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Computed tomography (CT) is becoming commonplace in avian and exotic animal medicine. Over the past 30 years, CT technology has rapidly advanced creating a diverse array of products and capabilities. Simply stated, not all CT scanners are equal or best suited for small avian and exotic animal species commonly encountered in practice. In particular, the newer high-definition volumetric cone beam scanners are providing significantly improved resolution and contrast over the more traditional slice based and older cone beam CT units. Contrast studies can dramatically improve visualization of soft tissue structures and better define normal versus abnormal anatomy not possible with plain CT. Newer iodine-based contrast protocols include higher doses (4-6 ml/kg IV in birds and reptiles and 3-4 ml/kg IV in exotic mammals) and longer administration times (full dose delivered over 2 minutes) compared to previously published protocols (generally consisting of 1-3 ml/kg IV delivered as a rapid bolus). Combined with pre, during and post-contrast CT scans, these new protocols are providing functional and significantly more patient data compared to older protocols. Additionally, CT technology is complex, and artifacts are common which can adversely affect interpretation. Artifacts can be divided into several types including physics based, patient based, scanner based and more. This presentation covers currently available CT technology, newer contrast protocols, and common artifact presentation and resolution. [ABSTRACT FROM AUTHOR]

Uric acid is commonly used for evaluation of kidney function in avian patients and may become significantly elevated with advanced renal disease, dehydration, or postprandially in carnivorous and piscivorous birds. Advanced imaging such as computed tomography (CT) has become notable in avian medicine for increased detail and precise information about patient anatomy and pathology. Avian orders examined included Psittaciformes, Bucerotiformes, Anseriformes, Pelecaniformes, and Accipitriformes. Iodinated intravenous contrast (370 mg/ml) was used at 4-6 ml/kg given over 2 minutes. All patients underwent pre-, during- and post-contrast scans. The 'during' scan was taken 30-60 seconds into contrast administration. A post-contrast scan was started after the completion of contrast delivery and the 'during' scan. Contrast studies allowed for kidney shape, size and position characterization and renal contrast uptake and clearance. Renal lesions identified on contrast CT include renomegaly, atrophy, cysts, hypoperfusion, mass invasion, and avulsion/trauma. At the time of submission, 47 avian cases met case inclusion criteria which included the CT protocol described above identifying renal lesions and uric acid values collected within 6 months prior to imaging. While the published normal values for uric acid range between species, we designated values greater than 12.0 mg/dl as hyperuricemic.2 Six of 47 cases had hyperuricemia. Of the 47 cases, 8/8 submitted for histopathology had confirmed renal disease with 2/8 of those cases having hyperuricemia. This study demonstrates poor correlation between hyperuricemia and renal lesions identified on contrast-based CT scans. [ABSTRACT FROM AUTHOR]

Detailed vascular anatomy is poorly documented in most avian species. Additionally, most publications depict anatomy in 2-dimensional picture formats that do not accurately reflect the 3-dimensional orientation of the vasculature. Three deceased grey parrots (Psittacus erithacus) were submitted to the Comparative Anatomy Research Project (formerly the Grey Parrot Anatomy Project) for computed tomography (CT) imaging with BriteVu® post-mortem vascular contrast. Individual segmentation of micro-CT data sets are being reviewed to define the anatomy of the vascular system of the grey parrot head. Advanced 3-dimensional modeling using Avizo 7.1 will be used to segment the vasculature to better understand their relationship with the skeletal and soft tissue structures present in the head and beak. The major vasculature of the skull and beak is identified based on the Handbook of Avian Anatomy: Nomina Anatomica Avium. These results allow improved diagnostic evaluation and surgical planning for diseases of the head and beak of grey parrots. At the time of writing, three grey parrot models were included in the study; however, additional samples are expected to minimize the effect of individual variation. The information gained from this study can serve as both a model for anticipated anatomy in grey parrots and other psittacine species and to perform similar studies in other animal models. [ABSTRACT FROM AUTHOR]