BACKGROUND AND PURPOSE High-grade carotid artery stenosis may alter hemodynamics in the ipsilateral hemisphere, but consequences of this effect are poorly understood. Cortical thinning is associated with cognitive impairment in dementia, head trauma, demyelination, and stroke. We hypothesized that hemodynamic impairment, as represented by a relative time-to-peak (TTP) delay on MRI in the hemisphere ipsilateral to the stenosis, would be associated with relative cortical thinning in that hemisphere. METHODS We used baseline MRI data from the NINDS-funded Carotid Revascularization and Medical Management for Asymptomatic Carotid Stenosis-Hemodynamics (CREST-H) study. Dynamic contrast susceptibility MR perfusion-weighted images were post-processed with quantitative perfusion maps using deconvolution of tissue and arterial signals. The protocol derived a hemispheric TTP delay, calculated by subtraction of voxel values in the hemisphere ipsilateral minus those contralateral to the stenosis. RESULTS Among 110 consecutive patients enrolled in CREST-H to date, 45 (41%) had TTP delay of at least 0.5 seconds and 9 (8.3%) subjects had TTP delay of at least 2.0 seconds, the maximum delay measured. For every 0.25-second increase in TTP delay above 0.5 seconds, there was a 0.006-mm (6 micron) increase in cortical thickness asymmetry. Across the range of hemodynamic impairment, TTP delay independently predicted relative cortical thinning on the side of stenosis, adjusting for age, sex, hypertension, hemisphere, smoking history, low-density lipoprotein cholesterol, and preexisting infarction (P=0.032). CONCLUSIONS Our findings suggest that hemodynamic impairment from high-grade asymptomatic carotid stenosis may structurally alter the cortex supplied by the stenotic carotid artery.

中文翻译：

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高级别无症状颈动脉狭窄的皮质变薄。

背景和目的高度颈动脉狭窄可能会改变同侧半球的血流动力学，但人们对这种效应的后果知之甚少。皮质变薄与痴呆、头部创伤、脱髓鞘和中风等认知障碍有关。我们假设血流动力学损伤（以狭窄同侧半球的 MRI 相对峰值时间 (TTP) 延迟为代表）可能与该半球的相对皮质变薄有关。方法 我们使用来自 NINDS 资助的无症状颈动脉狭窄血流动力学颈动脉血运重建和医疗管理 (CREST-H) 研究的基线 MRI 数据。动态对比磁化率 MR 灌注加权图像使用组织和动脉信号去卷积，通过定量灌注图进行后处理。该协议得出半球 TTP 延迟，通过减去同侧半球的体素值减去狭窄对侧的体素值来计算。结果 迄今为止，在 CREST-H 登记的 110 名连续患者中，45 名 (41%) 受试者的 TTP 延迟至少为 0.5 秒，9 名 (8.3%) 受试者的 TTP 延迟至少为 2.0 秒，这是测量的最大延迟。TTP 延迟每增加 0.25 秒（超过 0.5 秒），皮质厚度不对称性就会增加 0.006 毫米（6 微米）。在血流动力学损伤范围内，TTP延迟独立预测狭窄侧皮质相对变薄，调整年龄、性别、高血压、半球、吸烟史、低密度脂蛋白胆固醇和先前存在的梗塞（P=0.032）。