不同年龄组正常颈总动脉血流动力学参数的比较

Comparison Study of Hemodynamic Parameters of Common Carotid Arteries in Healthy Subjects of Different Age Groups

目的应用磁共振技术结合图像后处理方法,探讨不同年龄组颈总动脉血流动力学参数的差别。方法收集22名志愿者,按年龄分为两组,青年组(20～30岁)12人,高龄组(55～76岁)10人。应用3.0T磁共振扫描仪及颈部表面线圈对志愿者双侧颈总动脉进行扫描。应用三维抛物面拟合方法对局部血流速度进行拟合,计算血管壁切应力及其他血流动力学参数,对两组各参数进行比较。结果青年组及高龄组平均血管壁切应力值分别为0.861±0.209N/m2和0.628±0.179N/m2;两组平均血管壁切应力值、收缩峰值期血管壁切应力值和舒张末期血管壁切应力值之间的差异具有统计学意义(P均<0.01)。两组平均血管横截面积、平均血流速度、最大血流速度及血流率之间的差异也存在统计学意义(P<0.01～0.05);最小血管壁切应力值(P=0.226)及最大血管壁切应力时间梯度在两组之间的差别无统计学意义(P=0.156)。结论颈总动脉血流动力学参数随增龄出现生理性结构和功能性的差别;对正常高龄志愿者血管壁切应力参数的进一步研究可能为早期预测预防动脉粥样硬化病变提供重要的血流动力学信息。

Objective To compare difference of hemodynamic parameters between different age groups using MR imaging combined post-processing techniques. Methods Twenty-two healthy volunteers were divided into 2 groups by age： group 1 （12 adults, aged 20 to 30 years） and group 2 （10 adults, aged 55 to 76 years）. Cine Phase-contrast MR imaging was performed to acquire the through-plane flow velocity profiles at 2 cm below the carotid bifucation. Three-dimensional paraboloid model was applied to fit the velocity profiles. The hemodynamic parameters of different-aged groups were calculated and compared. Results Mean wall shear stress （WSS） values of two groups were 0.861±0.209 N/m^2 and 0.628± 0.179 N/m^2 respectively. Statistical significances were observed in mean WSS （P〈0.01）, WSS in peak-systole （P〈0.01） and end-diastole （P〈0.01）, cross-area （P=0.041）, mean velocity （P〈0.01）, and blood flow rate （P=0.035） of two groups. There was no statistical significance observed in minimal WSS （P=0.226） and maximum WSSTG （P=0.156） between two groups. Conclusion Vascular aging can generate physiological changes in structure and function. Further study on WSS parameters of aged people may provide important hemodynamic information for early prevention and prediction of atberosclerosis.