Department of Diagnostic and Interventional Neuroradiology, University Medical Center Hamburg-Eppendorf, Germany.
Clin Neuroradiol. 2012 Dec;22(4):305-13. doi: 10.1007/s00062-012-0143-4. Epub 2012 Apr 8.
Few magnetic resonance imaging (MRI) studies of stroke have evaluated the value of visual assessment of perfusion/diffusion mismatch, which is crucial for routine application. In this study an attempt was made to visually assess perfusion lesions resembling the acute clinical situation and identify parameters with the highest interobserver reliability when used to define a perfusion/diffusion mismatch and the highest accuracy for prediction of infarct growth.
Magnetic resonance imaging was performed within 6 h of symptom onset and again 1-11 days thereafter in 86 consecutive stroke patients who received intravenous thrombolytic therapy. The MRI protocol included diffusion-weighted imaging apparent diffusion coefficient (DWI/ADC), fluid-attenuated inversion recovery (FLAIR) and perfusion imaging (PI). Maps for different perfusion parameters, e.g. cerebral blood volume (CBV), cerebral blood flow (CBF), mean transit time (MTT) and time to peak (TTP) were calculated. Areas of perfusion deficits of all perfusion parameters were visually compared to corresponding ADCs and final infarct size by two independent observers.
The final infarct size was overestimated by TTP (in 81/83 patients by raters 1 and 2, respectively), MTT (82/83) and CBF (65/74) lesions. The ADC lesions were rated smaller than the final infarct size in 43/38 cases by raters 1 and 2 and the CBV decrease was rated to underestimate final infarct size in 40/31 cases. The only significantly increased OR of 3.883 (95 % CI 1.466-10.819, p = 0.004, rater 1)/5.142 (95 % CI 1.828-15.142, p = 0.001, rater 2) for predicting infarct growth was observed for the presence of a CBV > ADC mismatch, which also showed the highest kappa value of 0.407.
All mismatch patterns were prone to high interrater variability when assessed under conditions resembling the clinical setting. Of all tested mismatch patterns the CBV > ADC mismatch was the strongest predictor of lesion growth while visual assessment of TTP and CBF generally resulted in an overestimation of infarct sizes and the presence of a TTP > ADC or CBF > ADC mismatch was not significantly predictive for lesion growth. Visual inspection of these most commonly used mismatch patterns has a low value for the prediction of infarct growth and thus the estimation of the penumbra in ischemic stroke patients.
很少有磁共振成像（MRI）研究评估灌注/弥散失配的视觉评估价值，这对于常规应用至关重要。本研究试图通过视觉评估类似于急性临床情况的灌注损伤，并确定在定义灌注/弥散失配时具有最高观察者间可靠性的参数，以及预测梗死生长的最高准确性。
对 86 例连续接受静脉溶栓治疗的卒中患者，在症状发作后 6 小时内进行 MRI 检查，并在其后 1-11 天再次进行 MRI 检查。MRI 方案包括弥散加权成像表观弥散系数（DWI/ADC）、液体衰减反转恢复（FLAIR）和灌注成像（PI）。计算了不同灌注参数的图，例如脑血容量（CBV）、脑血流（CBF）、平均通过时间（MTT）和达峰时间（TTP）。由两名独立观察者将所有灌注参数的灌注缺损区域与相应的 ADC 值和最终梗死大小进行视觉比较。
TTP（评分 1 和 2 的 81/83 名患者）、MTT（82/83）和 CBF（65/74）病变高估了最终梗死大小。评分 1 和 2 的 43/38 例患者的 ADC 病变小于最终梗死大小，CBV 下降的评分低估了最终梗死大小的 40/31 例。唯一显著增加的 OR 为 3.883（95%CI 1.466-10.819，p=0.004，评分 1）/5.142（95%CI 1.828-15.142，p=0.001，评分 2），用于预测梗死生长，观察到 CBV>ADC 不匹配的存在，其kappa 值也最高为 0.407。
在类似于临床环境的条件下评估时，所有不匹配模式都容易出现高观察者间变异性。在所有测试的不匹配模式中，CBV>ADC 不匹配是病变生长的最强预测因子，而 TTP 和 CBF 的视觉评估通常导致梗死大小的高估，并且 TTP>ADC 或 CBF>ADC 不匹配的存在对病变生长没有显著预测作用。这些最常用的不匹配模式的视觉检查对梗死生长的预测价值较低，因此对缺血性脑卒中患者的半影区的估计价值较低。
