颈动脉粥样硬化斑块性质与磁共振灌注成像的关系

目的对比研究稳定与不稳定颈动脉粥样硬化斑块的磁共振脑灌注成像情况,探讨斑块性质与脑灌注的关系。方法单侧颈内动脉狭窄程度为70%-99%患者30例,行动态磁敏感对比增强磁共振成像。测定双侧大脑半球、额叶、顶叶、半卵圆中心、皮质分水岭前区、皮质分水岭后区患侧与健侧的平均通过时间(MTT)、相对脑血流量(rCBF)、相对脑血容量(rCBV)比值。将颈动脉粥样硬化斑块的纤维帽是否完整、斑块表面是否有大片钙化、其内是否有近期出血及是否有较大的脂质中心作为诊断标准,分为稳定和不稳定斑块两组,进行上述参数比较。结果不稳定性斑块组在皮质分水岭前区和后区的MTT值明显较稳定斑块组延长(P=0.042,t=1.561和P=0.038,t=1.227),rCBF和rCBV未见差异(P>0.05)。上述两组在其余部位的血液动力学参数比值差异无统计学意义。结论颈动脉粥样硬化斑块稳定性和相应皮质分水岭供血区域灌注情况有关,不稳定斑块容易导致同侧皮质分水岭区低灌注,MTT是最敏感的指标。

The relationship between the carotid atherosclerotic plaque and cerebral perfusion-weighted imaging

Objective To evaluate the appearance of the cerebral perfusion-Weighted imaging(PWI) between the stable and the unstable carotid atherosclerotic plaque for the patients with ICA stenosis ranging from 70% to 99%.Methods 30 patients with unilateral carotid artery stenosis ranging form 70% to 99% were selected to be scanned with PWI.On the MTT,rCBF and rCBV map,the region of interest(ROI) was placed on the brain hemisphere,frontal lobe,parietal lobe,centrum semiovale,anterior cortical watershed and posterior cortical watershed.The MTT,rCBF and rCBV ratio of the patients were calculated as stenosis side against contralateral side.Based on the status of the fibrous cap,with/without hemorrhage,superficial calcification,large lipid core,we divided the carotid plaque into two groups:stable and unstable plaque.The cerebral PWI of these two groups were evalutaed.Results The MTT ratios of the anterior cortical watershed and posterior cortical watershed were prolonged significantly in unstable group compared with stable group(P=0.042,t=1.561 and P=0.038,t=1.227),but the rCBF,rCBV were not changed obviously.There were no significantly difference in the MTT,rCBF and rCBV ratio of the brain hemisphere,frontal lobe,parietal lobe,centrum semiovale between the stable and unstable group.Conclusion The stability of the carotid atherosclerotic plaque has close relationship with the perfusion of relative cortical watershed region,and MTT is the most sensitive parameter to detect the unilateral hypoperfusion.PWI information and stability of the carotid atherosclerotic plaque must be considered together when we design the therapy plan.