Ultrasound is best at diagnosing abnormalities that are discrete. An example of this type of lesion would include a mass (tumour) in the liver. Once detected, the mass can be accurately measured for later comparison. If the mass is found in an organ that is not essential (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 can be 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 useful 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).
|Two examples of Intussusception
Ultrasound can often differentiate benign prostatic enlargement from prostatic cancer. In animals with a history of vomiting, ultrasound can be used to evaluate whether 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 detect an intestinal foreign body, thus preventing a labor intensive and costly upper GI barium study.
The diagnosis of pregnancy is commonly perfprmed 21 days postconception with ultrasound - much earlier than is possible with xrays (42 days).
In imaging the heart, ultrasound is at its best, as the heart is a fluid filled organ. Abnormalities such as diseased heart muscle (hypertrophic and dilated cardiomyopathy), fluid around the heart (pericardial effusion), and congenital abnormalities can be diagnosed and their severity can be assessed. Heart-base tumors, which are rarely visible on radiographs, are easily visualized with ultrasonography.
Ultrasonography can easily differentiate fluid within the cranial mediastinum from a mass.
Ultrasound guided fine needle aspirate or biopsy is a relatively safe and non-invasive way to reach a definitive diagnosis.