大鼠超急性脑梗死MR灌注加权成像:铁羧葡胺与Gd-DTPA的比较

目的 与Gd-DTPA相比较,探讨铁羧葡胺(Resovist)在大鼠超急性脑梗死MR灌注加权成像(MR PWI)中的应用价值. 方法 30只Wistar大鼠,随机数字法平均分成A、B两组,A组为8 μmol Fe/kg体质量Resovist灌注组,B组为0.2 mmol/kg体质量Gd-DTPA灌注组,两类不同对比剂剂量的选择以在正常脑组织的MR PWI中获得相同的最大信号强度变化为标准.全部动物均于大脑中动脉栓塞1 h后接受MR PWI.重建PWI原始图像,获得病灶中心区以及脑缺血半暗带脑血容量(CBV)、脑血流量(CBF)、平均通过时间(MTT)参数形态图.比较两组各项参数变化并与病理检查及TTC染色对照. 结果 A、B两组大鼠在脑缺血中心区以及病灶边缘区(即影像半暗带)所获得的信号-时间曲线基本一致,相应各兴趣区的rCBV、rMTT及TTP值两组差异均无统计学意义. 结论 在急性脑梗死的MR PWI中,与Gd-DTPA相比,Resovist同样有效,且所需剂量小,在脑灌注中具有广阔的应用前景.

Comparison of Resovist and Gd-DTPA as susceptibilitycontrast agents for MR perfusion weighted imaging of hyperacute cerebral infarction in rats

Objective To compare the value on assessment of perfusion weighted imaging (PWI) using Gd-DTPA and the superparamagnetic iron oxide (SPIO) particles (Resovist) in the experimental model of hyperacute cerebral infarction in rats. Methods Thirty Wistar rats were randomly divided into Group A and B (each n=15). After occluding the left middle cerebral artery with thread for 1 h in all rats, two dynamic MR perfusion imaging series were acquired after intravenous bolus injections of 8 μmol Fe/kg SPIO (Group A) and 0.2 mmol/kg Gd-DTPA (Group B), respectively. The doses were chosen to obtain similar maximum signal change in normally perfused brain. The perfusion imaging was compared between the region of interest (ROI) in the core area with severe ischemia and in the penumbra area of moderate ischemia. The parameters were compared between two groups with pathologic findings and TTC stain. Results The first-passage profiles were found to be similar for Gd-DTPA and SPIO, both in the core area with severe ischemia and in the penumbra area of moderate ischemia of rats models. No statistical difference of the parameters (CBV, MTT, TTP) of PWI for ischemic penumbra was detected between Group A and B. Conclusion The efficacy of the Resovist using in the MR PWI is similar to Gd-DTPA for diagnosis of the perfusion reduction in the rat stroke models. Strong susceptibility effects may be achieved with small injection volumes. Resovist may play an important role in MR PWI.