Diagnostic ultrasound provides a safe, economical, and noninvasive imaging modality in defining soft tissue architecture (of organs and structures) and the assessment of organ function (gastric and intestinal motility, echocardiography, and fetal viability). Ultrasound has reduced the need for many contrast radiographic examinations. It aids in guiding diagnostic or therapeutic needle aspirations and biopsies of organs or lesions for cytologic, bacteriologic, or histopathologic preparations. No ionizing radiation hazard or other known safety consideration is present with ultrasound.
The ultrasound transducer converts electrical energy into a brief pulse of high frequency sound waves that are then transmitted into the animal's tissues. The transducer then functions as a receiver, detecting echoes of sound energy reflected from the tissues. The depth of a structure producing an echo is determined by the amount of "round trip" time of the transmitted pulse and the returning echo. An image, representing the organs and tissues in the field of view, is produced by computer analysis of the time delay and amplitude of the returning echo. Images are updated approximately 30 times/second and provide real time assessment of cardiac movement, vascular pulsations, and gastrointestinal peristalsis.