Estimation of intrathoracic arterial diameter by means of computed tomographic angiography in Hispaniolan Amazon parrots
2011
Beaufrere, Hugues | Rodríguez, Daniel | Pariaut, Romain | Gaschen, Lorrie | Schnellbacher, Rodney | Nevarez, Javier G. | Tully, ThomasN. Jr
Objective--To establish a computed tomography (CT)-angiography protocol and measure the diameters of major arteries in parrots. Animals--13 Hispaniolan Amazon parrots (Amazona ventralis). Procedures--16-slice CT scanning was used to measure the apparent diameter of the ascending aorta, abdominal aorta, pulmonary arteries, and brachiocephalic trunk. Before scanning, all birds underwent ECG and echocardiographic assessment and were considered free of detectable cardiovascular diseases. Each bird was anesthetized, and a precontrast helical CT scan was performed. Peak aortic enhancement was established with a test bolus technique via dynamic axial CT scan over a predetermined single slice. An additional bolus of contrast medium was then injected, and a helical CT-angiography scan was performed immediately afterward. Arterial diameter measurements were obtained by 2 observers via various windows before and after injection, and intra- and interobserver agreement was assessed. Results--Reference limits were determined for arterial diameter measurements before and after contrast medium administration in pulmonary, mediastinal, and manual angiography windows. Ratios of vertebral body diameter to keel length were also calculated. Intraobserver agreement was high (concordance correlation coefficients ≥ 0.95); interobserver agreement was medium to high (intraclass correlation coefficients ≥ 0.65). Conclusions and Clinical Relevance--CT-angiography was safe and is of potential diagnostic value in parrots. We recommend performing the angiography immediately after IV injection of 3 mL of iohexol/kg. Arterial diameter measurements at the described locations were reliable.
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