Silent echo-planar imaging for auditory FMRI

MAGMA. 2008 Sep;21(5):317-25. doi: 10.1007/s10334-008-0132-4. Epub 2008 Aug 21.


Introduction: The effect of the acoustic scanner noise produced by gradient coil switching on the auditory evoked BOLD signal represents a well-known problem in auditory functional MRI (FMRI). In this paper, a new low-noise echo-planar imaging (EPI) sequence is presented that is optimized for auditory FMRI measurements.

Methods: The sequence produces a narrow-band acoustic frequency spectrum by using a sinusoidal readout echo train and a constant phase encoding gradient. This narrow band is adapted to the frequency response function of the MR scanner by varying the switching frequency of the sinusoidal readout gradient.

Results: Compared to a manufacturer-provided standard EPI sequence, the acoustic noise reduction amounts to up to 20 dBA. Using a simple block design paradigm contrasting presentation of a pure tone during ON blocks and "silence" (absence of the tone) during OFF blocks, the new low-noise sequence was evaluated and compared to the standard EPI sequence. Statistical parametric mapping (SPM) resulted in higher levels of significance of auditory activation for the low-noise sequence.

Discussion: These findings strongly suggest that the low-noise sequence may generate enhanced BOLD contrasts compared to the standard EPI sequences commonly used in FMRI.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acoustic Stimulation
  • Adult
  • Auditory Cortex / anatomy & histology*
  • Auditory Cortex / physiology*
  • Echo-Planar Imaging / methods*
  • Echo-Planar Imaging / statistics & numerical data
  • Equipment Design
  • Female
  • Humans
  • Image Processing, Computer-Assisted
  • Male
  • Noise