Display options
Cite
Bosshard JC, Yallapragada N, McDougall MP, et al. Exploration of highly accelerated magnetic resonance elastography using high-density array coils. Quant Imaging Med Surg. 2017;7(2):195-204doi: 10.21037/qims.2017.04.02.
Bosshard, J. C., Yallapragada, N., McDougall, M. P., & Wright, S. M. (2017). Exploration of highly accelerated magnetic resonance elastography using high-density array coils. Quantitative imaging in medicine and surgery, 7(2), 195-204. https://doi.org/10.21037/qims.2017.04.02
Bosshard, John C, et al. "Exploration of highly accelerated magnetic resonance elastography using high-density array coils." Quantitative imaging in medicine and surgery vol. 7,2 (2017): 195-204. doi: https://doi.org/10.21037/qims.2017.04.02
Bosshard JC, Yallapragada N, McDougall MP, Wright SM. Exploration of highly accelerated magnetic resonance elastography using high-density array coils. Quant Imaging Med Surg. 2017 Apr;7(2):195-204. doi: 10.21037/qims.2017.04.02. PMID: 28516045; PMCID: PMC5418148.
Copy Download .nbib Format: NLM
Share it on

Quant Imaging Med Surg. 2017 Apr;7(2):195-204. doi: 10.21037/qims.2017.04.02.

Exploration of highly accelerated magnetic resonance elastography using high-density array coils.

Quantitative imaging in medicine and surgery

John C Bosshard, Naresh Yallapragada, Mary P McDougall, Steven M Wright

Affiliations

  1. Department of Electrical and Computer Engineering, Texas A&M University, College Station, TX, USA.
  2. Department of Biomedical Engineering, Texas A&M University, College Station, TX, USA.
  3. Department of Radiology, Texas A&M Health Science Center, Bryan, TX, USA.

PMID: 28516045 PMCID: PMC5418148 DOI: 10.21037/qims.2017.04.02

Abstract

BACKGROUND: Magnetic resonance elastography (MRE) measures tissue mechanical properties by applying a shear wave and capturing its propagation using magnetic resonance imaging (MRI). By using high density array coils, MRE images are acquired using single echo acquisition (SEA) and at high resolutions with significantly reduced scan times.

METHODS: Sixty-four channel uniplanar and 32×32 channel biplanar receive arrays are used to acquire MRE wave image sets from agar samples containing regions of varying stiffness. A mechanical actuator triggered by a stepped delay time introduces vibrations into the sample while a motion sensitizing gradient encodes micrometer displacements into the phase. SEA imaging is used to acquire each temporal offset in a single echo, while multiple echoes from the same array are employed for highly accelerated imaging at high resolutions. Additionally, stiffness variations as a function of temperature are studied by using a localized heat source above the sample. A custom insertable gradient coil is employed for phase compensation of SEA imaging with the biplanar array to allow imaging of multiple slices.

RESULTS: SEA MRE images show a mechanical shear wave propagating into and across agar samples. A set of 720 images was obtained in 720 echoes, plus a single reference scan for both harmonic and transient MRE. A set of 2,950 wave image frames was acquired from pairs of SEA images captured during heating, showing the change in mechanical wavelength with the change in agar properties. A set of 240 frames was acquired from two slices simultaneously using the biplanar array, with phase images processed into displacement maps. Combining the narrow sensitivity patterns and SNR advantage of the SEA array coil geometry allowed acquisition of a data set with a resolution of 156 µm × 125 µm × 1,000 µm in only 64 echoes, demonstrating high resolution and high acceleration factors.

CONCLUSIONS: MRE using high-density arrays offers the unique ability to acquire a single frame of a propagating mechanical vibration with each echo, which may be helpful in non-repeatable or destructive testing. Highly accelerated, high resolution MRE may be enabled by the use of large arrays of coils such as used for SEA, but at lower acceleration rates supporting the higher resolution than provided by SEA imaging.

Keywords: Magnetic resonance imaging (MRI); RF coil arrays; gradient coils; magnetic resonance elastography (MRE); parallel imaging; single echo acquisition (SEA)

Conflict of interest statement

Conflicts of Interest: The authors have no conflicts of interest to declare.

References

  1. Magn Reson Med. 2005 Sep;54(3):605-15 - PubMed
  2. Magn Reson Med. 2001 Jan;45(1):80-7 - PubMed
  3. Magn Reson Med. 2005 Aug;54(2):386-92 - PubMed
  4. Magn Reson Med. 1989 Mar;9(3):369-78 - PubMed
  5. IEEE Eng Med Biol Mag. 2008 May-Jun;27(3):28-34 - PubMed
  6. Phys Med Biol. 2007 Oct 7;52(19):5909-19 - PubMed
  7. NMR Biomed. 2012 Mar;25(3):452-63 - PubMed
  8. Med Image Anal. 2001 Dec;5(4):237-54 - PubMed
  9. Magn Reson Imaging. 2015 Jan;33(1):31-7 - PubMed
  10. Magn Reson Med. 2007 Feb;57(2):388-95 - PubMed
  11. Magn Reson Med. 1987 Oct;5(4):318-22 - PubMed
  12. J Neurosci Methods. 2011 Oct 15;201(2):296-306 - PubMed
  13. Phys Med Biol. 2013 Dec 21;58(24):8663-75 - PubMed
  14. Magn Reson Med. 2012 Sep;68(3):850-6 - PubMed
  15. NMR Biomed. 2009 Nov;22(9):982-93 - PubMed
  16. Magn Reson Med. 1996 Aug;36(2):266-74 - PubMed
  17. Magn Reson Med. 2006 Jun;55(6):1381-9 - PubMed
  18. Magn Reson Med. 2005 Mar;53(3):628-39 - PubMed
  19. Clin Anat. 2010 Jul;23(5):497-511 - PubMed
  20. Conf Proc IEEE Eng Med Biol Soc. 2006;1:4877-80 - PubMed
  21. J Magn Reson Imaging. 2012 Oct;36(4):757-74 - PubMed
  22. Magn Reson Med. 2000 Oct;44(4):602-9 - PubMed
  23. J Magn Reson Imaging. 2008 May;27(5):1083-8 - PubMed
  24. IEEE Trans Biomed Eng. 2014 Jan;61(1):217-23 - PubMed

Publication Types