Hyperintense vessel sign on FLAIR maybe associated with cerebral collateral circulation in patients with acute ischemic stroke or transient ischemic attack： a retrospective case series study

Abstract

Objective To investigate the possible formation mechanism and imaging features of the hyperintense vessel sign （HVS） on fluid attenuated inversion recovery （FLAIR） in patients with ischemic stroke or transient ischemic attack （TIA）. Methods The baseline data of the patients with middle cerebral artery （MCA） ischemic stroke or TIA with digital subtraction angiography （DSA） showing the lesions of MCA M1 segment in clinical practice were retrospectively retrieved from Nanjing Stroke Registry Program from January 2010 to July 2011. FLAIR was used to observe HVS, and DSA was used to evaluate the degree of vascular stenosis and cerebral collateral circulation. Results A total of 101 patients were enrolled, 76 （75.2%） were males, and their mean age was 53.94 ±13.47 years; 90 patients （89. 1%） with ischemic stroke and 11 patients （10. 9%） with TIA; 55 patients （54. 5%） were HVS negative and 46 （45.5%） were HVS positive. Among the patients whose MCA stenosis 〈50%, 50% -70%, 70% -90% and ≥90%, the positive rates were 0% （0/8）, 25.0% （3/12）, 17. 6% （3/17）, and 62.5% （40/64）, respectively. There were significant differences （Z= -4.479, P〈 0.001）. The leptomeningeal collateral circulation of the HVS positive group was significantly more than that of the HVS negative group （Z = - 6. 196, P 〈 0. 001 ）. Multivariate logistic regression analysis showed that the degree of MCA stenosis was an independent risk factor for influencing the formation of HVS （odds ratio 3. 943, 95% confidence interval 2. 03-7. 659; P 〈 0. 001）. Conclusions The formed intracranial leptomeningeal collateral circulation after severe intracranial vascular stenosis or occlusion is a major pathophysiological basis of HVS formation on FLAIR sequences in oatients with ischemic stroke or TIA. Key words: Stroke; Brain Ischemia; Infarction, Middle Cerebral Artery; Collateral Circulation; MagneticResonance Imaging; Cerebral Angiography