title: Acoustic noise reduction in MRI using Silent Scan: an initial experience.
abstract: OBJECTIVE
  Acoustic noise during magnetic resonance imaging (MRI) is the main source for patient discomfort and leads to verbal communication problems, difficulties in sedation, and hearing impairment. Silent Scan technology uses less changes in gradient excitation levels, which is directly related to noise levels. Here, we report our preliminary experience with this technique in neuroimaging with regard to subjective and objective noise levels and image quality.
  
  
  METHODS
  Ten patients underwent routine brain MRI with 3 Tesla MR750w system and 12-channel head coil. T1-weighted gradient echo (BRAVO) and Silenz pulse sequence (TE=0, 3D radial center-out k-space filling and data sampling with relatively small gradient steps) were performed. Patients rated subjective sound impression for both sequences on a 6-point scale. Objective sound level measurements were performed with a dedicated device in gantry at different operation modes. Image quality was subjectively assessed in consensus by two radiologists on a 3-point scale.
  
  
  RESULTS
  Readers rated image quality as fully diagnostic in all patients. Measured mean noise was reduced significantly with Silenz sequence (68.8 dB vs. 104.65 dB with BRAVO, P = 0.024) corresponding to 34.3% reduction in sound intensity and 99,97% reduction in sound pressure. No significant difference was observed between Silenz sound levels and ambient sounds (i.e., background noise in the scanner room, 68.8 dB vs. 68.73 dB, P = 0.5). The patients' subjective sound level score was lower for Silenz compared with conventional sequence (1.1 vs. 2.3, P = 0.003).
  
  
  CONCLUSIONS
  T1-weighted Silent Scan is a promising technique for acoustic noise reduction and improved patient comfort.
authors.affiliation: MVZ Radiologie and Nuklearmedizin, Fürth, Germany. dr.s.alibek@t-online.de.
authors.forename: Sedat
authors.initials: S
authors.lastname: Alibek
authors.forename: Mika
authors.initials: M
authors.lastname: Vogel
authors.forename: Wei
authors.initials: W
authors.lastname: Sun
authors.forename: David
authors.initials: D
authors.lastname: Winkler
authors.forename: Christopher A
authors.initials: CA
authors.lastname: Baker
authors.forename: Michael
authors.initials: M
authors.lastname: Burke
authors.forename: Hubertus
authors.initials: H
authors.lastname: Gloger
mesh_terms: D000328:Adult; D000368:Aged; D001921:Brain / Q000473:pathology*; D004867:Equipment Design; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000295:instrumentation*; D008297:Male; D008875:Middle Aged; D059906:Neuroimaging / Q000295:instrumentation; D009622:Noise / Q000517:prevention & control*