Massachusetts General Hospital and Harvard Medical School, Department of Radiology, Gray 241H, Boston, MA 02114-9657, USA.
Stroke. 2011 May;42(5):1255-60. doi: 10.1161/STROKEAHA.110.600940. Epub 2011 Apr 14.
To characterize the spatial pattern of cerebral ischemic vulnerability to hypoperfusion in stroke patients.
We included 90 patients who underwent admission CT perfusion and MRI within 12 hours of ischemic stroke onset. Infarcted brain lesions ("core") were segmented from admission diffusion-weighted imaging and, along with the CT perfusion parameter maps, coregistered onto MNI-152 brain space, which was parcellated into 125 mirror cortical and subcortical regions per hemisphere. We tested the hypothesis that the percent infarction increment per unit of relative cerebral blood flow (rCBF) reduction differs statistically between regions using regression analysis to assess the interaction between regional rCBF and region variables. Next, for each patient, a "vulnerability index" map was constructed with voxel values equaling the product of that voxel's rCBF and infarction probability (derived from the MNI-152-transformed, binary, segmented, diffusion-weighted imaging lesions). Voxel-based rCBF threshold for core was determined within the upper 20th percentile of vulnerability index map voxel values.
Different regions had different percent infarction increase per unit rCBF reduction (P=0.001). The caudate body, putamen, insular ribbon, paracentral lobule, and precentral, middle, and inferior frontal gyri had the highest ischemic vulnerability to hypoperfusion. A voxel-based rCBF threshold of <0.42 optimally distinguished infarct core in the highly-vulnerable regions, whereas rCBF<0.16 distinguished core in the remainder of the brain.
We demonstrated regional ischemic vulnerability of the brain to hypoperfusion in acute stroke patients. Location-specific, rather than whole-brain, rCBF thresholds may provide a more accurate metric for estimating infarct core using CT perfusion maps.
描述脑缺血对灌注不足的易损性的空间模式。
我们纳入了 90 例缺血性卒中发病后 12 小时内行入院 CT 灌注和 MRI 检查的患者。入院弥散加权成像上的梗死病灶（“核心”）进行分割，并与 CT 灌注参数图一起配准到 MNI-152 脑空间，将其分为每个半球 125 个镜像皮质和皮质下区域。我们使用回归分析检验了这样的假设，即单位相对脑血流量（rCBF）减少的梗死百分比增量在不同区域之间存在统计学差异，以评估区域 rCBF 与区域变量之间的相互作用。接下来，对于每个患者，使用体积值等于该体素 rCBF 和梗死概率的乘积（由 MNI-152 转换的、二进制的、分割的、弥散加权成像病变衍生）来构建“易损性指数”图。核心的基于体素 rCBF 阈值是在易损性指数图体素值的上 20%百分位数内确定的。
不同的区域单位 rCBF 减少的梗死百分比增加不同（P=0.001）。尾状核、壳核、脑岛带、中央旁小叶和中央前、中、下回的额叶具有对灌注不足的最高缺血易损性。基于体素的 rCBF 阈值<0.42 可最佳地区分高度易损区域的梗死核心，而 rCBF<0.16 可区分大脑其余区域的核心。
我们在急性卒中患者中证明了脑缺血对灌注不足的区域易损性。基于位置的、而非全脑的 rCBF 阈值可能为使用 CT 灌注图估计梗死核心提供更准确的指标。
