颈动脉狭窄致脑低灌注损伤多模态MRI

目的：探讨颈动脉狭窄程度与颈内动脉血流动力学参数及相关脑区ADC值变化的关系。方法：27例患者经磁共振血管成像（MRA）证实有中度以上颈动脉狭窄。所有患者行颅脑常规 MRI、MRA和DWI检查，并采用血流定量测量（QFlow）和彩色多普勒超声（CDFI）对颈内动脉的血流动力学参数进行分析。对 QFlow技术与CDFI 测量的血流参数（血流量、平均流速、峰值流速及管腔面积）及其与颈动脉狭窄程度及相关脑区的表观扩散系数值（ADC ）之间的相关性行非参数检验。结果：①QFlow技术与CDFI测量的血流量和平均流速呈中度正相关（r＝0．695，P＜0．01；r＝0．795，P＜0．01），峰值流速和管腔面积呈低度正相关（r＝0．453，P＜0．01；r＝0．573，P＜0．01）。②颈动脉狭窄程度与 QFlow 技术测量的颈内动脉流量呈低度负相关（r＝－0．467，P＜0．01），与侧脑室旁前部和额叶白质的 ADC 值呈低度正相关（r＝0．373，P＜0．01；r＝0．372，P＜0．01）。③侧脑室旁前部和额叶白质的ADC 值与 QFlow 技术测量的颈内动脉流量分别呈中度和低度负相关（r＝－0．624，P＜0．01；r＝－0．533，P＜0．01）。结论：多模态 MRI能显示颈动脉狭窄所致的颈内动脉血流量减低及供血脑区的低灌注损伤，QFlow技术能较准确评价颈内动脉血流动力学变化。

Multimodal magnetic resonance imaging of chronic cerebral ischemia caused by carotid stenosis

Objective:To explore the relationship between stenosis degree of carotid artery (CA),hemodynamic pa-rameters of internal carotid artery (ICA)and ADC values of relevant brain regions.Methods:27 patients with moderate or severe stenosis of carotid artery diagnosed by MRA underwent conventional MRI,MRA,DWI of brain and 3D QFlow,color Doppler flow imaging (CDFI)of ICA.The relationships of the hemodynamic parameters including blood flow (BF),mean velocity (MV),peak velocity (PV)and lumen area (LA)measured by QFlow and CDFI,stenosis degree of carotid artery and ADC values of relevant brain regions were analyzed by nonparametric tests.Results:①Moderately positive correlations existed between the MVs (measured by 3D QFlow and CDFI)and BFs (r= 0.695,P<0.01;r= 0.795,P<0.01);low posi-tive correlation existed between the PVs (measured by QFlow and CDFI)and LAs (r= 0.453,P<0.01;r= 0.573,P<0.01).②Stenosis degree of CA had negative correlation with the BF measured by QFlow (r= -0.467,P<0.01),and posi-tive correlation with the ADC values of anterior region of periventricular white matter and the frontal white matter (r=0.373,P<0.01;r= 0.372,P<0.01).③The ADC values of periventricular white matter and the frontal white matter had moderately and low negative correlation with BF (r= -0.624,P<0.01;r= -0.533,P<0.01).Conclusion:Multimodal MRI can accurately display the decrease of blood flow of internal carotid artery and hypo-perfusion area of brain,and 3D QFlow MRA is a useful technique to evaluate hemodynamics of carotid artery.