大鼠中风模型的超小氧化铁粒子神经血管成像(英文)

USPIO High Resolution Neurovascular Imaging in a Rat Stroke Model of Transient Middle Cerebral Artery Occlusion

现今诱导血管增生剂在中风后的治疗效应引起了人们的关注.这项工作的一个目的是用短时脑中动脉栓塞大鼠中风模型(MCAO)和磁化率加权成像(SWI)的核磁共振成像(MRI)方法,监测在中风后半月形损伤区新生成的旁侧血管.P904是法国格尔伯实验室生产的超小超顺磁氧化铁粒子弛豫试剂(USPIO).它在低剂量减少T1弛豫时间,适中剂量时减少T2*弛豫时间.实验动物被随机分为3组:中风Sildenafil治疗组(n=6)、中风无治疗对照组(n=5)和无中风无治疗对照组(n=1).在P904注入前后分别进行MRI成像.磁化率加权成像的时间点是:栓塞手术前、栓塞手术后24小时、栓塞手术后两周和四周.结果表明,术后两周,在治疗组中中风严重的动物的缺血区的周边显示了MRI可见的新生血管.结论:在短时脑中动脉栓塞大鼠中风模型中,使用超小超顺磁氧化铁粒子弛豫试剂和7 T高分辨磁化率加权成像能够监测半月形损伤区新生血管的形成.

Angiogenesis inducing agents, such as Sildenafil, can be used to treat stroke. In this study, USPIO-enhanced MRI was used to visualize collateral vessels in the penumbral area of lesions of rats subjected to transient middle cerebral artery occlusion （tMCAO）, and the evaluate efficacy of the Sildenafil treatment. Here, P904, a USPIO agent, was used as a T1 reducing agent at a low dose for MR angiography and as a T2＊ reducing agent at a moderate dose for visualization of very small vessels on gradient echo susceptibility-weighted imaging （SWI）. SWI scans without/with USPIO injection were performed for the following cases： tMCAO without any treatment （n=5）, tMCAO with Sildenafil treatment （n=6）, and sham tMCAO （n=l） at four different time points （i.e., baseline, 24 h, two weeks and four weeks after tMCAO）. The presence of newly developed vessels in the periphery of the ischemic core was only observed in those animals showing severe ischemic brain damage and at the same time received Sildenafil treatment at two weeks post tMCAO. This work suggests that, at 7 T, high resolution SWI in conjunction with USPIO injection at a moderate dose can he used to visualize post-stroke angiogenesis in the tMCAO rat model.