Ask The Nurse // 5th November 2020
Myeloma patients have several different tests to both confirm their diagnosis and as part of their on-going care. The type and number of tests and investigations carried out will differ between patients. This is because tests are requested in relation to the stage of your myeloma and any complications you may have, so it can be difficult to know which tests you should expect and when. One type of test we often get asked about on the Myeloma Infoline and Ask the Nurse email service is imaging tests. Patients, their friends and family ask us why there are different imaging tests or how often they should receive them.
So, in this month’s blog, we answer some of the questions you ask us about imaging tests.
Why are there different types of imaging tests and what are they called?
Anyone diagnosed with or suspected of having myeloma may have several imaging tests or scans. Although they all take pictures of the inside of your body, they work differently and provide different information for your healthcare team.
X-rays use a small dose of radiation to take pictures of the inside of your body. A series of X-rays is called a skeletal survey. They are widely available, quick and an effective way of looking at bones to see if there are any fractures or bone damage. However, they are less sensitive than MRI or CT scans and may not detect bone damage caused by myeloma (lytic lesions) when the damage is less than 30%.
Magnetic resonance imaging (MRI) scans uses a combination of radio waves, a powerful magnetic field and a computer to generate pictures of the inside of your body. They are more sensitive than X-rays. They provide an in-depth picture of how the myeloma is affecting the bones, and where it is occurring throughout the bone marrow.
Computerised tomography (CT) scans use X-rays and a specialised computer to take pictures of the inside of your body. CT scans are quicker to perform and more sensitive than standard X-rays. Because they are more detailed, smaller and more difficult areas or bone damage can be seen.
Positron emission tomography (PET) scans use a radioactive substance called a tracer and a special camera to the take 3D pictures of the inside of your body. The tracer is given as an injection. Once in the body, the tracer is soaked up by myeloma cells. The camera can then produce an image that shows the locations of myeloma cells. In myeloma, PET scans are usually combined with CT scans (called PET/CT scans). PET scans can also be combined with MRI scans (PET-MRI scans). These combined scans help to provide a more detailed picture of a patient’s myeloma.
When should I get imaging tests?
Imaging tests are not routinely used to monitor myeloma. Typically, imaging tests like X-rays, MRI and CT-scans are carried out at diagnosis, sometimes when there are signs of your myeloma getting worse (relapse) or as part of a clinical trial.
Therefore, following diagnosis, an imaging test would only be given when there is a change in your symptoms or test results. For example, imaging tests may be given when there has been a steady increase in paraproteins or light chains, or if you are experiencing new or worsening pain.
I only had a skeletal survey (X-ray) at diagnosis, should I ask for an MRI or CT scan?
Although MRI and CT scans are more sensitive and are the recommended imaging tests for diagnosing myeloma, many patients still get a skeletal survey. This is because scanners aren’t available in every hospital and there may be longer waiting times for MRI or CT scanners.
If your myeloma was clearly visible in the skeletal survey and there are no signs of spinal damage your healthcare team may decide an MRI or CT scan is not needed.
However, if you only received a skeletal survey for suspected myeloma or as part of your monoclonal gammopathy of undetermined significance (MGUS) or smouldering myeloma diagnosis you may want to speak to your healthcare about receiving an MRI or CT scan.
Are X-rays and CT-scans safe?
X-rays and CT-scans are generally quick, painless and safe. Nevertheless, some people will be concerned about being exposed to radiation during an X-ray or CT-scan.
The amount of radiation you are exposed to during your scan is low. The level will vary depending on how much of your body is scanned.
Although being exposed to radiation does carry a risk of causing cancer many years or decades later, the risk is thought to be very small.
For more information about tests and investigations, you can read the Myeloma UK “Tests and investigations in myeloma Infoguide”, which is available to download from the Myeloma UK website.
If you have any questions about imaging tests, you can get in touch with us through the Infoline (0800 980 3332 (UK) or 1800 937 773 (Ireland)) or the Ask The Nurse email service.