Ultrasound scanning is a painless procedure that uses high frequency sound waves (inaudible to humans) to produce images of structures within the body. When sound waves are aimed into the body, some are absorbed by body tissues and others bounce back. The sound waves that bounce back are measured by the ultrasound machine and are transformed into an image of a particular body area.
When should ultrasound scanning be used?
Ultrasonography is most useful for looking at soft or fluid filled organs like the liver, kidney, bladder and heart. It is less effective for examining mineralised structures (like bones) or air-filled organs (like the lungs).
Preparing for an ultrasound scan
Here are some important steps that need to be taken before your pet has an ultrasound procedure.
- Do not feed your pet after 8 pm the night before their procedure. Fasting is important as a full stomach will make imaging organs around the stomach difficult (liver, adrenals etc). Water is permitted.
- Please do not let your pet urinate within 3 hours before their study. A full or partially full urinary bladder is very helpful for a complete examination.
Will your pet need to be sedated?
Most of our patients will not need sedation. However, if your pet is very anxious or painful, sedation may be helpful. It will also be indicated if a tissue biopsy is required. We will inform you if there are any contraindications to sedation.
A note on hair
After the procedure you may notice that your pet has been clipped. The hair on the abdomen (for abdominal ultrasound) or on the chest wall (thoracic ultrasound) will be shaved prior to the examination. This is necessary as the presence of hair obstructs the ultrasound waves and causes “blackout” on the picture. Blackout prevents us from obtaining the best possible view.
After the ultrasound
Following the examination the ultrasonographer will contact your veterinarian to discuss the findings. When you return to pick up your pet, you will be given a brief indication of the findings, but we ask that you visit or contact your regular veterinarian to fully discuss the findings from the study and any further recommendations as they relate to the clinical problem of your pet.
What does an ultrasound scan look like?
This image is of a normal kidney surrounded by fluid within the abdomen. In the kidney we might expect to see abnormalities such as kidney stones, cysts, lumps or other irregularities in the organ structure.
This image is from an abdominal ultrasound of a male dog focusing specifically on the liver. In this case, the liver has been overtaken by multiple masses. The next step would be to send a sample of the abnormal liver to a laboratory to determine if the tissue is cancerous.
Some ultrasound machine can conduct colour doppler studies as shown above. These look at the flow of blood through the heart as well as other major organs.