The association between asymmetrically hypointense veins on susceptibility-weighted imaging and collateral circulation

Objective To explore the relationship between asymmetrically hypointense veins (AHVs) on susceptibility-weighted imaging (SWI) and collateral circulation. Methods We retrospectively enrolled acute ischemic stroke patients with severe stenosis or occlusion of M1 segment of the middle cerebral artery±intracranial internal carotid artery. All the patients underwent diffusion-weighted imaging(DWI), SWI, and computed tomography angiography (CTA) of intracranial and cervical arteries within 72 hours from symptom onset. We explored the association of the level of AHVs with the degree of the regional leptomeningeal score (rLMC) on baseline CTA and other clinical and image data. The factors that might influence the prognosis of stroke were also analyzed. Results Fifteen patients with mild AHVs and 15 with extensive AHVs were enrolled in our study. The level of AHVs was positively correlated with CTA rLMC (r=0.481, P=0.007)and the degree of collateral circulation(r=0.402, P=0.028). Patients with extensive AHVs had better collateral status, smaller DWI infarction lesion ((11.62±9.07) ml vs (95.77±91.12) ml, t=3.559, P=0.001), and lower NIHSS scores on admission (6.47±4.34 vs 12.33±7.60, t=2.595, P=0.015)and at discharge(4.80±4.69 vs 9.60±7.03, t=2.200, P=0.036). The high degree of rLMC, small DWI lesion, young age and lower NIHSS scores, but not extensive AHVs were related with favorable outcome at 3 months after stroke. Conclusion Extensive AHVs can reflect good collateral circulation to some extent, but cannot be equivalent to or replace the collateral status. Key words: Stroke; Collateral circulation; Susceptibility magnetic resonance imaging; Regional leptomeningeal score