FLAIR Vascular Hyperintensity Research Articles

Prominent FLAIR Vascular Hyperintensity Is a Predictor of Unfavorable Outcomes in Non-thrombolysed Ischemic Stroke Patients With Mild Symptoms and Large Artery Occlusion.

Background and objective: The aim was to evaluate the clinical significance of prominent fluid-attenuated inversion recovery (FLAIR) vascular hyperintensity (FVH) on the prognosis of mild acute ischemic stroke with middle cerebral artery (MCA) occlusion.Methods: We recruited consecutive stroke patients with initial National Institutes of Health Stroke Scale (NIHSS) scores ≤5 and MCA occlusion on magnetic resonance angiography within 24 h of stroke onset. Prominent distal FVH was defined as an extension to more than one-third of the MCA territory. We compared clinical outcomes between prominent and non-prominent FVH groups in patients who had and had not received reperfusion therapy.Results: Of 112 participants [43 women; median age, 67 years [Interquartile range, 54–79]], prominent FVH was identified in 80 (71.4%). For 75 patients who had not received reperfusion therapy, the prominent FVH group had a more unfavorable outcome (modified Rankin Scale score >1) at 3 months than the non-prominent FVH group (44.4 vs. 15.0%, P = 0.029). In multivariate analysis, a higher NIHSS score [odd ratio [OR] = 1.67; 95% confidence interval [CI], 1.16–2.41; P = 0.006], proximal MCA occlusion [OR = 7.31; 95% CI, 1.68–31.9; P = 0.008], and prominent FVH [OR = 5.49; 95% CI, 1.29–23.4; P = 0.021], were independently associated with an unfavorable outcome. There was no association between prominent FVH and the clinical outcome in the reperfusion therapy group.Conclusions: For acute stroke patients with mild symptoms and MCA occlusion who do not receive reperfusion therapy, prominent FVH and proximal MCA occlusion may be independent predictors of an unfavorable outcome.

FLAIR hyperintensities-DWI mismatch in acute stroke: associations with DWI volume and functional outcome.

The value of fluid-attenuated inversion recovery vascular hyperintensity (FVH)-diffusion-weighted imaging (DWI)mismatch in predicting outcome with acute stroke is unclear. We assessed the association between FVH-DWI mismatch and functional outcome in patients with acute stroke patients receiving endovascular therapy. FVH-DWI mismatch, DWI volume, the functional outcome at 3months (modified Rankin scale; mRS) and other clinical data were collected for 59 acute stroke patients receiving MRI within 6h before endovascular therapy. Statistical analysis was performed to predict functional outcome after stroke. Patients with FVH-DWI mismatch (n = 39) had a higher FVH score (p = 0.038), smaller DWI volume (p = 0.007), higher American Society of Interventional and Therapeutic Neuroradiology (ASITN) (p = 0.043), higher interval time of ASITN (p = 0.038), and better functional outcome (p = 0.010) than patients with no FVH-DWI mismatch (n = 20). The good functional outcome group (n = 32) had a higher FVH score (p = 0.028), smaller DWI volume (p = 0.003) and higher ASITN grade (p = 0.043) than the poor functional outcome group (n = 27). Multivariable logistic analysis demonstrated that DWI volume (OR, 1.031; 95% CI, 1.005-1.058; P = 0.021) and FVH-DWI mismatch (OR, 14.311; 95% CI, 2.670-76.703; P = 0.002) were independently associated with functional outcome. Assessing DWI volume and FVH-DWI mismatch in acute stroke patients might be useful for predicting functional outcome after stroke.

Fluid-attenuated inversion recovery vascular hyperintensities in anterior circulation acute ischemic stroke: associations with cortical brain infarct volume and 90-day prognosis.

Fluid-attenuated inversion recovery vascular hyperintensity (FVH) is often observed in conjunction with acute ischemic stroke (AIS) of the carotid system. However, the significance of FVH in patients with AIS has not been fully elucidated. The purpose of this study is to investigate the effects of FVH on the final infarct volume (including cortical and deep brain infarct volume) and on 90-day prognosis in AIS patients. We analyzed data of 160 patients who had AIS of anterior circulation. FVH was identified and the cortical brain infarct volume (CBIV) and deep brain infarct volume (DBIV) were calculated. We assessed 90-day clinical outcome using the modified Rankin Scale (mRS). FVH was identified in 83 of the 160 patients (51.88%). Patients with FVH showed larger CBIV (13.94 ± 25.55 vs. 6.56 ± 13.49ml; p = 0.025), more frequent intracranial-large artery disease (74.70 vs. 27.27%; p < 0.001), and more severe clinical impairment on admission (NIHSS 7.22 ± 4.01 vs. 5.42 ± 4.52; p = 0.009). Considering the factors influencing prognosis, FVH positivity (OR = 2.12, 95% CI 1.13-3.99; p = 0.02) and NIHSS (at discharge) (OR = 2.14, 95% CI 1.64-2.78; p < 0.001) were independently associated with 90-day clinical outcome of AIS patients. FVH is a more common finding associated with larger CBIV, intracranial-large artery disease, and more severe strokes on admission. In the presence of good collateral circulation, FVH may be a predictor of better outcome in anterior circulation AIS patients at 90days.

Benefit from revascularization after thrombectomy according to FLAIR vascular hyperintensities-DWI mismatch.

We tested whether FLAIR vascular hyperintensities (FVH)-DWI mismatch could identify candidates for thrombectomy most likely to benefit from revascularization. We retrospectively reviewed 100 patients with proximal MCA occlusion from 18 stroke centers randomized in the IV-thrombolysis plus mechanical thrombectomy arm of the THRACE trial (2010-2015). We tested the associations between successful revascularization on digital subtraction angiography (modified Thrombolysis in Cerebral Infarction 2b/3) and 3-month favorable outcome (modified Rankin Scale score ≤ 2), stratified on FVH-DWI mismatch status, with secondary analyses adjusted on National Institutes of Health Stroke Scale (NIHSS) and DWI lesion volume. FVH-DWI mismatch was present in 79% of patients, with a similar prevalence at 1.5T (80%) and 3T (78%). Successful revascularization (74%) was more frequent in patients with FVH-DWI mismatch (63/79, 80%) than in patients without (11/21, 52%), p = 0.01. The OR of favorable outcome for revascularization were 15.05 (95% CI 3.12-72.61, p < 0.001) in patients with FVH-DWI mismatch and 0.83 (95% CI 0.15-4.64, p = 0.84) in patients without FVH-DWI mismatch (p = 0.011 for interaction). Similar results were observed after adjustment for NIHSS (OR = 12.73 [95% CI 2.69-60.41, p = 0.001] and 0.96 [95% CI 0.15-6.30, p = 0.96]) or for DWI volume (OR = 12.37 [95% CI 2.76-55.44, p = 0.001] and 0.91 [95% CI 0.16-5.33, p = 0.92]) in patients with and without FVH-DWI mismatch, respectively. The FVH-DWI mismatch identifies patients likeliest to benefit from revascularization, irrespective of initial DWI lesion volume and clinical stroke severity, and could serve as a useful surrogate marker for penumbral evaluation. • The FVH-DWI mismatch, defined by FLAIR vascular hyperintensities (FVH) located beyond the boundaries of the DWI lesion, is associated with large penumbra. • Among stroke patients with proximal middle cerebral artery occlusion referred for thrombectomy, those with FVH-DWI mismatch are most likely to benefit from revascularization. • FVH-DWI mismatch provides an alternative to PWI-DWI mismatch in order to select patients who are candidates for thrombectomy.

FLAIR vascular hyperintensity in acute stroke is associated with collateralization and functional outcome.

Fluid-attenuated inversion recovery vascular hyperintensity (FVH) is frequently found in stroke patients after intracranial arterial occlusion, but the prognostic value of FVH findings is unclear. We assessed whether FVH is associated with cerebral collateral status and functional outcome in patients with acute stroke patients receiving endovascular therapy. FVH score, American Society of Interventional and Therapeutic Neuroradiology (ASITN) grade, the functional outcome at 3months (modified Rankin Scale (mRS)), and other clinical data were collected for 37 acute stroke patients with large vessel occlusion (LVO) receiving MRI before and after endovascular therapy. Statistical analysis was performed to predict functional outcome after stroke. The good functional outcome group (n = 16) had a higher FVH1 (FVH before therapy) score (4.63 ± 1.20 vs 3.14 ± 1.15; p = 0.001) and ASITN grade (3.31 ± 0.48 vs 2.00 ± 1.22; p < 0.001) and a lower FVH2 (FVH after therapy) score than the poor functional outcome group (n = 21; 0.125 ± 0.50 vs 1.44 ± 2.16; p = 0.030). mRS at 3months was negatively correlated with FVH1 (r = - 0.525, p = 0.001) and the ASITN grade (r = - 0.478, p = 0.003) and positively correlated with FVH2 (r = 0.376, p = 0.034). FVH1 (OR, 0.085; 95% CI, 0.013-0.577; p = 0.012) and FVH2 (OR, 2.724; 95% CI, 1.061-6.996; p = 0.037) were independently associated with functional outcome in multivariable logistic regression analysis. Assessing FVH before and after therapy in acute stroke patients with LVO might be useful for predicting functional outcome after stroke. • Fluid-attenuated inversion recovery vascular hyperintensity is a circular or serpentine brightening in the brain parenchyma or cortical surface bordering the subarachnoid space on MR imaging. • A prospective study showed that fluid-attenuated inversion recovery vascular hyperintensity is associated with cerebral collateral circulation and prognosis. • Fluid-attenuated inversion recovery vascular hyperintensity helps clinicians to predict the prognosis of patients with acute stroke.

FLAIR vascular hyperintensities predict early ischemic recurrence in TIA.

To evaluate the relationship between fluid-attenuated inversion recovery (FLAIR) vascular hyperintensity (FVH) and early ischemic lesion recurrence (follow-up diffusion-weighted imaging [FU-DWI] [+]) in patients with lesion-negative TIA. We recruited consecutive patients with lesion-negative TIA within 24 hours of symptom onset, who underwent follow-up MRI during the acute period. FVH was defined as a focal or serpentine high signal intensity on FLAIR images. Other potential confounders were adjusted to evaluate the relationship between FVH and FU-DWI (+). Furthermore, to compare clinical outcomes between the FU-DWI (+) and FU-DWI (-) groups, we assessed 1-year recurrent ischemic stroke or TIA. Among 392 patients with lesion-negative TIA, 82 patients had FU-DWI (+) on the follow-up MRI. In the multivariate analysis, FVH remained an independent predictor of FU-DWI (+) (adjusted odds ratio [aOR] = 4.77, 95% confidence interval [CI] 2.45-9.29, p < 0.001). The time to initial MRI (aOR = 0.49, 95% CI = 0.33-0.70, p < 0.001) and intracranial atherosclerosis (aOR = 2.07, 95% CI = 1.10-3.92, p = 0.025) were also associated with FU-DWI (+), independent of FVH. In clinical outcomes, the FU-DWI (+) group showed more frequent 1-year recurrent ischemic stroke events than the FU-DWI (-) group (10.7% vs 3.1%, respectively, p = 0.007). FVH is associated with FU-DWI (+) in patients with lesion-negative TIA. As FU-DWI (+) frequently occurs during the acute period and has a subsequent worse outcome after discharge, additional radiologic or clinical markers for it are necessary.

Predictors of short-term outcome in patients with acute middle cerebral artery occlusion: unsuitability of fluid-attenuated inversion recovery vascular hyperintensity scores.

Fluid-attenuated inversion recovery (FLAIR) vascular hyperintensity (FVH) is used to assess leptomeningeal collateral circulation, but clinical outcomes of patients with FVH can be very different. The aim of the present study was to assess a FVH score and explore its relationship with clinical outcomes. Patients with acute ischemic stroke due to middle cerebral artery M1 occlusion underwent magnetic resonance imaging and were followed up at 10 days (National Institutes of Health Stroke Scale) and 90 days (modified Rankin Scale) to determine short-term clinical outcomes. Effective collateral circulation indirectly improved recovery of neurological function and short-term clinical outcome by extending the size of the pial penumbra and reducing infarct lesions. FVH score showed no correlation with 90-day functional clinical outcome and was not sufficient as an independent predictor of short-term clinical outcome.

Infarct morphology assessment in patients with carotid artery/middle cerebral artery occlusion using fast fluid-attenuated inversion recovery (FLAIR) vascular hyperintensity (FVH).

We aim to evaluate the value of fast fluid-attenuated inversion recovery (FLAIR) vascular hyperintensity (FVH) in assessing infarct morphology in patients with symptomatic internal carotid artery (ICA) or middle cerebral artery (MCA) occlusions. Magnetic resonance (MR) diffusion-weighted imaging (DWI) FLAIR sequences, and carotid/cerebral magnetic resonance angiography of 102 patients with symptomatic ICA or MCA occlusions were evaluated. The location and score of FVH were determined using Olindo’s method; patients were classified as having Low or High FVHs based on FVH score, and either Distal or Proximal FVH based on FVH location. The differences between infarct morphologies were analyzed. FVH were detectable in 62 patients with High FVH and in 40 patients with Low FVHs based on the Olindo’s scale. There were no statistically significant differences in age, gender, hypertension, diabetes, hyperlipidemia, smoking history, and vascular occlusive site between High and Low FVHs patients, except for infarct morphology (P<0.01). Patients with Distal FVH presented with significant (P<0.01) perforating artery and border zone infarcts, whereas those with Proximal FVH had significant (P<0.01) large territorial infarcts. The scores and locations of FVH could be a predictive imaging marker for infarct morphology in patients with symptomatic ICA or MCA occlusion.

Do Fluid-Attenuated Inversion Recovery Vascular Hyperintensities Represent Good Collaterals before Reperfusion Therapy?

In acute ischemic stroke, whether FLAIR vascular hyperintensities represent good or poor collaterals remains controversial. We hypothesized that extensive FLAIR vascular hyperintensities correspond to good collaterals, as indirectly assessed by the hypoperfusion intensity ratio. We included 244 consecutive patients eligible for reperfusion therapy with MCA stroke and pretreatment MR imaging with both FLAIR and PWI. The FLAIR vascular hyperintensity score was based on ASPECTS, ranging from 0 (no FLAIR vascular hyperintensity) to 7 (FLAIR vascular hyperintensities abutting all ASPECTS cortical areas). The hypoperfusion intensity ratio was defined as the ratio of the time-to-maximum >10-second over time-to-maximum >6-second lesion volumes. The median hypoperfusion intensity ratio was used to dichotomize good (low hypoperfusion intensity ratio) versus poor (high hypoperfusion intensity ratio) collaterals. We then studied the association between FLAIR vascular hyperintensity extent and hypoperfusion intensity ratio. Hypoperfusion was present in all patients, with a median hypoperfusion intensity ratio of 0.35 (interquartile range, 0.19-0.48). The median FLAIR vascular hyperintensity score was 4 (interquartile range, 3-5). The FLAIR vascular hyperintensities were more extensive in patients with good collaterals (hypoperfusion intensity ratio ≤0.35) than with poor collaterals (hypoperfusion intensity ratio >0.35; P for Trend = .016). The FLAIR vascular hyperintensity score was independently associated with good collaterals (P for Trend = .002). In patients eligible for reperfusion therapy, FLAIR vascular hyperintensity extent was associated with good collaterals, as assessed by the pretreatment hypoperfusion intensity ratio. The ASPECTS assessment of FLAIR vascular hyperintensities could be used to rapidly identify patients more likely to benefit from reperfusion therapy.

Influential factors and clinical significance of fluid-attenuated inversion recovery vascular hyperintensities in transient ischemic attacks of carotid arterial system.

Fluid-attenuated inversion recovery vascular hyperintensity (FVH) is often observed in conjunction with acute ischemic stroke (AIS) of the carotid system. Despite its bearing on patient care outcomes, factors influencing FVH and its clinical significance in patients with transient ischemic attacks (TIAs) of the carotid arterial system have yet to be evaluated. Consecutive inpatients (N=154) diagnosed with TIAs of the carotid system in a 2-year period (2012-2014) were enrolled in our study. Each had undergone magnetic resonance imaging (MRI) within 72h of symptom onset, followed by intracranial and extracranial vascular imaging. We investigated the frequency and nature of factors associated with FVH, also examining its clinical significance in the 30-day prognosis of TIA. Of the 154 patients enrolled (male, 92; mean age 63.0±11.9), FVH was confirmed in 61 patients (39.6%). In logistic regression analysis, intracranial large-artery disease (LAD) (OR=2.39, 95% CI 1.16-4.92; p=0.018) and prior stroke (OR=3.33, 95% CI 1.48-7.51; p=0.004) emerged as factors independently associated with FVH positivity. Ultimately, 25 patients (16.2%) progressed to AIS within a 30-day follow-up period. Logistic regression analysis indicated that contralateral FVH positivity (OR=5.98, 95% CI 1.81-19.76; p=0.003), atrial fibrillation (OR=7.05, 95% CI 1.33-37.40; p=0.022), and extracranial LAD (OR=4.12, 95% CI 1.26-13.41; p=0.019) were independently associated with AIS during the 30-day follow-up of TIAs in these patients. Intracranial LAD and previous stroke are independently associated with FVH in patients experiencing carotid system TIAs. If present, FVH may predict an oncoming AIS in the 30days following a TIA.

Fluid-attenuated inversion recovery vascular hyperintensities in predicting cerebral hyperperfusion after intracranial arterial stenting.

No reliable imaging sign predicting cerebral hyperperfusion after intracranial arterial stenting (IAS) had been described in the literature. This study evaluated the effect of fluid-attenuated inversion recovery vascular hyperintensities (FVHs), also called hyperintense vessel sign on T2-weighted fluid-attenuated inversion recovery (T2-FLAIR) MR images, in predicting significant increase in cerebral blood flow (CBF) defined by arterial spin labeling (ASL) after IAS. We reviewed ASL CBF images and T2-FLAIR MR images before (D0), 1day after (D1), and 3days after (D3) IAS of 16 patients. T1-weighted MR images were used as cerebral maps for calculating CBF. The changes in CBF values after IAS were calculated in and compared among stenting and nonstenting vascular territories. An increase more than 50% of CBF was considered as hyperperfusion. The effect of FVHs in predicting hyperperfusion was calculated. The D1 CBF value was significantly higher than the D0 CBF value in stenting vascular, contralateral anterior cerebral artery, contralateral middle cerebral artery, and contralateral posterior cerebral artery (PCA) territories (all P<.05). The D1 and D3 CBF values were significantly higher than the D0 CBF value in overall vascular (P<.001), overall nonstenting vascular (P<.001), and ipsilateral PCA (P<.05) territories. The rate of more than 50% increases in CBF was significantly higher in patients who exhibited asymmetric FVHs than in those who did not exhibit these findings. FVHs could be a critical predictor of a significant increase in CBF after IAS.

Fluid-Attenuated Inversion Recovery Vascular Hyperintensities in Patients with Transient Ischemic Attack

Fluid-attenuated inversion recovery (FLAIR) vascular hyperintensities (FVHs) are common in patients with acute ischemic stroke, possibly representing impaired hemodynamics in the ischemic territory due to intracranial steno-occlusive disease. There are few reports on FVHs in patients with transient ischemic attack (TIA). We investigated the prevalence of FVHs and its clinical correlations in patients with TIA. We evaluated consecutive patients admitted with TIA from February 2009 to June 2012 who had undergone magnetic resonance imaging within 30 hours of symptoms onset and intracranial and extracranial vascular imaging. Two independent neuroradiologists determined the presence of FVHs. We assessed the relationship between FVHs, clinical presentation, vascular risk factors, neuroimaging characteristics, and the presence of large artery stenosis or occlusion. Seventy-two patients with TIA were evaluated. FVHs were present in 12 (16.7%) patients. The overall agreement between examiners was good (κ = .67). There were no differences in the frequency of intracranial or cervical arterial stenosis in patients with and without FVH. In a multivariate logistic regression analysis including atrial fibrillation (AF), congestive heart failure, and diabetes, only AF remained in the final model. FVH signals on FLAIR images occur in patients with TIA and might correlate with clinical variables like AF and not only with large vessel occlusion. The presence of FVH in patients with TIA and AF might be a surrogate marker for a large vessel occlusion spontaneously recanalized or for impaired autoregulation in a previously ischemic vascular territory.

FLAIR vascular hyperintensities and 4D MR angiograms for the estimation of collateral blood flow in anterior cerebral artery ischemia.

PurposeTo assess FLAIR vascular hyperintensities (FVH) and dynamic (4D) angiograms derived from perfusion raw data as proposed magnetic resonance (MR) imaging markers of leptomeningeal collateral circulation in patients with ischemia in the territory of the anterior cerebral artery (ACA).MethodsForty patients from two tertiary care university hospitals were included. Infarct volumes and perfusion deficits were manually measured on DWI images and TTP maps, respectively. FVH and collateral flow on 4D MR angiograms were assessed and graded as previously specified.ResultsForty-one hemispheres were affected. Mean DWI lesion volume was 8.2 (± 13.9; range 0–76.9) ml, mean TTP lesion volume was 24.5 (± 17.2, range 0–76.7) ml. FVH were observed in 26/41 (63.4%) hemispheres. Significant correlations were detected between FVH and TTP lesion volume (ρ = 0.4; P<0.01) absolute (ρ = 0.37; P<0.05) and relative mismatch volume (ρ = 0.35; P<0.05). The modified ASITN/SIR score correlated inversely with DWI lesion volume (ρ = -0.58; P<0.01) and positively with relative mismatch (ρ = 0.29; P< 0.05). ANOVA of the ASITN/SIR score revealed significant inter-group differences for DWI (P<0.001) and TTP lesion volumes (P<0.05). No correlation was observed between FVH scores and modified ASITH/SIR scores (ρ = -0.16; P = 0.32).ConclusionsFVH and flow patterns on 4D MR angiograms are markers of perfusion deficits and tissue at risk. As both methods did not show a correlation between each other, they seem to provide complimentary instead of redundant information. Previously shown evidence for the meaning of these specific MR signs in internal carotid and middle cerebral artery stroke seems to be transferrable to ischemic stroke in the ACA territory.

Fluid-Attenuated Inversion Recovery Vascular Hyperintensity Topography, Novel Imaging Marker for Revascularization in Middle Cerebral Artery Occlusion.

In acute arterial occlusion, fluid-attenuated inversion recovery vascular hyperintensity (FVH) has been linked to slow flow in leptomeningeal collaterals and cerebral hypoperfusion, but the impact on clinical outcome is still controversial. In this study, we aimed to investigate the association between FVH topography or FVH-Alberta Stroke Program Early CT Score (ASPECTS) pattern and outcome in acute M1-middle cerebral artery occlusion patients with endovascular treatment. We included acute M1-middle cerebral artery occlusion patients treated with endovascular therapy (ET). All patients had diffusion-weighted imaging (DWI) and fluid-attenuated inversion recovery before ET. Distal FVH-ASPECTS was evaluated according to distal middle cerebral artery-ASPECT area (M1-M6) and acute DWI lesion was also reviewed. The presence of FVH inside and outside DWI-positive lesions was separately analyzed. Clinical outcome after ET was analyzed with respect to different distal FVH-ASPECTS topography. Among 101 patients who met inclusion criteria for the study, mean age was 66.2±17.8 years and median National Institutes of Health Stroke Scale was 17.0 (interquartile range, 12.0-21.0). FVH-ASPECTS measured outside of the DWI lesion was significantly higher in patients with good outcome (modified Rankin Scale [mRS] score of 0-2; 8.0 versus 4.0, P<0.001). Logistic regression demonstrated that FVH-ASPECTS outside of the DWI lesion was independently associated with clinical outcome of these patients (odds ratio, 1.3; 95% confidence interval, 1.06-1.68; P=0.013). FVH-ASPECTS inside the DWI lesion was associated with hemorrhagic transformation (odds ratio, 1.3; 95% confidence interval, 1.04-1.51; P=0.019). Higher FVH-ASPECTS measured outside the DWI lesion is associated with good clinical outcomes in patients undergoing ET. FVH-ASPECTS measured inside the DWI lesion was predictive of hemorrhagic transformation. The FVH pattern, not number, can serve as an imaging selection marker for ET in acute middle cerebral artery occlusion.

Clinical Significance of Fluid-Attenuated Inversion Recovery Vascular Hyperintensities in Borderzone Infarcts.

Fluid-attenuated inversion recovery vascular hyperintensities (FVHs) are seen in some cases with cerebral hemodynamic impairment and collateral flow. Because the worst outcomes of patients with borderzone infarcts were mainly correlated with impaired hemodynamics, the presence of FVH might provide another clue for predicting the prognosis of patients with borderzone infarcts. We reviewed 1377 consecutive patients with ischemic stroke. Cortical borderzone (CBZ) and internal borderzone infarcts were selected based on diffusion-weighted imaging. FVHs were defined as tubular- or serpentine-shaped hyperintensities in the subarachnoid space. We investigated the clinical significance of FVHs in borderzone-infarcted patients. Among 87 patients with borderzone infarcts, the presence of FVH was observed in 30 (34.5%). We identified 62 patients with CBZ infarcts and 25 patients with internal borderzone infarcts. In the cases with CBZ infarcts, the initial National Institutes of Health Stroke Scale scores and the portions of nonfavorable outcome at 3 months in the FVH(+) group were significantly higher than in the FVH(-) group (P<0.05 and P<0.001, respectively). Unlike the cases with CBZ infarcts, there were no significant differences of these clinical features between the FVH(+) group and the FVH(-) group in the patients with internal borderzone infarcts. The findings of FVH are associated with relatively severe clinical presentation and nonfavorable prognosis in patients with CBZ infarcts, but not in patients with internal borderzone infarcts. The presence of FVH may help to identify CBZ-infarcted patients who require close observation and hemodynamic control.

Abstract TP64: Negative-FLAIR Vascular Hyperintensities Serves as a Marker of Chronic Major Arterial Occlusion in Acute Stroke

Introduction: Because acute fluid-attenuated inversion recovery vascular hyperintensities (FVH) represent disordered blood flow, FVH has been considered as a marker of major arterial occlusions. Contrary, the role of absence of FVH (negative-FVH) is unknown. Hypothesis: We hypothesized that negative-FVH may indicate chronic occlusion. Thus, we investigated the clinical characteristics and neuroimaging findings in patients with negative-FVH and major arterial occlusion. Methods: Consecutive acute stroke patients within 24 hours of onset and major arterial occlusion on magnetic resonance angiography (MRA) were studied. All patients were examined using serial angiography to evaluate the presence of recanalization. Patients were classified into two groups (NF: group without FVH, F: group with FVH). Results: Seventy-two patients (49 [68%] males, 76 [66-83] years) were enrolled. Thirty-six (50%) patients were treated with acute recanalization therapy, including the intravenous thrombolysis or endovascular therapy. On admission, 10 patients were NF group and 62 were F group. Initial National Institutes of Health Stroke Scale (NIHSS) score was 4 (2-8) in NF group and 10 (4-21) in F group (p=0.012). The rate of internal carotid artery occlusion was similar between NF and F group (20% vs. 29%, p=0.716). Serial angiography studies revealed that recanalization was achieved in only 1 (10%) of the 10 patients with NF group and 49 (79%) of the 62 patients with F group during hospitalization (p&lt;0.001). When all patients divided into 2 groups based on the presence or absence of recanalization, patients with recanalization were younger (p=0.023), had higher NIHSS (p=0.008), earlier admission (p=0.014), higher prevalence of atrial fibrillation (p=0.010), and frequently treated with acute recanalization therapy (p=0.040). When multivariate regression analysis was conducted, that Negative-FVH (odds ratio 0.061, 95% CI 0.06-0.620, p=0.018) was a negative independent factor associated with recanalization during hospitalization. Conclusions: Negative-FVH was independently associated with no recanalization during hospitalization. Negative-FLAIR may present not acute occlusion but chronic occlusion.

Abstract WP46: FLAIR Vascular Hyperintensity ASPECTS (FVH-ASPECTS) Pattern Predicts Outcome in Endovascular Therapy in Acute M1-MCA Occlusion

Introduction: In acute arterial occlusion, the FLAIR vascular hyperintensity (FVH) sign have been linked to slow flow in leptomeningeal collaterals and cerebral hypoperfusion, but the impact on clinical outcome is still controversial. In this study, we aimed to investigate the association between FVH-ASPECTS pattern and outcome in acute M1-MCA occlusion patients with endovascular treatment. Methods: We included acute M1-MCA occlusion patients treated with endovascular therapy. All patients had DWI and FLAIR before endovascular therapy. Distal FVH ASPECT score was evaluated according to distal MCA-ASPECT area (M1-M6) and acute DWI lesion was also reviewed. Presence of FVH inside DWI positive lesion and outside DWI positive lesion was separately analyzed. We analyzed clinical outcome after endovascular therapy based on these different FVH-ASPECTS patterns. Results: Among 101 patients that met inclusion criteria for the study, mean age was 66.2±17.8 and median NIHSS was 17.0 (IQR 12.0-21.0). FVH-ASPECTS measured outside of the DWI lesion was significantly higher in patients with good outcome (mRS 0-2), (8.0 vs 4.0, p&lt;0.001). Logistic regression demonstrated that FVH-ASPECTS outside of the DWI lesion was independently associated with clinical outcome of these patients (OR 1.3, p=0.013). FVH-ASPECTS inside the DWI lesion was associated with hemorrhage transformation (OR 1.3, p=0.019). Conclusion: Higher FVH-ASPECTS measured outside the DWI lesion is associated with good clinical outcomes in patients undergoing endovascular therapy. FVH-ASPECTS measured inside the DWI lesion was predictive of hemorrhage transformation. FVH pattern, not number, can predict outcome of acute M1-MCA occlusion patients after endovascular therapy.

Abstract TMP39: Brain FLAIR Ischemic Lesion Burden as a Biomarker of Intracranial Atherosclerosis in SAMMPRIS

Background: FLAIR lesion burden is an established biomarker in small vessel disease. To examine its role in intracranial atherosclerosis, we studied ischemic lesion burden throughout the brain at baseline or enrollment in the SAMMPRIS trial and also on serial MRIs in the medical arm, investigating its relationship with recurrent stroke. Methods: We performed blinded measurement of lesion burden on baseline and followup FLAIR and DWI images. Baseline FLAIR and DWI lesion volume and FLAIR vascular hyperintensities (FVH) were analyzed with respect to baseline variables including prior history, co-morbidities and angiographic measures and also correlated with subsequent ischemic stroke in the territory of the stenotic artery. Results: Of 451 SAMMPRIS subjects, baseline MRI included DWI in 309 (69%) with FLAIR in 293 (65%). Ischemic lesion burden on baseline FLAIR was median 2.7 cc (0-87.0) cc, with greater extent in those older than 60 years (p=0.03) and those on anti-thrombotics (p=0.01). Increased FLAIR lesion burden showed a trend towards worse collateral status by angiography (p=0.10). The presence of FVH in 72/194 (37%) anterior circulation stenoses reflected more robust collateral status (p=0.002). Corresponding baseline DWI lesion volume was median 5.16 cc (range 0-71.8). Baseline FLAIR lesion burden predicted subsequent stroke in the territory (HR 1.028 [95% CI 1.013-1.043], p=0.0002) in both medical and endovascular therapy arms, whereas baseline DWI size was not predictive of subsequent stroke in the territory. Serial FLAIR in the medical arm revealed interval burden growth in 31/47 (66%), whereas only 13/47 (28%) had clinical stroke outcomes. Conclusions: FLAIR MRI is a potent biomarker of ischemic lesion burden that reflects prior strokes and collateral status. Baseline FLAIR lesion burden throughout the brain may identify stroke risk in intracranial atherosclerosis. “Silent” ischemic lesion progression on serial MRI in this study may have clinical sequelae, such as cognitive impairment, and deserves greater scrutiny.

Fluid-Attenuated Inversion Recovery Vascular Hyperintensities-Diffusion-Weighted Imaging Mismatch Identifies Acute Stroke Patients Most Likely to Benefit From Recanalization.

Fluid-attenuated inversion recovery vascular hyperintensities (FVH) beyond the boundaries of diffusion-weighted imaging (DWI) lesion (FVH-DWI mismatch) have been proposed as an alternative to perfusion-weighted imaging (PWI)-DWI mismatch. We aimed to establish whether FVH-DWI mismatch can identify patients most likely to benefit from recanalization. FVH-DWI mismatch was assessed in 164 patients with proximal middle cerebral artery occlusion before intravenous thrombolysis. PWI-DWI mismatch (PWITmax>6sec/DWI>1.8) was assessed in the 104 patients with available PWI data. We tested the associations between 24-hours complete recanalization on magnetic resonance angiography and 3-month favorable outcome (modified Rankin Scale score ≤2), stratified on FVH-DWI (or PWI-DWI) status. FVH-DWI mismatch was present in 121/164 (74%) patients and recanalization in 50/164 (30%) patients. The odds ratio for favorable outcome with recanalization was 16.2 (95% confidence interval, 5.7-46.5; P<0.0001) in patients with FVH-DWI mismatch and 2.6 (95% confidence interval, 0.6-12.1; P=0.22) in those without FVH-DWI mismatch (P=0.048 for interaction). Recanalization was associated with favorable outcome in patients with PWI-DWI mismatch (odds ratios, 9.9; 95% confidence interval, 3.1-31.3; P=0.0001) and in patients without PWI-DWI mismatch (odds ratios, 7.0; 95% confidence interval, 1.1-44.1; P=0.047), P=0.76 for interaction. The FVH-DWI mismatch may rapidly identify patients with proximal occlusion most likely to benefit from recanalization.

FLAIR Vascular Hyperintensity is a Surrogate of Collateral Flow and Leukoaraiosis in Patients With Acute Stroke Due to Proximal Artery Occlusion.

Fluid attenuated inversion recovery (FLAIR) vascular hyperintensity (FVH) is a novel radiographic marker detected in acute ischemic stroke (AIS) patients, which is linked to slow blood flow and potentially salvageable brain tissue. Poor leptomeningeal collateral status in AIS patients with proximal artery occlusion (PAO) is associated with larger final infarct and worse clinical outcomes, which are also affected by severity of white matter hyperintensity (WMH). We sought to evaluate FVH utility as a marker of acute collateral vessel status and its association with WMH burden in AIS patients. Consecutive AIS patients with PAO on baseline CT angiography (CTA) were retrospectively selected from a prospectively derived database. FVH was graded by its location, degree, and score on admission MRI obtained immediately after intravenous tissue plasminogen activator administration. Leptomeningeal collateral flow grade was ranked on admission CTA. WMH volume (WMHV) was assessed using a validated volumetric protocol. Relationship between FVH, collateral flow grade, and WMHV were analyzed. Among 39 patients (mean age 70.5 ± 12.7 years; 56% women, mean National Institutes of Health Stroke Scale score 17.2 (± 4.4)), median WMHV was 6.0 cm(3). FVH score and collateral flow grade were significantly correlated (Spearman's ρ = .41, P = .009). In a univariate regression model, FVH degree was inversely associated with WMHV (β = -.33, P = .04). FVH score detected on acute MRI can be used as a surrogate of collateral flow grade in AIS patients. FVH degree is inversely associated with WMHV, possibly signifying diffuse disease of cerebral vasculature in patients with severe leukoaraiosis.