Rapid flow assessment of congenital heart disease using high spatio-temporal gated spiral phase-contrast MR
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Rapid flow assessment of congenital heart disease using high spatio-temporal gated spiral phase-contrast MR Jennifer A Steeden1*, David Atkinson1, Andrew M Taylor2, Vivek Muthurangu2 From 2011 SCMR/Euro CMR Joint Scientific Sessions Nice, France. 3-6 February 2011 Purpose Many sick adults and children are unable to perform long breath-holds required for conventional, Cartesian phase-contrast (PC) sequences. Using a prospectivelytriggered spiral PCMR sequence accelerated with sensitivity encoding (SENSE), it should be possible to achieve high resolution PCMR data in a short breath-hold. The aim of this study was to compare flow volumes measured using: a) reference free-breathing, gated Cartesian PCMR, b) standard breath-hold, gated, Cartesian PCMR, and c) gated, spiral, SENSE, breath-hold PCMR. Methods 40 consecutive children and adults were enrolled in this study (M:22, F:18, age:21.4±13.8 years). Flow was measured in the: - Ascending aorta (AAO, N=40) - Main pulmonary artery (MPA, N=38) - Right pulmonary artery (RPA, N=22) - Left pulmonary artery (LPA, N=24) Flow assessment was performed in each vessel using the three sequences above (parameters shown in Table 1). Stroke volume and regurgitation fraction were calculated for each patient. Additionally, Qp/Qs (N=38) and RPA/LPA (N=20) ratios were quantified where possible. Results Average scan time was 91±17 seconds for the reference free-breathing sequence, 16±3 seconds for the standard breath-hold sequence, and 5±1 seconds for the spiral breath-hold sequence.
1
University College London, London, UK Full list of author information is available at the end of the article
Combining all vessels (N=124), there were no statistical differences in mean stroke volume calculated from the reference free-breathing sequence (60.3±27.3 mL), the standard breath-hold sequence (59.8±27.6 mL) and the spiral breath-hold sequence (59.5±27.1 mL). BlandAltman analyses are shown in Figure 1. There was no clinically significant bias using either breath-hold sequence (spiral breath-hold: -0.7 mL, standard breathhold: -0.5 mL). However, the limits of agreement were smaller and the correlation better for the spiral breath-
Table 1 FreeBreathing PCMR
Standard Breathhold PCMR
Spiral Breathhold PCMR
TE/TR (ms)
~2.2 / 7.0
~2.2 / 7.0
2.1 / 8.0
Spiral Readouts
-
-
36
Acceleration factor
2 (GRAPPA)
2 (GRAPPA)
3 (SENSE)
Matrix Size
256 x 192
192 x 113
256 x 256
FOV (mm)
200 - 400
290 - 400
400
Rectangular FOV 75 (%)
66
100
Readouts per segment
4
2
Pixel bandwidth 543 (Hz/pixel)
543
1220
VENC (cm/s)
180 - 400
180 - 400
180 - 400
NSAs
3
1
1
Gating
Retrospective
Retrospective
Prospective
Total Scan Duration (s)
44 - 144
11 - 24
3-8
Voxel Size (mm) ~ 0.8 - 1.5
~ 1.5 - 2.1
1.6
Temporal resolution
~ 40.0 ms
32.0 ms
3
~ 30.0 ms
© 2011 Steeden et al; licensee BioMed Central Ltd. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/license
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