Normal computed tomographic features and reference values for the coelomic cavity in pet parrots

Abstract

Background: The increasing popularity gained by pet birds over recent decades has highlighted the role of avian medicine and surgery in the global veterinary scenario; such a need for speciality avian medical practice reflects the rising expectation for high-standard diagnostic imaging procedures. The aim of this study is to provide an atlas of matched anatomical cross-sections and contrast-enhanced CT images of the coelomic cavity in three highly diffused psittacine species.

Results: Contrast-enhanced computed tomographic studies of the coelomic cavity were performed in 5 blue-and-gold macaws, 4 African grey parrots and 6 monk parakeets by means of a 4-multidetector-row CT scanner. Both pre- and post-contrast scans were acquired. Anatomical reference cross-sections were obtained from 5 blue-and-gold macaw, 7 African grey parrot, and 9 monk parakeet cadavers. The specimens were stored in a -20 °C freezer until completely frozen and then sliced at 5-mm intervals by means of a band saw. All the slices were photographed on both sides. Individual anatomical structures were identified by means of the available literature. Pre- and post-contrast attenuation reference values for the main coelomic organs are reported in Hounsfield units (HU).

Conclusions: The results provide an atlas of matched anatomical cross-sections and contrast-enhanced CT images of the coelomic cavity in three highly diffused psittacine species.

Keywords: African grey parrot; Blue-and-gold macaw; Coelomic cavity; Computed tomography; Monk parakeet.

Fig. 1

Three-dimensional reconstruction of the body of a blue-and-gold macaw. Lines A-E indicate the level of the matched cross-sections and CT images displayed in Figs. 2, 3, 4, 5, 6 and 7

Fig. 2

Matched cross-sections and CT images at the level of the heart corresponding to line A in Fig. 1. Matched cross-sections and CT images of blue-and-gold macaw (a-c), African grey parrot (d-f) and monk parakeet (g-i). The CT images have been reconstructed with a soft tissue kernel and displayed in pulmonary (b-e-h) and abdomen (c-f-i) window. Do is dorsal and R are right. Bar = 1 cm. 1. Lung; 2. Scapulohumeralis muscle; 3. Intrapulmonary primary bronchus; 4. Scapulohumeral caudal muscle; 5. Right atrium; 6. Pectoral muscle (thoracobrachialis portion); 7. Right ventricle; 8. Pectoral muscle (sternobrachialis portion); 9. Vertebra; 10. Spinal cord; 11. Aorta; 12. Oesophagus; 13. Pulmonary trunk; 14. Cranial thoracic air sac; 15. Carina sterni; 16. Cardiac muscle, left ventricle; 17. Supracoracoid muscle

Fig. 3

Matched cross-sections and CT images at the level of the liver corresponding to line B in Fig. 1. Matched cross-sections and CT images of blue-and-gold macaw (a-c), African grey parrot (d-f) and monk parakeet (g-i). The CT images have been reconstructed with a soft tissue kernel and displayed in pulmonary (b-e-h) and abdomen (c-f-i) window. Do is dorsal and R are right. Bar = 1 cm. 1. Vertebra; 2. Kidney (cranial lobe); 3. Common iliac vein; 4. Spleen; 5. Caudal vena cava; 6. Liver, right lobe; 7. Carina Sterni; 8. Longissimus dorsi muscle; 9. Spinal cord; 10. Gonads; 11. Air sac; 12. Proventriculus; 13. Liver, medial part of the left lobe; 14. Liver, lateral part of the left lobe; 15. Pectoral muscle; 16. Supracoracoid muscle

Fig. 4

Matched cross-sections and CT images at the level of the ventriculus corresponding to line C in Fig. 1. Matched cross-sections and CT images of blue-and-gold macaw (a-c), African grey parrot (d-f) and monk parakeet (g-i). The CT images have been reconstructed with a soft tissue kernel and displayed in pulmonary (b-e-h) and abdomen (c-f-i) window. Do is dorsal and R are right. Bar = 1 cm. 1. Spinal cord; 2. Medial lobe of the right kidney; 3. Air sac wall; 4. Small intestine; 5. Pancreas. 6. Ingesta; 7. Liver; 8. Vertebra; 9. Left ureter; 10. Ventriculus, muscular wall

Fig. 5

Matched cross-sections and CT images at the level of the kidneys corresponding to line D in Fig. 1. Matched cross-sections and CT images of blue-and-gold macaw (a-c), African grey parrot (d-f) and monk parakeet (g-i). The CT images have been reconstructed with a soft tissue kernel and displayed in pulmonary (b-e-h) and abdomen (c-f-i) window. Do is dorsal and R are right. Bar = 1 cm. 1. Vertebra; 2. Medial lobe of the right kidney; 3. Intestine; 4. Pectoral muscle (thoracic portion); 5. Spinal cord; 6. Left ureter

Fig. 6

Matched cross-sections and CT images at the level of the cloaca corresponding to line E in Fig. 1. Matched cross-sections and CT images of blue-and-gold macaw (a-c), African grey parrot (d-f) and monk paraket (g-i). The CT images have been reconstructed with a soft tissue kernel and displayed in pulmonary (b-e-h) and abdomen (c-f-i) window. Do is dorsal and R are right. Bar = 1 cm. 1. Musculus levator caudae; 2. Spinal cord; 3. Vertebra; 4. Musculus levator cloacae; 5. Musculus transversus cloacae; 6. Cloaca; 7. Pectoral muscle (abdominal portion); 8. Left ureter

Fig. 7

Matched cross-sections and CT images at the level of the gonads corresponding to line E in Fig. 1. Matched cross-sections and CT images of female blue-and-gold macaw (a-c), and male blue-and-gold macaw (d-f). The CT images have been reconstructed with a soft tissue kernel and displayed in pulmonary (b-e) and abdomen (c-f) window. Do is dorsal and R are right. Bar = 1 cm. 1. Vertebra; 2. Spinal cord; 3. Kidney; 4. Ovary; 5. Spleen; 6. Liver; 7. Pectoral muscle; 8. Longissimus dorsi muscle; 9. Proventriculus; 10. Coracoid bone; 11. Testicles