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<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.