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Updated: Jul 2, 2026
Functional Imaging of Auditory Cortex in Adult Cats using High-field fMRI
Published on: February 19, 2014
Silent echo-planar imaging for auditory FMRI
S Schmitter1, E Diesch, M Amann
1Division of Medical Physics in Radiology, German Cancer Research Center, Im Neuenheimer Feld 280, 69120, Heidelberg, Germany. s.schmitter@dkfz.de
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.
