Ultrasound of the Abdomen
Ultrasound of the abdomen has been in widespread use for many years, as it is a simple, noninvasive means to assess the abdominal organs. Your physician may request ultrasound as the first imaging procedure in evaluation of abdominal symptoms. With ultrasound, the liver, spleen, gallbladder , biliary tree, pancreas, kidneys, and abdominal aorta can all be evaluated. Your physician may order this test if you have abdominal pain or abnormal laboratory tests suggesting possible abnormality in these regions.
Cysts, solid masses, fluid collections, and kidney or bile duct obstructions are diagnosed with ultrasound. Some kidney stones can be seen with ultrasound, and most gallstones are first detected with ultrasound. Do not be alarmed or surprised if the ultrasound yields a finding which prompts another imaging procedure such as CT or MRI. Because ultrasound is so low-risk and non-invasive, it is often ordered first as a “screening” procedure, and some nonspecific findings may need further evaluation with another imaging modality.
Limitations of abdominal ultrasound generally are related to factors which limit transmission of the ultrasound beam. These limitations include obesity, excessive bowel gas, and barium in the intestines from recent fluoroscopic procedure. In addition, the bowel is generally much better evaluated with CT or fluoroscopy than with ultrasound.
Evaluation of individual abdominal organs with ultrasound:
Liver, gallbladder and biliary tree
Ultrasound is ideal for evaluation of these organs. It is very sensitive in the detection of gallstones and is the first imaging modality of choice in suspected biliary obstruction. Liver cysts and solid lesions can be visualized with ultrasound. Suspected enlargement of the liver, as well as fatty change in the liver, are well assessed with ultrasound. In addition, Doppler technology allows assessment of the blood vessels in the liver for abnormal or obstructed flow.
Abnormalities of the pancreas can be seen with ultrasound but this organ is generally better visualized with CT and MRI, as bowel gas can obscure portions of the pancreas during ultrasound imaging
Spleen: Your physician may request an ultrasound if splenic enlargement is suspected. Cysts and masses in the spleen are also well visualized.
Ultrasound is excellent for assessing kidney size and tissue texture, as well as suspected kidney obstruction. Most masses and cysts of the kidney are well seen on ultrasound, and kidney stones can be visualized as well. Sometimes on CT there will be a finding in the kidney which is not clearly a mass or cyst, and ultrasound can usually differentiate between these two entities. In addition, if your physician suspects renal artery stenosis (narrowing of one of the arteries supplying the kidneys), ultrasound with Doppler is a widely used screening tool.
If your physician suspects an abdominal aortic aneurysm, ultrasound is often the screening procedure of choice, as it can easily determine whether or not the aorta is normal size. Again, Doppler is necessary in evaluation of this region.