Department of Radiology, Massachusetts General Hospital, Gray B285, 55 Fruit Street, Boston, MA 02114, USA.
Stroke. 2011 Jul;42(7):1923-8. doi: 10.1161/STROKEAHA.110.610618. Epub 2011 May 5.
Admission infarct core lesion size is an important determinant of management and outcome in acute (<9 hours) stroke. Our purposes were to: (1) determine the optimal CT perfusion parameter to define infarct core using various postprocessing platforms; and (2) establish the degree of variability in threshold values between these different platforms.
We evaluated 48 consecutive cases with vessel occlusion and admission CT perfusion and diffusion-weighted imaging within 3 hours of each other. CT perfusion was acquired with a "second-generation" 66-second biphasic cine protocol and postprocessed using "standard" (from 2 vendors, "A-std" and "B-std") and "delay-corrected" (from 1 vendor, "A-dc") commercial software. Receiver operating characteristic curve analysis was performed comparing each CT perfusion parameter-both absolute and normalized to the contralateral uninvolved hemisphere-between infarcted and noninfarcted regions as defined by coregistered diffusion-weighted imaging.
Cerebral blood flow had the highest accuracy (receiver operating characteristic area under the curve) for all 3 platforms (P<0.01). The maximal areas under the curve for each parameter were: absolute cerebral blood flow 0.88, cerebral blood volume 0.81, and mean transit time 0.82 and relative Cerebral blood flow 0.88, cerebral blood volume 0.83, and mean transit time 0.82. Optimal receiver operating characteristic operating point thresholds varied significantly between different platforms (Friedman test, P<0.01).
Admission absolute and normalized "second-generation" cine acquired CT cerebral blood flow lesion volumes correlate more closely with diffusion-weighted imaging-defined infarct core than do those of CT cerebral blood volume or mean transit time. Although limited availability of diffusion-weighted imaging for some patients creates impetus to develop alternative methods of estimating core, the marked variability in quantification among different postprocessing software limits generalizability of parameter map thresholds between platforms.
入院时的梗死核心病变大小是急性（<9 小时）脑卒中患者治疗和预后的重要决定因素。我们的目的是：（1）使用不同的后处理平台确定最佳 CT 灌注参数来定义梗死核心；（2）确定这些不同平台之间阈值的可变性程度。
我们评估了 48 例血管闭塞伴入院 CT 灌注和弥散加权成像的连续病例，且这两种检查在彼此 3 小时内完成。CT 灌注采用“第二代”66 秒双期电影协议采集，并使用“标准”（来自 2 个供应商，“A-std”和“B-std”）和“延迟校正”（来自 1 个供应商，“A-dc”）商业软件进行后处理。通过比较各 CT 灌注参数（绝对和与对侧未受累半球标准化）在与弥散加权成像配准的梗死和非梗死区域之间的受试者工作特征曲线分析来进行评估。
在所有 3 个平台上，脑血流量（CBF）的准确性最高（受试者工作特征曲线下面积）（P<0.01）。各参数的最大曲线下面积为：绝对脑血流量为 0.88，脑血容量为 0.81，平均通过时间为 0.82，相对脑血流量为 0.88，脑血容量为 0.83，平均通过时间为 0.82。不同平台之间最佳受试者工作特征操作点阈值差异显著（Friedman 检验，P<0.01）。
与 CT 脑血容量或平均通过时间相比，入院时的绝对和标准化“第二代”电影 CT 脑血流病变体积与弥散加权成像定义的梗死核心更密切相关。尽管有些患者弥散加权成像的可用性有限，促使开发替代的核心估计方法，但不同后处理软件之间的定量差异很大，限制了参数图阈值在平台之间的通用性。
