Effect of a Thin Fluid Layer on Surface Wave Speed Measurements: A Lung Phantom Study

Area of Science:

• Medical Imaging
• Biophysics
• Pulmonary Medicine

Background:

• Lung ultrasound (US) surface wave elastography (SWE) is an emerging technique for assessing superficial lung tissue elasticity.
• The impact of the thin pleural fluid layer on SWE measurements of lung properties remains unclear.

Purpose of the Study:

• To investigate the effect of a thin pleural fluid layer on lung surface wave speed measurements using SWE.
• To determine if the presence of a thin fluid layer influences the accuracy of SWE in assessing lung elasticity.

Main Methods:

• A physical model simulating lung and pleural fluid was created using sponges and a thin layer of ultrasound transmission gel.
• Surface wave speeds were measured using SWE on the sponge model, both with and without the gel layer.
• Measurements were conducted across three distinct wave excitation frequencies.

Main Results:

• Surface wave speed measurements obtained via SWE were compared between the sponge model with and without the thin gel layer.
• The results demonstrated no significant difference in measured surface wave speeds due to the presence of the thin gel layer.
• This indicates the thin layer did not alter the elastic property measurements.

Conclusions:

• A thin pleural fluid layer does not appear to affect the accuracy of lung ultrasound surface wave elastography measurements.
• SWE is a potentially reliable method for evaluating superficial lung tissue elasticity, even in the presence of a thin fluid layer.