Background:Intracranial stenosis (ICS) may contribute to cognitive dysfunction by decreased cerebral blood flow (CBF) which can be measured quantitatively by arterial spin labelling (ASL). Interpretation of CBF measurements with ASL, however, becomes difficult in patients with vascular disease dueto prolonged arterial transit time (ATT). Recently, spatial coefficient of variation (sCoV) of ASL signal has been proposed that approximates ATT and utilized as a proxy marker for assessment of hemodynamic status of cerebral circulation. Objective:We investigate the association of ICS with CBF and sCoV parameters and its eventual effects on cognition in a memory clinic population. Methods:We included 381 patients (mean age = 72.3±7.9 years, women = 53.7%) who underwent 3T MRI and detailed neuropsychological assessment. ICS was defined as≥50% stenosis in any intracranial vessel on 3D Time-of-Flight MR Angiography. Gray matter sCoV and CBF were obtained from 2D EPI pseudo-continuous ASL images. Results:ICS was present in 58 (15.2%) patients. Patients with ICS had higher gray matter sCoV and lower CBF. The association with sCoV remained statistically significant after correction for cardiovascular risk factors. Moreover, ICS was associated with worse performance on visuoconstruction, which attenuated with higher sCoV. Mediation analysis showed that there was an indirect effect of ICS on visuoconstruction via sCoV. Conclusion:These findings suggest that compromised CBF as detected by higher sCoV is related to cognitive impairment among individuals diagnosed with ICS. We also showed that sCoV partially mediates the link between ICS and cognition. Therefore, sCoV may provide valuable hemodynamic information in patients with vascular disease.

中文翻译：

---

颅内狭窄对脑灌注和认知能力的影响

背景：颅内狭窄 (ICS) 可能通过脑血流量 (CBF) 减少导致认知功能障碍，脑血流量 (CBF) 可通过动脉自旋标记 (ASL) 进行定量测量。然而，由于动脉通过时间 (ATT) 延长，血管疾病患者很难用 ASL 解释 CBF 测量值。最近，已经提出了 ASL 信号的空间变异系数 (sCoV)，它近似于 ATT，并用作评估脑循环血流动力学状态的代理标记。目的：我们调查 ICS 与 CBF 和 sCoV 参数的关联及其对记忆临床人群认知的最终影响。方法：我们纳入了 381 名接受 3T MRI 和详细神经心理学评估的患者（平均年龄 = 72.3±7.9 岁，女性 = 53.7%）。ICS 被定义为 3D 飞行时间 MR 血管造影中任何颅内血管狭窄≥50%。灰质 sCoV 和 CBF 是从 2D EPI 伪连续 ASL 图像中获得的。结果：58 名（15.2%）患者出现 ICS。ICS 患者具有较高的灰质 sCoV 和较低的 CBF。在校正心血管危险因素后，与 sCoV 的关联仍然具有统计学意义。此外，ICS 与视觉结构的较差表现相关，随着 sCoV 的升高而减弱。中介分析表明，ICS 通过 sCoV 对视觉构建有间接影响。结论：这些发现表明，较高 sCoV 检测到的受损 CBF 与诊断为 ICS 的个体的认知障碍有关。我们还表明 sCoV 部分介导了 ICS 和认知之间的联系。所以，