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The Effect of Spatial and Temporal Resolution of Cine Phase Contrast MRI on Wall Shear Stress and Oscillatory Shear Index Assessment

View Article: PubMed Central - PubMed

ABSTRACT

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.

No MeSH data available.


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The mean OSI of each quarter by CFD and by PC-MRI measurements at 4 different spatial and temporal resolutions in the CCA and ICA.* shows the highest OSI quarter and + shows the lowest OSI quarter.
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pone.0163316.g006: The mean OSI of each quarter by CFD and by PC-MRI measurements at 4 different spatial and temporal resolutions in the CCA and ICA.* shows the highest OSI quarter and + shows the lowest OSI quarter.

Mentions: The mean OSI of each quarter for four measurements is shown in Fig 6. OSI was generally low in all quarters of the CCA. The highest OSI quarter in the CCA was the top left quarter (0.04 ± 0.02) which was found in 23/30 measurements (77%) and in CFD calculation (0.07). The lowest OSI quarter was the bottom right quarter in 29/30 (97%) measurements (0 ± 0.01) and in also CFD calculation (0.0). For the ICA, the lowest OSI quarter was the bottom right quarter which was found in all measurements (0.01 ± 0.01) and also in CFD calculation (0.01). The highest OSI quarter was the top left quarter (0.20 ± 0.08) in all measurements regardless of spatial and temporal resolution. CFD based OSI was lower in the ICA. The highest OSI quarter (0.12) was the bottom left quarter and the OSI at the top left quarter was 0.07.


The Effect of Spatial and Temporal Resolution of Cine Phase Contrast MRI on Wall Shear Stress and Oscillatory Shear Index Assessment
The mean OSI of each quarter by CFD and by PC-MRI measurements at 4 different spatial and temporal resolutions in the CCA and ICA.* shows the highest OSI quarter and + shows the lowest OSI quarter.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5036833&req=5

pone.0163316.g006: The mean OSI of each quarter by CFD and by PC-MRI measurements at 4 different spatial and temporal resolutions in the CCA and ICA.* shows the highest OSI quarter and + shows the lowest OSI quarter.
Mentions: The mean OSI of each quarter for four measurements is shown in Fig 6. OSI was generally low in all quarters of the CCA. The highest OSI quarter in the CCA was the top left quarter (0.04 ± 0.02) which was found in 23/30 measurements (77%) and in CFD calculation (0.07). The lowest OSI quarter was the bottom right quarter in 29/30 (97%) measurements (0 ± 0.01) and in also CFD calculation (0.0). For the ICA, the lowest OSI quarter was the bottom right quarter which was found in all measurements (0.01 ± 0.01) and also in CFD calculation (0.01). The highest OSI quarter was the top left quarter (0.20 ± 0.08) in all measurements regardless of spatial and temporal resolution. CFD based OSI was lower in the ICA. The highest OSI quarter (0.12) was the bottom left quarter and the OSI at the top left quarter was 0.07.

View Article: PubMed Central - PubMed

ABSTRACT

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.

No MeSH data available.


Related in: MedlinePlus