High speed, high resolution in vivo dynamic lung imaging using a laboratory x-ray source to measure regional lung function and pulmonary vasculature

M Preissner, I Pinar, R Carnibella, C Samarage, G Zosky, S Dubsky, H Jones, A Fouras

Research output: Contribution to journalMeeting AbstractOther

Abstract

Background and Aims
Our laboratory has achieved fast lung imaging at high resolution in vivo using a high brightness laboratory X‐ray source coupled with a high‐speed detector. This system is used to image breathing mice at sufficient spatio‐temporal resolution to track lung tissue patterns. This technique enables us to segment key features, such as the airways, lobes and pulmonary vasculature, without the use of contrast agents. Recent work into dead space ventilation in a mouse model of lung injury showed progressive increases in airway volume in response to mechanical ventilation (Kim et al., J Appl Physiol, 2017). Measurement of the pulmonary vasculature is based on the contrast‐free angiography technique developed by our laboratory, in which diameters can be measured down to approximately 60 μm (Samarage et al., Med Phys, 2016).

Methods
We used a murine model of ventilator‐induced lung injury whereby BALBc mice were ventilated for either 2 or 5 hours (PIP = 20 cmH2O, zero PEEP). The imaging provides a displacement vector field for the entire 3D lung parenchyma, thus providing the ability to measure the tidal volume on a regional level (see panel A). Measurements of the pulmonary vasculature were obtained by applying a filter that detects tubular structures in the 3D image (panel B).

Results
Difference in tissue patterns in the CT slices after 5 hours mechanical ventialtion were consistent with tissue injury (panels C, D). Although there was no evidence of change in global lung tissue expansion (ie tidal volume), regional contours showed decreases (relative to maximum) post‐ventilation (panels E, F). Results from contrast‐free vascular imaging in the same model showed global increases in the measured diameters of pulmonary vessels.

Conclusions
Our novel in vivo imaging technique provides high‐resolution, non‐invasive data on lung function and the pulmonary vasculature, and the ability to capture changes in these measures over time in the same animal and without contrast agents. Regional quantitative data on a lobar (or sub‐lobar) level is also possible with this imaging technology and is the focus of ongoing work.
Original languageEnglish
Pages (from-to)26
Number of pages1
JournalRespirology
Volume22
Issue numberS3
DOIs
Publication statusPublished - 1 Nov 2017

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