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|Year : 2017 | Volume
| Issue : 2 | Page : 427-428
Posterior inferior cerebellar artery susceptibility sign in lateral medullary syndrome
BM Krishna Vadana, R Adhithyan, C Kesavadas, Veerendra Malik
Department of Imaging Sciences and Interventional Radiology, Sri Chitra Thirunal Institute of Medical Science and Technology, Thiruvananthapuram, Kerala, India
|Date of Web Publication||10-Mar-2017|
B M Krishna Vadana
Room no. 305, A Block, Men's Hostel Sri Chitra Thirunal Institute of Medical Science and Technology, Thiruvananthapuram, Kerala
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Krishna Vadana B M, Adhithyan R, Kesavadas C, Malik V. Posterior inferior cerebellar artery susceptibility sign in lateral medullary syndrome. Neurol India 2017;65:427-8
|How to cite this URL:|
Krishna Vadana B M, Adhithyan R, Kesavadas C, Malik V. Posterior inferior cerebellar artery susceptibility sign in lateral medullary syndrome. Neurol India [serial online] 2017 [cited 2017 Aug 24];65:427-8. Available from: http://www.neurologyindia.com/text.asp?2017/65/2/427/201858
Susceptibility vessel sign is an important sign to localize the thrombosis in a vessel in case of ischemic stroke.
We report a patient with a classical lateral medullary syndrome in which posterior inferior cerebellar artery (PICA) susceptibility sign was very nicely demonstrated in the susceptibility weighted imaging (SWI) on magnetic resonance imaging (MRI) even before computed tomography (CT) angiography was done.
A 41-year-old male patient, who was an occasional alcoholic and smoker, presented with complaints of sudden onset of occipital headache associated with vomiting, ataxia, hemifacial sensory loss on the left side, and blurring of vision. Clinically, posterior circulation stroke was suspected. An emergency MRI with stroke protocol was performed [diffusion weighted imaging (DWI), apparent diffusion coefficient, SWI, fluid-attenuated inversion recovery, and time-of-flight angiography]. On DWI, there was a small acute infarct in the posterolateral aspect of the left medulla. Hence, a diagnosis of lateral medullary syndrome was made. On SWI, there was a curvilinear hypointensity with susceptibility blooming observed along the expected course of the left PICA. CT angiography performed on the next day showed cut-off in the left PICA [Figure 1].
|Figure 1: (a) Diffusion weighted imaging and (b) apparent diffusion coefficient images showing the infarct with restriction of diffusion in the posterolateral aspect of medulla on the left side indicated by the white arrows. Susceptibility weighted images (c) and (d) show evidence of susceptibility blooming in the left posterior inferior cerebellar artery (PICA) which is thrombosed. (e) Plain computed tomography (CT) scan shows a small hypodensity in the region of infarct; (f) and (g) CT angiography axial, coronal, and sagittal maximum intensity projection images showing an abrupt cut-off of the left PICA due to thrombosis|
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Ischemic stroke, a neurological emergency, is most commonly caused by thrombosis of the involved vessel. SWI helps in identifying an intra-arterial thrombus. The presence of a higher concentration of deoxyhemoglobin and clot retraction makes acute intra-arterial thrombus paramagnetic, which produces a blooming artifact.
Positive “susceptibility sign” is defined when the diameter of a hypointense vessel exceeds the diameter of the contralateral artery on SWI images. Magnetic properties of hemoglobin vary according to its oxygenation status. Deoxyhemoglobin is a paramagnetic substance whereas oxyhemoglobin is diamagnetic. The intra-arterial thrombus contains more deoxyhemoglobin as compared to flowing blood.
Susceptibility vessel sign is a very useful sign in patients with acute stroke in localizing the site of the intra-arterial thrombus.
The authors would like to thank the faculty of the Radiology and Neurology Department of the SCTIMST.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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