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Table 2 Averages, standard deviations and confidence intervals of the different QUS measurements

From: Quantitative ultrasound imaging of Achilles tendon integrity in symptomatic and asymptomatic individuals: reliability and minimal detectable change

Outcome measures (QUS Measurements)
  All tendons
n = 86
Symptomatic
n = 23
Asymptomatic
n = 63
Difference between groups (%)
  Average Stand. Dev. 95 % CIa Average Stand. Dev. 95 % CIa Average Stand. Dev. 95 % CIa
Longitudinal view
 Geometric
  Thickness (cm) 0.56 0.16 0.53–0.59 0.68 0.21 0.60–0.76 0.52 0.10 0.49–0.54 31.88
 Grayscale histogram
  Echogenicity (0–255) 82.37 14.44 79.31–85.42 79.32 14.22 73.51–85.13 83.48 13.32 80.19–86.77 −4.98
  Variance 618.72 216.98 572.86–664.58 654.93 213.52 567.66–742.19 605.50 160.62 565.83–645.16 8.16
  Skewness 0.52 0.34 0.45–0.59 0.65 0.25 0.55–0.75 0.47 0.21 0.42–0.53 38.13
  Kurtosis 3.82 1.28 3.54–4.09 4.18 1.02 3.76–4.59 3.68 0.64 3.52–3.84 13.41
  Entropy 6.50 0.24 6.45–6.55 6.51 0.24 6.41–6.61 6.50 0.19 6.46–6.55 0.10
 Co –occurrence matrix
  Contrast 0.64 0.13 0.61–0.67 0.61 0.11 0.57–0.66 0.65 0.11 0.62–0.68 −5.67
  Energy 0.21 0.05 0.20–0.22 0.21 0.04 0.19–0.22 0.21 0.04 0.20–0.22 −2.76
  Homogeneity 0.76 0.03 0.76–0.77 0.77 0.02 0.76–0.77 0.76 0.02 0.75–0.77 0.82
Transverse view
 Geometric
  Area (CSA) (cm2) 0.61 0.23 0.56–0.66 0.76 0.33 0.63–0.90 0.56 0.14 0.52–0.59 36.61
  Thickness (cm) 0.57 0.15 0.54–0.60 0.67 0.20 0.59–0.75 0.53 0.09 0.51–0.55 26.73
  Width (cm) 1.32 0.16 1.28–1.35 1.37 0.19 1.29–1.44 1.30 0.13 1.27–1.33 5.30
 Grayscale histogram
  Echogenicity (0–255) 90.98 13.42 88.14–93.81 86.62 14.85 80.55–92.68 92.57 10.97 89.86–95.28 −6.43
  Variance 767.57 207.20 723.77–811.36 789.63 180.44 715.88–863.37 759.51 150.15 722.44–796.59 3.96
  Skewness 0.54 0.25 0.49–0.60 0.63 0.20 0.55–0.71 0.51 0.20 0.46–0.56 24.15
  Kurtosis 3.61 0.83 3.43–3.78 3.78 0.75 3.48–4.09 3.55 0.58 3.40–3.69 6.68
  Entropy 6.74 0.15 6.71–6.77 6.73 0.11 6.68–6.78 6.74 0.12 6.71–6.77 −0.15
 Co-occurrence matrix
  Contrast 0.90 0.16 0.86–0.93 0.84 0.16 0.78–0.91 0.92 0.13 0.89–0.95 −8.33
  Energy 0.14 0.04 0.13–0.15 0.15 0.03 0.13–0.16 0.14 0.03 0.13–0.14 5.76
  Homogeneity 0.73 0.03 0.72–0.73 0.74 0.03 0.72–0.75 0.72 0.02 0.72–0.73 1.95
  1. aConfidence intervals (CI) are calculated at a 95 % confidence level