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