ROI面积对PC-MRI测量基底动脉血流动力学参数的影响

Impact of ROI size on hemodynamic parameters of basilar artery measured with PC-MRI

目的观察不同面积ROI对于相位对比MRI(PC-MRI)测量基底动脉(BA)血流动力学参数的影响。方法采集48名健康志愿者BA中间段PC-MRI,勾画ROI,使之分别占血管截面面积的100%、80%、60%及40%,依次记为ROI 1、ROI 2、ROI 3及ROI 4。比较不同ROI所测血管平均流量(MF)、平均流速(MV)及收缩期最高流速与舒张期最低速度差值(ΔV)的差异。结果ROI 1与ROI 3及ROI 4间BA各参数(MF、MV、ΔV)差异均有统计学意义(ROI 1 vs ROI 3:H=56.74、-47.56、-34.49,ROI 1 vs ROI 4:H=101.47、-64.49、-47.08,P均<0.05),ROI 2与ROI 3及ROI 4间MF差异均有统计学意义(H=32.24、76.97,P均<0.05),ROI 3与ROI 4间MF差异有统计学意义(H=44.73,P<0.01),ROI 2与ROI 4间MV差异有统计学意义(H=-37.67,P=0.01),其余各参数各ROI间差异均无统计学意义(P均>0.05)。结论采用PC-MRI测量健康成年人BA血流动力学参数时,ROI不应小于血管截面面积的80%,否则可低估MF而高估MV、ΔV。

Objective To observe the impact of ROI size on hemodynamic parameters of basilar artery(BA)measured with phase contrast MRI(PC-MRI).Methods PC-MRI of the middle segment of BA were obtained in 48 healthy volunteers.ROIs were plotted with 100%(ROI 1),80%(ROI 2),60%(ROI 3)and 40%(ROI 4)of the cross-sectional area of BA,respectively.The mean flux(MF),mean velocity(MV),the peak systolic velocity and end diastolic velocity(ΔV)of BA were compared among different ROIs.Results There were statistical differences of MF,MV andΔV of BA between ROI 1 and ROI 3 or ROI 4(ROI 1 vs ROI 3:H=56.74,-47.56,-34.49,ROI 1 vs ROI 4:H=101.47,-64.49,-47.08,all P<0.05).There were significant differences of MF between ROI 2 and ROI 3 or ROI 4(H=32.24,76.97,both P<0.05),also of MF between ROI 3 and ROI 4(H=44.73,P<0.01),of MV between ROI 2 and ROI 4(H=-37.67,P=0.01).No significant difference of other parameters was found(all P>0.05).Conclusion Measuring hemodynamic parameters of BA of healthy adult,ROI should not be sketched less than 80%of the cross-sectional area of BA,otherwise MF might be underestimated,while MV andΔV might be overestimated.