Reith W, Forsting M, Vogler H, Heiland S, Sartor K
Department of Neuroradiology, University of Heidelberg Medical School, Germany.
AJNR Am J Neuroradiol. 1995 Jan;16(1):53-60.
To evaluate early patterns of MR changes in a rat model of cerebral ischemia using the first pass of two magnetic susceptibility contrast agents.
One hours after endovascular middle cerebral artery occlusion, all animals were examined in an experimental MR unit. After bolus application of gadopentetate dimeglumine and, 10 minutes later, of iron oxide particles, the MR changes of the first pass of these contrast agents were followed using a T2*-weighted fast low-angle shot sequence. Time-density curves of both contrast agents were analyzed and compared.
After bolus injection of either (paramagnetic) gadopentetate dimeglumine or superparamagnetic particles, nonischemic brain parenchyma decreased markedly in signal, whereas the ischemic brain area remained relatively hyperintense (and thus became clearly delineated). Only after application of gadopentetate dimeglumine did a mild reduction in signal occur in the ischemic hemisphere, although the main artery was occluded. An explantation for this phenomenon might be residual capillary perfusion (plasma flow), which is detectable only when the smaller (paramagnetic) contrast molecules are being used.
Cerebral perfusion deficits can be detected 1 hour after vascular occlusion with T2*-weighted fast low-angle shot sequences and bolus injection of paramagnetic or superparamagnetic MR contrast agents. Gadopentetate dimeglumine may be used as a marker of microcirculatory plasma flow.
使用两种磁敏感性对比剂的首次通过，评估大鼠脑缺血模型中磁共振成像（MR）变化的早期模式。
在血管内大脑中动脉闭塞1小时后，所有动物在实验性MR设备中进行检查。在静脉注射钆喷酸葡胺，10分钟后再注射氧化铁颗粒后，使用T2 *加权快速低角度激发序列跟踪这些对比剂首次通过时的MR变化。分析并比较两种对比剂的时间-密度曲线。
在静脉注射（顺磁性）钆喷酸葡胺或超顺磁性颗粒后，非缺血性脑实质信号明显降低，而缺血性脑区仍相对呈高信号（从而清晰显示）。尽管主要动脉已闭塞，但仅在注射钆喷酸葡胺后，缺血半球才出现轻度信号降低。对此现象的一种解释可能是残余毛细血管灌注（血浆流动），只有在使用较小的（顺磁性）对比分子时才能检测到。
在血管闭塞1小时后，通过T2 *加权快速低角度激发序列和静脉注射顺磁性或超顺磁性MR对比剂，可以检测到脑灌注不足。钆喷酸葡胺可用作微循环血浆流动的标志物。
