What is the role of imaging at a myeloma diagnosis? What types of imaging are recommended?

When you're first diagnosed with multiple myeloma, one of the most important steps in addition to the myeloma-specific blood tests is imaging. But why and which scans are used? X-rays, MRIs, PET, CT? What's the difference and what are doctors actually looking for? Today we're diving into the critical role of imaging in multiple myeloma diagnosis. Why it's done, what each type of scan reveals, and how these images help shape your treatment plan from day one. What is the role of imaging at a myeloma diagnosis? Large question because we have a lot of things that imaging can tell us. In the beginning, of course, we want to figure out how much bone disease a patient has. We know that 80 to 90 percent of patients with myeloma develop bone disease at one point. Most of them actually 80 percent have it at first diagnosis already. So imaging shows us where the bone disease happens, where the bone destruction is happening. If there's a risk for fracture, if there's more areas where we have to be concerned, where we have to maybe do surgery, do radiation, do chifroblasty. So that's what's at the beginning. We also know that it's prognostically significant how much a patient has at the first diagnosis, but it's also very important to see what is left after treatment because we know that those areas might be a reason for a relapse where the disease comes back and where we see development of new myeloma. What imaging is recommended at diagnosis by the International Myeloma Working Group Guidelines? In MGUS, we usually say if a patient has a low risk, intermediate risk, MGUS, it does really not make sense to do an imaging that would be an overkill because we, I don't know how many thousand pages, we would find one non-secretory myeloma and usually those patients already have other issues. So it's not really worth the screening. In higher risk, MGUS and smoldering myeloma, we recommend a CT. If CT is positive, then you have a myeloma because you have oscillated lesions. If CT is negative, then we recommend an MRI because it's more sensitive and we would see changes before the actual bone destruction has happened. So that's kind of the sequence there. In symptomatic myeloma, a CT to assess the bone disease is the most important thing and if you have the ability to add a PET, you also get this information on the tumor burden at the same time. So how do we do advanced imaging as we determine bone disease and other sites of myeloma activity in patients? And we're fortunate that we have now some papers that are looking at this, including international guidelines that have looked at the PET scan. But I like to simplify it in the following way. I believe, and I think the community believes at large now, that the metastatic bone survey that is taking individual X-rays of all the different bones is an outdated technique. I think we need to move on from that. So we don't order those anymore. We don't do metastatic bone surveys anymore. They would only detect very large lesions, so they're very insensitive. And there's areas such as in the pelvis where they're going to miss a lot of things. So we don't do them. So there's three types of testing that one can do. MRI, PET scan, and one that we frequently will use nowadays is called the whole body low dose CT. And low dose means low doses of radiation. Now, in my practice, if I see a patient who needs to start on treatment, and it's very evident that they need to start on treatment, I normally will do a whole body low dose CT scan. The reason for that, I just want to make sure there's not an area that may be at risk for pathologic fracture. And it gives us a good baseline so we can use that in the future for monitoring. I do PET scans primarily in patients who have smoldering multiple myeloma, where the smoldering also appears to be advanced. And one does not want to miss the possibility of perhaps a large plasma cytoma somewhere that may not be symptomatic, but that we might want to consider as a possibility for starting treatment or we might find several lesions. And that would tell us by new criteria, which is adapted from the new criteria, that one should consider treatment. So that's how we do PET scans at baseline. Now we do them at follow up too. In my practice, I do them at the day 100, that is three months out for the stem cell transplant. It's been an important prognostic tool for patients with multiple myeloma. And then in selective cases where we have, for instance, a patient who has non-secretory myeloma or a person who has had repeated fractures with bone only disease, there's like multiple plasma cytomas we may want to do a PET scan. The MRI can be used as well too, it's quite useful. It's particularly useful for looking at the spine and looking at the structure of the spinal column and it can tell you about the bone marrow. The MRI is a little bit, it's not as good as the PET or the CT to look at the cortex of the bone, but it can tell you more about the possibility of lesions and within vertebral bodies if you make plasma cytomas. And that's why the MRI has been used now as a criteria for starting treatment. If patients have two or more or more than one, so it's two or more, more than one lesions in the MRI, but for all practical purposes we use the same information for the PET scan. I predominantly use the first two, the PET scan and the whole body. And the reason I don't do the PET when you start myeloma is because you already know you're going to start treatment. So I just want to make sure I have the baseline and that there are no areas at risk for fracture. We know that 90% of myelopatients in their lifetime will end up with bone damages whether it's bacterial B fractures, bone lesions. It also might have already been there even in patients who may be coming to us with anemia, kidney failure and so on. So understanding the extent of bone damage is critical. Myeloma doesn't pick where it wants to be involved, so the kind of imaging we want actually cover head to toes. Older technologies require just x-rays. You probably have heard about the skeletal surveys where you're having 13 pictures that you went through x-rays everywhere in the body. But newer technologies allow us to see early changes and you might see whole body CAT scan, whole body MRI or probably still more commonly used in the US is probably a whole body PET scan. The PET CT use different techniques. CAT scan is a cross-section picture just sliced top of the head down to the toes. It's laid on top of the PET imaging that PET imaging requires us injecting nuclear material, label glucose into the patient's bloodstream and wherever in the body that takes in a lot of glucose will light up as hotspots. When you put them on top of each other, it hopefully tells us does someone started to have those holes in the bones and also are there hotspots, increased activities inside the bone that might be hard to see by other technologies. So this is why the bone imaging is important. It also does tell us about the risk for fracture, which is aiding in some treatment tools as well because vertebral collapse can be treated with bone cement, a procedure called kyphoplasty or verteplasty and that really does improve patient's quality of life and their ability to perform daily activities down the road. We also see too that based on the extent of the bone involvement, there's going to be a discussion about using medications to improve bone health and that will be the group of medicine like salicylic acid or Zomata or Dinosomab or Xjiva and that's why bone imaging is important. Does it matter what type of whole body imaging you get for multiple myeloma, like PET CT versus other types? Or is any whole body scan sufficient? This has so much to do with when the International Myeloma Working Group guideline kind of came together. They wanted to have a guideline that's broadly applicable, globally really. So partly it's also about what's available. PET CT is probably just because of the PET technology. It gives additional information more than just the classic CAT scan. So that's where all of my newly diagnosed patients or people were relapsing. That's the tool that I would get. On the other hand, if you're relying on this test all the time, there is an increased radiation exposure. So whole body low dose CAT scan is used a lot in Europe and started to kind of get picked up here as well. And you'll see that MRI, particularly for the spine, is very, very good because it doesn't just show the activity that relates to myeloma but probably also other causes of back pain, which is, I think, could be targeted, could be treated more appropriately. Imaging plays a critical role in diagnosing and managing multiple myeloma. From detecting bone lesions to guiding treatment decisions, the right imaging at diagnosis can provide valuable insights into disease extent and activity. Whether it's whole body MRI, PET CT, or low dose CT, each has its strengths. So the best choice often depends on your specific situation and what your health care team needs to see. If you're newly diagnosed, don't hesitate to ask your doctor which imaging approach is right for you. Managing your disease clearly is the first step toward personalized effective treatment.