Huang Kuo-Lun, Chang Ting-Yu, Chang Chien-Hung, Liu Ho-Ling, Chang Yeu-Jhy, Liu Chi-Hung, Wong Ho-Fai, Wu Yi-Ming, Lee Tsong-Hai, Ho Meng-Yang
Stroke Center and Department of Neurology, Linkou Chang Gung Memorial Hospital and College of Medicine, Chang Gung University, Taoyuan, Taiwan.
Department of Imaging Physics, University of Texas MD Anderson Cancer Center, Houston, Texas, United States.
Curr Neurovasc Res. 2017;14(4):347-358. doi: 10.2174/1567202614666171005141716.
The time to maximum of the residue function (TMax) has been employed to identify the penumbra in acute ischemic stroke. Cognitive impairment in patients with Carotid Artery Stenosis (CAS) has been attributed to chronic cerebral hypoperfusion. The study aimed to examine whether cognitive impairment can be detected based on a preliminary TMax cutoff in patients with unilateral CAS.
Fifty unilateral CAS patients underwent dynamic susceptibility contrast MR perfusion. The preliminary TMax cutoff (3 seconds) was derived on the basis of the upper limit of 95% confidence interval of TMax in the Middle Cerebral Artery (MCA) contralateral to the CAS side. All patients were allocated to the Right-delayed group (n=18), Left-delayed group (n=12), and Nondelayed group (n=20) by the cutoff. Cognitive assessment was also administered on all patients and 22 healthy volunteers.
No significant interhemispheric mean TMax differences of the Non-delayed group were noted (p=0.75), but the mean TMax of ipsilateral MCA was significantly longer than that of the contralateral MCA of the Left- and Right-delayed groups (ps<0.001), respectively. Compared to healthy volunteers, the Right-delayed group performed significantly worse on most of the visuospatial tests (ps<0.04), while the Left-delayed group performed significantly worse on most of the verbal tests (ps<0.05). The performance of the Non-delayed group on all cognitive domains was similar to that of healthy volunteers (ps>0.07).
TMax can be used to differentiate the chronic hypoperfusion state in unilateral CAS patients. Prolonged TMax in the MCA of either hemisphere may lead to lateralized impairment in cognition functions in patients with unilateral CAS.
残余函数的最大时间（TMax）已被用于识别急性缺血性卒中的半暗带。颈动脉狭窄（CAS）患者的认知障碍归因于慢性脑灌注不足。本研究旨在探讨基于单侧CAS患者的初步TMax临界值是否能检测出认知障碍。
50例单侧CAS患者接受了动态磁敏感对比磁共振灌注成像。初步的TMax临界值（3秒）是根据CAS侧对侧大脑中动脉（MCA）TMax 95%置信区间的上限得出的。根据该临界值，所有患者被分为右侧延迟组（n = 18）、左侧延迟组（n = 12）和非延迟组（n = 20）。对所有患者和22名健康志愿者也进行了认知评估。
非延迟组半球间平均TMax差异无统计学意义（p = 0.75），但左侧和右侧延迟组同侧MCA的平均TMax分别显著长于对侧MCA（p<0.001）。与健康志愿者相比，右侧延迟组在大多数视觉空间测试中的表现显著更差（p<0.04），而左侧延迟组在大多数语言测试中的表现显著更差（p<0.05）。非延迟组在所有认知领域的表现与健康志愿者相似（p>0.07）。
TMax可用于区分单侧CAS患者的慢性灌注不足状态。任何一侧半球MCA的TMax延长可能导致单侧CAS患者认知功能的偏侧化损害。
