![]() It turns out that occlusion of the PICA accounts for only a small number of cases. Anatomically the infarcted area in Wallenberg syndrome is supplied by the posterior inferior cerebellar artery (PICA). The syndrome can also be due to occlusion of the vertebral artery or the inferior, middle, or superior medullary vessels. The primary pathology of Wallenberg syndrome is occlusion of the posterior inferior cerebellar artery (PICA) or one of its branches. The trunk of PICA is divided into five segments: The fourth segment of the vertebral artery gives off the PICA, the largest branch of the vertebral artery. The vertebral artery, arising from the subclavian artery, is classically divided into four segments. The posterior inferior cerebellar artery (PICA) usually originates from the vertebral artery at an average distance of approximately 16 or 17 mm below the vertebrobasilar junction. This neurological disorder is associated with various symptoms that result from damage to the lateral segment of the medulla posterior to the inferior olivary nucleus. Wallenberg syndrome is also called lateral medullary or posterior inferior cerebellar artery syndrome. However, a more detailed description given in 1895 by Adolf Wallenberg identified this condition as infarction of the lateral medulla oblongata following occlusion of the vertebral artery (VA) or Posterior inferior cerebellar artery (PICA). The authors would like to thank the faculty of the Radiology and Neurology Department of the SCTIMST.Wallenberg syndrome was first described in 1808 by Gaspard Vieusseux. Susceptibility vessel sign is a very useful sign in patients with acute stroke in localizing the site of the intra-arterial thrombus. The intra-arterial thrombus contains more deoxyhemoglobin as compared to flowing blood. Deoxyhemoglobin is a paramagnetic substance whereas oxyhemoglobin is diamagnetic. Magnetic properties of hemoglobin vary according to its oxygenation status. Positive “susceptibility sign” is defined when the diameter of a hypointense vessel exceeds the diameter of the contralateral artery on SWI images. The presence of a higher concentration of deoxyhemoglobin and clot retraction makes acute intra-arterial thrombus paramagnetic, which produces a blooming artifact. SWI helps in identifying an intra-arterial thrombus. Ischemic stroke, a neurological emergency, is most commonly caused by thrombosis of the involved vessel. (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 Susceptibility weighted images (c) and (d) show evidence of susceptibility blooming in the left posterior inferior cerebellar artery (PICA) which is thrombosed. įigure 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. CT angiography performed on the next day showed cut-off in the left PICA. On SWI, there was a curvilinear hypointensity with susceptibility blooming observed along the expected course of the left PICA. Hence, a diagnosis of lateral medullary syndrome was made. On DWI, there was a small acute infarct in the posterolateral aspect of the left medulla. An emergency MRI with stroke protocol was performed. Clinically, posterior circulation stroke was suspected. 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.Ī 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. Susceptibility vessel sign is an important sign to localize the thrombosis in a vessel in case of ischemic stroke. Posterior inferior cerebellar artery susceptibility sign in lateral medullary syndrome. How to cite this URL: Krishna Vadana B M, Adhithyan R, Kesavadas C, Malik V. ![]() How to cite this article: Krishna Vadana B M, Adhithyan R, Kesavadas C, Malik V.
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