Imaging lung tissue oscillations using high-speed X-ray velocimetry.

This work utilized synchrotron imaging to achieve a regional assessment of the lung's response to imparted oscillations. The forced oscillation technique is increasingly being used in clinical and research settings for the measurement of lung function. During the forced oscillation technique, pressure oscillations are imparted to the lungs via the subjects' airway opening and the response is measured. This provides information about the mechanical properties of the airways and lung tissue. The quality of measurements is dependent upon the input signal penetrating uniformly throughout the lung. However, the penetration of these signals is not well understood. The development and use of a novel image-processing technique in conjunction with synchrotron-based imaging was able to regionally assess the lungs' response to input pressure oscillation signals in anaesthetized mice. The imaging-based technique was able to quantify both the power and distribution of lung tissue oscillations during forced oscillations of the lungs. It was observed that under forced oscillations the apices had limited lung tissue expansion relative to the base. This technique could be used to optimize input signals used for the forced oscillation technique or potentially as a diagnostic tool itself.