Radiographic measurement of internal organs in Spix's macaws (Cyanopsitta spixii).

Radiology is an important diagnostic instrument in avian medicine, but standard measurement ranges for the objective evaluation of radiographs of birds are rare. To establish radiographic reference ranges for the critically endangered Spix's macaw (Cyanopsitta spixii), we measured radiographic silhouettes of the heart, liver, kidneys, spleen, proventriculus, and keel of the sternum on 29 radiographs taken under standardized conditions in adult and juvenile, clinically healthy birds. Ratios were determined for the proventricular diameter-to-keel height, the width of the heart to the width of the thorax, and for the "hourglass shape" (ratio of the width of the heart to the width of the liver). No significant differences were found between the sexes among the adult birds. Compared with adult birds, juvenile females had a significantly larger heart width (19.8 +/- 1.4 mm versus 21.2 +/- 0.7 mm), ratio of the heart width to the thorax width (0.86 +/- 0.08 versus 0.94 +/- 0.09), and horizontal width of the spleen (7.7 +/- 0.6 mm versus 8.5 +/- 0.4 mm). Results of radiographic measurements in the Spix's macaws were comparable to those published from other psittacine species. These reference ranges will facilitate a more objective radiographic evaluation of captive Spix's macaws.

Effect of anesthesia, positioning, time, and feeding on the proventriculus: keel ratio of clinically healthy parrots.

Healthy, adult Hispaniolan Amazon parrots (Amazona ventralis) were imaged on three occasions to determine the effects of anesthesia, patient rotation, feeding, and short/long-term temporal factors on the proventriculus:keel ratio. Increasing rotation up to 15 degrees from right lateral resulted in increased inability to measure the proventriculus in up to 44% of birds, meaning that the proventriculus:keel ratio could not be calculated from those radiographs. There was a significant difference between the proventriculus:keel ratio for individual parrots when quantified 3 weeks apart. Despite this difference, all ratios remained within normal limits. No significant effect was identified due to anesthesia, feeding, fasting, or repeated imaging through an 8-h period. Interobserver agreement for measurability and correlation for the proventriculus:keel ratio values was high. It is recommended that the proventriculus:keel ratio be calculated from anesthetized parrots to attain images in true lateral recumbency. Ratio fluctuations within the normal range between radiographs obtained on different dates may be observed in normal parrots.

Prognostic accuracy of the proventriculus: keel ratio for short-term survival in psittacines with proventricular disease.

The proventriculus:keel ratio was evaluated as a prognostic indicator for short-term survival in parrots with proventricular disease. Measurements were made from right lateral radiographs of 41 parrots with proventricular disease. Results were compared with the previously described abnormal proventriculus:keel ratio range and to short-term clinical outcome at 1-month postdiagnosis. The ratio in all parrots was > 0.52, and 39% of parrots succumbed to their disease within 1 month of diagnosis. There was no significant association between the proventriculus:keel ratio and survival duration (P = 0.9). The proventriculus:keel ratio is a sensitive indicator of proventricular disease in parrots but is insensitive as a prognostic indicator.

Radiographic determination of proventricular diameter in psittacine birds.

OBJECTIVE: To establish an objective method of determining proventricular diameter in psittacine birds by assessment of lateral whole-body radiographic views. DESIGN: Retrospective case-control study. ANIMALS: 100 parrots with no signs of gastric disease and 19 parrots with signs of gastric disease. PROCEDURES: Measurements were obtained for the following variables: proventricular diameter at the level of the junction between the last thoracic vertebra and synsacrum, maximum distance between the dorsal serosa of the proximal aspect of the proventriculus and dorsal border of the sternum, maximum coelomic cavity height at the level of the proximal aspect of the proventriculus, and maximum dorsoventral height of the keel of the sternum. The ratio of proventricular diameter to each of those measurements was calculated and compared among species within the group without signs of gastric disease and between the gastric and nongastric disease groups. RESULTS: No significant differences were seen among species of parrots without signs of gastric disease for any ratio, but there were significant differences between parrots with gastric signs and those without gastric signs for all ratios. Only the proventricular diameterto-maximum dorsoventral height of the keel of the sternum ratio had no numeric overlap between groups. Sensitivity and specificity of the ratio for detection of proventricular enlargement were both 100%. Six causes associated with proventricular enlargement were identified. CONCLUSIONS AND CLINICAL RELEVANCE: Evaluation of the proventricular diameter-to-keel height ratio is a new method for evaluating proventricular size in psittacines. Ratio values < 0.48 indicate normal proventricular diameter and the absence of proventricular disease.

Psittacine proventricular dilatation syndrome in an umbrella cockatoo.

Psittacine proventricular dilatation syndrome (macaw wasting disease) is a fatal disease of the gastrointestinal tract and, sometimes, the CNS. The disease most often affects macaws and is thought to be of viral origin. An Umbrella cockatoo was referred with signs of neurologic dysfunction. Other unusual findings included flaccid crop, distended duodenum, and acute weight loss. Because treatment has not been reported to be effective, the affected cockatoo was euthanatized to limit spread of the disease.