Diagnosing Mesothelioma Using Imaging Scans

Multiple types of imaging scans are used to help diagnose mesothelioma and locate tumors throughout the body. There is no single type of imaging scan that provides all the information needed to identify mesothelioma. These noninvasive imaging techniques include X-rays, computed tomography scans, magnetic resonance imaging and positron emission tomography.

Mesothelioma shares many signs and symptoms with other diseases, making it difficult to diagnose. Mesothelioma cannot be diagnosed with imaging alone, however. A biopsy is required.

Key facts about mesothelioma imaging scans:
  • X-rays are the most common imaging type used for mesothelioma, but they only provide a two-dimensional view of parts of the body.
  • CT scans combine X-rays with computer technology to produce high-resolution images that show cross-sections of the entire body or specific parts of the body.
  • MRI scans are similar to CT scans but use a strong magnet instead of X-rays. MRI scans are better than CT scans for imaging soft tissue in the body but can take 30-90 minutes to complete.
  • PET scans use an injected radioactive tracer to help find cancer cells throughout the body. It is often combined with CT but takes 30-90 minutes, like an MRI.

Imaging scans provide doctors with essential information needed to help diagnose mesothelioma. This includes identifying fluid accumulation, invasion of cancer cells into tissue, the size and location of tumors and other abnormalities.

Mesothelioma tumors can occur in the chest, abdomen, and in the lining surrounding the heart and testes. Metastatic tumors can occur throughout the body. Finding all tumors and lymph nodes affected by cancer is important for mesothelioma staging, which helps determine the best treatment strategy.

Role of Imaging Scans in Consults and Second Opinions

Imaging scans are an essential part of a mesothelioma diagnosis, but it takes experience to identify mesothelioma and not confuse it for another disease, such as lung cancer. Because few doctors have extensive experience diagnosing and treating mesothelioma, getting a second opinion is important if you have been diagnosed with mesothelioma or think you may have mesothelioma. 

Mesothelioma is rare, so doctors do not routinely see the disease, except at mesothelioma treatment centers. It is important to have a doctor with mesothelioma experience look at all of your previous diagnostic tests. According to Dr. Jeffrey Velotta, “For consultations or second opinions, really it’s about the imaging,” emphasizing the importance of imaging scans for mesothelioma.

Doctors need every bit of available information to inform their decisions about diagnosis and treatment, especially when it comes to surgery and radiation treatment for mesothelioma

“What patients want to know when they get a second opinion is, ‘Can you do something about it?’ They want to know whether or not as a surgeon if you feel you can operate on them. What we really need to see first is the CT and PET scans,” Velotta told The Mesothelioma Center.

X-Rays and Mesothelioma

X-ray scans use a very small amount of radiation to produce a two-dimensional image that shows the inside of the body. A chest X-ray is the first imaging test your doctor will order if you have lung symptoms, such as shortness of breath, difficulty breathing or a chronic cough. This is done to look for signs of lung diseases, including mesothelioma, lung cancer and various others. A mesothelioma X-ray can show pleural effusions and tumors in the chest caused by mesothelioma.

X-Ray scan of someone's chest.
X-ray scans can show abnormalities in the body such as tumors.

X-rays have limited usefulness in diagnosing mesothelioma. However, they can identify abnormalities that may suggest mesothelioma and point doctors toward a diagnosis. In an X-ray, pleural mesothelioma tumors can appear as wispy white areas. Tumors can also distort the normal shape of the lungs and, in some cases, elevate the diaphragm. These changes are easily visible in an X-ray.

X-rays are very safe; they expose you to the same level of radiation that you are naturally exposed to over a period of 10 days. The safety and wide availability of chest X-rays make them a very useful tool for diagnosing lung diseases. They are an important first step in mesothelioma diagnosis.

CT Scans for Mesothelioma

Computed tomography or computed axial tomography scans use X-rays to produce three-dimensional images of the body that can be viewed in cross-section. Mesothelioma CT scans provide much more detail than a standard X-ray, allowing doctors to see small tumors throughout the body. CT scans for mesothelioma can be limited to the chest or abdomen but can also scan the entire body.

Image of someone using a CT scan machine.
CT scans can give doctors a more detailed look at tumors.

CT scans are perhaps the most important scan used to detect mesothelioma. It can help with mesothelioma diagnosis and staging as well as surgical planning. Recent research has shown that CT scans may be able to identify different mesothelioma cell types, further aiding in diagnosis.

The CT scanner takes hundreds of small X-rays while rotating around your body and moving your body through the machine. This exposes you to significantly more radiation than a chest X-ray — about 70 times more. While it is safe to have repeated chest X-rays, multiple CT scans are generally avoided due to the higher level of radiation exposure.

What Can I Expect During a CT Scan?

When you arrive for your CT scan, the CT technologists will guide you through the process and answer any questions you have about your scan. You will need to lie flat on your back and remain still throughout the scan. If you have limited mobility or pain that affects your ability to lie flat for a scan, you should tell the CT personnel so they can take steps to keep you safe and comfortable. Like other types of radiology scans, you will need to wear a hospital gown so that your clothing doesn’t interfere with the scan.

The CT scan process:
  1. You may be given a contrast dye, either by mouth or intravenously, to enhance the visibility of specific parts of the body.
  2. You will lie flat on your back on a platform that moves your body into the CT scanner.
  3. The CT tech will communicate instructions to you through a speaker, such as when to briefly hold your breath during a chest CT.
  4. You will need to remain as motionless as possible during the scan.
  5. The scan may take as little as 10 minutes but can be longer depending on how much of your body is being scanned.

After your scan, a computer processes all of the images taken and reconstructs a 3D model of the body. By looking at cross-sections of the body, doctors can identify small tumors and other abnormalities. You will not get the results of a CT scan the same day; it can take a day or two for a radiologist to carefully read the scans and write a report. Your primary care doctor, cancer doctor, or other health care provider will review the results to help them diagnose your condition.

MRI Scans to Detect Mesothelioma

MRI scans are not typically used to detect mesothelioma, but research shows that newer MRI techniques make it more useful. MRIs subject the body to a powerful magnetic field. The MRI machine can detect small changes on the atomic level caused by the magnetic field. MRI is very good at identifying changes in soft tissue that can’t be seen clearly using X-rays or CT, meaning MRI can potentially detect mesothelioma earlier than other scans.

MRI Scan Graphic
MRI scans can help locate tumors earlier than X-ray or CT scans.

Unlike X-rays and CTs, MRIs do not use radiation, making them safer in terms of radiation exposure. However, the magnetic field is strong enough to attract metal objects in the same room and can pull metal out of the body. Be sure to inform your doctor and MRI technicians if you have any metal in your body before your scan. This includes surgical implants and prosthetics as well as shrapnel or other metal embedded in the body.

Like a CT scan, an MRI can produce highly detailed images of the body in cross-section. MRI provides additional detail that can show changes in soft tissue not seen with X-rays or CT. MRI can show whether tumors have invaded nearby tissue, which is important for mesothelioma staging.

What To Expect During an MRI 

An MRI scan is mostly similar to a CT scan, with some important differences. You will need to wear a hospital gown and must remove all jewelry and piercings. You must inform the MRI techs of any possible metal in your body that could be affected by the magnetic field. 

Unlike a CT scanner, an MRI scanner is very loud. The scanner makes banging noises throughout the scan — this is completely normal. MRI scanners are more enclosed than most CT scanners. It is normal to be nervous about being in a confined space — you will be able to communicate with the MRI staff in case you are in distress.

The MRI scan process:
  1. You may be given a contrast dye, either by mouth or intravenously, to enhance the visibility of specific parts of the body.
  2. You will lie flat on your back on a platform that moves your body into the MRI scanner.
  3. You will wear a headset for hearing protection and to allow the MRI tech to communicate with you.
  4. You will have a button you can press if you are in distress and need to be removed from the machine.
  5. You will need to remain as motionless as possible during the scan.
  6. The scan may take 30 to 90 minutes.

During an MRI, some people experience dizziness, nausea, a metallic taste and brief flashes of light. These are caused by the magnetic field and they are temporary. After your scan, you will not know the results immediately; the MRI readings need to be processed by a computer. A radiologist can then read the results and produce a report within several days. This report will help your doctor diagnose and stage mesothelioma.

Young scientist reviewing sample under a microscope
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PET Scans To Diagnose Mesothelioma

PET Scan Graphic
PET scans are widely used since they can find even the smallest of tumors.

PET scans use radioactive isotopes combined with glucose (sugar) to identify cancer cells. PET identifies cells in the body that are using the most glucose, including cancer cells, which are highly metabolically active. PET is often combined with CT. PET/CT can locate cancerous tumors throughout the body, including very small metastases. Mesothelioma PET scans can be used to help diagnose disease and monitor response to treatment. Research also indicates that PET/CT may be able to help determine disease prognosis in mesothelioma.

PET is extremely sensitive and can locate very small tumors and lymph nodes affected by cancer. It is useful for early detection of mesothelioma as well as staging. Combined PET/CT uses a machine that performs a PET scan and CT scan at the same time. This utilizes the best features of PET and CT. Research shows PET may be superior to both CT and MRI for staging mesothelioma. However, the high expense and limited availability of PET limits its widespread use. 

The PET Scan Process

A PET scan is very similar to a CT scan. You will need to put on a hospital gown for the scan and will receive an IV infusion of the radioactive tracer. You will have to wait about an hour to allow time for tumor cells to absorb the tracer.

PET scan process:
  1. You will have an IV infusion of the radioactive tracer an hour before your scan.
  2. You will lie flat on your back on a platform that moves your body into the PET scanner.
  3. The PET tech will communicate instructions to you through a speaker, such as when to briefly hold your breath while your chest is being imaged.
  4. You will need to remain as motionless as possible during the scan.
  5. The scan will take 30 to 90 minutes.

After your scan, the data collected is processed by a computer. Like other scans, it can take several days for a radiologist to carefully analyze the results. PET scans may be read in as little as 24 hours, but it may take several days to get the results. Your doctor can then use the information to help diagnose and stage mesothelioma.

Managing Anxiety About Scans

Many people have anxiety about CT scans, MRIs and PET scans. It is understandable and completely normal. Whether you are concerned about the results of a scan or the process itself, it is completely natural to fear the worst. Some people are also claustrophobic or simply do not like being in small, confined spaces like an MRI scanner.

Understanding what to expect during a scan can help ease anxiety. Ask questions when you see your doctor and when you arrive for your scan. The process may be new to you, but doctors and radiology technicians have a great deal of experience performing scans and helping patients like you feel as safe and comfortable as possible during your scan. If you might have difficulty during a scan, talk to your doctor about prescribing a sedative to keep you calm during the procedure.

Tips that can help you deal with anxiety include:
  • Relax. Practice breathing exercises or mindfulness exercises to calm your mind and body.
  • Stay positive. Don’t focus on the negative aspects of having a scan or the possible results.
  • Talk about your anxiety. If you are nervous, let those around you know what you are going through.
  • Don’t be afraid to ask for help. Your friends, family and doctors can help you find ways to handle your anxiety.

Mesothelioma and other complicated diseases can require multiple imaging scans over the course of weeks to years. Mesothelioma diagnosis, staging and treatment is a long process that can be physically and emotionally exhausting. Maintaining a positive outlook can be difficult, but it can help you deal with stress and anxiety.