MRI与DSA对颈动脉狭窄和粥样硬化斑块评估能力的比较

目的 探讨MRI与DSA对颈动脉粥样硬化患者血管狭窄及粥样硬化斑块病变特点评估能力的差异.方法 46例缺血性脑血管疾病患者,超声发现颈动脉粥样硬化斑块后分别行颈动脉MRI及DSA检查.颈动脉MR检查序列包括三维时间飞跃法(3D TOF)、T1WI、T2WI、质子密度加权成像( PDWI)及增强T1WI；颈动脉DSA检查分别摄取颈动脉的正位像和侧位像.观察颈动脉分叉处管腔的狭窄程度和斑块的病变特征,包括纤维帽的状况、斑块内出血和钙化.计算Kappa值分析MRI和DSA对血管狭窄程度判断结果的一致性；应用配对卡方检验检测两种方法对溃疡斑块的检出差异.结果 89支血管的MR图像质量均满足诊断要求.MRI显示血管狭窄程度的M(范围)为50％(16％～78％),DSA显示为47％(7％～73％),二者具有很好的一致性(Kappa值为0.882,P＜0.01).MRI发现34支血管具有斑块纤维帽破溃,DSA发现10支血管具有溃疡斑块(x2=20.346,P＜0.01).此外,MRI发现37支血管有斑块内出血,71支血管有斑块内钙化,而DSA均不能显示.结论 MRI可以准确判断颈动脉的狭窄程度,在显示溃疡斑块、斑块内出血以及钙化方面较DSA更具优势.

Comparison of MRI and DSA in assessment of carotid artery stenosis and atherosclerotic plaque

Objective To compare the efficacy of MRI and DSA in assessment of carotid artery stenosis and atherosclerotic plaque.Methods Forty-six patients with carotid plaque detected by ultrasound were enrolled in this study,and 89 carotid arteries were evaluated by MRI and DSA.MRI examination was acquired with 3.0 T MR scanner and 8 channel phase-array surface coil.The MRI sequences consisted of pre-and post-contrast T1WI,T2WI,PDWI,TOF.Anterior-posterior and lateral views of carotid artery were performed on DSA.The degree of carotid artery stenosis was evaluated by the NASCET standard.Fibrous cap rupture,intraplaque hemorrhage,and calcification were also evaluated on MRI and DSA.Statistical comparison was performed with the Kappa value and paired Chi-square test.Results The degree of carotid artery stenosis was 50％ (16％-78％) on MRI and 47％ (7％-73％) on DSA.Two imaging modalities were in good consistency in evaluation of the degree of stenosis ( Kappa =0.882,P ＜ 0.01 ).There was statistical difference in detecting fibrous cap rupture by MRI and DSA (34 vessels vs 10 vessels,respectively,x2 =20.346,P ＜ 0.01 ).Furthermore,thirty-seven vessels with intraplaque hemorrhage and 71 vessels with calcification in the plaque were found on MRI but none on DSA.Conclusion MRI is a reliable tool in assessment of the degree of the carotid stenosis and it is superior to DSA in detecting fibrous cap rupture,intraplaque hemorrhage,and calcification.