Volume 13 Supplement 1

Abstracts of the 2011 SCMR/Euro CMR Joint Scientific Sessions

Open Access

Rapid flow assessment of congenital heart disease using high spatio-temporal gated spiral phase-contrast MR

  • Jennifer A Steeden1,
  • David Atkinson1,
  • Andrew M Taylor2 and
  • Vivek Muthurangu2
Journal of Cardiovascular Magnetic Resonance201113(Suppl 1):P380

https://doi.org/10.1186/1532-429X-13-S1-P380

Published: 2 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 prospectively-triggered 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).

Table 1

 

Free-Breathing PCMR

Standard Breath-hold PCMR

Spiral Breath-hold 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

3

4

2

Pixel bandwidth (Hz/pixel)

543

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

~ 30.0 ms

~ 40.0 ms

32.0 ms

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.

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). Bland-Altman analyses are shown in Figure 1. There was no clinically significant bias using either breath-hold sequence (spiral breath-hold: -0.7 mL, standard breath-hold: -0.5 mL). However, the limits of agreement were smaller and the correlation better for the spiral breath-hold compared to the standard breath-hold sequence (-4.4 to 2.9 mL vs. -10.3 to 9.3 mL, respectively).

Figure 1

There was also an excellent agreement in QP/QS and RPA/LPA ratios between all sequences, however the spiral breath-hold sequence was found to be superior to the standard breath-hold sequence in terms of limits of agreement and correlation. There was a small but statistically significant underestimation of regurgitation fraction using the spiral sequence.

Conclusion

Flow volumes can be accurately and reliably quantified using a spiral SENSE PCMR sequence, with high spatio-temporal resolution in a short breath-hold. As the standard method of measuring flow in congenital heart disease is free-breathing, cardiac gated PCMR, this spiral sequence could reduce total flow imaging from ~10 minutes, to <1 minute. This is a marked reduction in total scan time and has implications for patient throughput and compliance for congenital cardiac MR scanning.

Authors’ Affiliations

(1)
University College London
(2)
UCL, Institute of Child Health

Copyright

© Steeden et al; licensee BioMed Central Ltd. 2011

This article is published under license to BioMed Central Ltd. This is an open access article distributed under the terms of the Creative Commons Attribution License (<url>http://creativecommons.org/licenses/by/2.0</url>), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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