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Application of through-time spiral GRAPPA to phase velocity mapping (PVM)

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PVM is an established technique for measuring blood and myocardial velocities... However, long scan times can restrict its application... Peak-GRAPPA has been used to accelerate Cartesian PVM up to a factor of 6 (R = 6) without degrading peak velocity measurements, however use of efficient k-space trajectories could allow higher temporal resolution (TR) in similar scan time... Through-time spiral GRAPPA allows highly accelerated spiral data to be reconstructed using through-time calibration information... By collecting multiple repetitions of fully sampled calibration data, which can be collected without gating during free breathing, through-time information can be used to generate GRAPPA weights specific to the local undersampling in the non-Cartesian data... This abstract presents preliminary work on a single volunteer to apply this reconstruction to myocardial spiral PVM data... The curves have very similar shapes in all cases... All peak velocities are well preserved up to R = 4, and some are also well preserved at R = 8 (Long1, Circ1, Rad2)... However some of the peaks (Long2, Rad1, Circ2) are beginning to be degraded by R8... Through-time spiral GRAPPA can be used to accelerate spiral PVM acquisitions... In this example very little degradation of peak velocities was seen up to R4 and results at higher factors could be improved with further optimisation.

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Global longitudinal, radial and circumferential velocity-time curves measured for SENSE factor 2 and GRAPPA factors 2, 4 and 8. The main peaks in each direction are labelled. Global peak velocities measured from these curves can be found in Table 1.
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Figure 1: Global longitudinal, radial and circumferential velocity-time curves measured for SENSE factor 2 and GRAPPA factors 2, 4 and 8. The main peaks in each direction are labelled. Global peak velocities measured from these curves can be found in Table 1.

Mentions: Figure 1 shows global longitudinal, radial and circumferential peak velocities measured using images generated by the four reconstructions (through-time spiral GRAPPA R = 2, R = 4, and R = 8, and CG SENSE R = 2), while Table 1 shows measured global peak velocities. The curves have very similar shapes in all cases. All peak velocities are well preserved up to R = 4, and some are also well preserved at R = 8 (Long1, Circ1, Rad2). However some of the peaks (Long2, Rad1, Circ2) are beginning to be degraded by R8.


Application of through-time spiral GRAPPA to phase velocity mapping (PVM)
Global longitudinal, radial and circumferential velocity-time curves measured for SENSE factor 2 and GRAPPA factors 2, 4 and 8. The main peaks in each direction are labelled. Global peak velocities measured from these curves can be found in Table 1.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4045687&req=5

Figure 1: Global longitudinal, radial and circumferential velocity-time curves measured for SENSE factor 2 and GRAPPA factors 2, 4 and 8. The main peaks in each direction are labelled. Global peak velocities measured from these curves can be found in Table 1.
Mentions: Figure 1 shows global longitudinal, radial and circumferential peak velocities measured using images generated by the four reconstructions (through-time spiral GRAPPA R = 2, R = 4, and R = 8, and CG SENSE R = 2), while Table 1 shows measured global peak velocities. The curves have very similar shapes in all cases. All peak velocities are well preserved up to R = 4, and some are also well preserved at R = 8 (Long1, Circ1, Rad2). However some of the peaks (Long2, Rad1, Circ2) are beginning to be degraded by R8.

View Article: PubMed Central - HTML

AUTOMATICALLY GENERATED EXCERPT
Please rate it.

PVM is an established technique for measuring blood and myocardial velocities... However, long scan times can restrict its application... Peak-GRAPPA has been used to accelerate Cartesian PVM up to a factor of 6 (R = 6) without degrading peak velocity measurements, however use of efficient k-space trajectories could allow higher temporal resolution (TR) in similar scan time... Through-time spiral GRAPPA allows highly accelerated spiral data to be reconstructed using through-time calibration information... By collecting multiple repetitions of fully sampled calibration data, which can be collected without gating during free breathing, through-time information can be used to generate GRAPPA weights specific to the local undersampling in the non-Cartesian data... This abstract presents preliminary work on a single volunteer to apply this reconstruction to myocardial spiral PVM data... The curves have very similar shapes in all cases... All peak velocities are well preserved up to R = 4, and some are also well preserved at R = 8 (Long1, Circ1, Rad2)... However some of the peaks (Long2, Rad1, Circ2) are beginning to be degraded by R8... Through-time spiral GRAPPA can be used to accelerate spiral PVM acquisitions... In this example very little degradation of peak velocities was seen up to R4 and results at higher factors could be improved with further optimisation.

No MeSH data available.