Assessing the variability in respiratory acoustic thoracic imaging (RATHI)

Area of Science:

• Pulmonary medicine
• Biomedical engineering
• Medical imaging

Background:

• Multichannel analysis of lung sounds (LSs) generates functional images for studying LS intensities.
• Respiratory acoustic thoracic imaging (RATHI) is an acoustic imaging technique applied to pulmonary conditions.
• Understanding RATHI's spatial distribution, airflow dependence, and variability is crucial.

Purpose of the Study:

• To assess intra-subject and inter-subject RATHI variabilities in healthy males.
• To quantify RATHI characteristics using objective indices.
• To evaluate the repeatability of RATHI patterns.

Main Methods:

• LSs acquired at 25 posterior thoracic positions (75-1000 Hz) under controlled airflow (1.0, 1.5, 2.0 L/s).
• Intra-subject variability assessed using quadratic mutual information (I(CS)) for inspiratory acoustic image similarity.
• Inter-subject variability assessed via RATHI and X-ray image registration for average and variance acoustic images.

Main Results:

• High intra-subject RATHI similitude (I(CS-global)) averaged 0.960±0.008 across airflow conditions.
• Low inter-subject variability observed, with variance image values ranging from 0.01 to 0.04.
• Quantitative indices confirmed repeatability of acoustic image patterns.

Conclusions:

• RATHI demonstrates high repeatability in acoustic image patterns within and across subjects.
• The technique is reliable for assessing spatial distribution and regional pulmonary ventilation.
• RATHI shows potential as a non-invasive tool for pulmonary diagnostics.