Reduced acoustic noise in diffusion tensor imaging on a compact MRI system

Ek T. Tan, Christopher J. Hardy, Yunhong Shu, Myung Ho In, Arnaud Guidon, John Huston, Matt A. Bernstein, Thomas K.F. Foo

Research output: Contribution to journalArticle

4 Scopus citations

Abstract

Purpose: To investigate the feasibility of substantially reducing acoustic noise while performing diffusion tensor imaging (DTI) on a compact 3T (C3T) MRI scanner equipped with a 42-cm inner-diameter asymmetric gradient. Methods: A-weighted acoustic measurements were made using 10 mT/m-amplitude sinusoidal waveforms, corresponding to echo-planar imaging (EPI) echo spacing of 0.25 to 5.0 ms, on a conventional, whole-body 3T MRI and on the C3T. Acoustic measurements of DTI with trapezoidal EPI waveforms were then made at peak gradient performance on the C3T (80 mT/m amplitude, 700 T/m/s slew rate) and at derated performance (33 mT/m, 10 to 50 T/m/s) for acoustic noise reduction. DTI was acquired in two different phantoms and in seven human subjects, with and without gradient-derating corresponding to multi- and single-shot acquisitions, respectively. Results: Sinusoidal waveforms on the C3T were quieter by 8.5 to 15.6 A-weighted decibels (dBA) on average as compared to the whole-body MRI. The derated multishot DTI acquisition noise level was only 8.7 dBA (at 13 T/m/s slew rate) above ambient, and was quieter than non-derated, single-shot DTI by 22.3 dBA; however, the scan time was almost quadrupled. Although derating resulted in negligible diffusivity differences in the phantoms, small biases in diffusivity measurements were observed in human subjects (apparent diffusion coefficient = +9.3 ± 8.8%, fractional anisotropy = +3.2 ± 11.2%, radial diffusivity = +9.4 ± 16.8%, parallel diffusivity = +10.3 ± 8.4%). Conclusion: The feasibility of achieving reduced acoustic noise levels with whole-brain DTI on the C3T MRI was demonstrated. Magn Reson Med 79:2902–2911, 2018.

Original languageEnglish (US)
Pages (from-to)2902-2911
Number of pages10
JournalMagnetic Resonance in Medicine
Volume79
Issue number6
DOIs
StatePublished - Jun 2018

Keywords

  • compact 3T
  • diffusion tensor imaging
  • head-only gradient
  • silent MRI

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging

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