Temperature dependency of quantitative ultrasound

Area of Science:

• Biomedical Engineering
• Medical Imaging
• Orthopedics

Background:

• Quantitative ultrasound (QUS) is a non-invasive technique used for bone health assessment.
• QUS parameters, including speed of sound (SOS) and broadband ultrasound attenuation (BUA), are known to be influenced by temperature.
• Understanding the extent of temperature dependency is crucial for accurate clinical interpretation of QUS data.

Purpose of the Study:

• To investigate the effect of temperature variations on QUS parameters using Lunar Achilles+ and Hologic Sahara devices.
• To assess the in vivo temperature dependency of QUS in a cadaveric foot and in human volunteers.
• To evaluate the clinical significance of temperature variations on QUS measurements.

Main Methods:

• QUS scans were performed on a cadaveric foot using both Lunar Achilles+ and Hologic Sahara at temperatures from 15 to 40°C.
• In vivo studies involved 5 volunteers, with QUS scans conducted at varying water bath temperatures (10-42°C) using the Lunar Achilles+.
• Analysis focused on correlations between temperature and QUS parameters such as SOS, BUA, Stiffness, and Quantitative Ultrasound Index (QUI).

Main Results:

• In the cadaveric foot, temperature showed strong negative correlations with SOS and moderate positive correlations with BUA.
• Stiffness and QUI in the cadaveric foot exhibited strong negative correlations with temperature, primarily due to SOS dependence.
• In volunteers, variations in water bath temperature caused minor changes in Stiffness, even with assumed constant foot temperature.

Conclusions:

• Temperature variations significantly affect QUS parameters like Stiffness and QUI, despite opposite effects on SOS and BUA.
• The precision of QUS measurements can be compromised by environmental or patient limb temperature fluctuations.
• Standardization of water bath temperature in QUS devices is essential for maximizing measurement precision and clinical reliability.