Evaluation of PET/MR and PET/CT Imaging for Bone Marrow Lesions

Developing an MRI protocol at 1.5 T allowing quantification of the hematopoietic, fatty and trabecular moieties of marrow. An ideal protocol would differentiate red marrow from neoplastic cellular infiltration, and detect loss of trabecular bone. This study assesses the feasibility of a multiple gradient echo sequence for differentiation of water and fat constituents of marrow, combined with T2* mapping to interrogate the trabecular component The investigators hypothesize that these techniques will allow better identification of lesion type than routine MR sequences, and can be used to quantitatively characterize myelomatous marrow replacement, with iliac crest biopsy (which is routinely performed in the diagnosis of myeloma) as gold standard.

Fluoro-deoxyglucose (FDG)/PET CT imaging can detect FDG uptake in active myeloma and is obtained routinely for certain cohorts of patients with myeloma. PET/CT is commonly used in both initial whole body assessment and in monitoring remission. PET has been found to be about 59% sensitive and 75% specific for detection of myeloma .

Myelomatous lesions are detected on MRI by the replacement of marrow fat. Routine MRI however is limited by scope/field of view, usually evaluating marrow in a single anatomic region (such as an extremity, the pelvis or spine). To assess the diffuse marrow involvement in MM, whole body MRI imaging potentiates near global assessment of the marrow, which aids in evaluating tumor burden, and may be useful in staging.