Ultrasound examination and guided fine-needle aspiration of the liver in Amazon parrots (Amazona species)

Techniques for ultrasound imaging and percutaneous, ultrasound-guided fine-needle aspiration of the liver were initially tested on 5 Amazon parrots. The techniques were then applied to 27 clinically normal Amazon parrots. Each of the 27 birds was anesthetized with isoflurane and placed in dorsal recumbency with the head elevated 30 degrees. Optimal imaging of the liver was achieved by cranially directing a 7.5-MHz pediatric mechanical sector transducer through a parasternal acoustic window. The normal sonographic appearance of the liver was evaluated. In each bird, an ultrasound-guided aspirate of the liver was collected by using a 22-gauge, 1-in needle connected to a 6-in extension set and a 3-ml syringe. Three techniques were used to collect the aspirates for cytologic evaluation, and the quality of the samples was compared microscopically. Samples with the lowest degree of hemodilution and the highest number and quality of hepatic cells were obtained by penetrating the liver parenchyma multiple times with the needle while simultaneously applying 0.5 mi of suction. Ultrasonographic examination of the liver 5 minutes after fine-needle aspiration revealed no hemorrhage in any bird. No morbidity or mortality occurred in any of the parrots during or after ultrasound imaging or ultrasound-guided fine-needle aspiration of the liver.