Development of ultrasonographic methods for diagnosis of diseases and disorders in some Philippine wild animals

Application of ultrasonogrphy in wild animals is a big challenge because of the wide variety in anatomy, size, location of organs, physiology and temperament of animals. To be able to utilize diagnostic ultrasound efficiently, specific methods of ultrasonographic methods must be developed for individual species. Ultrasonographic methods for diagnosis include preparation of the animal, selection of the proper equipment, appropriate B-mode and M-mode examinations and analysis of ultrasonograms. The preparation of the animals is generally dictated by the size and temperature of the animals. In some species, manual restraint is sufficient to allow ultrasonographic examination while in others, there is a need to sedate or anesthetize the animal. The ultrasound machine to be used, including the type and frequency of scanner is dependent on the size of the species, anatomy and the location of the organs to be examined. Linear scanners are generally used when there is a wide acoustic window and the organs are located superficially. Sector or micro-convex scanners are used in areas where there is a small acoustic window, like in turtles or tortoises, or where the organs to be examined are located deeply. B-mode and M-mode ultrasonographic examinations necessitate the application of adequate coupling gel on the scanner and the skin of the animals. In reptiles, the gel can be applied in between the scales of the patient can be submerged in water and the scanner placed near the skin, to facilitate examination. In birds, the feathers may be plucked to provide sufficient contact between the transducer and the skin. Differences in position and anatomy of the organs and physiology of the animals should be considered during examination and interpretation of ultrasonograms. Analysis of ultrasonograms include measurement of organ dimensions, calculations of echogenicity through histogram analysis, determination of M-mode ultrasound patterns and measurement of cardiovascular structures and parameters. The length, width, height, circumference and volume of the organs can be determined to provide comparison with other organs. The brightness of the different organs can also be quantitatively determined through digital analysis and calculation of echo mean values. M-mode patterns of different cardiovascular structures can also be analyzed and measurements obtained for computation of various cardiac paramaters to determine cardiac output and status of the heart. Reference values for these different parameters can be established to serve as guide for evaluation of ultrasonograms. These ultrasonographic methods can be useful in diagnosis of disease and disorders of different wild animals.