Airway segmentation and analysis for the study of mouse models of lung disease using micro-CT

Abstract

Animal models of lung disease are gaining importance in understanding the underlying mechanisms of diseases such as emphysema and lung cancer. Micro-CT allows in vivo imaging of these models, thus permitting the study of the progression of the disease or the effect of therapeutic drugs in longitudinal studies. Automated analysis of micro-CT images can be helpful to understand the physiology of diseased lungs, especially when combined with measurements of respiratory system input impedance. In this work, we present a fast and robust murine airway segmentation and reconstruction algorithm. The algorithm is based on a propagating fast marching wavefront that, as it grows, divides the tree into segments. We devised a number of specific rules to guarantee that the front propagates only inside the airways and to avoid leaking into the parenchyma. The algorithm was tested on normal mice, a mouse model of chronic inflammation and a mouse model of emphysema. A comparison with manual segmentations of two independent observers shows that the specificity and sensitivity values of our method are comparable to the inter-observer variability, and radius measurements of the mainstem bronchi reveal significant differences between healthy and diseased mice. Combining measurements of the automatically segmented airways with the parameters of the constant phase model provides extra information on how disease affects lung function.

Evaluation of micro-CT for emphysema assessment in mice: comparison with non-radiological techniques

“…The lungs were automatically delineated in the 3D micro-CT images using a previously published segmentation algorithm [13] and the airways were removed from the lung delineation [14]. Mean lung voxel intensity (MLVI) and relative volume below −900 HU (RVB -900 HU) were computed.…”

Longitudinal study of a mouse model of chronic pulmonary inflammation using breath hold gated micro-CT

“…Finally, the airways were segmented and the radii of the right (RRB) and left (RLB) mainstem bronchi were measured, using a method previously developed by us [25].…”

Dynamic contrast-enhanced micro-CT on mice with mammary carcinoma for the assessment of antiangiogenic therapy response

“…Micro-CT imaging has been used to study the structure and disorder in bones [9][10][11][12][13][14], microvasculature anatomy [15,16], oncology models [17][18][19], drug or radiation delivery [20][21][22] and pulmonary diseases such as asthma and emphysema [23][24][25][26][27] in small animals. Dynamic micro-CT examinations were not possible in general in the past.…”