Mesothelioma imaging scans help specialists find malignant tumors and make more accurate diagnoses. Imaging also helps guide biopsies and treatment and track the progress of the disease.
The Importance of Imaging in a Mesothelioma Diagnosis
Diagnosing mesothelioma is not straightforward or simple. It requires multiple steps and tools, including medical and asbestos history, physical examination and symptoms, biopsies, blood tests, and imaging scans.
Imaging is important in diagnosing mesothelioma. It provides information such as the extent of disease in the original organ and shows if cancer has spread to other locations. It is not uncommon for a combination of several imaging exams to be performed at initial diagnosis.
Once treatment is underway, your doctors will determine the best imaging studies to evaluate the effectiveness of the plan. Images can help doctors adjust treatments as needed.[1]
X-Ray
This is a common initial study performed when someone has trouble breathing, coughing, or chest discomfort. It is useful in ruling out more common conditions, like pneumonia. An X-ray uses high-energy electromagnetic radiation to image dense tissue in the body.
Using an X-ray image, the doctor can see if the pleura around the lungs has thickened, indicating cancer. X-rays also indicate fluid build-up, another type of asbestos-related condition that may indicate mesothelioma.[2]
X-rays are useful in beginning the diagnostic process, but they are limited. They don’t provide enough detail to give a complete diagnosis or to help stage cancer.
CT Scan
Computed tomography, or CT scans, also uses X-rays. Instead of taking two-dimensional images created with a chest X-ray, this technique takes cross-sectional images of the body. CT imaging is the most commonly used imaging scan for diagnosing and staging mesothelioma.
CT scans are useful for diagnosing mesothelioma. Mesothelioma, as seen on cross-sectional imaging, shows similar features as X-rays but more clearly and with more detail. Radiologists look for:[3]
- Thickening and nodules in the pleura
- A pleural mass
- The spread of cancer to the adjacent pleura
- Invasion of the cancer into the chest wall, diaphragm, or mediastinum
- Pericardial effusion
- Metastasis to lymph nodes or the adjacent lung
- Calcified pleural plaques
Doctors can use CT scans to help stage cancer, determining how much it has spread to other tissues.[4] CT scans also help doctors determine if treatment is working and the effect it has had on tumor number and size.
What to Expect When Getting a CT Scan
You may need to use a contrast dye for your CT scan. You will be given something to take orally or be given the dye intravenously. The dye improves the contrast and makes the image clearer.
To undergo the scan, you will lie on a platform on your back. The platform moves into the CT machine, where you will have to lie motionless. A technician will speak to you from another room and may ask you to hold your breath for a few seconds.
A CT scan might take as little as 15 minutes or more, depending on how much of your body the technician needs to scan. It is a painless procedure.
MRI
An MRI, or magnetic resonance imaging, creates a picture similar to a CT scan. Instead of X-rays, an MRI uses radio waves to take detailed pictures of the body’s soft tissues.
MRI scans typically require a dye to show a contrast between blood vessels and other tissues. If a patient is allergic to the dye used for CT scans, an MRI is an alternative, and vice versa.
MRIs are particularly useful for imaging the diaphragm.[1] The diaphragm is often difficult to see in a CT scan because it is located underneath the lungs.
The image produced by an MRI is slightly more detailed than a CT scan.[4] However, an MRI takes significantly longer. To have an MRI, you must lie inside a hollow tube. Because the space is tight, it may not be an option for those who are obese or overweight.
What to Expect When Getting an MRI
The process of an MRI is similar to that of a CT scan. You may need to use a contrast dye. You will lie on your back on a platform that moves you into the MRI machine. A headset protects your ears from the scan but allows you to communicate with the technician. Tell the technician if you have any metal on you or inside your body.
The MRI scanner is more enclosed than a CT scanner and makes loud noises, which can make some people uncomfortable or scared. The technician will show you a button you can press to get out of the machine.
Although it is painless, the magnetic field used in an MRI scanner may cause a metallic taste, flashes of light, dizziness, or nausea.
PET Scan
Positron emission tomography, or PET scans, uses a radioactive material to image the inside of the body. First, a radioactive substance is injected into the body. Next, a scanner takes pictures of the radioactivity.
The process requires you to lie on a table for about half an hour. The image is not as clear as a CT or MRI scan but is useful in other ways.
A PET scan can determine whether abnormal tissue is malignant or benign. Because it produces a whole-body image, it can also determine where the cancer has spread.
The PET scanner can be combined with a CT scan to give your doctor a more detailed and comprehensive image. This combination also produces a three-dimensional image.[1]
What to Expect When Getting a PET Scan
For a PET scan, you will be given an intravenous infusion of a radioactive tracer. You will lie on your back and be moved into the scanner. The technician will speak to you from another room and tell you if you need to hold your breath.
A PET scan usually takes between 30 and 90 minutes. Although it is painless, you must remain as still as possible, which can be uncomfortable.
Echocardiogram
This is a specialized ultrasound to evaluate the function of the heart. This helps determine if there is fluid in the lining around the heart as well as the overall function.
It allows for visualization of the valves as the heart pumps. This is helpful when your doctors want to take a closer look at heart function beyond what is seen on a CT or MRI.[1]
Other Uses for Imaging Scans in Mesothelioma
These imaging techniques are crucial for a complete mesothelioma diagnosis; however, they are useful for much more than that.
If you have mesothelioma, scans can help your doctor stage cancer. The images also allow your doctor to see how far the cancer has spread, as well as how large the tumors are in the original location.
Images also track cancer progression and treatment. If you have surgery, chemotherapy, or radiation, an imaging scan can show how successful that treatment has been. Because they allow your doctor to see the progress of the treatment, these images also influence the next step of cancer treatment.[5]
When Do You Get a Diagnosis After Imaging Scans?
An imaging scan is just one of many steps in a complete mesothelioma diagnosis. In the early part of the diagnostic process, your team will use imaging to find areas of abnormal tissue or tumors. They use these images to guide the location of a biopsy.
A biopsy involves removing a small amount of tissue. That sample goes to a pathology lab, where a pathologist examines it under a microscope. The pathologist can determine if the cells are malignant, where they originated, and other features that help diagnose the cancer.
Imaging scans are essential to diagnosing, staging, and treating mesothelioma. Talk to your doctor about what scans you need and what to expect.
