Diagnostic Ultrasound
How Ultrasound Works
Unlike x-rays, which use radiation to form an image, ultrasound uses sound waves. A transducer (probe) is used to send sound waves into the animal and receives the returning echoes which are converted into an electrical signal to generate an image. Veterinarians are trained to interpret the images based on their echogenicity, or relative brightness, which is a lot like differentiating between shades of gray. Video and images of your pet's ultrasound can even be recorded and printed for your pet's permanent record.
How Ultrasound is Used at Bellwood
Ultrasound is most frequently used to survey the abdominal cavity. This includes evaluation of the liver, gallbladder, spleen, kidneys, adrenal glands, stomach, intestine, pancreas, bladder, lymph nodes, and prostate in males. Samples of masses, organ tissue, urine, or fluid in the abdomen or chest can be obtained with ultrasound guided fine needle aspirate and can be submitted for cytology or histopathology to help reach a diagnosis. Ultrasound can also be used to diagnose pregnancy as early as 35 days post ovulation; which is prior to when this can be done with x-rays.
What to Expect When You Make an Appointment
Please remove your pet's food beginning at 10 p.m. prior to the morning of your appointment. While ultrasound can be performed in a non-fasted pet, a stomach distended with ingesta can make it difficult to completely evaluate all organ systems. Please do not allow your pet to urinate on the way to the hospital. The bladder is best imaged when full, and this also allows for the opportunity to collect a urine sample if needed. If your veterinarian would like to take fine needle aspirate samples during the procedure, your pet may need to have blood work prior to the ultrasound appointment.
Please be aware that a large area of your cat or dog's abdomen will be shaved before the ultrasound, because air that is trapped between the hair and skin will disrupt image quality or can prevent visualization altogether.
References
- Nyland, Thomas and and John Mattoon. Small Animal Diagnostic Ultrasound 2nd ed. Saunders, 2002.
- Owens, Jerry and Darryl Biery. Radiographic Interpretation for the Small Animal Clinician 2nd ed. Lippincott Williams & Wilkins, 1998.
- Thrall, Donald. Textbook of Veterinary Diagnostic Radiology 5th ed. Saunders, 2007.