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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.

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Related in: MedlinePlus

a) Mean flow [mL/s] vs. spatial resolution [mm] b) Mean flow [mL/s] vs. temporal resolution [ms] c) Peak flow [mL/s] vs. spatial resolution and d) Peak flow [mL/s] vs. temporal resolution at the CCA and ICA. Red lines show the mean and peak flow measured by ultrasound probe.
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pone.0163316.g003: a) Mean flow [mL/s] vs. spatial resolution [mm] b) Mean flow [mL/s] vs. temporal resolution [ms] c) Peak flow [mL/s] vs. spatial resolution and d) Peak flow [mL/s] vs. temporal resolution at the CCA and ICA. Red lines show the mean and peak flow measured by ultrasound probe.

Mentions: The cross-sectional area was 24.6 ± 0.6 mm2 at the CCA and 29.0 ± 2.9 mm2 at the ICA. The mean flow based on PC-MRI measurements was 2.5 ± 0.2 mL/s at the CCA and 1.3 ± 0.2 mL/s at the ICA. The mean flow vs. the different spatial resolutions is plotted in Fig 3a and the mean flow vs. the different temporal resolutions in Fig 3b. A significant association was found between mean flow and the spatial resolution (slope -13.0%/mm for the CCA and -49.0%/mm for the ICA). No correlation was observed between mean flow and temporal resolution. The mean flow based on the ultrasound flow probe measurement was 2.7 ± 0.02 mL/s at the CCA; hence, the ratio of the mean flow based on PC-MRI measurements and the ultrasound flow probe measurement was 95.1 ± 7.9%.


The Effect of Spatial and Temporal Resolution of Cine Phase Contrast MRI on Wall Shear Stress and Oscillatory Shear Index Assessment
a) Mean flow [mL/s] vs. spatial resolution [mm] b) Mean flow [mL/s] vs. temporal resolution [ms] c) Peak flow [mL/s] vs. spatial resolution and d) Peak flow [mL/s] vs. temporal resolution at the CCA and ICA. Red lines show the mean and peak flow measured by ultrasound probe.
© Copyright Policy
Related In: Results  -  Collection

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

pone.0163316.g003: a) Mean flow [mL/s] vs. spatial resolution [mm] b) Mean flow [mL/s] vs. temporal resolution [ms] c) Peak flow [mL/s] vs. spatial resolution and d) Peak flow [mL/s] vs. temporal resolution at the CCA and ICA. Red lines show the mean and peak flow measured by ultrasound probe.
Mentions: The cross-sectional area was 24.6 ± 0.6 mm2 at the CCA and 29.0 ± 2.9 mm2 at the ICA. The mean flow based on PC-MRI measurements was 2.5 ± 0.2 mL/s at the CCA and 1.3 ± 0.2 mL/s at the ICA. The mean flow vs. the different spatial resolutions is plotted in Fig 3a and the mean flow vs. the different temporal resolutions in Fig 3b. A significant association was found between mean flow and the spatial resolution (slope -13.0%/mm for the CCA and -49.0%/mm for the ICA). No correlation was observed between mean flow and temporal resolution. The mean flow based on the ultrasound flow probe measurement was 2.7 ± 0.02 mL/s at the CCA; hence, the ratio of the mean flow based on PC-MRI measurements and the ultrasound flow probe measurement was 95.1 ± 7.9%.

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