Accurate measures of regional lung air volumes from chest X-rays of small animals

TL;DR

This paper introduces a new X-ray based method to accurately measure regional lung air volumes in small animals, avoiding the need for CT scans, with high correlation to true volumes, useful for research and clinical studies.

Contribution

A novel technique using X-ray intensity changes to measure regional lung volumes accurately without CT, validated against high-resolution CT measurements.

Findings

Strong correlation (R^2=0.98) with true lung volumes

Effective measurement of regional lung volume changes in small animals

Potential for clinical application in biomedical research

Abstract

We present a robust technique for calculating regional volume changes within the lung from X-ray radiograph sequences captured during ventilation, without the use of computed tomography (CT). This technique is based on the change in transmitted X-ray intensity that occurs for each lung region as air displaces the attenuating lung tissue. Lung air volumes calculated from X-ray intensity changes showed a strong correlation ($R^2$=0.98) against the true volumes, measured from high-resolution CT. This correlation enables us to accurately convert projected intensity data into relative changes in lung air volume. We have applied this technique to measure changes in regional lung volumes from X-ray image sequences of mechanically ventilated, recently-deceased newborn rabbits, without the use of CT. This method is suitable for biomedical research studies and shows potential for clinical application.