In vivo ultrasonic attenuation in cetacean soft tissues

Area of Science:

• Marine biology
• Biophysics
• Veterinary medicine

Background:

• Non-invasive ultrasonic assessment is crucial for marine mammal health monitoring.
• Understanding tissue properties aids in accurate diagnostic imaging.
• Previous studies have not extensively characterized ultrasonic attenuation in marine mammal soft tissues.

Purpose of the Study:

• To estimate in vivo ultrasonic attenuation in the extracranial soft tissues of bottlenose dolphins (Tursiops truncatus) and beluga whales (Delphinapterus leucas).
• To establish baseline data for ultrasonic attenuation in these species.
• To assess the feasibility of using routine ultrasound for quantitative tissue property estimation.

Main Methods:

• Collected non-invasive backscatter ultrasound data from Tursiops truncatus and Delphinapterus leucas.
• Utilized a transducer operating in the 1.6-3.7 MHz frequency range.
• Processed data using a reference tissue phantom with independently determined properties to estimate attenuation in proximal mandible and temporal regions.

Main Results:

• Estimated ultrasonic attenuation values were found to be at the lower end of literature-reported ranges for mammalian fatty and connective tissues.
• A model-based analysis quantified potential errors attributed to tissue composition and sound speed uncertainties.

Conclusions:

• The study provides novel in vivo ultrasonic attenuation data for bottlenose dolphins and beluga whales.
• Findings suggest that marine mammal soft tissues exhibit relatively low ultrasonic attenuation.
• Accurate attenuation estimation is feasible using non-invasive ultrasound, with error quantification being essential for reliable results.