# Acoustic System for Diagnosis of Pneumonia and Pneumothorax using Transfer Function Analysis

> **NIH NIH F30** · UNIVERSITY OF CALIFORNIA, SAN FRANCISCO · 2020 · $50,520

## Abstract

PROJECT SUMMARY/ABSTRACT
Every year pneumonia is the cause of death for over a million people worldwide, with most of these deaths
occurring in areas that do not have access to advanced medical infrastructure. The current clinical gold
standard for detecting pneumonia is a chest x-ray, which, while effective for diagnosis, is often unavailable to
patients in resource limited settings due to inhibitive financial costs. For these populations, physical
examinations provide an accessible, convenient, and low-cost alternative---thus, all doctors are trained to
perform the physical exam. The physical exam technique of percussion is performed by tapping specific areas
of the back and assessing whether the resulting sound corresponds to healthy or diseased tissue.
Unfortunately, differences in physician technique lead to inconsistent findings and dismissal of the percussion
method when x-ray machines are available. The goal of our device is to quantify these findings to eliminate
interobserver error and harness the diagnostic power of percussion to provide a low-cost, quantitative physical
examination tool for the diagnosis of pneumonia in patient populations with limited access to chest
radiography. We have developed a prototype device that provides acoustic stimulation to the chest; sound is
recorded from the back using an electronic stethoscope and this recording is used to estimate the chest
cavity's acoustic transfer function. The transfer function characterizes the strength of response of a system to
different frequencies and can be used to distinguish between different systems. Our specific aims focus on
developing a method to study the effects on the acoustic transfer function due to structural changes in the
lungs during pneumonia (Aim 1) and to explore the generalizability of this approach to pneumothorax
specifically as well as other lung pathologies (Aim 2). In Aim 1, we hypothesize that the accumulation of
exudate (fluid) in a lobe of the lungs in pneumonia will lead to better sound transmission of higher frequencies
compared to healthy lung. First, we will use a sponge with similar density to human lung tissue as an imaging
phantom to improve our device's signal-to-noise ratio and streamline data analysis. Second, we will perform
our experiments in patients comparing the healthy side of their lungs to the side with lobar pneumonia. Finally,
we will develop a classifier that can take additional variables such as age and gender into consideration to
improve performance of our test and return a severity score of pneumonia based on acoustic findings. For Aim
2, our hypothesis is that the accumulation of air in pleural spaces will reduce transmission of sound, especially
at higher frequencies. We will first perform an experiment with an air-filled cavity (stomach) compared to solid
tissue (knee) to determine the effect of air accumulation on the transfer function. Next, as in Aim 1, we will
perform tests on patients comparing the side with the p...

## Key facts

- **NIH application ID:** 9875473
- **Project number:** 5F30HL140906-03
- **Recipient organization:** UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
- **Principal Investigator:** Adam Rao
- **Activity code:** F30 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $50,520
- **Award type:** 5
- **Project period:** 2018-02-01 → 2022-01-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9875473

## Citation

> US National Institutes of Health, RePORTER application 9875473, Acoustic System for Diagnosis of Pneumonia and Pneumothorax using Transfer Function Analysis (5F30HL140906-03). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/9875473. Licensed CC0.

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