沿颈内虹吸的血流搏动阻尼：形态是否随功能而变化？
Dampening of blood-flow pulsatility along the carotid siphon: does form follow function?
机构信息
Departments of Radiology, University Hospital Basle, Switzerland.
出版信息
AJNR Am J Neuroradiol. 2011 Jun-Jul;32(6):1107-12. doi: 10.3174/ajnr.A2426. Epub 2011 Apr 7.
BACKGROUND AND PURPOSE
The tortuous distal part of the ICA may have an attenuating effect on pulsatile arterial flow. We investigated local arterial blood flow patterns in the ICA proximal and distal to the carotid siphon to detect quantitative waveform changes.
MATERIALS AND METHODS
Arterial flow patterns were analyzed by using flow-sensitized 4D PC MR imaging (time-resolved 3D PCMR) at 3T in 17 healthy volunteers. Time-resolved blood flow velocities were extracted from the source data at the C4 and C7 segments of the ICA. PI, RI, and PA were calculated by using time-resolved flow volume. A linear mixed-effects model was applied to compare values at C4 and C7. Furthermore, 3D blood flow visualization was performed for all 34 ICAs.
RESULTS
PI, RI, and PA were significantly lower at the distal C7 segment compared with the proximal C4 segment of the ICA (P < .0001). Helical flow patterns were observed in 5 ICAs of 4 subjects.
CONCLUSIONS
Arterial flow patterns showed a significant reduction in PI, RI, and PA when compared distal to proximal to the carotid siphon. The observed attenuation of flow pulsatility is most likely related to the contorted shape of the distal ICA and may bear a protective effect for downstream cerebral vasculature.
背景与目的
颈内动脉（ICA）迂曲的远段可能对脉动性动脉血流产生衰减作用。我们研究了虹吸段前后 ICA 的局部动脉血流模式，以检测定量波形变化。
材料与方法
在 3T 磁共振扫描仪上使用流动敏感 4D PC MR 成像（时间分辨 3D PCMR）对 17 名健康志愿者的动脉血流模式进行分析。在 ICA 的 C4 和 C7 节段从源数据中提取时间分辨血流速度。通过时间分辨流量计算 PI、RI 和 PA。应用线性混合效应模型比较 C4 和 C7 处的值。此外，对所有 34 个 ICA 进行了 3D 血流可视化。
结果
与 ICA 的近端 C4 节段相比，远端 C7 节段的 PI、RI 和 PA 显著降低（P<0.0001）。4 名受试者的 5 个 ICA 中观察到螺旋形血流模式。
结论
与虹吸段前后相比，动脉血流模式的 PI、RI 和 PA 明显降低。观察到的血流搏动衰减很可能与远段 ICA 的扭曲形状有关，可能对下游脑血管具有保护作用。
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