title: Parallel imaging-based reduction of acoustic noise for clinical magnetic resonance imaging.
abstract: OBJECTIVE
  The objective of this study was to demonstrate the feasibility of improving perceived acoustic comfort for a standard clinical magnetic resonance imaging protocol via gradient wave form optimization and validate parallel imaging as a means to achieve a further reduction of acoustic noise.
  
  
  METHODS
  The gradient wave forms of a standard T2 axial turbo spin-echo (TSE) sequence in head examinations were modified for acoustic performance while attempting to keep the total acquisition and inter-echo spacing the same. Parallel imaging was then used to double the inter-echo spacing and allow further wave form optimization. Along with comparative acoustic noise measurements, a statistical analysis of radiologist scoring was conducted on volumes from standard and modified sequences acquired from 10 patients after informed consent was obtained.
  
  
  RESULTS
  Compared with TSE, significant improvement of acoustic comfort was measured for modified-sequences quiet TSE and quiet TSE with generalized autocalibrating partially parallel acquisitions (P = 0.0034 and P = 0.0003, respectively), and no statistically significant difference in diagnostic quality was observed without the use of parallel imaging.
  
  
  CONCLUSIONS
  Standard clinical magnetic resonance imaging protocols can be made quieter through adequate gradient wave form optimization. In scans with high signal-to-noise ratio, parallel imaging can be used to further reduce acoustic noise.
authors.affiliation: From the *Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH; †Siemens AG, Erlangen, Germany; ‡Department of Radiology, University Hospitals of Cleveland, Case Western Reserve University, Cleveland, OH; §Haraldsplass Deaconess Hospital, Bergen, Norway; ∥Division of Biostatistics, Case Western Reserve University, Cleveland, OH; and ¶Siemens Medical Solutions USA Inc, Malvern, PA.
authors.forename: Eric Y
authors.initials: EY
authors.lastname: Pierre
authors.forename: David
authors.initials: D
authors.lastname: Grodzki
authors.forename: Gunhild
authors.initials: G
authors.lastname: Aandal
authors.forename: Bjoern
authors.initials: B
authors.lastname: Heismann
authors.forename: Chaitra
authors.initials: C
authors.lastname: Badve
authors.forename: Vikas
authors.initials: V
authors.lastname: Gulani
authors.forename: Jeffrey L
authors.initials: JL
authors.lastname: Sunshine
authors.forename: Mark
authors.initials: M
authors.lastname: Schluchter
authors.forename: Kecheng
authors.initials: K
authors.lastname: Liu
authors.forename: Mark A
authors.initials: MA
authors.lastname: Griswold
mesh_terms: D000328:Adult; D000368:Aged; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D059629:Signal-To-Noise Ratio; D055815:Young Adult