Distal Hyperintense Vessels on Flair: A Prognostic Indicator of Acute Ischemic Stroke
Department of Neurology, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China. European Neurology
(Impact Factor: 1.36).
09/2012; 68(4):214-20. DOI: 10.1159/000340021
Hyperintense vessels (HVs) on fluid-attenuated inversion recovery (FLAIR) are frequently observed in acute ischemic stroke (AIS). The presence of HVs represents altered blood flow from collaterals distal to arterial occlusion or stenosis. This study aimed to evaluate the prognostic value of HVs in AIS.
Fifty-four consecutive patients with acute middle cerebral artery occlusion were enrolled in the study. The location and extent of the HVs was determined by FLAIR. Clinical data were obtained and compared between patients with different grades of HVs. Additionally, the relationship between distal HVs and leptomeningeal collaterals (LMCs) was assessed using angiography.
HVs were observed in 41 (75.9%) of the 54 patients enrolled. The initial NIHSS score was lower (p<0.001) and the infarction volume was smaller (p<0.001) in patients with distal HVs. Adjusting of other factors, regression analysis revealed that distal HVs are an independent predictor of a favorable outcome at 90 days (p=0.006; OR 0.049; 95% CI 0.006-0.420). Furthermore, the presence of distal HVs was correlated with the presence of LMCs.
Distal HVs may be a marker for LMCs and act as a predictor of a favorable clinical outcome for patients with AIS.
Available from: PubMed Central
- "Sometimes they can be observed in patients with cerebral arterial occlusion but without infarction, i.e. those with moyamoya disease . FHVs have been reported in 10-97% of ischemic stroke patients [1,3,4,5,6,7,8]. Their prevalence varies according to the arterial status; moreover, FHVs are observed more frequently in patients with middle cerebral artery (MCA) or internal carotid artery occlusion (75-80%) [5,6,7], in contrast to 14% of patients without arterial occlusion . "
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ABSTRACT: Fluid-attenuated inversion recovery hyperintense vessels (FHVs) are known to reflect stagnant or slow blood flow within the cerebral artery. FHVs are frequently observed in patients with acute cerebral infarction accompanied by arterial occlusion or significant stenosis of the anterior cerebral circulation. However, FHVs have not been studied in the context of posterior cerebral circulation. Thus, we investigated the prevalence of FHVs and its clinical significance in patients with acute posterior cerebral artery (PCA) territory infarction.
In this retrospective study, consecutive patients with PCA territory infarction who underwent MRI within 1 week after symptom onset were enrolled. Two neurologists who were blinded to the angiographic findings read the images and determined the presence of FHVs. Afterwards, FHVs were graded according to the extent (subtle or prominent) and location (proximal or distal) of the hyperintense vessels. Neurologic deficits of the patients were assessed by the National Institutes of Health Stroke Scale (NIHSS) upon admission and after 5 days. The clinical outcome between patient groups based on FHVs grading was compared using the NIHSS. Among the patients with PCA occlusion, infarction volume on the diffusion-weighted image was compared between the two groups with and without distal FHVs.
FHVs were observed in 25 of the 87 patients (28.7%) with PCA territory infarction and in 65.7% of the 35 patients with significant arterial stenosis (10 patients) or occlusion (25 patients) in the posterior cerebral circulation. Among the 18 patients with PCA occlusion, the NIHSS score was significantly improved in patients with distal FHVs compared to the others (2.00 ± 2.18 vs. 0.56 ± 1.01, p = 0.04). The infarction volume was smaller in the distal FHV group than in the others (8.3 ± 8.7 vs. 16.8 ± 17.6 ml), but the difference was not statistically significant.
FHVs are detected in patients with PCA territory infarction, especially in those with an occlusive lesion in the PCA. FHVs can be used as an imaging marker of PCA occlusion. Although this study showed a better clinical improvement in patients with distal FHVs, further study is needed to elucidate the clinical meaning of FHVs in PCA infarction.
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Hyperintensity of distal vessels on FLAIR-MRI has been associated with a higher grade of arterial collaterals and a smaller infarct volume in acute stroke patients. No studies analyze the influence of the hyperintense vessel (HV) sign on the speed of the ischemia progression during the first hours. Our aim was to study the association of the HV sign with progression of infarction in acute stroke patients.
From a prospectively derived stroke database, we retrospectively selected acute stroke patients with a large artery occlusion of the anterior circulation admitted to our comprehensive stroke center with available baseline CT scan and a multimodal MRI carried out thereafter to make a decision about endovascular treatment. Progression of the ischemic area was calculated as the difference in the Alberta Stroke Program Early CT Scan (ASPECTS) score between CT scan and diffusion-weighted imaging (DWI). Slow progression was considered as no change or 1 point decrease on the ASPECTS score between both exams. The presence of HV on FLAIR sequence was graded as absent, subtle or prominent by two readers.
A total of 70 patients were included in the study. Mean time between baseline CT and MRI was 124 ± 82 min. ASPECTS score on baseline CT was 10 in 34% of patients, 9 in 49% and 8 or less in 17%. ASPECTS score was 2 (1-3) points lower in the DWI and this decrease did not correlate with the time elapsed between the two exams. Distal HV sign was observed in 57/70 (81%) patients (subtle in 33 and prominent in 24). HV was more frequently observed in patients with proximal artery occlusion. There were no differences regarding stroke severity, stroke subtype and ASPECTS score on baseline CT between groups. Patients with prominent HV showed a lower progression of the ischemic area [median ASPECTS score decrease, 1 (1-0)] compared with patients with subtle HV [median ASPECTS score decrease, 2 (2-1)] and patients with absence of HV [median ASPECTS score decrease, 3 (4-3)] (p < 0.001). Prominent HV was independently associated with slow progression of ischemia in a multivariate logistic regression analysis adjusted by systolic blood pressure on admission, site of occlusion and time elapsed between both neuroimaging exams compared to the absence of HV (OR, 16.2; 95% CI, 2.1-123.1) and to subtle HV sign (OR, 6.1; 95% CI, 1.5-23.9).
HV sign on FLAIR, especially if prominent, is associated with a slow progression of the ischemic area in acute stroke patients with cerebral artery occlusion of the anterior circulation. This radiological sign may predict the speed of the ischemia progression, opening an opportunity for reperfusion therapies in longer time windows.
Available from: Carsten Hobohm
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ABSTRACT: FLAIR-hyperintense vessels are known to be a sign of sluggish collateral blood flow in hemispheric vessel occlusion. Additionally, they seem to have a prognostic implication. The aim of the current study was to evaluate the hyperintense configuration of the basilar artery (FLAIR-hyperintense basilar artery) as a marker of basilar artery occlusion and as a predictor of patient outcome.
We retrospectively identified 20 patients with basilar artery occlusion who initially underwent MR imaging with subsequent DSA. The diagnostic accuracy of the FLAIR-hyperintense basilar artery sign was tested by 4 independent readers in a case-control design, and the relation among FLAIR-hyperintense basilar artery and DWI posterior circulation-ASPECTS, patient outcome, and patient survival was evaluated. To grade the extent of the FLAIR-hyperintense basilar artery sign, we generated a score by counting the number of sections from the basilar tip to the foramen magnum in which a hyperintense signal in the vessel lumen was present multiplied by the section thickness.
The FLAIR-hyperintense basilar artery sign showed moderate sensitivity (65%-95%) but very good specificity (95%-100%) and accuracy (85%-93%) for the detection of basilar artery occlusion. Substantial or excellent inter-reader agreement was observed (Cohen ĸ, 0.64-0.85). The FLAIR-hyperintense basilar artery inversely correlated with the posterior circulation-ASPECTS (r = -0.67, P = .01). Higher FLAIR-hyperintense basilar artery scores were associated with patient death (28.3 ± 13.7 versus 13.4 ± 11.1, P < .05).
The FLAIR-hyperintense basilar artery sign proved to be a valuable marker of vessel occlusion and may substantially support the diagnosis of basilar artery occlusion. The established FLAIR-hyperintense basilar artery score may be helpful for the prediction of individual patient survival.
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