33 - A normalized ferret tracheobronchial diameter model using µCT

Poster Board Number: 33
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Co-authors:

Nora Bensellam - Research Assistant, Dermatology, Harvard University; Thomas Lynch - Cardiothoracic Surgery - Univeristy of Iowa, Carver College of Medicine; Kalpaj Parekh - Professor, Cardiothoracic Surgery, University of Iowa, Carver College of Medicine; John Engelhardt - Professor, Anatomy and Cell Biology, Univesity of Iowa, Carver College of Medicine; Marc Pizzimenti - Associate Professor, Anatomy and Cell Biology, University of Iowa, Carver College of Medicine

Abstract Body :The ferret is a common animal model to study respiratory diseases such as cystic fibrosis, alpha-1 antitrypsin deficiency, influenza infection, and chronic lung allograft dysfunction after lung transplantation, as this species recapitulates human lung pathology in these diseases. In the ferret lung, submucosal gland containing cartilaginous bronchi are present throughout the early bifurcations and continues into the lobar segments. Moreover, like the human system, the ferret proximal and distal airways contain goblet and club cells, respectively. Knowledge of the ferret tracheobronchial tree (TBT) branching pattern and its anatomical measurements are currently unavailable but critical to understanding lung pathologies in this species. This study builds on previous work to further detail the tracheobronchial branching pattern, extending into the lobar segments, of 9 (M4, F5) ferret lung specimens. Proximal and distal segments along the TBT were measured across their short axes using µCT imaging. Locally referenced three-dimensional coordinate data were determined at 25 node locations in each lung along the TBT. Data indicate variability among individual specimens and include bronchial diameter differences associated with sexual dimorphism. Differences in the proximal right (R) and left (L) primary bronchus for males (5.06 ± 0.73 mm) and females (3.97 ±0.47 mm) were evident (p< 0.05). Additional differences in diameter were observed in smaller bronchi associated with the right accessory and right inferior lobes (p< 0.05). Measures of body mass (g) and lung length (apex to base) were highly correlated (r = 0.94) suggesting that overall lung length (mm) may serve as a proxy to normalize bronchial diameters across specimens. Diameters within each specimen were normalized to tracheal diameter located at a determined location superior to the carina. With normalized data, no differences in bronchial diameters were observed between M/F specimens (p > 0.05). Local coordinate data from a single lung specimen and normalized bronchial diameters from all lung specimens, were used to create a representative model of the TBT. This model will be improved upon in the future to include normalized segment length data. The normalized TBT model will inform future studies utilizing the ferret to interrogate respiratory diseases.