title: Synchronous MRI of muscle motion induced by electrical stimulation.
abstract: Assessing the functionality of muscle fibers is essential to monitor both pathological and physiological processes. Here, we present a new method for accurate, quantitative measurement of muscle contraction with magnetic resonance imaging (MRI) using an electrical muscle stimulator (EMS), hence allowing the direct assessment of muscle kinematics.
  
  
  
  A commercially available EMS device was used to induce involuntary periodic muscle contraction of the vastus lateralis muscle (VL) synchronized with high-temporal-resolution cine phase contrast MRI acquisition at 3T. The proposed method was evaluated in ten male volunteers at varying levels of stimulation (10-18 mA) and maximum velocity, strain, and strain rate were calculated offline.
  
  
  
  Artifact-free velocity, strain and strain rate maps were produced and were consistent across the volunteers. Quantitatively, all parameters varied significantly at different levels of stimulation, in an approximately power-law dependence on the stimulation current. At 18 mA maximum contraction speeds at the beginning of the contraction were 4.28 ± 2.64 cm/s; principal strain was 0.30 ± 0.12; and positive in-plane strain rate was 0.25 ± 0.14 s-1.
  
  
  
  MRI of EMS-controlled involuntary muscle contraction is feasible and allows offline calculation of velocity, strain and strain rate maps, which appear to depend significantly on the stimulation current used. Magn Reson Med 77:664-672, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
authors.affiliation: Department of Radiology, Division of Radiological Physics, University of Basel Hospital, Basel, Switzerland.|Department of Biomedical Engineering, University of Basel, Basel, Switzerland.
authors.forename: Xeni
authors.initials: X
authors.lastname: Deligianni
authors.affiliation: Department of Radiology, Kantonsspital Basel-Landschaft Bruderholz, Bruderholz, Switzerland.
authors.forename: Michele
authors.initials: M
authors.lastname: Pansini
authors.affiliation: Department of Radiology, University of Basel Hospital, Basel, Switzerland.
authors.forename: Meritxell
authors.initials: M
authors.lastname: Garcia
authors.affiliation: Department of Radiology, University of Basel Hospital, Basel, Switzerland.
authors.forename: Anna
authors.initials: A
authors.lastname: Hirschmann
authors.affiliation: Department of Sports Medicine, University of Basel, Basel, Switzerland.
authors.forename: Arno
authors.initials: A
authors.lastname: Schmidt-Trucksäss
authors.affiliation: Department of Radiology, Division of Radiological Physics, University of Basel Hospital, Basel, Switzerland.|Department of Biomedical Engineering, University of Basel, Basel, Switzerland.
authors.forename: Oliver
authors.initials: O
authors.lastname: Bieri
authors.affiliation: Department of Radiology, Division of Radiological Physics, University of Basel Hospital, Basel, Switzerland.|Department of Biomedical Engineering, University of Basel, Basel, Switzerland.
authors.forename: Francesco
authors.initials: F
authors.lastname: Santini
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena / Q000502:physiology*; D004558:Electric Stimulation / Q000379:methods*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D009068:Movement / Q000502:physiology; D018482:Muscle, Skeletal / Q000502:physiology*; D012815:Signal Processing, Computer-Assisted; D055815:Young Adult
keywords: electrical stimulation; skeletal muscle function; strain; strain rate; velocity-encoded phase contrast MRI