Supplementary Material for: Carotid Arterial Hemodynamic in Ischemic Levkoaraiosis Suggests Hypoperfusion Mechanism

<b><i>Background:</i></b> Leukoaraiosis (ILA) is believed to be ischaemic in origin due to its similar location as that of lacunar infarctions and its association with cerebrovascular risk factors. However, its pathophysiology is not well understood. The ischaemic injuries may be a result of increased pulsatility or cerebral hypo-perfusion. We used carotid duplex ultrasound to prove that the underlying mechanism is hypo-perfusion. <b><i>Methods:</i></b> We compared 55 ILA patients to 44 risk factor-matched controls with normal magnetic resonance imaging (MRI) of the head. ILA diagnosis was based on MRI and was further categorised according to the Fazekas scale. We measured carotid artery blood flow velocity and diameter and calculated carotid blood flow and resistance indexes. <b><i>Results:</i></b> Blood flow velocities and blood flows were significantly lower in the ILA group, including diastolic, systolic and mean pressures (p ≤ 0.05). The resistance indices were higher in the ILA group, but the differences were not statistically significant. All the velocities and blood flows showed a decreasing trend with higher Fazekas score, whereas resistance indexes showed an increasing trend. <b><i>Conclusions:</i></b> Lower blood flow and higher resistance of carotid arteries are consistent with the hypo-perfusion theory of ILA. Carotid ultrasound could have a diagnostic and prognostic role in ILA patients.

<b><i>背景：</i></b> 脑白质疏松症（Leukoaraiosis, ILA）目前被认为系缺血性病因引发，因其病变部位与腔隙性脑梗死高度相似，且与脑血管病危险因素密切相关。然而其具体病理生理机制尚未完全阐明。此类缺血性损伤可能源于搏动性增强或脑灌注不足。本研究采用颈动脉双功能超声，旨在验证其潜在发病机制为脑灌注不足。<b><i>方法：</i></b> 本研究纳入55例脑白质疏松症患者，另选取44例危险因素匹配的头部磁共振成像（MRI）正常者作为对照。脑白质疏松症的诊断基于磁共振成像结果，并采用Fazekas量表（Fazekas scale）进行分级。研究人员测量了颈动脉血流速度与管径，并计算了颈动脉血流量及阻力指数。<b><i>结果：</i></b> 脑白质疏松症组的血流速度与血流量均显著降低，涵盖舒张期、收缩期及平均血流速度（p ≤ 0.05）。脑白质疏松症组的阻力指数更高，但差异无统计学意义。随着Fazekas量表评分升高，所有血流速度与血流量均呈下降趋势，而阻力指数则呈上升趋势。<b><i>结论：</i></b> 颈动脉血流量降低与阻力升高，与脑白质疏松症的脑灌注不足理论相符。颈动脉超声可在脑白质疏松症患者的诊断及预后评估中发挥重要作用。