Liver Nuclear Medicine Scan
Definition
A liver scan is a diagnostic procedure to evaluate the liver for suspected disease. A radioactive substance that concentrates in the liver is injected intravenously and the image of its distribution in the body is analyzed to diagnose certain abnormalities.
Purpose
In the past, liver scans were used to evaluate the liver in a wide variety of situations. It was considered a useful study to detect abnormalities, but was often not able to establish a specific diagnosis. In the 1990s, radionuclide imaging of the liver (use of a radioactive form of cobalt or iodine) evolved into a more specialized study, used to identify individual diseases or conditions. This is accomplished by using different radioisotopes precisely designed to further evaluate a particular case. Isotopes are different forms of the same substance, such as radioactive iodine, that are injected into the body. This allows the physician to trace the process of the substance throughout the part of the body that is being tested for disease.
A liver scan is usually ordered after blood studies and other imaging procedures have shown a liver abnormality. It is most often used to further evaluate masses or tumors. These may be benign growths in the liver, or cancer which has developed in the liver or has spread (or metastasized) from another organ.
A liver scan may also be helpful in diagnosing specific disorders, by detecting features which are characteristic of a disorder, such as cirrhosis of the liver. This study may also be part of the battery of tests used to evaluate potential candidates for liver transplant.
Precautions
Women who are pregnant or breast feeding should not have this test.
Description
This test can be performed in an outpatient setting or a hospital x-ray department. The patient usually lies down while a radioactive substance (radioactive isotope) which accumulates in the liver is injected through a vein in the arm. Scanning times may vary, depending on the specific radioisotope used. It most often begins within minutes after injection. The radionuclide scanner, sometimes called a gamma camera or scintillation camera, is positioned above the upper abdomen and may lightly touch the patient. It is important for the patient to lie quietly. Position changes and brief periods of breath holding may be required. The test usually takes approximately one hour.
A specialized liver scan used to assess blood flow is frequently used. It may be referred to as a radionuclide blood pool or volume study, a labeled red cell scintigram, or some combination of these terms. Other studies may be named for the radioisotope used. This test may also be called a liver-spleen scan.
