title: Ultrasound elastography is a reproducible and feasible tool for the evaluation of the patellar tendon in healthy subjects.
abstract: OBJECTIVE
  To evaluate the feasibility and reproducibility of ultrasound elastography (UE) in the assessment of healthy patellar tendon and to describe its UE pattern.
  
  
  METHODS
  Twenty-two patellar tendons of 11 out of 16 healthy subjects who met the inclusion criteria were evaluated three times by ultrasound (US) and UE at their proximal, middle and distal portions, by two separate sonographers with different experiences in UE.
  
  
  RESULTS
  In all tendon portions the color map analysis showed a predominance of green (highly elastic), with good values of intra-observer (Operator 1: P-values = 0.790, 0.864, 0.865; Operator 2: P = 0.642, 0.882, 0.613 for proximal, middle and distal portions, respectively) and inter-observer (P = 0.657) agreement. For both operators the intra-observer analysis of the elasticity ratio (ER) between the tendon and the subcutis showed high agreement values (P < 0.001 for both operators). The inter-observer analysis showed also high agreement values (P < 0.001 at proximal, P = 0.001 at middle, P = 0.005 at distal portions). The overall analysis of the ER of the tendon portions showed values of (mean ± SD): 1.47 ± 0.64, 4.38 ± 1.36, 3.32 ± 1.20 for proximal, middle and distal portions, respectively. The mean time to perform the UE evaluation for the inexperienced operator was 5 min at the beginning of the study but decreased to 2 min after a few examinations were done. The mean time for the expert was 2 min for the entire study.
  
  
  CONCLUSIONS
  UE is a feasible and reproducible tool for the evaluation of the healthy patellar tendon and further data are needed to define its role in the assessment of tendon pathology.
authors.affiliation: Division of Rheumatology AOUC, Department of Sperimental and Clinical Medicine, University of Florence, Florence, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Porta
authors.forename: N
authors.initials: N
authors.lastname: Damjanov
authors.forename: F
authors.initials: F
authors.lastname: Galluccio
authors.forename: A
authors.initials: A
authors.lastname: Iagnocco
authors.forename: M
authors.initials: M
authors.lastname: Matucci-Cerinic
mesh_terms: D000328:Adult; D054459:Elasticity Imaging Techniques / Q000379:methods*; D005240:Feasibility Studies; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D008297:Male; D015588:Observer Variation; D017847:Patellar Ligament / Q000000981:diagnostic imaging*; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D055815:Young Adult
keywords: feasibility; healthy subjects; patellar tendon; reproducibility; ultrasound elastography