FLAIR Vascular Hyperintensity Research Articles

Abstract T P40: FLAIR Vascular Hyperintensity is a Marker of Collateral Flow Grade and Severity of Leukoaraiosis in Patients with Acute Ischemic Stroke

Introduction: FLAIR Vascular Hyperintensity (FVH) is a novel radiographic marker detected on FLAIR MRI sequence in patients with acute ischemic stroke (AIS), which is linked to abnormal 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 size and worse clinical outcomes, which are also known to be affected by severity of white matter hyperintensity (WMH). We sought to evaluate the utility of FVH as a marker of acute collateral vessel status and its association with WMH burden in AIS patients. Methods: Consecutive AIS patients admitted to our center with PAO on baseline CT angiography (CTA) were retrospectively selected from a prospectively derived database. FVH was assessed on admission FLAIR MRI obtained immediately after IV tPA administration. FVH was graded by its location (0-none, 1-proximal, 2-distal, and 3-both); degree (0-none, 1-subtle, 2-prominent, and 3-both); and its score (0-none, 1-less than four hyperintense vessels, and 2-four or more hyperintense vessels). Collateral flow grade was ranked on admission CTA using previously published method. WMH volume (WMHV) was assessed using a validated, semi-automated volumetric MRI-based protocol. The relationship between FVH, collateral flow grade, and WMHV were analyzed. Results: A total of 39 patients were included in this study (mean age 70.5±12.7 years; 56% women, mean NIHSS score 17.2±4.4 points). Median WMHV was 6.0 cm3 (interquartile range [IQR] 3.4-9.6 cm3). Median DWI volume was 17.7 cm3 (IQR 9.9-26.0 cm3). FVH score and collateral flow grade were significantly correlated (Spearman’s rank correlation ρ=0.41, p=0.009). In a univariate regression model, FVH degree was inversely associated with WMHV volume (β=-0.33, p=0.04). Conclusions: FVH score detected on acute FLAIR MRI can be used as a marker of collateral flow grade in patients with AIS. Degree of FVH is inversely associated with WMHV, possibly signifying the diffuse disease of cerebral vasculature in patients with severe leukoraiosis.

Stroke : Highlights of Selected Articles

HomeStrokeVol. 46, No. 2Stroke: Highlights of Selected Articles Free AccessResearch ArticlePDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toFree AccessResearch ArticlePDF/EPUBStroke: Highlights of Selected Articles Originally published1 Feb 2015https://doi.org/10.1161/STROKEAHA.114.008576Stroke. 2015;46:321Reliability and Limitations of Automated Arrhythmia Detection in Telemetric Monitoring After StrokeAll patients with acute ischemic stroke should have continuous ECG monitoring during admission to the hospital because of the increased risk of serious cardiac arrhythmia and for the detection of possible atrial fibrillation. Data on the use of continuous cardiac monitoring for patients with stroke are lacking. The current study by Kurka et al aimed to determine the validity of cardiac monitoring in a stroke unit after acute stroke. A total of 151 patients were included in the study, and >4800 hours of monitoring were evaluated. In total, 22 509 alarms were detected. Approximately 73% of all nonlife threatening alarms were correct. In contrast, only 8.6% of the 140 alarms deemed life-threatening arrhythmias were correct. Of these, asystole had the highest false-positive rate, as only 2% of these alarms were true asystole. In summary, continuous cardiac monitoring in acute stroke seems sensitive but not specific. The high false positivity can lead to noise disturbances and alarm fatigue. Further improvement in specificity of continuous cardiac monitoring is needed. See p 560.Bright Vessel Appearance on Arterial Spin Labeling MRI for Localizing Arterial Occlusion in Acute Ischemic StrokeArterial spin labeling (ASL) is a perfusion-weighted MRI sequence. The current study by Yoo et al reviewed the MRIs of 117 patients with acute ischemic stroke. All MRIs were analyzed for the presence or absence of bright vessel signal on ASL, susceptibility vessel sign, fluid-attenuated inversion recovery vascular hyperintensity, and arterial occlusion on MR angiography (MRA). The purpose of the study was to determine whether bright vessel signal on ASL could help localize arterial occlusion on MRI in patients with acute stroke. ASL bright vessel appearance was more common in patients with arterial occlusion seen on MRA than those without occlusion. The bright appearance on ASL was seen both proximal and distal to the site of occlusion. The sensitivity of ASL bright vessel appearance in detecting arterial occlusion was far more sensitive than susceptibility vessel sign when using MRA as a standard reference (94%, 33/35 versus 66%, 23/35; P=0.002). Among the 82 cases of negative MRA, ASL bright vessel appearance detected more peripheral occlusions than susceptibility vessel sign (21%, 17/82 versus 10%, 8/82; P=0.012). Importantly, this study showed that bright vessel signal on ASL may be helpful in identifying arterial occlusions not seen on MRA. Although further confirmatory studies are needed, the use of ASL in acute stroke MRI protocol may be helpful in diagnosing embolic lesions. See p 564.Safety and Effect of Metoclopramide to Prevent Pneumonia in Patients With Stroke Fed via Nasogastric Tubes TrialPneumonia is a major cause of morbidity and mortality after stroke. Dysphagia and aspiration are important causes of pneumonia after stroke. Patients receiving tube feeds via nasogastric tubes are at high risk of pneumonia. Metoclopramide, a dopamine antagonist, is both an antiemetic and gastric prokinetic. The authors hypothesized that the reduction in vomiting and reflux in patients on metoclopramide would lead to a reduction in the risk of aspiration and pneumonia. Metoclopramide to Prevent Pneumonia in Patients With Stroke Fed Via Nasogastric Tubes (MAPS) trial is a randomized, double blind, placebo-controlled trial of prophylactic metoclopramide versus placebo in patients with stroke fed via nasogastric tubes. Sixty patients were enrolled in this study in the 1:1 ratio. Pneumonia was significantly more common in the placebo group compared with the metoclopramide group (rate ratio, 5.24; P<0.001). There were also significantly more episodes of aspiration and days on antibiotics in the placebo group. There was no significant difference in mortality between both treatment groups. Extrapyramidal reactions, such as dystonic reactions and tardive dyskinesia, were not seen in the metoclopramide group. The results of the MAPS study show that the prophylactic use of metoclopramide in patients with stroke with nasogastric tubes is safe and reduces the incidence of pneumonia. Although these results are certainly promising, this study is limited by its size, and thus, larger studies will be needed before best determine the effect of metoclopramide in this stroke population. See p 454. Previous Back to top Next FiguresReferencesRelatedDetails February 2015Vol 46, Issue 2 Advertisement Article InformationMetrics © 2015 American Heart Association, Inc.https://doi.org/10.1161/STROKEAHA.114.008576 Originally publishedFebruary 1, 2015 PDF download Advertisement

Fluid Attenuated Inversion Recovery Vascular Hyperintensities Possibly Indicate Slow Arterial Blood Flow in Vertebrobasilar Dolichoectasia.

Vertebrobasilar dolichoectasia (VBD) is a dilatative arteriopathy associated with a decreased blood flow velocity. Fluid attenuated inversion recovery (FLAIR) vascular hyperintensity (FVH) is a phenomenon most likely representing slow arterial blood flow. We sought to examine the frequency and extent of FVH in VBD. We analyzed magnetic resonance imaging (MRI) findings in 77 VBD patients with special emphasis on FVH in relation to the diagnostic MRI criteria of VBD and the etiology in symptomatic patients. In 49 (63.6%) VBD patients, FVH could be detected: in 22 (44.9%) a small hyperintense rim near the vessel wall (grade 1), in 20 (40.8%) a strong hyperintense rim near the vessel wall (grade 2), and in 7 (14.3%) the hyperintense signal filled the complete vessel lumen (grade 3). The diameter of the basilar artery moderately correlated with the extent of FVH. A higher FVH grade (2 and 3) was more common in patients with TIA/stroke related to VBD (9/16 [56.3%]) in comparison to patients with other etiology and asymptomatic patients (18/61 [29.5%]; P = .046). FVH may be useful to demonstrate the decreased blood flow velocity in VBD. More pronounced FVH in patients with posterior circulation TIA/stroke might reflect the underlying stroke pathomechanism.

Clinical Significance of Fluid-Attenuated Inversion Recovery Vascular Hyperintensities in Transient Ischemic Attack

Fluid-attenuated inversion recovery vascular hyperintensity (FVH) is often identified in patients with acute ischemic stroke. The purpose of this study was to determine the clinical significance of FVH in patients with transient ischemic attack (TIA). Consecutive inpatients with TIA who underwent MRI within 24 hours of symptom onset were studied. The frequency, relative factors, and time course of FVH were determined. Of the 202 patients who were enrolled (76 women, mean age, 69.0 ± 13.2 years), FVH was identified in 41 patients (20%). Multivariate analysis showed that atrial fibrillation (odds ratio, 7.14; 95% confidence interval [CI], 2.69-18.1), arterial occlusive lesion (odds ratio, 4.89; 95% CI, 3.03-12.2), and hemiparesis (odds ratio, 2.81; 95% CI, 1.17-7.48) was independently associated with FVH. Of 23 recurrence-free patients with FVH positive undergoing follow-up MRI at a median of 7 days after the onset, FVH was no longer positive in 15 patients (65%). Atrial fibrillation was more common (P=0.027) and arterial occlusive lesion was less common (P<0.001) in patients with transient FVH compared with those with persistent FVH. Within 90 days after the onset, 13 patients developed recurrent TIA or ischemic stroke. After Cox proportional hazard analysis, FVH (hazard ratio, 3.65; 95% CI, 1.09-12.7), arterial occlusive lesion (hazard ratio, 4.15; 95% CI, 1.18-17.1), and coexistence of FVH and arterial occlusive lesion (hazard ratio, 13.9; 95% CI, 3.36-71.0) were significantly associated with recurrent TIA or ischemic stroke. The presence of FVH early after symptom onset may help to diagnosis TIA, to identify the potential mechanisms of TIA and to predict recurrence risk after a TIA.

Fluid-attenuated inversion recovery vascular hyperintensities are not visible using 3D CUBE FLAIR sequence

Fluid-attenuated inversion recovery (FLAIR) vascular hyperintensities (FVH), initially described on 2D FLAIR images, are a useful imaging marker in patients with acute ischaemic stroke. We aimed to compare the sensitivity of the 3D CUBE FLAIR sequence with 2D FLAIR for the detection of FVH. Forty-seven consecutive patients admitted for a suspected stroke were explored by 2D and 3D CUBE FLAIR MR sequences at 1.5 and 3 T. Three blinded readers assessed FVH defined as hyperintensities within cerebral arteries. Location of FVH, acute brain infarct and arterial stenosis were also assessed. 2D images were compared with 3D images for the detection of FVH. Agreement between readers was assessed. Of the 47 patients, 21 FVHs were observed on 2D FLAIR images of 15 patients (11 with acute brain infarct and 11 with an arterial stenosis). No FVH was visualised on 3D CUBE FLAIR images for either proximal or distal locations. Agreement between readers was excellent. FVHs are not visible using 3D CUBE FLAIR images. This study suggests that, in suspected acute ischaemic stroke, the assessment of FVH should only be performed on conventional 2D FLAIR images. • Fluid-attenuated inversion recovery (FLAIR) vascular hyperintensities (FVH) are of neuroradiological importance. • FVHs are useful imaging markers in patients with an acute ischaemic stroke. • FVHs are not visible using 3D CUBE FLAIR images. • Assessment of FVH should be performed on conventional 2D FLAIR images.

Abstract WP229: Clinical Significance Of Fluid-attenuated Inversion Recovery Vascular Hyperintensities In Transient Ischemic Attack

BACKGROUND AND PURPOSE: Fluid-attenuated inversion recovery vascular hyperintensities (FVH) is often seen in patients with acute ischemic stroke attributable to arterial stenosis or occlusion. However, clinical significance of FVH in patients with transient ischemic attack (TIA) remains understudied. METHODS: Consecutive patients with TIA who underwent brain MRI within 24 hours of onset were studied. The frequency, relative factors, and time course of FVH were determined. Large artery atherosclerosis (LAA) was defined as more than 50 % stenosis or occlusion of the cervicocranial artery presumably due to atherosclerosis. RESULTS: Of 202 patients enrolled (76 women, 69.0±13.2 years old, median onset-to-arrival time 98 min [IQR 60-200], none undergoing thrombolysis), FVH was identified in 41 (20%). Atrial fibrillation (AF, 49% vs. 19%, P&lt;0.001), LAA (56% vs. 25%, P&lt;0.001), and positive findings on diffusion weighted image were more common (32% vs. 14%, P=0.020) in FVH-positive patients than in FVH-negative patients. Multivariate analysis showed that AF (OR 7.50 ; 95% CI 2.85-16.8) and LAA (OR 6.60; 95% CI 3.18-16.8) were independently associated with FVH. Within 90 days after the onset, 13 patients developed recurrent TIA or ischemic stroke (17% in FVH-positive vs. 4% in FVH-negative, P=0.010); 9 did within a week, 1 did between 2-4 weeks, and 3 did later. After multivariate analysis, LAA was independently associated (OR 6.38; 95% CI 1.59-33.0) and FVH tended to be associated (OR 3.30; 95% CI 0.89-12.6) with the recurrent episode. Of 36 recurrence-free FVH-positive patients, 23 underwent follow-up MRI median 7 days (IQR 6-11) after onset. FVH was no longer positive in 15 patients (65%). In these 15 patients, AF was more common (67% vs 13%, P=0.027) and LAA was less common (13% vs 88%, P=0.001) than the other 8 patients with persistent FVH. CONCLUSION: FVH was identified in 20% of acute TIA patients. AF and LAA were positively associated with FVH; AF seems to be associated with transient FVH and LAA does with persistent FVH.

Fluid-Attenuated Inversion Recovery Vascular Hyperintensity

Few data are available on the relationship between fluid-attenuated inversion recovery vascular hyperintensities and proximal middle cerebral artery occlusion prognosis. To assess a fluid-attenuated inversion recovery vascular hyperintensities score (FVHS) and explore its relationship with recanalization status and clinical outcomes after intravenous thrombolysis. Retrospective study. Stroke unit in a university hospital. Consecutive patients with proximal middle cerebral artery occlusion, thrombolysed within 6 hours, were selected from our prospective database. The FVHS (range,0-10; divided into low, medium, and high thirds) was quantified on the magnetic resonance image obtained at admission. Recanalization rates, infarction size (Alberta Stroke Program Early CT Score applied to diffusion weighted imaging [ASPECTS-DWI]), and 3-month functional outcomes (modified Rankin Scale score) were determined. Poor outcomes and large infarctions were defined as a modified Rankin Scale score higher than 2and an ASPECTS-DWI score of 5 or lower, respectively. Interaction among FVHS,recanalization status, and outcomes. Thirty-four patients had a low FVHS (4), 32 had a medium FVHS (5 or 6), and 39 had a high FVHS (≥7). The rate of poor functional outcome (modified Rankin Scale score >2) was higher for the group with low FVHSs than those with medium FVHSs and high FVHSs(82.3% vs 43.7% and 43.5%, respectively; P.001). Therate of 24-hour large infarctions(ASPECTS-DWI score 5)was higher for those with low FVHSs than those with medium and high FVHSs (88.2% vs 56.2% and 51.3%, respectively;P=.002). The recanalization rate was not associated with FVHS. Multivariate analysis retained low FVHS as an independent early predictor of poor clinical outcome (odds ratio=9.91; 95% CI, 2.01-48.93; P=.004)and large infarction (odds ratio=6.99; 95% CI, 1.78-27.46; P=.005).Low FVHS remained associated with poor outcomes regardless of recanalization status. Early recanalization in patients with a low FVHS decreased the poor functional outcome rate from 100% to 64.7% (P=.02). The FVHS is an early independent prognostic marker for patients with proximal middle cerebral artery occlusion. Synergy between FVHS and recanalization status appears to be a critical determinant of final outcomes, supporting intensive reperfusion treatment for patients with a low FVHS.

FLAIR Vascular Hyperintensities in Acute ICA and MCA Infarction: A Marker for Mismatch and Stroke Severity?

Background: Vascular hyperintensities of brain-supplying arteries on stroke FLAIR MRI are common and represent slow flow or stasis. FLAIR vascular hyperintensities (FVH) are discussed as an independent marker for cerebral hypoperfusion, but the impact on infarct size and clinical outcome in acute stroke patients is controversial. This study evaluates the association of FVH with infarct morphology, clinical stroke severity and infarct growth in patients with symptomatic internal carotid artery (ICA) or middle cerebral artery (MCA) occlusion. Methods: MR images of 84 patients [median age 73 years (IQR 65–80), 56.0% male, median NIHSS 7 (IQR 3–13)] with acute stroke due to symptomatic ICA or MCA occlusion or stenosis were reviewed. Vessel occlusions were identified by MRA time of flight and graded with the TIMI score. Diffusion and perfusion deficit volumes on admission and FLAIR lesion volumes on discharge were assessed. The presence and number of FVH were evaluated according to MCA-ASPECT areas, and associations with MR volumes, morphology of infarction, recanalization status, presence of white matter disease and hemorrhagical transformation as well as with stroke severity (NIHSS), stroke etiology and thrombolysis rate were analyzed. Results: FVH were detectable in 75 (89.3%) patients. The median number of FVH was 4 (IQR 2–7). Patients with FVH >4 presented with more severe strokes due to NIHSS (p = 0.021), had larger initial DWI lesions (p = 0.008), perfusion deficits (p = 0.001) and mismatch volumes/ratios (p = 0.005). The final infarct volume was larger (p = 0.005), and hemorrhagic transformation was more frequent (p = 0.029) in these patients. Conclusions: The presence of FVH indicates larger ischemic areas in brain parenchyma predominantly caused by proximal anterior circulation vessel occlusion. A high count of FVH might be a further surrogate marker for initial ischemic mismatch and stroke severity.

The Thrombus and Discontinuity of FLAIR Vascular Hyperintensity

The Thrombus and Discontinuity of FLAIR Vascular Hyperintensity

Angiography Reveals That Fluid-Attenuated Inversion Recovery Vascular Hyperintensities Are Due to Slow Flow, Not Thrombus

Fluid-attenuated inversion recovery (FLAIR) vascular hyperintensities (FVH) are commonly encountered on MR imaging studies performed shortly after the onset of acute ischemic stroke. Prior reports have speculated regarding the pathogenesis of this finding, yet definitive correlative angiographic studies have not been performed. We studied the pathophysiologic and hemodynamic correlates of FVH on conventional angiography and concurrent MR imaging sequences. Retrospective review of FLAIR and gradient-refocused echo MR imaging sequences acquired immediately before conventional angiography for acute stroke was conducted in a blinded fashion. The presence, location, and morphology of FVH were noted and correlated with markers of thrombotic occlusion and collateral flow on angiography. Angiographic collaterals were graded on a 5-point scale incorporating extent and hemodynamic aspects. A prospective ischemic stroke registry of 632 patients was searched to identify 74 patients (mean age, 63.4 +/- 20 years; 48% women) having undergone FLAIR sequences immediately before angiography. Median time from FLAIR to angiography was 2.9 hours (interquartile range, 1.1-4.7 hours). FVH were present in 53/74 (72%) of all acute stroke cases with subsequent angiography. FVH distal to an arterial occlusion were associated with a high grade of leptomeningeal collateral blood flow. FVH are observed in areas of blood flow proximal and distal to stenosis or occlusion and are noted with more extensive collateral circulation.

FLAIR vascular hyperintensity may predict stroke after TIA

FLAIR vascular hyperintensities (FVH) are frequently encountered in acute ischemic stroke. We report two cases presenting with transient ischemic attack (TIA) with isolated FVH on MRI who went on to have a stroke during hospitalization. Isolated FVH may be an important imaging correlate in acute ischemia, and may suggest proximal occlusion with the presence of slow flow through retrograde leptomeningeal collaterals. Recognition of these subtle correlates may complement clinical predictors of stroke after TIA.