Effect of different injection rates and doses of contrast medium on the image quality of computed tomographic angiography in African grey parrots (Psittacus erithacus)

Abstract

Atherosclerosis is a common cardiovascular disease in parrots but the antemortem diagnosis is challenging. In human medicine, computed tomography angiography (CTA) has been used widely for the diagnosis of atherosclerosis. By adjusting the injection rate and total dose of contrast medium, the image quality can be improved. To test the effects of different injection conditions on the image quality of major arteries, 10 African grey parrots (Psittacus erithacus) were used. Three injection rates (0.3, 0.4, 0.5mL/s) and three doses (740, 370, 222mg of iodine/bird) were tested while the other variables of the studies were fixed. A higher injection dose led to a significantly higher attenuation, image noise and diameter, with a lower signal-to-noise ratio and contrast-to-noise ratio of the six major arteries. The 370mg of iodine/bird group showed significantly better subjective image quality. Furthermore, with increasing injection rates, the prevalence of heterogeneity decreased. However, we found an increased risk of injection failure for the 0.5mL/s groups. We recommend a combination of 370mg of iodine/bird with 0.4mL/s for clinical use to achieve better image quality for CTA.