Effects of cerebral ischemia on evoked cerebral blood oxygenation responses and BOLD contrast functional MRI in stroke patients
Effects of cerebral ischemia on evoked cerebral blood oxygenation responses and BOLD contrast functional MRI in stroke patients
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DOI：
10.1161/01.str.0000239698.50656.3b
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发表时间：
2006-10-01
期刊：
影响因子：
8.3
通讯作者：
Katayama, Yoichi
中科院分区：
文献类型：
--
作者：
Murata, Yoshihiro;Sakatani, Kaoru;Katayama, Yoichi
背景和目的：评价脑卒中患者血氧水平依赖性（BOLD）成像失败的机制，我们比较了慢性脑卒中伴中、重度脑缺血患者BOLD功能MRI（fMRI）的诱发脑血氧（CBO）反应和激活体积（AV）。红外光谱在对侧运动任务。我们比较了非病变侧和病变侧PSMC的BOLD功能MRI AV。单光子发射计算机断层扫描被用来分类缺血状态为中度（轻微减少局部脑血流量和脑血管储备能力[CVRC]）或严重（显着减少局部脑血流量和CVRC;即痛苦perfusion）。非病变侧的PSMC表现出正常的CBO反应模式。在病变侧，中度脑缺血不影响CBO反应模式，但严重的脑缺血引起的脱氧血红蛋白的增加，在任务过程中，与氧合血红蛋白和总血红蛋白的增加。中度脑缺血仅引起病变侧AV轻微降低;然而，重度脑缺血显著降低病变侧AV。BOLD信号并没有改变在某些领域的PSMC的病变侧在严重的脑缺血，而它往往会减少在其他领域的tasks. Conclusions痛苦灌注造成了显着减少的AV BOLD成像，与激活过程中脱氧血红蛋白浓度的增加。脑卒中患者的BOLD-fMRI检查应考虑基线循环状态。功能性近红外光谱可以作为评估CVRC的替代手段。
Background and Purpose-To evaluate the mechanisms of failure of blood oxygenation level-dependent (BOLD) imaging in stroke, we compared the evoked cerebral blood oxygenation (CBO) responses and activation volumes (AVs) of BOLD functional MRI (fMRI) in chronic stroke patients with moderate and severe cerebral ischemia.Methods-We measured the evoked CBO responses in the primary sensorimotor cortex (PSMC) by means of near-infrared spectroscopy during contralateral motor tasks. We compared the AV of BOLD-functional MRI in the PSMC on the nonlesion and lesion sides. Single-photon emission computed tomography was used to classify ischemic status as moderate (slight reduction of regional cerebral blood flow and cerebrovascular reserve capacity [CVRC]) or severe (marked reduction of regional cerebral blood flow and CVRC; ie, misery perfusion).Results-In age-matched controls, deoxyhemoglobin concentration decreased with concomitant increases in oxyhemoglobin and total hemoglobin concentrations during activation. The PSMC on the nonlesion side exhibited a normal CBO response pattern. On the lesion side, moderate cerebral ischemia did not affect the CBO response pattern, but severe cerebral ischemia caused an increase of deoxyhemoglobin during the task, associated with increases of oxyhemoglobin and total hemoglobin. Moderate cerebral ischemia induced only a slight reduction of the AV on the lesion side; however, severe cerebral ischemia markedly reduced the AV on the lesion side. The BOLD signal did not change in some areas of the PSMC on the lesion side in severe cerebral ischemia, whereas it tended to decrease in other areas during the tasks.Conclusions-Misery perfusion caused a marked reduction of the AV on BOLD imaging, associated with an increase of deoxyhemoglobin concentration during activation. BOLD-fMRI investigations of stroke patients should be performed while giving consideration to baseline circulatory status. Functional near-infrared spectroscopy could be an alternative means to assess the CVRC.