title: Shear Wave Elastography Is a Reliable and Repeatable Method for Measuring the Elastic Modulus of the Rectus Femoris Muscle and Patellar Tendon.
abstract: OBJECTIVE
  The purpose of this study was to determine intraobserver, interobserver, and inter-day reliability levels for stiffness measurements of the patellar tendon and rectus femoris muscle using shear wave elastography (SWE).
  
  
  METHODS
  This study was conducted on 12 healthy male individuals. Two examiners measured mean shear wave velocity values of the patellar tendons and rectus femoris muscles of both extremities using a 9L4 (4-9 MHz) transducer and an Acuson S3000 ultrasound system (Siemens Medical Solutions, Mountain View, CA). The elasticity images were acquired by the Virtual Touch tissue imaging quantification technique (Siemens Medical Solutions). Measurements were repeated 20 minutes and 1 week after the first measurements. The reliability of SWE measurements was assessed by means of the intraclass correlation coefficient (ICC).
  
  
  RESULTS
  The 12 participants ranged in age from 19 to 33 years (mean age ± SD, 25.33 ± 4.56 years). For the patellar tendon stiffness measurements with SWE, it was found that intraobserver reliability (ICC, 0.91-0.92) and interday reliability (ICC, 0.81-0.83) were excellent, and interobserver reliability (ICC, 0.71) was good. For the rectus femoris muscle stiffness measurements with SWE, it was found that the intraobserver reliability (ICC, 0.93-0.94), interday reliability (ICC, 0.81-0.91), and interobserver reliability (ICC, 0.95) were perfect.
  
  
  CONCLUSIONS
  Shear wave elastography using the Virtual Touch tissue imaging quantification technique is a reliable and repeatable technique for patellar tendon and rectus femoris stiffness measurements according to intraobserver, interday, and interobserver ICC values.
authors.affiliation: Hacettepe University, Beytepe Hospital, Ankara, Turkey.
authors.forename: Serkan
authors.initials: S
authors.lastname: Taş
authors.affiliation: Department of Radiology, Hacettepe University, School of Medicine, Ankara, Turkey.
authors.forename: Mehmet Ruhi
authors.initials: MR
authors.lastname: Onur
authors.affiliation: Hacettepe University, Beytepe Hospital, Ankara, Turkey.
authors.forename: Seval
authors.initials: S
authors.lastname: Yılmaz
authors.affiliation: Department of Biophysics, Hacettepe University, School of Medicine, Ankara, Turkey.
authors.forename: Abdullah Ruhi
authors.initials: AR
authors.lastname: Soylu
authors.affiliation: Department of Sports Medicine, Hacettepe University, School of Medicine, Ankara, Turkey.
authors.forename: Feza
authors.initials: F
authors.lastname: Korkusuz
mesh_terms: D000328:Adult; D055119:Elastic Modulus / Q000502:physiology*; D054459:Elasticity Imaging Techniques / Q000379:methods*; D006801:Humans; D008297:Male; D017847:Patellar Ligament / Q000033:anatomy & histology* / Q000502:physiology*; D052097:Quadriceps Muscle / Q000033:anatomy & histology* / Q000502:physiology*; D012016:Reference Values; D015203:Reproducibility of Results; D055815:Young Adult
keywords: muscle; musculoskeletal ultrasound; reliability; shear wave elastography; sonography; tendon