title: Acoustic-noise-optimized diffusion-weighted imaging.
abstract: OBJECTIVE
  This work was aimed at reducing acoustic noise in diffusion-weighted MR imaging (DWI) that might reach acoustic noise levels of over 100 dB(A) in clinical practice.
  
  
  METHODS
  A diffusion-weighted readout-segmented echo-planar imaging (EPI) sequence was optimized for acoustic noise by utilizing small readout segment widths to obtain low gradient slew rates and amplitudes instead of faster k-space coverage. In addition, all other gradients were optimized for low slew rates. Volunteer and patient imaging experiments were conducted to demonstrate the feasibility of the method. Acoustic noise measurements were performed and analyzed for four different DWI measurement protocols at 1.5T and 3T.
  
  
  RESULTS
  An acoustic noise reduction of up to 20 dB(A) was achieved, which corresponds to a fourfold reduction in acoustic perception. The image quality was preserved at the level of a standard single-shot (ss)-EPI sequence, with a 27-54% increase in scan time.
  
  
  CONCLUSIONS
  The diffusion-weighted imaging technique proposed in this study allowed a substantial reduction in the level of acoustic noise compared to standard single-shot diffusion-weighted EPI. This is expected to afford considerably more patient comfort, but a larger study would be necessary to fully characterize the subjective changes in patient experience.
authors.affiliation: Research Center for Magnetic-Resonance-Bavaria, Am Hubland, 97074, Würzburg, Germany. mott@physik.uni-wuerzburg.de.
authors.forename: Martin
authors.initials: M
authors.lastname: Ott
authors.affiliation: Research Center for Magnetic-Resonance-Bavaria, Am Hubland, 97074, Würzburg, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Blaimer
authors.affiliation: Siemens Healthcare, Erlangen, Germany.
authors.forename: David M
authors.initials: DM
authors.lastname: Grodzki
authors.affiliation: Research Center for Magnetic-Resonance-Bavaria, Am Hubland, 97074, Würzburg, Germany.
authors.forename: Felix A
authors.initials: FA
authors.lastname: Breuer
authors.affiliation: Department of Neuroradiology, University of Erlangen, Erlangen, Germany.
authors.forename: Julie
authors.initials: J
authors.lastname: Roesch
authors.affiliation: Department of Neuroradiology, University of Erlangen, Erlangen, Germany.
authors.forename: Arnd
authors.initials: A
authors.lastname: Dörfler
authors.affiliation: Siemens Healthcare, Erlangen, Germany.
authors.forename: Björn
authors.initials: B
authors.lastname: Heismann
authors.affiliation: Department of Experimental Physics 5, University of Würzburg, Würzburg, Germany.
authors.forename: Peter M
authors.initials: PM
authors.lastname: Jakob
mesh_terms: D000162:Acoustics; D001307:Auditory Perception; D001931:Brain Mapping / Q000379:methods; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D017352:Echo-Planar Imaging / Q000379:methods; D005240:Feasibility Studies; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D009622:Noise
keywords: Acoustic noise reduction; DWI; Patient comfort; Quiet MRI; Readout-segmented EPI