Clinical Significances Of MRI Fluid-attenuated Inversion Recovery Hyperintense Vessel Sign In Ischemic Cerebralvascular Disease

Part I Initial research of mechanism of FLAIR hyperintense vessel sign in ischemic cerebralvascular diseaseBackground and Purpose:Hyperintense vessel sign (HVS) on MR images (MRI) fluid-attenuated inversion recovery (FLAIR) was described as focal, tubular, or serpentine hyperintensities seen in the subarachnoid space against the relative hypointensity of CSF. Previous studies revealed that HVS is an early sign of ischemia in patients with ischemic stroke. However, the mechanism of HVS on FLAIR is still unclear. Therefore, in this study, we aimed to investigate the mechanism and features of HVS in ischemic cerebralvascular disease by comparing brain MRI and digital subtraction angiography (DSA).Methods:One hundred and one consecutive patients with ischemic cerebralvascular disease [76male (75.2%), mean age (53.94±13.47) years,90cerebral infarction (89.1%) and11TIA (10.9%)] in the territory of middle cerebral artery (MCA), retrieved from Nanjing Stroke Registry Program between January2010and July2011, were enrolled as subjects. All subjects should completed brain MRI and DSA, which indicated steno-occlusive lesions in Ml segment of MCA. Clinic date including age, sex, history of hypertension, diabetes mellitus and hyperlipidemia and clinic manifestions were collected. The HVS were determined on FLAIR sequence and the leptomeningeal collateral circulation was assessed by DSA.Results:HVS was observed in46of the101enrolled patients (45.5%). The percentage of the positive HVS was gradually increased from MCA stenosis<50%to MCA occlusion [0/8(0%),3/12(25%),3/17(17.6%),40/64(62.5%) VS8/8(100%),9/12(75%),14/17(83.4%),24/64(37.5%), respectively, Z=-4.479, P<O.01]. HVS was sigificantly associated with leptomeningeal collateral circulation (Z=-5.593, P,O.01). IN addition, patients with HVS [(50.19±12.56) years] were younger than those without distal HV [(57.07±13.52) years, Z=-2.242, P=0.025]. The percentage of history of hypertension (50%) and hyperlipidemia (13%) in patients with HVS was fewer than that without distal HV [72.7%,X2=5.513, P=0.019;30.9%,X2=4.546, P=0.033).Conclusion:Leptomeningeal collateral circulation caused by intracerebral arterial steno-occlusive lesions may be the underling structures for HVS. Part Ⅱ Clinic prognostic value of FLAIR hyperintense vessel sign in acute middle cerebral artery occlusionBackground and Purpose:Cerebral collateral circulation refers to the subsidiary network of vascular channels that provides compensatory cerebral blood flow to arterial insufficiency via regurgitant leptomeningeal collateral circulation or subsidiary channels (communicating arteries). A number of studies have shown that the collateral circulation play a pivotal role in the progosis of cerebral infarction. Although previous studies revealed that HVS is an economical and convenient marker of leptomeningeal collateral circulation in ischemic stroke, the prognostic value of HVS on FLAIR is still unclear.Therefore, in this study, we aimed to evaluate the prognostic value of HVS in patients with acute middle cerebral artery occlusion.Methods:Seventy-seven consecutive patients with first ever acute ischemic stroke [52male (67.6%), mean age (59.26±15.59) years, media NIHSS11(1-25)] in the territory of middle cerebral artery (MCA), retrieved from Nanjing Stroke Registry Program between May2009and August2011, were enrolled as subjects. All subjects should completed brain MRI and MR angiography (MRA), which indicated occlusive lesions in M1segment of the MCA. According to the location and extent of HVS, all subjects were classified into3groups: without HVS, proximal HVS and distal HVS. Clinical data including age, sex, history of hypertension and diabetes mellitus, NIHSS score, mRS score and infarction volume, were obtained and compared among patients with different grades of HVS. Logistic regression analysis was employed to confirm the relevant factors of prognosis90days after index stroke.Results:HVS was observed in59(76.6%) of the77enrolled patients. Among patients with HVS,7were classified as proximal HVS (9.1%) and52as distal HVS (67.5%).Initial NIHSS score [9.5(1-22)], infarction volume [scale3:7cases (13%)], and90-day mRS score [3-6scores:9cases (17%)] were significantly lower in patients with distal HVS than those without distal HV [15(3-25), Z=-4.505;19cases (76%),X2=30.912;22cases (88%),X2=35.080; all P<0.01]. Although the NIHSS score decreased from baseline to that on10days is no significant difference between the two groups (Z=-1.223, P=0.221), the mRS score decreased from on10days to that on90days in patients with distal HVS was more than that without distal HVS (Z=-4.483, P<0.01).After adjusting for age, sex, the history of hypertension and diabetes mellirus and infartion volume, distal HVS (OR0.076,95%CI0.007-0.796, P=0.031) is an independent predictor for favorable outcome on90days after the index stroke in patients with acute middle cerebral artery occlusion.Conclusion:Distal HVS was an independent perdictor for a favorable outcome in patients with acute middle cerebral artery occlusion.