Respiratory acoustic thoracic imaging (RATHI): assessing intrasubject variability

Area of Science:

• Pulmonary Medicine
• Medical Imaging
• Acoustics

Background:

• Respiratory acoustic thoracic imaging (RATHI) analyzes lung sound (LS) distribution.
• Understanding RATHI repeatability with pulmonary function is crucial for clinical application.
• Intrasubject variability of RATHI at different airflows requires evaluation.

Purpose of the Study:

• To assess the intrasubject variability of RATHI at varying airflow rates.
• To determine the repeatability of RATHI patterns during changes in airflow.
• To investigate the relationship between airflow and RATHI characteristics.

Main Methods:

• Lung sounds (LS) were acquired from the posterior thoracic surface of eleven subjects.
• RATHI images were generated using Hermite function interpolation during inspiratory phases.
• Quadratic mutual information (I(CS)) based on Cauchy-Schwartz inequality evaluated RATHI similarity.
• Acoustic data was collected at airflows of 1.0, 1.5, and 2.0 L/s.

Main Results:

• Intrasubject RATHI similarity (I(CS)) averaged 0.893, 0.897, and 0.902 at 1.0, 1.5, and 2.0 L/s, respectively.
• Increased airflow led to higher intensity values in RATHI.
• Higher airflow also resulted in greater spatial dispersion of sound distribution in RATHI.
• Low intrasubject variability was observed for RATHI across the tested airflow range.

Conclusions:

• RATHI demonstrates repeatable lung sound distribution patterns during airflow variations between 1.0 and 2.0 L/s.
• The study confirms the low intrasubject variability of RATHI within this airflow range.
• While sound distribution patterns are repeatable, variations in sound intensity must be considered in RATHI analysis.