FDG PET/CT and MRI in multiple myeloma patients: preliminary results of the IMAJEM study

Objectives The goal of the IMAJEM study (NCT01309334, supported by STIC grant of the French NCI) was to compare prospectively MRI and PET-CT at diagnosis, after 3 cycles of induction therapy and prior to maintenance therapy in a group of patients enrolled into IFM-DFCI 2009 trial comparing frontline or delayed ASCT. Results of the initial evaluation are presented here.

Methods 134 of the 700 patients included in the IFM-DFCI 2009 trial underwent spine and pelvic MRI and whole-body FDG-PET/CT at diagnosis. Images were reviewed blindly by an independent committee.

Results At diagnosis, MRI was positive in 127/134 (94.7%), and PET-CT in 122/134 (91%) patients, respectively (McNemar test = 0.94, p-value = 0.33). MRI patterns of marrow involvement were the following: (1) normal in 7 cases (5%); (2) focal lesions (FL) in 46 cases (34%); (3) homogeneous diffuse infiltration in 41 cases (31%); (4) combined diffuse infiltration and FL in 35 cases (26%); (5) variegated or "salt-and-pepper" pattern with inhomogeneous bone marrow in 5 cases (4%). PET-CT patterns were the following: (1) normal in 12 cases (9%); (2) FL in 44 cases (33%); (3) diffuse infiltration in 12 cases (9%); (4) combined diffuse infiltration and FL in 66 cases (49%); (5) extramedullary disease in 10 cases (7.5%). The median number of FL assessed by PET-CT was 3 (0 to >10) with a median SUVmax of 4.1 (range 1.5-28.4).

Conclusions MRI of the spine and pelvis and whole-body PET-CT are equally effective to detect bone involvement in symptomatic patients at diagnosis.