Imaging Studies

• X-Rays are the first imaging study done to search for myeloma-caused bone damage.  A full skeletal x-ray survey is needed to demonstrate loss or thinning of bone (osteoporosis or osteopenia), holes in bone (lytic lesions),  and/or fractures.  X-rays are simple to do and are inexpensive.  Their limitations are that 30% or more of the bone must be missing before x-ray can reveal the damage, and that damage to a bone shows up permanently on x-ray, even if there is no longer any active myeloma.
• MRI (Magnetic Resonance Imaging) is a non-invasive study that uses magnetic energy to produce a detailed two- or three-dimensional image of structures inside the body.  It is useful for imaging plasmacytomas (tumors formed from massing of myeloma cells inside or outside the bone marrow); infiltration of the bone marrow by clumps of myeloma; and compression of the spinal cord.  Although it is useful for detecting new disease rapidly, there is a 9-month or more lag time before an MRI will look normal after an area of myeloma has been successfully treated and is no longer active.    It is an expensive study compared to x-ray, takes 30-60 minutes to complete, and covers a limited area of the body. 
• CT or CAT Scan (Computerized Axial Tomography) uses x-ray technology to create a three-dimensional digital image of the body.  It is a much more precise study than x-ray, and can provide clear, detailed images of bone.  Downsides include expense, limited coverage of the body, and the need to use contrast agents that can pose problems for myeloma patients with kidney dysfunction.
• PET Scan (Positron-Emission Tomography) requires that a patient be injected with a sugar-fluorine compound (FDG, or fluoro-deoxyglucose) that is taken up by the body's actively multiplying cells.  When the body is scanned, the areas with the highest concentrations of fluorine "glow," revealing "hot spots" where rapid metabolism can indicate areas of cancer cells.  This scan covers the whole body, is very sensitive in detecting potential tumor activity, and is the only "real-time" imaging study.  It is a valuable tool for patients who do not secrete monoclonal protein and whose myeloma is therefore difficult to assess, and for situations where x-ray, MRI, and CT do not provide enough information about potential new disease.  It is, however, expensive and time-consuming, requiring 90-150 minutes to perform.
• PET/CT combines PET and CT scans in one imaging study, providing information both about past damage and current cancer activity, thus enabling the doctor to study changes over time.  It is a highly accurate study, but like standard PET, it is expensive and time-consuming.