Ultrasonography

Ultrasonography is the second most commonly used imaging format in veterinary practice. It uses
ultrasonic sound waves to create images of body structures based on the pattern of echoes reflected
from the tissues and organs being imaged. Several types of image formats can be displayed.
Ultrasounds operate by taking a small percentage of these echoes and reflect them back to the
transducer, which then reconverts the energy of the echoes into electrical impulses recorded
by the computer in the ultrasound machine. The image may then be frozen and recorded in a digital
format, which also allows for recording of short segments of the real-time scan.

Although ultrasound can be used to evaluate most soft tissues, the heart and abdominal organs still constitute the majority of examinations performed in small animals. Though ultrasonography can be quite sensitive to detection of disease, the changes are not specific for a given disease in most cases unless a characteristic change in anatomy is detected.   Ultrasonography can also be used to direct biopsy instruments to acquire tissue for a specific pathologic diagnosis. This avoids the need for an open surgical exploration in many cases. Also, lesions buried within large organs such as the liver
and kidneys that might not be detectable at surgery may be detected and biopsied with ultrasonographic guidance.