向量血流成像技术评估兔腹主动脉早期动脉粥样硬化的价值

目的:探讨全新的向量血流成像技术(vector flow imaging technique,V Flow)测量的血管壁应力(wall shear stress,WSS)在评估兔腹主动脉早期动脉粥样硬化(atherosclerosis,AS)中的价值。方法:选用健康雄性新西兰兔7只,高脂饮食喂养建立兔腹主动脉AS模型。喂养14周后,每周采用常规灰阶超声观察兔腹主动脉管壁是否有硬化斑块形成,采用彩色多普勒血流图(color Doppler flow imaging,CDFI)测量腹主动脉血流量(blood flow volume,BFV)及收缩期峰值流速(peak systolic velocity,PSV),采用V Flow观察并测量兔腹主动脉前、后壁WSS值。34周后,以病理检查结果为金标准,对比并分析WSS在兔腹主动脉AS形成及发展过程中的动态变化。结果:病理结果显示,高脂饮食喂养34周后兔腹主动脉出现AS脂纹期的典型改变,37周后兔腹主动脉有AS纤维斑块的表现。腹主动脉前、后壁WSS随着AS病程的进展动态变化:从14周开始呈降低趋势,20/21周至27周表现为增高趋势,27周之后又逐渐降低。腹主动脉前壁和后壁WSS最大值(WSS_(max))、WSS平均值(WSS_(mean))的拐点值与第0周基线值差异具有统计学意义(P0.05),WSS_(max)、WSS_(mean)变化曲线出现拐点的时间早于常规CDFI测得的PSV及BFV值。结论:V Flow较传统的CDFI可更早预测腹主动脉AS斑块及评估相应血流动力学改变,具有潜在的临床应用价值。

Evaluation of hemodynamic changes of early atherosclerosis in rabbit aorta by vector flow imaging technology

Objective: To evaluate the change of V Flow and wall shear stress (WSS) parameter in evaluation the early aorta atherosclerosis (AS) in rabbit models. Materials Methods: Rabbit AS models were established by feeding high fat forage in healthy New Zealand rabbits (n = 7). Before the high fat forage feeding, ultrasound evaluations of aorta were performed as the baseline values. During the follow-up period, ultrasound evaluations were performed once per week since 14th week. A Mindray Resona 7s ultrasound system equipped with a L9-3U linear array transducer (3-9 MHz) and updated V Flow imaging function was used. The maximum WSS (WSSmax) value, mean WSS (WSSmean) value measured by V Flow technology were compared with blood flow volume (BFV), peak systolic velocity (PSV) value measured by conventional color Doppler flow imaging (CDFI). The histopathological results after 34th weeks were used as gold standard to make correlation analysis between the WSS value during follow-up. Results: On 34th week, pathological results showed typical fatty streak changes of AS on the wall of rabbit aorta. Since 37th week, AS plaques could be detected. The WSS values of aorta changed with the progression of AS, which began to decrease at 14th week, increased between 20th/21st and 27th week, and gradually decreased after 27th week. Significant difference was found between the WSS values and the baseline values (P < 0.05). Statistical results showed earlier statistical changes of WSSmax and WSSmean value, while comparing with PSV and BFV values. Conclusion: The WSS value measured by V Flow technology changes dynamically during the progress of aorta AS in rabbit models. WSS values might have potential clinical value in evaluation of early hemodynamics changes in AS.