Atherosclerosis is a common disease of aging parrots as suggested by results of retrospective pathologic surveys.1–6 The disease is characterized by the thickening of arterial walls through lipid accumulation and plaque formation in the tunica intima, ultimately resulting in arterial luminal stenosis of the great vessels.6,7 Atherosclerosis can also lead to arterial aneurysms in pet birds.8
Birds are susceptible to diet-induced and spontaneous atherosclerosis.7 Spontaneous atherosclerosis in pet psittacine birds typically develops in older birds fed a nutritionally unbalanced diet, with risk factors similar to those described for human atherosclerosis.2,7 Parrots can develop a central form of atherosclerosis, in which the great vessels at the base of the heart are most commonly affected.2,6,7,9 Antemortem diagnosis of atherosclerosis in these birds has been considered difficult and remains one of the challenges of avian medicine. Only advanced cases of disease with considerable calcification of the great vessels or with secondary heart changes can be diagnosed.10–13
Clinical antemortem diagnostic imaging of atherosclerosis in humans includes the use of various modalities of vascular imaging that mainly involve angio-graphic techniques through the use of high-speed CT scan and magnetic resonance imaging.14 The main site of arterial stenosis in people is the carotid arteries, and CTA is the principal imaging method to measure carotid diameters and quantify stenosis.15 Whereas angiography appears to be used in birds, no studies have been conducted to evaluate an angiography protocol in detail and to determine the apparent diameter of intrathoracic arteries in healthy companion birds. The purpose of the study reported here was to establish a CT angiography protocol and provide reference limits for cross-sectional measurements of the great arteries in Hispaniolan Amazon parrots (Amazona ventralis).
Region of interest
Kaytee Exact Rainbow, Chilton, Wis.
S12-4 Sector Array Transducer, Philips Healthcare, Andover, Mass.
IE 33, Philips Healthcare, Andover, Mass.
Vetspecs VMS7, VetSpecs Inc, Canton, Ga.
Bair Hugger, Arizant Inc, Prairie, Minn.
Abdocath-T, Hospira Venisystems, Sligo, Ireland.
Surflo Injection Plug, Terumo Medical Products, Somerset, NJ.
Tegaderm, 3M, Saint Paul, Minn.
Vacutainer Safety-Lok blood collection set, Becton Dickinson, Franklin Lakes, NJ.
Light Speed GE Healthcare, Milwaukee, Wis.
Omnipaque 240 mg/mL, GE Healthcare Inc, Princeton, NJ.
OsiriX Imaging Software, version 3.5.1, OsiriX Foundation, Geneva, Switzerland. Available at: www.osirix-viewer.com. Accessed Jun 1, 2009.
SAS, version 9.1.3, SAS Institute Inc, Cary, NC.
SPSS, version 16.0, SPSS Inc, Chicago, Ill.
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