Comparison of whole-body MR imaging and conventional X-ray examination in patients with multiple myeloma and implications for therapy.

Skeletal X-ray survey is the established method of diagnosis in patients with multiple myeloma; however, whole-body magnetic resonance imaging (wb-MRI) has become an important additional tool. The aim of this study was to compare the different patterns of infiltration on conventional X-ray examinations (X-ray survey) with findings from wb-MRI to subsequently determine the influence of wb-MRI on therapy changes. In 60 patients with a mean age of 65.1 +/- 11.7 years, wb-MRI examinations were correlated with a recent X-ray survey. The results were independently assessed by two radiologists and the patterns of infiltration were described in both modalities. Subsequently, the disease was staged according to Salmon and Durie and Salmon and Durie PLUS. Additionally, the influence of MRI on potential changes in therapy was assessed using a three-range Likert-type scale. In all, 480 skeletal regions were compared. In 183 skeletal regions, an increased degree of infiltration was identified on wb-MRI. Significant differences (p < 0.05) between the modalities could be found in the thorax, spine, pelvis, and both lower extremities. Based on wb-MRI, tumor stage was upgraded in 19 of the 60 patients using the Durie and Salmon PLUS classification. In ten out of these 19 patients (42%), the wb-MRI result was essential for making the decision to initiate further therapy due to the degree of infiltration, extramedullary tumor extension, and/or further risk of fracture. Whole-body MRI provides a more detailed assessment of the pattern of bone marrow infiltration and strongly influences therapeutic strategies.