Measurement of ultrasound speed of articular cartilage in variable conditions.

Ultrasound (US) imaging and measurement have been widely used for the assessment of articular cartilage (AC) in recent years. Assessment involved the measurement of acoustic properties such as US speed in AC. Those measurements were normally carried out either at room temperature or at 37 degrees C and at 0.15 M saline concentrations. The changes in the structure of AC due to the change in the concentration of bathing saline solution have been previously reported. However, the change in the US speed of AC has not been yet documented. In addition, the variation of temperature during measurements may affect the US speed in AC. The objective of this study is to investigate the change of the US speed in AC with the variations in temperature and the bathing saline concentration. Results demonstrated that the US speed significantly increased with the increase of temperature (15 degrees C to 40 degrees C) and saline concentration (0 M to 2.5 M).