title: Piezoelectric actuator design for MR elastography: implementation and vibration issues.
abstract: BACKGROUND
  MR elastography (MRE) is an emerging technique for tumor diagnosis. MRE actuation devices require precise mechanical design and radiofrequency engineering to achieve the required mechanical vibration performance and MR compatibility.
  
  
  METHODS
  A method of designing a general-purpose, compact and inexpensive MRE actuator is presented. It comprises piezoelectric bimorphs arranged in a resonant structure designed to operate at its resonant frequency for maximum vibration amplitude. An analytical model was established to understand the device vibration characteristics.
  
  
  RESULTS
  The model-predicted performance was validated in experiments, showing its accuracy in predicting the actuator resonant frequency with an error < 4%. The device MRI compatibility was shown to cause minimal interference to a 1.5 tesla MRI scanner, with maximum signal-to-noise ratio reduction of 7.8% and generated artefact of 7.9 mm in MR images.
  
  
  CONCLUSIONS
  A piezoelectric MRE actuator is proposed, and its implementation, vibration issues and future work are discussed.
authors.affiliation: Harvard Medical School, Radiology Department, Brigham and Women's Hospital, 221 Longwood Avenue, LM-010, Boston, MA 02115, USA. ziontse@bwh.harvard.edu.
authors.forename: Zion Tsz Ho
authors.initials: ZT
authors.lastname: Tse
authors.forename: Yum Ji
authors.initials: YJ
authors.lastname: Chan
authors.forename: Henning
authors.initials: H
authors.lastname: Janssen
authors.forename: Abbi
authors.initials: A
authors.lastname: Hamed
authors.forename: Ian
authors.initials: I
authors.lastname: Young
authors.forename: Michael
authors.initials: M
authors.lastname: Lamperth
mesh_terms: D016477:Artifacts; D054459:Elasticity Imaging Techniques / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design; D006801:Humans; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging / Q000295:instrumentation* / Q000379:methods; D008280:Magnetics; D009369:Neoplasms / Q000175:diagnosis* / Q000473:pathology; D009991:Oscillometry; D011846:Radio Waves; D015203:Reproducibility of Results; D059629:Signal-To-Noise Ratio; D013314:Stress, Mechanical; D014732:Vibration