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.

1. The objective of this study was to evaluate the prediction potential of a computer tomography (CT) data collection protocol for determining total body composition used for analysis of tibiotarsal bone quality features.2. The CT image acquisition was performed on 54 healthy TETRA SL genotype laying hens at 90weeks of age as well as in the 69th week of the egg production period in vivo and their tibiotarsal bones, ex vivo.3. Breaking strengths and ash content of the tibiotarsal bones were estimated based on the calculated mineral density of skeletal and tibiotarsal bones by means of CT with an estimation accuracy R-2 0.963 and 0.975, respectively.4. In conclusion, the current investigation demonstrated that the acquisition protocol of CT for total-body composition analysis has a good potential for measuring the mineral status and breaking strength of the reference bone in laying hen.

Background: Computed tomography (CT) became an important diagnostic imaging method in the veterinary practice in the past decades. Data gained with the scanning can be used for 3D displaying of organs or body regions as well. The viewer softwares provide more and more options for reconstruction of the target area. Objectives: The authors present their own results about the 3D reconstruction of the avian air sacs (turkey) and the paranasal sinuses of the horse head based on data gained with a Siemens Definition Flash Dual CT. Materials and Methods: A Siemens Definition Flash Dual Source 2x128 slices CT was used to scan 5 male turkey toms at the age of 20 weeks. A head of a 7 years old stallion cadaver was examined with the same scanner. The resulting DICOM data were reconstructed with the 3 DSlicer software using manual and semi-automatic segmentations, focusing on the air sac system and the paranasal sinuses. Results and discussion: Based on the Hounsfield Unit (HU) of the air the authors created 3D models of the avian air sac system, the nasal cavity, the guttural pouch and paranasal sinuses of the horse. The slice thickness of the scans (2 mm for the turkeys and 0.6 mm for the horse head) were sufficient to generate anatomically correct and detailed shape of the above-mentioned parts of the airways. The methods used for these reconstructions can be used for other organs, organ systems or body regions as well but require high contrast difference between the different anatomical structures or tissues. If such contrast deviations are not present naturally, contrast enhancement for the scanning procedures (in vivo contrast media administration, post mortem contrast enhancement methods) could be used. The resulted 3D anatomical models can be used in education, surgical planning and in animal breeding. In the second part of this article series the authors will present the bony and soft tissue model of the equine stifle joint, based on CT and MR image fusion.