions; both techniques are accepted, and the choice between them often depends on various patient-related factors 11.

Despite advances in management, acute occlusion of the basilar artery is a life-threatening event, which can carry a mortality of >40%, and combined mortality and significant disability of >80% 2,13.

References

  • 1. Abdalkader M, Finitsis S, Li C et al. Endovascular Versus Medical Management of Acute Basilar Artery Occlusion: A Systematic Review and Meta-Analysis of the Randomized Controlled Trials. J Stroke. 2023;25(1):81-91. doi:10.5853/jos.2022.03755 – Pubmed
  • 2. Drumm B, Banerjee S, Qureshi M et al. Current Opinions on Optimal Management of Basilar Artery Occlusion: After the BEST of BASICS Survey. SVIN. 2022;2(5). doi:10.1161/svin.122.000538
  • 3. Jovin T, Li C, Wu L et al. Trial of Thrombectomy 6 to 24 Hours After Stroke Due to Basilar-Artery Occlusion. N Engl J Med. 2022;387(15):1373-84. doi:10.1056/NEJMoa2207576 – Pubmed
  • 4. Tao C, Nogueira R, Zhu Y et al. Trial of Endovascular Treatment of Acute Basilar-Artery Occlusion. N Engl J Med. 2022;387(15):1361-72. doi:10.1056/NEJMoa2206317 – Pubmed
  • 5. New P & Aronow S. Attenuation Measurements of Whole Blood and Blood Fractions in Computed Tomography. Radiology. 1976;121(3 Pt. 1):635-40. doi:10.1148/121.3.635 – Pubmed
  • 6. Wittram C, Maher M, Halpern E, Shepard J. Attenuation of Acute and Chronic Pulmonary Emboli. Radiology. 2005;235(3):1050-4. doi:10.1148/radiol.2353040387 – Pubmed
  • 7. Castillo M. The Core Curriculum, Neuroradiology. (2002) ISBN:0781736641. Read it at Google Books – Find it at Amazon
  • 8. Thomas L. Pope, John H. Harris, Jr.. Harris & Harris’ Radiology of Emergency Medicine. (2012) ISBN: 9781451107203 – Google Books
  • 9. Mattle H, Arnold M, Lindsberg P, Schonewille W, Schroth G. Basilar Artery Occlusion. Lancet Neurol. 2011;10(11):1002-14. doi:10.1016/S1474-4422(11)70229-0 – Pubmed
  • 10. Goyal N, Tsivgoulis G, Nickele C et al. Posterior Circulation CT Angiography Collaterals Predict Outcome of Endovascular Acute Ischemic Stroke Therapy for Basilar Artery Occlusion. J Neurointerv Surg. 2016;8(8):783-6. doi:10.1136/neurintsurg-2015-011883 – Pubmed
  • 11. Lee W, Correia Maciel R, Abo Kasem R et al. Direct Aspiration Versus Stent Retriever as First-Line Thrombectomy Techniques for Acute Basilar Artery Occlusions: An Updated Systematic Review and Meta-Analysis. Neuroradiology. 2025;67(10):2851-67. doi:10.1007/s00234-025-03749-0 – Pubmed
  • 12. Sloan M, Krumholz A, Rigamonti D. Transcranial Doppler Findings During Spontaneous Recanalization of Vertebrobasilar Occlusions. J Stroke Cerebrovasc Dis. 1993;3(1):9-14. doi:10.1016/S1052-3057(10)80127-2 – Pubmed
  • 13. Chhabra N, O’Carroll C, Wang H et al. Presentation, Treatment and Outcomes of Acute Basilar Artery Occlusion: A Retrospective Analysis. J Stroke Cerebrovasc Dis. 2025;34(1):108153. doi:10.1016/j.jstrokecerebrovasdis.2024.108153 – Pubmed
  • 14. Caplan L. “Top of the Basilar” Syndrome. Neurology. 1980;30(1):72. doi:10.1212/wnl.30.1.72 – Pubmed

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