Quantitative ultrasound (QUS) assessment of tissue properties for Achilles tendons

Quantitative ultrasound (QUS) techniques have recently been widely applied for the characterization of tissues. For example, they can be used for the quantification of Achilles tendon properties based on the broadband ultrasound attenuation (BUA) and the speed of sound (SOS) when the ultrasound wave passes through the tissues. This study is to develop an integrated system to investigate the properties of Achilles tendons using QUS images from UBIS 5000 (DMS, Montpellier, France) and B-mode ultrasound images from HDI 5000 (ATL, Ultramark, USA). Subjects including young (32 females and 17 males; mean age: 23.7 2.0) and middle-aged groups (8 female and 8 males; mean age: 47.3 8.5 s) were recruited and tested for this study. Only subjects who did not exercise regularly and had no record of tendon injury were studied. The results show that the BUA is significantly higher for the young group (45.2 1.6 dB MHz ^-1) than the middle-age group (40.5 1.9 dB MHz^-1), while the SOS is significantly lower for the young (1601.9 11.2 ms^-1) compared to the middle-aged (1624.1 8.7 m s^-1). On the other hand, the thicknesses of Achilles tendons for both groups (young: 4.31 0.23 mm; middle age: 4.24 0.23 mm) are very similar. For one patient who had an Achilles tendon lengthening (ATL) surgery, the thickness of the Achilles tendon increased from 4 mm to 4.33 mm after the surgery. In addition, the BUA increased by about 7.2% while the SOS decreased by about 0.6%. In conclusion, noninvasive ultrasonic assessment of Achilles tendons is useful for assisting clinical diagnosis and for the evaluation of a therapeutic regimen.