Doerfler Arnd, Engelhorn Tobias, Heiland Sabine, Benner Thomas, Forsting Michael
Department of Neuroradiology, University of Essen Medical School, Germany.
J Neurosurg. 2002 May;96(5):933-40. doi: 10.3171/jns.2002.96.5.0933.
The aim of this study was to use two types of serial magnetic resonance (MR) imaging-perfusion-weighted (PW) and diffusion-weighted (DW)-to monitor craniectomy in rats with hemispheric stroke.
Focal cerebral ischemia was induced in 36 rats by using an endovascular method of occlusion of the middle cerebral artery (MCAO). Craniectomy was performed 4 or 24 hours later in 12 animals each. Twelve control animals underwent occlusion but did not receive treatment. Perfusion-weighted, DW, and T2-weighted MR images were obtained at 4, 24, 48, 72, and 168 hours postocclusion in all animals. Relative regional cerebral blood volumes and apparent diffusion coefficients (ADCs) were calculated for the cortex and basal ganglia. Hemispheric lesion volumes (expressed as percentages of total brain volumes; %HLV) as they appeared on DW and T2-weighted MR images and on histological slices stained with 2,3,5-triphenyltetrazolium chloride were compared. Neurological performances and infarct volumes measured 7 days postocclusion were used as study end points. Both PW and DW images demonstrated ischemic tissue 4 hours after MCAO in all animals. Early treatment by performing craniectomy significantly improved cortical perfusion (p < 0.01), whereas the same procedure conveyed no benefit to the basal ganglia. Compared with findings in control animals, the DW image-derived %HLV was significantly reduced (p < 0.01) and the cortical ADCs at 4 and 24 hours postocclusion were significantly higher in animals treated early (p < 0.05). Late treatment with craniectomy did not significantly affect cerebral perfusion. The correlation between the DW imaging-derived %HLV and the histologically derived %HLV at 4 to 72 hours postocclusion was good (r = 0.74), whereas at Day 7 postocclusion the %HLV was underestimated up to 41% on DW imaging. At 4 hours postocclusion T-weighted imaging failed to demonstrate the ischemic lesion, whereas from 24 to 72 hours postocclusion the correlation between the T2-weighted imaging-derived %HLV and the histologically derived %HLV was good (r > 0.81). Neurological performance was significantly improved in animals treated using craniectomy.
Early craniectomy significantly improves cortical perfusion through leptomeningeal collateral vessels, significantly reduces infarct size, and improves neurological performance in animals with experimental acute hemispheric infarction. Both PW and DW imaging are suitable for noninvasive monitoring of the effects of decompressive craniectomy.
本研究旨在使用两种类型的系列磁共振（MR）成像——灌注加权（PW）成像和扩散加权（DW）成像——来监测半球性卒中大鼠的颅骨切除术。
采用血管内闭塞大脑中动脉（MCAO）的方法，在36只大鼠中诱导局灶性脑缺血。4小时或24小时后，分别对12只动物进行颅骨切除术。12只对照动物接受闭塞手术但未接受治疗。在所有动物闭塞后4、24、48、72和168小时获取灌注加权、DW和T2加权MR图像。计算皮质和基底节的相对局部脑血容量和表观扩散系数（ADC）。比较DW和T2加权MR图像以及用2,3,5 - 三苯基四氮唑氯化物染色的组织切片上出现的半球病变体积（以全脑体积的百分比表示；%HLV）。将闭塞后7天测量的神经功能表现和梗死体积用作研究终点。所有动物在MCAO后4小时，PW和DW图像均显示出缺血组织。早期进行颅骨切除术可显著改善皮质灌注（p < 0.01），而相同操作对基底节无益处。与对照动物的结果相比，早期治疗的动物中，DW图像得出的%HLV显著降低（p < 0.01），闭塞后4小时和24小时皮质ADC显著更高（p < 0.05）。晚期进行颅骨切除术对脑灌注无显著影响。闭塞后4至72小时，DW成像得出的%HLV与组织学得出的%HLV之间相关性良好（r = 0.74），而在闭塞后第7天，DW成像低估%HLV高达41%。闭塞后4小时，T加权成像未能显示缺血性病变，而在闭塞后24至72小时，T2加权成像得出的%HLV与组织学得出的%HLV之间相关性良好（r > 0.81）。接受颅骨切除术治疗的动物神经功能表现显著改善。
早期颅骨切除术通过软脑膜侧支血管显著改善皮质灌注，显著减小梗死灶大小，并改善实验性急性半球梗死动物的神经功能表现。PW和DW成像均适用于无创监测减压性颅骨切除术的效果。
