title: Delayed-Onset Muscle Soreness: Temporal Assessment With Quantitative MRI and Shear-Wave Ultrasound Elastography.
abstract: OBJECTIVE
  The objective of our study was to assess delayed-onset muscle soreness (DOMS) over time using quantitative MRI and shear-wave ultrasound (US) elastography.
  
  
  METHODS
  Five male (mean age ± SD, 39.6 ± 4.6 years) and five female (30.6 ± 13.5 years) volunteers underwent 1.5-T MRI before and after (15 minutes, 1 day, 3 days, 7 days) performing unilateral eccentric resistance exercise of the elbow flexor muscles. The MRI examinations included fluid-sensitive, DWI, and diffusion-tensor imaging sequences of the distal upper arm. Muscle edema, apparent diffusion coefficient (ADC), and fractional anisotropy (FA) were assessed. US of the brachialis muscle was performed before and after (15 minutes, 12 hours, 1 day, 2 days, 3 days, 7 days) exercise to measure mean shear-wave velocity (SWV). Pain and muscle tightness were assessed.
  
  
  RESULTS
  For men, muscle edema was moderate and peaked 3 days after exercise; for women, muscle edema was mild and peaked 1-3 days after exercise. ADC was highest 3 days after exercise in men (mean, 1809.22 × 10-6mm2/s; before exercise, 1529.88 × 10-6mm2/s) and women (1741.90 × 10-6mm2/s; before exercise, 1475.80 × 10-6mm2/s). FA dropped from 361.00 in men and 389.00 in women before exercise to a minimum of 252.12 and 321.28, respectively, 3 days after exercise. Mean SWV increased after exercise in men (before exercise, 3.00 ± 0.30 m/s; peak [15 minutes after exercise], 4.04 ± 0.90 m/s) and women (before, 2.82 ± 0.40 m/s; peak [1 day after exercise], 3.23 ± 0.40 m/s) and subsequently returned to normal. In men, the ADC values of the brachialis muscle positively correlated with mean SWV (r = 0.92, p = 0.028). FA negatively correlated with pain in men (r = -0.993, p = 0.001) Muscle edema outlasted clinical symptoms in most volunteers.
  
  
  CONCLUSIONS
  FA inversely correlates with pain and may be a useful imaging parameter for assessment of DOMS. Shear-wave US elastography shows a temporary increase of muscle stiffness after DOMS-inducing exercise but does not correlate with quantitative MRI parameters or clinical symptoms.
authors.affiliation: 1 Department of Radiology, Orthopedic University Hospital Balgrist, Forchstrasse 340, CH-8008 Zurich, Switzerland.|2 University of Zurich, Faculty of Medicine, Zurich, Switzerland.
authors.forename: Christoph A
authors.initials: CA
authors.lastname: Agten
authors.affiliation: 1 Department of Radiology, Orthopedic University Hospital Balgrist, Forchstrasse 340, CH-8008 Zurich, Switzerland.|2 University of Zurich, Faculty of Medicine, Zurich, Switzerland.
authors.forename: Florian M
authors.initials: FM
authors.lastname: Buck
authors.affiliation: 3 Department of Physiotherapy, Orthopedic University Hospital Balgrist, Zurich, Switzerland.
authors.forename: Linda
authors.initials: L
authors.lastname: Dyer
authors.affiliation: 2 University of Zurich, Faculty of Medicine, Zurich, Switzerland.|4 Department of Orthopedic Research, Orthopedic University Hospital Balgrist, Zurich, Switzerland.
authors.forename: Martin
authors.initials: M
authors.lastname: Flück
authors.affiliation: 1 Department of Radiology, Orthopedic University Hospital Balgrist, Forchstrasse 340, CH-8008 Zurich, Switzerland.|2 University of Zurich, Faculty of Medicine, Zurich, Switzerland.
authors.forename: Christian W A
authors.initials: CW
authors.lastname: Pfirrmann
authors.affiliation: 1 Department of Radiology, Orthopedic University Hospital Balgrist, Forchstrasse 340, CH-8008 Zurich, Switzerland.|2 University of Zurich, Faculty of Medicine, Zurich, Switzerland.
authors.forename: Andrea B
authors.initials: AB
authors.lastname: Rosskopf
mesh_terms: D000328:Adult; D055119:Elastic Modulus; D054459:Elasticity Imaging Techniques / Q000379:methods*; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D018482:Muscle, Skeletal / Q000000981:diagnostic imaging* / Q000473:pathology / Q000503:physiopathology*; D063806:Myalgia / Q000000981:diagnostic imaging* / Q000473:pathology / Q000503:physiopathology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D033081:Shear Strength; D013314:Stress, Mechanical; D055815:Young Adult
keywords: MRI; muscle soreness; shear-wave velocity; ultrasound elastography