Negative Susceptibility Vessel Sign and Underlying Intracranial Atherosclerotic Stenosis in Acute Middle Cerebral Artery Occlusion

Abstract

BACKGROUND AND PURPOSE:The role of MR imaging in predicting underlying intracranial atherosclerotic stenosis before endovascular stroke therapy has not been studied. Our aim was to determine the diagnostic value of the negative susceptibility vessel sign on T2*-weighted gradient-echo MR imaging for predicting underlying intracranial atherosclerotic stenosis in patients with acute MCA occlusion.

Inflammatory mediator expression within retrieved clots in acute ischemic stroke

“…In this study, clots with a GRE SVS showed significantly lower IL‐1 β , TNF‐ α and MMP‐9 expression compared to clots without an SVS. These results support the idea that a GRE SVS is more frequently observed in patients with cardiogenic embolic stroke than in those with other stroke subtypes3, 12 and clots with a negative SVS could be associated with atherosclerosis 3, 13. The T2‐shortening effect of the intracellular deoxyhemoglobin component in red blood cells within the clot is the pathophysiologic basis of an SVS 3.…”

“…It was previously established that the presence of an SVS on GRE imaging was markedly associated with a higher red blood cell count in the clot, whereas fibrin‐dominant clots were associated with the absence of an SVS 3, 12. Fibrin‐dominant clots are typically formed because of endothelium injury overlies the complicated plaque in the setting of advanced atherosclerosis 13. Therefore, fibrin‐dominant clots related to advanced atherosclerosis would not appear as an SVS on GRE imaging due to the lack of deoxyhemoglobin, and could have increased expression of cytokines, matrix‐degrading proteases, or other inflammatory mediators.…”

“…These results support the idea that a GRE SVS is more frequently observed in patients with cardiogenic embolic stroke than in those with other stroke subtypes 3,12 and clots with a negative SVS could be associated with atherosclerosis. 3,13 The T2-shortening effect of the intracellular deoxyhemoglobin component in red blood cells within the clot is the pathophysiologic basis of an SVS. 3 Paramagnetic intracellular deoxyhemoglobin leads to a nonuniform magnetic field causing marked signal loss on the GRE sequence because of spin dephasing.…”

“…3,12 Fibrin-dominant clots are typically formed because of endothelium injury overlies the complicated plaque in the setting of advanced atherosclerosis. 13 Therefore, fibrin-dominant clots related to advanced atherosclerosis would not appear as an SVS on GRE imaging due to the lack of deoxyhemoglobin, and could have increased expression of cytokines, matrix-degrading proteases, or other inflammatory mediators. Our results confirm this hypothesis, indicating that intracranial clots with a negative SVS showed significantly higher expression of IL-1b, TNF-a, and MMP-9.…”

“…11,12 Previous studies suggested that the presence of SVS may predict cardioembolic stroke and absence of SVS may be associated with large artery atherosclerosis. 3,12,13 In this study we investigate the existence of an association between the expression of representative inflammatory mediators measured in intracranial clots and stroke etiology, as well as the SVS on T2*-weighted GRE MR imaging in acute ischemic stroke patients.…”