, Volume 59, Issue 10, pp 989–996 | Cite as

Mid-cervical flame-shaped pseudo-occlusion: diagnostic performance of mid-cervical flame-shaped extracranial internal carotid artery sign on computed tomographic angiography in hyperacute ischemic stroke

  • Supada Prakkamakul
  • Nantaporn Pitakvej
  • Netsiri Dumrongpisutikul
  • Sukalaya Lerdlum
Diagnostic Neuroradiology



Flame-shaped pseudo-occlusion of the extracranial internal carotid artery (ICA) is a flow-related phenomenon that creates computed tomographic angiography (CTA) and digital subtraction angiography (DSA) findings that mimic tandem intracranial-extracranial ICA occlusion or dissection. We aim to determine the diagnostic performance of mid-cervical flame-shaped extracranial ICA sign on CTA in hyperacute ischemic stroke patients.


We retrospectively included consecutive anterior circulation ischemic stroke patients presenting within 6 h of symptom onset who underwent 4D brain CTA and arterial-phase neck CTA using a 320-detector CT scanner during August 2012 to July 2015. Two blinded readers independently reviewed arterial-phase neck CTA and characterized the extracranial ICA configurations into mid-cervical flame-shaped, proximal blunt/beak-shaped, and tubular-shaped groups. 4D whole brain CTA was used as a reference standard for intracranial ICA occlusion detection. Diagnostic performance of the mid-cervical flame-shaped extracranial ICA sign and interobserver reliability were calculated.


Of the 81 cases, 11 had isolated intracranial ICA occlusion, and 6 had true extracranial ICA occlusion. Mid-cervical flame-shaped extracranial ICA sign was found in 45.5% (5/11) of isolated intracranial ICA occlusions but none in the true extracranial ICA occlusion group. The sensitivity, specificity, PPV, NPV, and accuracy of the mid-cervical flame-shaped extracranial ICA sign for the detection of isolated intracranial ICA occlusion were 45.5, 100, 100, 92.1, and 92.6%, respectively. Interobserver reliability was 0.90.


The mid-cervical flame-shaped extracranial ICA sign may suggest the presence of isolated intracranial ICA occlusion and allow reliable exclusion of tandem extracranial-intracranial ICA occlusion in hyperacute ischemic stroke setting.


Stroke Hyperacute Pseudo-occlusion Flame-shaped CTA 


Compliance with ethical standards


No funding was received for this study.

Conflict of interest

The authors declare that they have no conflict of interest.

Ethical approval

This article does not contain any studies with human participants or animals performed by any of the authors. For this type of study formal consent is not required.

Informed consent

For this type of retrospective study formal consent is not required.


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Copyright information

© Springer-Verlag GmbH Germany 2017

Authors and Affiliations

  1. 1.Department of RadiologyKing Chulalongkorn Memorial Hospital the Thai Red Cross SocietyBangkokThailand
  2. 2.Department of Radiology, Faculty of MedicineChulalongkorn UniversityBangkokThailand

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