Imaging studies

Bone disease is a common symptom of multiple myeloma: 70%–80% of patients are found to have bone disease at diagnosis. Imaging studies that assess the status of a patient's bones and/or bone marrow at diagnosis and relapse are:

• X-rays 
• CT scans
• MRI studies
• PET scans
• PET/CT scans

You can learn more about each of these imaging studies below:

X-rays

X-rays are the oldest and least sensitive method to detect myeloma-caused bone damage. A full skeletal X-ray survey can show

• loss or thinning of bone (osteoporosis or osteopenia)
• holes in bone (lytic lesions), and/or 
• fractures

X-rays are simple and quick procedures. Insurance covers most X-rays. While they are widely available, other imaging studies often are more precise than X-rays. 

X-rays can detect bone damage only after 30% or more of the hard outer bone has been destroyed. Moreover, X-rays cannot distinguish between old bone damage where myeloma is no longer active and sites of active disease
 

MRI (Magnetic Resonance Imaging)

Magnetic resonance imaging (MRI) is a non-invasive way to produce a detailed two- or three-dimensional image of structures inside the body.

The Positive Aspects of MRIs 

MRIs are able to

• take images of the spine, pelvis, back, hips, and chest
• detect focal lesions (early abnormal areas in the bone) in patients with smoldering myeloma
• obtain images of plasmacytomas as well as spinal cord compression 
• rapidly detect new disease

The Negative Aspects of MRIS

• MRIs pose at least a nine-month lag before these scans will look normal after an area of myeloma has been successfully treated and is no longer active.
• Patients who have metal implants may not be able to have MRIs.

Whole-body MRIs

Whole-body MRIs may provide more precise results for patients with MGUS, SMM, and myeloma. Availability, cost, and standardization of this technique remain areas of concern.

The Use of Contrast Agent Gadolinium

Before scheduling an MRI, discuss the use of contrast agent gadolinium with your oncologist. In December 2017, the Food and Drug Administration (FDA) required "a new class warning and other safety measures for all gadolinium-based contrast agents (GBCAs) for magnetic resonance imaging (MRI) concerning gadolinium remaining in patients’ bodies, including the brain, for months to years after receiving these drugs," according the FDA's website.

Gadolinium contrast is a particular problem for myeloma patients with kidney involvement. It should be possible to perform an MRI without gadolinium contrast to assess myeloma bone disease.

CT or CAT Scan (Computerized Axial Tomography)

Whole-body low-dose computed tomography (WBLDCT) is the new standard for evaluating myeloma bone disease. Computerized axial tomography (CT or CAT) scan uses X-ray technology to create a three-dimensional digital image of the body that is more precise than X-ray. Also, a CT scan can provide clear, detailed images of bone lesions.

PET Scans

Positron emission tomography (PET) requires that a patient be injected with fluoro-deoxyglucose (FDG), a sugar-fluorine compound that is taken up by the body's actively multiplying cells. The areas with the highest concentrations of fluorine glow. These areas can indicate actively growing cancer cells.

PET scans are valuable when

• standard blood and urine tests do not provide enough information about potential disease activity, and a patient has non-secretory myeloma (myeloma cells that secrete no monoclonal protein)
• a patient has non-secretory myeloma (myeloma cells that secrete no monoclonal protein)

PET scans

• cover the whole body
• are sensitive in detecting potential tumor activity
• are the only "real-time" imaging study
• detect early changes in the bone marrow before there is destruction of bone
• allow an assessment of disease status without the need for a bone marrow biopsy
• are the only imaging study that detect extramedullary disease, which is myeloma that grows outside the bone marrow

The International Myeloma Working Group's (IMWG's) consensus statement on assessment of response to treatment includes PET scanning. The IMWG states that PET scans are required, along with either Next-Generation Flow (NGF) or Next-Generation DNA Sequencing (NGS)—both of which analyze tissue from the bone marrow—to assess minimal residual disease (MRD). Only PET scans are able to detect areas where myeloma is growing both outside and inside the bone marrow.

PET/CT Scans

PET/CT combines PET and CT scans in sequential studies, allowing the radiologist to perform a CT scan of areas that light up on PET.

The Positive Aspects of PET/CT Scans

• Doctors can monitor a patient's changes over time because these scans provide information about past damage and current cancer activity.
• They are highly accurate for diagnosis, therapy assessment, and prognosis of myeloma.

The Negative Aspects of PET/CT Scans

They may be expensive and time-consuming.

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