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Quantitative Ultrasound Elastography With an Acoustic Coupler for Achilles Tendon Elasticity
Author(s) -
Yamamoto Yohei,
Yamaguchi Satoshi,
Sasho Takahisa,
Fukawa Taisuke,
Akatsu Yorikazu,
Nagashima Kengo,
Takahashi Kazuhisa
Publication year - 2016
Publication title -
journal of ultrasound in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 91
eISSN - 1550-9613
pISSN - 0278-4297
DOI - 10.7863/ultra.14.11042
Subject(s) - medicine , elastography , achilles tendon , ultrasound , elasticity (physics) , achilles tendon rupture , acoustic radiation force , radiology , tendon , acoustics , surgery , composite material , materials science , physics
Objectives The purposes of this study were to measure intraobserver and interobserver repeatability of quantitative elastography using an acoustic coupler for the Achilles tendon, to compare elastographic values among different age groups, and to assess the correlation between quantitative and conventional qualitative measurements. Methods One hundred asymptomatic Achilles tendons of 50 volunteers were examined. For quantitative elastography, the strain value of the tendon was divided by that of the acoustic coupler with a known Young modulus, and the strain ratio was calculated. B‐mode image assessment and qualitative elastography were also performed. Intraobserver repeatability and interobserver repeatability of strain ratio measurements were calculated. The strain ratios were compared among age groups by the Kruskal‐Wallis test. Additionally, strain ratios for each B‐mode grade and qualitative elastographic grade were compared by the Wilcoxon signed rank test. Results Intraobserver repeatability intraclass correlation coefficient (1, 3) values were 0.87 and 0.93, respectively. The correlation coefficient between the observers' measurements was 0.61. The strain ratio for the 30s age group was 0.27, which was significantly lower than the values for the other age groups ( P < .001). Although 97 of 100 tendons were normal on B‐mode evaluations, 36 of the 97 tendons were degenerated on qualitative elastography and also had higher strain ratio values than normal tendons. Conclusions Quantitative elastography using an acoustic coupler is a reproducible technique for measuring the elasticity of the Achilles tendon. It may detect early tendon degeneration that is not depicted on B‐mode imaging.