Annals of Indian Academy of Neurology
  Users Online: 8117 Home | About the Journal | InstructionsCurrent Issue | Back IssuesLogin      Print this page Email this page  Small font size Default font size Increase font size

Table of Contents
Year : 2022  |  Volume : 25  |  Issue : 4  |  Page : 710

The differential arterial flow signal sign: An early brain MRI sign of circulatory arrest

1 Department of Radio-diagnosis and Imaging, PGIMER, Chandigarh, India
2 Department of Internal Medicine, PGIMER, Chandigarh, India

Date of Submission16-Jan-2022
Date of Acceptance05-Mar-2022
Date of Web Publication06-Apr-2022

Correspondence Address:
Vikas Bhatia
Neuroradiology Section, Department of Radio-Diagnosis, PGIMER, Chandigarh - 160 012
Login to access the Email id

Source of Support: None, Conflict of Interest: None

DOI: 10.4103/aian.aian_57_22

Rights and Permissions


How to cite this article:
Bhatia V, Khalid S, Seth R, Saroch A. The differential arterial flow signal sign: An early brain MRI sign of circulatory arrest. Ann Indian Acad Neurol 2022;25:710

How to cite this URL:
Bhatia V, Khalid S, Seth R, Saroch A. The differential arterial flow signal sign: An early brain MRI sign of circulatory arrest. Ann Indian Acad Neurol [serial online] 2022 [cited 2022 Dec 2];25:710. Available from:

A 52-year-old male with encephalopathy for 5 days, underwent an MRI brain examination. On MRI [Figure 1], there was the loss of signal void in bilateral internal carotid arteries (ICA); however, with preserved flow void in the intracranial arteries on the T2W images. Susceptibility weighted imaging (SWI) showed accentuated susceptibility changes in the intracranial arteries with hyperintense signal in bilateral ICA. We term this sign as a “differential arterial flow signal sign.” The likely cause of hyperintense signal in the ICA in our case is slow/stagnant flow, whereas hypointense signal on T2W/SWI in the intracranial arteries represent the loss of signal due to increased cerebral oxygen extraction and deoxygenated blood representing cerebral autoregulation. The increased susceptibility effect in the intracranial arteries has been reported earlier in a series of brain-dead patients due to hypoxia.[1]
Figure 1: (a) Coronal T2W image showing loss of flow void in bilateral internal carotid arteries (ICA) (thick white arrows) and presence of flow void in the intracranial vessels (thick white arrows). (b) Axial SW image shows presence of prominent cortical (thick black arrow) and medullary veins (thin black arrow). (c) Axial SW image showing hyperintense signal in bilateral ICA (black arrow head) (d) Axial SW image showing prominent susceptibility-relatedsignal loss in intracranial arteries (white arrow heads)

Click here to view

We also observed prominent medullary and cortical veins on the SWI. This finding has been previously reported to be due to increased oxygen extraction, increased deoxyhemoglobin and/or venous stasis/dilatation after cell death. A similar finding is also seen in stroke, trauma, comatose patients, and brain death.[2] MR angiography and contrast imaging were not done in our case, and the patient was immediately shifted to emergency, where he was declared dead due to cardio-respiratory arrest.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

   References Top

Tsai FY, Lee KW, Kao HW, Chen CY. Susceptibility weighted imaging, an additional tool to diagnose brain death: Initial experience. Neuroradiol J 2012;25:505-8.  Back to cited text no. 1
Sohn CH, Lee HP, Park JB, Chang HW, Kim E, Kim E, et al. Imaging findings of brain death on 3-tesla MRI. Korean J Radiol 2012;13:541-9.  Back to cited text no. 2


  [Figure 1]


Print this article  Email this article


    Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
    Article in PDF (491 KB)
    Citation Manager
    Access Statistics
    Reader Comments
    Email Alert *
    Add to My List *
* Registration required (free)  

    Article Figures

 Article Access Statistics
    PDF Downloaded44    
    Comments [Add]    

Recommend this journal