Heiss Wolf-Dieter, Sobesky Jan, Smekal Ulrich v, Kracht Lutz W, Lehnhardt Fritz-Georg, Thiel Alexander, Jacobs Andreas H, Lackner Karl
Max Planck Institute for Neurological Research, University of Cologne, Cologne, Germany.
Stroke. 2004 Aug;35(8):1892-8. doi: 10.1161/01.STR.0000134746.93535.9b. Epub 2004 Jun 24.
The differentiation of reversible from irreversible ischemic damage is essential for identifying patients with acute ischemic deficits who may benefit from therapeutic interventions. Diffusion-weighted imaging (DWI) has become the method of choice to detect ischemic lesions. Positron emission tomography (PET) of the central benzodiazepine receptor ligand 11C flumazenil (FMZ) has been shown to be a reliable marker of neuronal integrity. These 2 imaging parameters were compared with respect to the probability to predict cortical infarction in early ischemic stroke.
In 12 patients with acute stroke, results from DWI (median, 6.5 hours after symptom onset) and FMZ-PET (interval, 85 minutes between DWI and PET) were compared with infarct extension 24 to 48 hours after onset of stroke on T2-weighted magnetic resonance imaging (T2-MRI). Probability curves predictive of eventual infarction were computed using respective DWI, FMZ, and apparent diffusion coefficient (ADC) values for voxels of interest (VOI) later classified as representing infarcted or noninfarcted tissue.
Ninety-five percent limits predictive of cortical infarction were determined for relative FMZ binding (< or =3.2), DWI signal intensity (> or =1.18), and ADC values (< or =0.83). Cortical regions with values beyond these 95% limits did not necessarily overlap with nor were fully congruous with final cortical infarct volumes. The respective median volumes for these regions were FMZ median 10.9, range 0 to 99.7 cm3; DWI median 15.2, range 0 to 116.0 cm3; ADC median 12.4, range 0 to 112.7 cm3; and final infarct median 14.9, range 0 to 114.7 cm(3). Overall, 83.5% of the final infarct, on average, was predicted by decreased FMZ binding, 84.7% by increased DWI signal intensity, and 70.9% by a decreased ADC value. The portions of the final infarct not predicted in the early investigation (false-negatives) were 4.8 cm3 (median) for FMZ, 3.7 cm3 for DWI, and 6.0 cm3 for ADC. The false-positive volumes not included in the final infarct were 0 cm3 (median) for FMZ, 5.1 cm3 for DWI, and 3.6 cm3 for ADC.
These results indicate that FMZ-PET and DWI are comparable in the prediction of probability of ischemic cortical infarction, but FMZ-PET carries a lower probability of false-positive prediction. The final infarcts include tissue not identified by these imaging modalities; at the time of the study, these tissue compartments are viable and could benefit from treatment. The discrepancy in predictive probability could be related to the fundamental difference of the measured variables: benzodiazepine receptor activity is a reliable marker of neuronal integrity in the cortex, and movement of water molecules in the extracellular space might be a more variable indicator of tissue damage.
区分可逆性与不可逆性缺血性损伤对于识别可能从治疗干预中获益的急性缺血性神经功能缺损患者至关重要。弥散加权成像（DWI）已成为检测缺血性病变的首选方法。中枢苯二氮䓬受体配体11C氟马西尼（FMZ）的正电子发射断层扫描（PET）已被证明是神经元完整性的可靠标志物。比较了这两种成像参数预测早期缺血性卒中皮质梗死的可能性。
对12例急性卒中患者，将DWI（症状发作后中位时间6.5小时）和FMZ-PET（DWI与PET之间间隔85分钟）的结果与卒中发作后24至48小时T2加权磁共振成像（T2-MRI）上的梗死灶扩展情况进行比较。使用感兴趣体素（VOI）的各自DWI、FMZ和表观扩散系数（ADC）值计算预测最终梗死的概率曲线，这些VOI随后被分类为代表梗死或未梗死组织。
确定了相对FMZ结合（≤3.2）、DWI信号强度（≥1.18）和ADC值（≤0.83）预测皮质梗死的95%界限。超出这些95%界限值的皮质区域不一定与最终皮质梗死体积重叠，也不完全一致。这些区域各自的中位体积为FMZ中位值10.9，范围0至99.7 cm³；DWI中位值15.2，范围0至116.0 cm³；ADC中位值12.4，范围0至112.7 cm³；最终梗死灶中位值14.9，范围0至114.7 cm³。总体而言，平均83.5%的最终梗死灶可通过FMZ结合降低预测，84.7%可通过DWI信号强度增加预测，70.9%可通过ADC值降低预测。早期检查中未预测到的最终梗死灶部分（假阴性），FMZ为4.8 cm³（中位值），DWI为3.7 cm³，ADC为6.0 cm³。未包含在最终梗死灶中的假阳性体积，FMZ为0 cm³（中位值），DWI为5.1 cm³，ADC为3.6 cm³。
这些结果表明，FMZ-PET和DWI在预测缺血性皮质梗死概率方面具有可比性，但FMZ-PET假阳性预测概率较低。最终梗死灶包括这些成像方式未识别的组织；在研究时，这些组织区域是存活的，可能从治疗中获益。预测概率的差异可能与测量变量的根本差异有关：苯二氮䓬受体活性是皮质神经元完整性的可靠标志物，细胞外空间水分子的移动可能是组织损伤更具变异性的指标。
