Comparison of three computed tomographic angiography protocols to assess diameters of major arteries in African grey...

OBJECTIVE To evaluate 3 contrast medium infusion (CMI) protocols for CT angiography (CTA) and measurement of major artery diameters in African grey parrots (Psittacus erithacus). ANIMALS 9 African grey parrots with no detectable cardiovascular disease. PROCEDURES Each bird was anesthetized and underwent placement of an IV catheter in the left basilic vein and 16-slice CTA scanning (started at peak aortic enhancement) with each of 3 CMI protocols at ≥ 1-month intervals. Protocol 1 involved catheter flushing with saline (0.9% NaCl) solution and IV infusion of iopamidol (2 mL) followed by saline solution (0.2 mL; total infused volume, 5 mL). Protocol 2 involved IV infusion of iopamidol (2 mL) followed by saline solution (0.4 mL; total infused volume, 2.4 mL). Protocol 3 involved catheter flushing with saline solution and IV administration of iopamidol (2 mL; total infused volume, 4.8 mL). The diameters of 6 major arteries were measured by 2 observers, and intra- and interobserver agreement, time-enhancement variables, and patient factors affecting contrast medium enhancement were assessed. RESULTS Among the 3 CMI protocols, CTA-derived arterial diameters differed significantly. Measurements obtained with protocol 2 were significantly larger than those obtained with the other protocols. Uniformity of the time-enhancement variables differed among CMI protocols. Patient factors had nonsignificant effects on contrast medium enhancement. CONCLUSIONS AND CLINICAL RELEVANCE Of the CMI protocols assessed, a 2-phase CMI protocol with a post-CMI saline solution flush was the most reliable for CTA-derived measurements of the major thoracic and abdominal arteries in African grey parrots. However, further technique modification is needed.