Ultrasound is a valuable diagnostic tool for imaging soft tissue and internal organs. An ultrasound probe generates high-frequency sound waves (in the 2-15 Mega Hertz range) that penetrate tissue.  The sound waves are reflected back at different rates, depending on the density of the tissue encountered.  The probe receives the echoed signals, and the ultrasound machine then analyzes the depth and density of the tissue and creates an image such as the one you see on top of this page.  Tissue and fluids reflect sound waves best, while gas and bones prevent transmission of the waves.

Ultrasound images are updated approximately 30 times per second, so organs like the heart may be viewed as they are functioning.  In addition to confirming pregnancies, certain abnormalities, such as tumors, abscesses, cysts, bladder or kidney stones, fluid pockets and obstructions are all easily detected and measured with ultrasound.  Ultrasound may also be used to help guide a needle when performing a needle biopsy of tissue.

Ultrasound is considered very safe.  Depending on the tissues being analyzed, sedation is usually not required.  The sound waves at this frequency do not travel well through air, so fur must be shaved prior to ultrasound and a "coupling gel" applied to the skin.

Dr. Vargas and Dr. Roy have both pursued ultrasound training in their continuing education, and are especially skilled at interpreting ultrasound images.

Ultrasound scanning has been used to diagnose many diseases in small animals since the early 1980's.  It is now considered to be an essential service in all veterinary teaching hospitals and large referral centers and many small animal practices such as Orchid Springs Animal Hospital. The reason for this is simple: Ultrasound offers a non-invasive, non-painful method for the diagnosis and staging of many diseases.  Ultrasound is the best modality to evaluate fluid filled and soft tissue organs.  Our ultrasound machine helps us diagnose difficult cases that may not be solved with convetional tools such as bloodwork or radiographs (x-rays).

Why Ultrasound?

Ultrasound allows us to visualize the internal architecture of many organs.  Radiographically inapparent internal abnormalities such as nodules, masses, cysts and abscesses cannot only be seen, but can also be counted and measured.  Although the ultrasound examination alone is in many cases non-specific for a particular disease, in conjunction with the animal's age, sex, breed, history, physical exam, radiographic findings and labwork, as well as ultrasound guided fine needle aspirates or true-cut biopsies, the specificity for disease can be high.  Many organs that are difficult to see on plain film x-rays (prostate) can be easily seen with ultrasound.  Real-time echocardiography (ultrasound examination of the heart) also allows us to see the heart in motion.  From these images, measurements of cardiac contractility, areas of abnormal wall motion, chamber dilatation and wall thickening are made and compared to normal values.  The typical ultrasound examination requires no tranquilization or anesthesia and is easily performed on awake animals.  Prior fasting or water withholding is NOT required.  The only patient preparation necessary is clipping of the hair overlying the area to be scanned (the ultrasound will not penetrate through hair) and placing coupling gel on the skin surface just prior to the exam process.  The entire scanning takes 30-40 minutes.  Images are acquired on the monitor of our ultrasound machine as well as on a compact disc for later viewing and as an archive in your patient record.

What Can I See With Ultrasound?

Ultrasound is best at diagnosing abnormalities that are discrete.  An example of this type of lesion would include a mass (tumor) in the liver.  Once found, the mass can be accurately measured for later comparison.  If the mass is found in an organ that is not required (such as the spleen), careful examination of the other organs (such as the liver) for the presence of metastatic disease (tumor spread) is needed prior to surgical removal of the "expendable" organ.  Ultrasound is used to diagnose a variety of both benign and malignant diseases such as the presence of stones within the urinary bladder, kidneys or gall bladder, infection of the gall bladder, urinary bladder, prostate or kidneys, the presence of enlarged lymph nodes, abnormal blood vessels, or free fluid within the abdomen.   It is especially good in diagnosing disease of the pancreas (pancreatitis), adrenal abnormalities, urinary bladder wall tumors, uterine infections (pyometra) and masses that are located behind the eyeball (retrobulbar masses).  Ultrasound can often differentiate benign prostatic enlargement from prostatic cancer.  In animals with a history of vomiting, ultrasound can be used to evaluate if the problem is within the liver, gall bladder or pancreas.  It can often diagnose problems that are associated with the stomach or small intestinal wall, or see an intestinal foreign body, thus preventing a labor intensive and costly upper GI barium study.  The diagnosis of pregnancy and fetal viability (heartbeats) are commonly seen by 21 days post-conception with ultrasound, which is much earlier than can be done with x-rays (42 days).  In the heart, ultrasound is at it's best, as the heart is a fluid filled organ.  Abnormalities such as a diseased heart muscle (hypertrophic and dilatory cardiomyopathy), fluid around the heart (pericardial effusion), and congenital abnormalities can be diagnosed and the severity can be assessed.  Heartbase tumors, which are rarely seen on radiographs, are easily visualized with ultrasonography.  Ultrasound can easily differentiate fluid within the cranial mediastinum from a mass.  Recently, ultrasound has been used to evaluate tendon abnormalities of the shoulder and knee (stifle).  Using ultrasound, we can often diagnose problems earlier than would otherwise be possible.  This dramatically increases our opportunities for successful treatments.