FLAIR vascular hyperintensity combined with asymmetrical prominent veins in acute anterior circulation ischemic stroke: prediction of collateral circulation and clinical outcome

BACKGROUND

To investigate the value of fluid-attenuated inversion recovery vascular hyperintensity (FVH) within asymmetrical prominent veins sign (APVS) on susceptibility-weighted imaging predicting collateral circulation and prognosis in patients with acute anterior circulation ischemic stroke.

METHOD

Patients with severe stenosis or occlusion of ICA or MCA M1, who underwent MRI within 72 h from stroke onset were reviewed. The Alberta Stroke Program Early CT Score was used to evaluate the volume of infarction on DWI, the degree of FVH and APVS. Spearman correlation analysis was used to evaluate the correlation between FVH and APVS. All patients were divided into the good prognosis group and the poor prognosis group according to the score of the modified ranking scale (mRS) 90 days after the stroke. Logistic regression analysis was used to explore the relationship between FVH and APVS and functional prognosis, while receiver operating characteristic (ROC) curves were plotted to assess the value of FVH and APVS in predicting prognosis.

RESULTS

Spearman correlation analysis revealed moderate positive correlations between FVH and APVS (r = 0.586, P < 0.001). The poor prognosis group had a higher rate of a history of atrial fibrillation, a larger cerebral infarction volume, a higher NIHSS score at admission, and a higher FVH and APVS score compared with the good prognosis group (all P < 0.05). A further logistic regression indicated that the NIHSS score, cerebral infarction volume, FVH and APVS were independent risk factors for a poor functional prognosis. In terms of FVH, APVS, alone and their combination for the diagnosis of poor prognosis, the sensitivity, specificity, area under the ROC curve (AUC), and 95% confidence interval (CI) were 86.8%, 83.3%, 0.899 (95% CI 0.830-0.968); 60.5%, 93.7%, 0.818 (95% CI 0.723-0.912); 86.8%, 89.6%, 0.921 (95% CI 0.860-0.981), respectively.

CONCLUSION

The presence of FVH and APVS can provide a comprehensive assessment of collateral circulation from the perspective of veins and arteries, and the correlation between the two is positively correlated. Both of them were independent risk factors for poor prognosis, their combination is complementary and can improve the predictive value.

FLAIR Vascular Hyperintensity: An Important MRI Marker in Patients with Transient Ischemic Attack

Purpose

We aimed to investigate the prevalence of fluid-attenuated inversion recovery (FLAIR) vascular hyperintensities (FVHs) and the clinical-radiological correlation in transient ischemic attack (TIA) patients.

Materials and Methods

We performed a retrospective analysis of TIA patients who had undergone magnetic resonance imaging (MRI) within 24 h of symptom onset. Two independent neuroradiologists investigated the presence of FVHs, large-artery severe stenosis or occlusion (LASO) in magnetic resonance angiograms, and the nature of factors associated with FVH.

Results

A total of 207 patients were enrolled in this study. FVHs were detected in 42 (20.3%) patients, in whom atrial fibrillation (AF) was confirmed in 25 (59.5%) cases and LASO was confirmed in 30 (71.4%) cases. The corresponding figures were 33 (20.0%) and 10 (6.1%), respectively, for the 165 FVH-negative patients. Logistic regression analysis showed that time from symptom onset to MRI (odds ratio [OR] = 0.82, 95% CI 0.76-0.97, p = 0.042), previous stroke (OR = 2.95, 95% CI 1.58-6.74, p = 0.002), AF (OR = 5.83, 95% CI 2.24-9.46, p < 0.001), and LASO (OR = 4.28, 95% CI 2.96-10.28, p < 0.001) were independently associated with FVH. Overall, the sensitivity and specificity of FVH for predicting LASO were 0.75 and 0.93, respectively, and the positive predictive value, negative predictive value, and accuracy were 0.71, 0.94, and 0.89, respectively. The area under the receiver operating characteristic curve was 0.839. FVH-positive TIA patients with LASO had less AF (14 [46.7%] versus 11 [91.7%], p = 0.019) and longer times from symptom onset to MRI (6.8 ± 2.8 h versus 4.8 ± 1.3 h, p = 0.004) than those without LASO.

Conclusion

The presence of FVH could be an important marker in TIA patients. Many factors, including LASO, AF, and time from symptom onset to MRI, are associated with the detection of FVH.

Fluid-Attenuated Inversion Recovery Vascular Hyperintensity in Cerebrovascular Disease: A Review for Radiologists and Clinicians

Neuroradiological methods play important roles in neurology, especially in cerebrovascular diseases. Fluid-attenuated inversion recovery (FLAIR) vascular hyperintensity (FVH) is frequently encountered in patients with acute ischemic stroke and significant intracranial arterial stenosis or occlusion. The mechanisms underlying this phenomenon and the clinical implications of FVH have been a matter of debate. FVH is associated with large-vessel occlusion or severe stenosis, as well as impaired hemodynamics. Possible explanations suggested for its appearance include stationary blood and slow antegrade or retrograde filling of the leptomeningeal collateral circulation. However, the prognostic value of the presence of FVH has been controversial. FVH can also be observed in patients with transient ischemic attack (TIA), which may have different pathomechanisms. Its presence can help clinicians to identify patients who have a higher risk of stroke after TIA. In this review article, we aim to describe the mechanism and influencing factors of FVH, as well as its clinical significance in patients with cerebrovascular disease.

FLAIR vascular hyperintensity with DWI for regional collateral flow and tissue fate in recanalized acute middle cerebral artery occlusion

PURPOSE

Fluid-attenuated inversion recovery (FLAIR) vascular hyperintensity (FVH) extent or FVH-DWI mismatch as a primary influencing factor of clinical outcome in acute ischemic stroke is controversial. This study elucidated the regional pathophysiology and tissue fate in four types of cortical territories classified by the initial FVH and DWI findings in patients with acute proximal middle cerebral artery (M1) occlusion successfully recanalized using mechanical thrombectomy.

METHODS

We retrospectively evaluated 35 patients successfully recanalized within 24 h of acute M1 occlusion onset between 2016 and 2019. Each Alberta stroke program early CT score area of M1-M6 were categorized as group A (DWI-, FVH-), B (DWI-, FVH+), C (DWI+, FVH+), or D (DWI+, FVH-). Territorial collateral status was graded on a 4-point scale by initial angiogram. Follow-up head computed tomography (CT) findings on days 2-9 were assessed for the territorial outcome.

RESULTS

Overall, 210 cortical territories were identified; of these, 88 (41.9 %) were categorized into group A; 72 (34.3 %), group B; 37 (17.6 %), group C; and 13 (6.2 %), group D. The rate of territories with good collaterals (grade 2 or 3) significantly decreased in the order of groups as 78.3 %, 62.7 %, 27.6 %, and 0%, respectively (P_trend <.001). Conversely, the rate of territories with any hypo- or hyper-density on follow-up CT significantly increased in the order of groups as 13.4 %, 23.1 %, 88.5 %, and 85.7 %, respectively (P_trend <.001).

CONCLUSION

Categorization of cortical areas based on the FVH and DWI findings can stratify territorial collateral status and tissue fate.

The impact of FLAIR vascular hyperintensity on clinical severity and outcome : A retrospective study in stroke patients with proximal middle cerebral artery stenosis or occlusion

BACKGROUND

The clinical significance of fluid-attenuated inversion recovery vascular hyperintensity (FVH) has not been clarified. The aim of this study was to clarify the effects of FVH on the clinical severity and long-term prognosis of patients with proximal middle cerebral artery (MCA) occlusion or severe stenosis.

METHOD

Because their clinical and imaging data is not accessible, we excluded the patients being treated with IV thrombolysis or mechanical thrombectomy. Clinical and imaging characteristics were documented in 282 consecutive AIS patients with proximal MCA occlusion or severe stenosis. We assessed clinical severity using the National Institutes of Health Stroke Scale (NIHSS) score and clinical outcomes using mRS scores. The average time interval between symptom onset and imaging was 16-18 h. The FVH score according to FVH-ASPECTS ranged from 0 to 7, based on the numbers of territories where FVH is positive.

RESULTS

FVH was observed in 235 (83.33%) of the AIS patients. The FVH(+) group tended to have more alcoholics (65 [27.66%] vs 6 [12.77%], P = 0.032), a higher NIHSS score on the 7th day (3 [1-6] vs 2 [1-3], P = 0.039), more instances of early neurological deterioration (END) (27 [11.4%] vs 1 [2.12%], P = 0.05), and more patients with MCA occlusion (94 [40.00%] vs 3 [6.38%]). Among the patients with positive FVH, a high FVH score represented severe clinical impairment (higher NIHSS score on admission [P = 0.009] and 7th day since admission [P = 0.02]) and poor clinical outcomes. Spearman's rank correlations showed that FVH scores were positively correlated with NIHSS scores on admission and NIHSS scores on the 7th day (P = 0.039; P = 0.017, respectively).

CONCLUSION

In patients with proximal middle cerebral artery (MCA) occlusion or stenosis ≥ 70%, a high FVH score represented severe clinical impairment and poor clinical outcomes. In acute ischemic stroke (AIS) patients with proximal MCA occlusion, a high FVH score represented favorable clinical outcomes.

Association of FLAIR vascular hyperintensity and acute MCA stroke outcome changes with the severity of leukoaraiosis

PURPOSE

The clinical significance of FLAIR vascular hyperintensity (FVH), a marker of collateral circulation in ischaemic stroke, remains controversial. We hypothesised that the association between FVH and outcomes varies with the severity of leukoaraiosis (LA), another marker of collaterals, and that their combined significance may vary with time.

METHODS

We included 459 consecutive patients with middle cerebral artery (MCA) stroke. Proximal and distal FVHs were distinguished based on location. LA was divided into two grades, according to Fazekas scores of 0-2 and 3-6. Symptom-to-MRI time was divided into two categories: ≤ 14 days and ≥ 15 days.

RESULTS

We found no difference in FVH proportion according to LA grade. Multivariate analysis revealed that LA and FVH status were independently associated with unfavourable outcomes (modified Rankin scale ≥ 2) in patients with symptom-to-MRI times ≤ 14 days (P = 0.008), but not in those with symptom-to-MRI times ≥15 days (P = 0.61). In the group with symptom-to-MRI times ≤14 days, patients with LA 3-6 and FVH(+) (OR, 3.044; 95% CI, 1.116-8.305) were more likely to have unfavourable clinical outcomes compared with patients with LA 0-2 and FVH(+) but not compared with those with LA 0-2 and FVH(-) or LA 3-6 and FVH(-). In addition, FVH location did not influence the relationship between FVH and outcomes.

CONCLUSIONS

The association between FVH and outcomes was influenced by the degree of LA in the acute but not in the subacute and chronic stages of MCA infarction. FVH predicts clinical outcomes independently only in those with more extensive LA.

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

BACKGROUND AND PURPOSE

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.

METHODS

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.

RESULTS

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).

CONCLUSIONS

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.