by ecancer reporter Vanessa Lane

Biomedical imaging techniques such as 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (FDG-PET/CT), skeletal survey, bone scintigraphy and magnetic resonance imaging (MRI) are routinely used for staging and post-treatment follow up in multiple myeloma (MM) patients. Imaging not only plays an important role in the diagnosis and management of MM, but also in the prediction of clinical outcomes.

Imaging is particularly important in discriminating MM from its precursor states such as smouldering MM and monoclonal gammopathy of undetermined significance (MGUS). Radiographic skeletal survey can detect osteolytic lesions only after 30%–50% cortical bone destruction, limiting its sensitivity for imaging early stage myeloma bone lesions.

MRI and FDG-PET/CT are comparatively better at detecting bone marrow plasma cell infiltration than conventional radiographs, and both can help to predict outcomes at diagnosis in symptomatic disease, as well as during the early phases of treatment and at the end of treatment. PET/CT can also predict risk of progression in patients achieving conventionally defined complete responses.

MRI has limitations such as prolonged acquisition time, limiting patient factors such as claustrophobia or metal devices in the body and its limitation in providing reliable images for skull, clavicle or ribs.

FDG-PET/CT also has limitations. It is not a cancer-specific agent. This has led to the investigation and development of other radiolabelled pharmaceuticals more specific to MM, including the amino acid based radiolabelled tracer, 11C-labelled methionine (MET). Preliminary data suggest that MET-PET can identify more viable lesions in patients with plasma cell malignancies (which include MM) than 18F-FDG. With further study, this imaging technique may enable improvements in future therapeutic decision making in the management of MM.