Mesothelioma Imaging Tests
To diagnose mesothelioma, doctors use a variety of procedures to pinpoint the size, shape, origin and possible spread of the disease. One of the most important procedures are imaging tests, which allow medical professionals to look at the inside of the body without surgery or other invasive procedures.
There are several kinds of imaging tests that offer different types of views. These tests use various forms of energy, including sound waves, X-rays, magnetic fields and radioactive particles, to create images or pictures. These images are used to see normal body structures and functions as well as abnormal ones, such as cancerous tumors and the spread of the disease.
Although imaging testing is the norm in diagnosing mesothelioma, the procedures do have some limitations. Some imaging tests cannot pinpoint the exact type of mesothelioma present or the types of cells involved. Instead, most patients must undergo a biopsy for a more detailed look at the cancer. Also, if the mesothelioma is in the very early stages, most imaging tests cannot detect cancer because it takes millions of cells for tumors to grow.
Overall, imaging tests are considered to be a necessary step in diagnosing mesothelioma. However, there is some controversy surrounding which imaging test is best in mesothelioma cases. For example, CT scans, which are considered to be a gold standard in imaging, can easily detect enlarged lymph nodes, which often indicate a later-stage disease process. However, enlarged lymph nodes alone should not be the indicator for advanced mesothelioma. Blood work and biopsies should confirm the diagnosis.
Types of Tests
Below are a list of the most commonly used imaging tests when diagnosing mesothelioma.
Also known as radiography, X-ray images are the most common imaging tests used in a mesothelioma diagnosis but also have several limitations. An X-ray image cannot pick up abnormalities in soft tissue, so it is not a useful tool in diagnosing mesothelioma that has metastasized. Also, X-rays are known to be carcinogenic, so patients should undergo only a limited number of these tests. X-rays are effective in detecting pleural thickening and pleural effusions, which are indicative of mesothelioma. Patients usually stand while X-rays are taken.
Also known as Computed Tomography or a CAT scan, this is a combination of X-rays and computer technology. It is a useful tool in diagnosing pleural mesothelioma and peritoneal mesothelioma. CT scans can create three-dimensional images from different angles in the body. For a scan, a patient is inserted horizontally into a donut-shaped machine. That machine then spins around the supine patient to produce several cross-section images. The machine then combines the pictures to give doctors a detailed view.
MRI – Also known as Magnetic Resonance Imaging, this tool produces high-resolution images of bone and soft tissue that are superior to CT scans and X-rays. For this test, a patient is inserted horizontally into a tube and the machine spins around them. Unlike the two previous imaging tools, MRIs produce color images that show the differences among the bodily tissues. This allows for a very clear and concise picture of the tumors and spread of the disease. For claustrophobic patients, an MRI is not a comfortable procedure so a sedative may be prescribed.
Also known as Positron Emission Tomography, this test uses radioactive materials to produce colorful, three-dimensional images. For this test, a patient is injected with a radioactive fluid. The scanner detects the radiation and produces images that show the function of the diseased tissue. It is useful to determining the spread of the disease, especially in suspected cases of peritoneal and pleural mesothelioma. This imaging test is often used to stage mesothelioma and to determine the best course of treatment.