功能磁共振对颈动脉狭窄患者支架植入术前后脑功能改变的评估作用

Study of brain function changes before and after carotid artery stenting in patients with carotid artery stenosis by functional magnetic resonance imaging

目的研究磁共振灌注成像(PWI)及磁共振扩散张量成像(DTI)对颈动脉狭窄患者支架植入术前后脑功能变化的评估作用。方法选取20例经脑血管造影证实的单侧颈动脉重度狭窄患者,于颈动脉支架植入术(CAS)前后行PWI、DTI检查,评估术前术后脑血流量(CBF)、脑血流容积(CBV)、平均通过时间(MTT)的变化以及各向异性分数(FA)的变化情况。结果 20例患者术前双侧脑灌注存在差异,患侧MTT延长,CBF、CBV降低,术后患侧MTT缩短(t=4.396,P=0.000),CBF升高(t=-2.812,P=0.011),差异有统计学意义;CBV变化不明显。术前患侧额叶FA值较对侧降低(t=-2.539,P=0.013),术后患侧额叶FA值较术前升高(t=-2.322,P=0.032),而顶叶、枕叶、颞叶、内囊前肢、内囊后肢FA值变化不明显。结论联合应用PWI、DTI技术可提示脑组织血流灌注及脑白质受损情况,从而评估单侧颈动脉狭窄患者CAS术前术后脑功能的变化。

Objective To evaluate the changes of brain function before and after carotid artery stenting in patients with carotid stenosis by MR perfusion-weighted imaging （PWI） and MR diffusion tensor imaging （DTI）. Methods Twenty pa- tients with carotid artery stenosis were underwent PWI and DTI before and after CAS. Cerebral blood volume （CBV）, cerebral blood flow（CBF）, mean transit time （MTI＇） and fractional anisotropy （FA） values were measured. Results There were differences in bilateral cerebral perfusion before operation in 20 patients with unilateral carotid stenosis. MTY in the affected side lengthened, while CBF and CBV decreased. After CAS, the MTY of the affected side was shortened（t= 4.396, P=0.000）, and CBF increased （t=-2.812, P=0.011）, and the changes were statistically significant. Preoperative frontal lobe FA was lower than contralateral（t=-2.539, P=0.013）, and the frontal lobe FA value was higher（t=-2.322, P= 0.032） than that before operation. The FA values of the parietal lobe, occipital lobe, temporal lobe, anterior limb of in- ternal capsule and posterior limb of internal capsule were not significantly changed. Conclusion The application of PWI and DTI can indicate the cerebral blood flow perfusion and the damage of brain white matter, so as to evaluate the changes of brain function before and after CAS in patients with unilateral carotid stenosis.