ABSTRACT
PURPOSE: In multiple myeloma, skeletal radiographs are still regarded as the reference imaging examination because they help to establish the stage of the disease according to the Durie-Salmon Staging System. Whole-body MRI using T1 and STIR sequences increases the detection of myeloma lesions. MRI-measured diffusion has demonstrated high sensitivity in terms of detection in oncology. The main objective of this study is to compare conventional radiographic staging with an MRI whole-body diffusion technique (called DWIBS) in detecting bone lesion monoclonal plasma cell pathologies (multiple myeloma, plasma cell leukaemia, plasmacytoma and MGUS). MATERIALS AND METHODS: Twenty-seven patients were included (multiple myeloma: 24; plasma cell leukaemia, MGUS and plasmacytoma: 1 each). All of them had a whole-body MRI diffusion examination (using a DWIBS sequence). Diffusion MRI and conventional radiographs were compared according to the Durie-Salmon Staging System. In case of doubtful lesions, 12 months of monitoring was used as the reference method for the definitive diagnosis. RESULTS: The overall concordance rate between the two techniques was 63%. The DWIBS sequence detected a higher number of lesions leading to a higher Durie-Salmon stage in 37% of the patients: one stage I to II, seven stage I to III, and two stage II to III. In 18.5% of the patients, the MRI was positive while the radiographs were normal and these discrepancies were most often located in sites poorly explored by X-ray (spine, pelvis and ribs). In one patient (4%), the MRI provided a stage lower than that of the X-rays (stage II vs. III). In this case, the X-rays were positive at the humerus and femur, unlike the DWIBS sequence. Our per site analysis confirmed the clear superiority of the DWIBS sequence when compared with X-rays in the exploration of the cervical spine (56 vs. 0%, P<0.001), dorsal spine (81vs. 31%,P<0.0002), lumbar spine (70 vs. 35%, P<0.0124), pelvis (81 vs. 33%, P<0.0005) and ribs (74 vs. 36%, P<0.0009). CONCLUSION: The DWIBS MRI leads to an increase in the final Durie-Salmon stage. Although its place in the preoperative treatment of multiple myeloma still has to be assessed, this study suggests its potential interest.
