TDK conference 2024

Due to the size of the horse's thoracic and abdominal cavities, these regions are challenging to examine thoroughly, and even with ultrasound and X-ray imaging they cannot be fully visualized, and in ponies even rectal examination is impossible. Computed tomography (CT) could provide additional valuable information for clinical practice when examining these areas as the 90 cm diameter gantry could accommodate small- and medium-sized horses.

The aim of this study was to determine which organs can be imaged under physiological conditions and to identify the limitations of this diagnostic method. To our knowledge, no detailed CT anatomical description exists for these regions in horses, and we aimed to address this gap. For this purpose, an adult pony mare was used which was euthanized due to a metatarsal fracture, with no known pathological changes in the examined area and no signs of colic. Comparative study of high-quality CT images and anatomical cross-sectional images of the pony's thoracic and abdominal cavities was accomplished.

Immediately after euthanasia, a CT scan was performed on the animal in dorsal recumbency. A helical 16-slice multislice scanner with a 90 cm gantry diameter, 2 mm slice thickness, 135 kV, and 450 mA exposure settings, and a 0.75-second rotation time was used. The resulting images were later reviewed with two settings: WL=45 HU, WW=250 HU and WL=260 HU, WW=3500 HU. After the scan, the cadaver was frozen in the same position at -18°C, and in a frozen state, it was sliced into 39 sections, each 2 cm thick, from the manubrium sterni to the rectum using a Reich Plastination Band Saw HL-30. The structures were labelled on photographs of the caudal surfaces of these slices and on the corresponding CT images using the 6th edition of the Nomina Anatomica Veterinaria. Upon identifying the abdominal structures, we concluded that the pelvic flexure was filled with contents and had shifted caudally into the bony pelvis, while the apex of the cecum was found at the level of the left iliac region.

The most clinically significant organs were easily identifiable and well visualized in the CT images, suggesting that this method could be useful in clinical diagnostics. In the future it would be worthwhile to establish anatomical standards, perform the procedure on male animals due to the differing anatomy of the pelvis, and process more clinical cases. To improve the precision of comparative studies, the thickness of the anatomical slices could be reduced.