电影相位对比磁共振成像的空间和时间分辨率对壁面切应力及振荡切变指数评估的影响
The Effect of Spatial and Temporal Resolution of Cine Phase Contrast MRI on Wall Shear Stress and Oscillatory Shear Index Assessment.
作者信息
Cibis Merih, Potters Wouter V, Gijsen Frank J, Marquering Henk, van Ooij Pim, vanBavel Ed, Wentzel Jolanda J, Nederveen Aart J
机构信息
Biomedical Engineering Department, Erasmus MC, Rotterdam, The Netherlands.
Radiology Department, Academic Medical Center (AMC), Amsterdam, The Netherlands.
出版信息
PLoS One. 2016 Sep 26;11(9):e0163316. doi: 10.1371/journal.pone.0163316. eCollection 2016.
INTRODUCTION
Wall shear stress (WSS) and oscillatory shear index (OSI) are associated with atherosclerotic disease. Both parameters are derived from blood velocities, which can be measured with phase-contrast MRI (PC-MRI). Limitations in spatiotemporal resolution of PC-MRI are known to affect these measurements. Our aim was to investigate the effect of spatiotemporal resolution using a carotid artery phantom.
METHODS
A carotid artery phantom was connected to a flow set-up supplying pulsatile flow. MRI measurement planes were placed at the common carotid artery (CCA) and internal carotid artery (ICA). Two-dimensional PC-MRI measurements were performed with thirty different spatiotemporal resolution settings. The MRI flow measurement was validated with ultrasound probe measurements. Mean flow, peak flow, flow waveform, WSS and OSI were compared for these spatiotemporal resolutions using regression analysis. The slopes of the regression lines were reported in %/mm and %/100ms. The distribution of low and high WSS and OSI was compared between different spatiotemporal resolutions.
RESULTS
The mean PC-MRI CCA flow (2.5±0.2mL/s) agreed with the ultrasound probe measurements (2.7±0.02mL/s). Mean flow (mL/s) depended only on spatial resolution (CCA:-13%/mm, ICA:-49%/mm). Peak flow (mL/s) depended on both spatial (CCA:-13%/mm, ICA:-17%/mm) and temporal resolution (CCA:-19%/100ms, ICA:-24%/100ms). Mean WSS (Pa) was in inverse relationship only with spatial resolution (CCA:-19%/mm, ICA:-33%/mm). OSI was dependent on spatial resolution for CCA (-26%/mm) and temporal resolution for ICA (-16%/100ms). The regions of low and high WSS and OSI matched for most of the spatiotemporal resolutions (CCA:30/30, ICA:28/30 cases for WSS; CCA:23/30, ICA:29/30 cases for OSI).
CONCLUSION
We show that both mean flow and mean WSS are independent of temporal resolution. Peak flow and OSI are dependent on both spatial and temporal resolution. However, the magnitude of mean and peak flow, WSS and OSI, and the spatial distribution of OSI and WSS did not exhibit a strong dependency on spatiotemporal resolution.
引言
壁面切应力（WSS）和振荡切变指数（OSI）与动脉粥样硬化疾病相关。这两个参数均由血流速度得出，血流速度可通过相位对比磁共振成像（PC-MRI）进行测量。已知PC-MRI时空分辨率的局限性会影响这些测量。我们的目的是使用颈动脉模型研究时空分辨率的影响。
方法
将颈动脉模型连接到提供脉动血流的流动装置上。在颈总动脉（CCA）和颈内动脉（ICA）处放置MRI测量平面。使用30种不同的时空分辨率设置进行二维PC-MRI测量。通过超声探头测量对MRI血流测量进行验证。使用回归分析比较这些时空分辨率下的平均血流、峰值血流、血流波形、WSS和OSI。回归线的斜率以%/mm和%/100ms表示。比较不同时空分辨率下低WSS和高WSS以及低OSI和高OSI的分布情况。
结果
PC-MRI测量的CCA平均血流（2.5±0.2mL/s）与超声探头测量结果（2.7±0.02mL/s）相符。平均血流（mL/s）仅取决于空间分辨率（CCA：-13%/mm，ICA：-49%/mm）。峰值血流（mL/s）取决于空间分辨率（CCA：-13%/mm，ICA：-17%/mm）和时间分辨率（CCA：-19%/100ms，ICA：-24%/100ms）。平均WSS（Pa）仅与空间分辨率呈反比关系（CCA：-19%/mm，ICA：-33%/mm）。OSI对于CCA取决于空间分辨率（-26%/mm），对于ICA取决于时间分辨率（-16%/100ms）。在大多数时空分辨率下，低WSS和高WSS以及低OSI和高OSI的区域相匹配（WSS：CCA为30/30例，ICA为28/30例；OSI：CCA为23/30例，ICA为29/30例）。
结论
我们表明平均血流和平均WSS均与时间分辨率无关。峰值血流和OSI取决于空间分辨率和时间分辨率。然而，平均血流和峰值血流的大小、WSS和OSI以及OSI和WSS的空间分布对时空分辨率的依赖性并不强。
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