CT-based 3D reconstruction and basic anatomical analysis of the 3D anatomy of the air sac system in domestic birds

The complex anatomy of the avian respiratory system makes it necessary to broaden our knowledge using modern imaging and reconstructional possibilities. The visualization of these structures can be used for clinical situations, in research or as teaching aids in veterinary education. For this we generated 3D models from diagnostic imaging data (computed tomography [CT] scans) of birds. We describe in detail a repeatable method of animal preparation for scanning, data handling and image analysis. CT scans with varying slice thickness and resolution were obtained in prone and supine body positions to analyse air sac morphology and volume changes relative to posture or sexual dimorphism in birds. The resulting data were prepared and analysed using a reconstructional software (3D Slicer) based on manual and semi-automatic labelling and subsequent 3D models of the air sac system were created. The terminology employed has been referenced from the Nomina Anatomica Avium, Second Ed.