What imaging is done at diagnosis to detect myeloma bone disease?

What imaging is done at diagnosis to detect myeloma bone disease?

It's been known for many, many years that myeloma cells seem to stimulate normal bone cells, called osteoclasts, to break down bone.

In a healthy individual, your bone is constantly being renewed by cells that destroy and rebuild it to keep your bones healthy and strong. Osteoclasts break down the bone and are followed by bone-forming cells called osteoblasts.

However, in myeloma, osteoclasts are stimulated to break down more than they should. Now, we don't really understand why this happens, but we know that this is again a very common feature.

Therefore, years ago, the concept of doing what's called a bone survey was introduced. That means basically taking X-rays of the skull, ribs, arm bones, and leg bones, usually not the hands or feet, which would help in a search for bone loss or literally holes in the bone that can be seen with multiple myeloma.

So many years ago, the bone survey, or skeletal survey, was incorporated as part of a way to see if somebody had myeloma or not. We still do that test, and part of the reason we are interested in looking at the skull is because there is a very large expanse of bone that you can examine. If you are looking for holes, they are relatively easier to see in that situation.

It doesn't mean that there is anything in the brain or anything like that. I think it's very scary for people sometimes to think about, but it's just a good place to look for those bone changes.

However, most people believe that those bone surveys can be insensitive and may miss actual bone disease caused by myeloma. More and more, we're doing what's called advanced imaging, which means a test other than a bone survey or in addition to a bone survey to look for bone problems.

Some of the most common advanced imaging techniques include magnetic resonance imaging (MRI) of the pelvis and spine. These areas are chosen because they contain a lot of marrow in the body, and between them, you're talking about almost 80% of bone marrow in an adult.

You do these tests looking for lytic lesions, which are the holes in the bone that can occur with myeloma. You're also looking for changes in the bone marrow that might signal that a person meets the definition of myeloma.

I mentioned that nowadays we use the greater than 100 kappa lambda ratio to define myeloma, along with that 60% plasma cells. If on an MRI, a person has more than one deposit that looks like myeloma, we would say that person has myeloma with some of those other lab test findings.

Other tests that can be done include a low dose whole body CAT scan (CT scan). This gives you a nice picture of the skeleton with a fairly low amount of radiation and is available in some centers, although not all.

You can also consider doing a positron emission tomography scan (PET scan). A PET scan measures a couple of different things, including metabolic activity in various places in the body. In myeloma, you're looking for areas that have increased metabolic activity over normal, primarily in bones.

You're also looking for asymmetry, as that can signal that somebody has myeloma, meaning there aren't symmetrical changes in the bones on one side compared to the other. A CAT scan is included in this process, allowing you to look for actual lytic lesions as well.

One feature that people like about PET scans is that if a person has what's called extramedullary myeloma (a deposit of myeloma outside of the bone), that kind of scan can pick it up.

There have been some studies looking at the utility of MRI and PET scans in people who are recently diagnosed with myeloma. While they are not perfectly accurate, they pick up abnormalities around 95% of the time. These studies are increasingly offered to patients to establish a diagnosis of myeloma.

A PET scan can also be done after a certain treatment is delivered, sometimes to check how well that treatment is working. Some studies suggest that improvement in a PET scan or normalization of a PET scan can be associated with better myeloma control.