Whole-body MRI versus whole-body MDCT for staging of multiple myeloma

OBJECTIVE. The purpose of our study was to compare the detection rate of bone manifestations of multiple myeloma in whole-body MRI compared with MDCT and to assess accuracy in staging. SUBJECTS and METHODS. Forty-one patients with histologically confirmed myeloma were prospectively examined with a whole-body MDCT protocol and whole-body MRI on a 1.5-T system. The MRI protocol consisted of T1-weighted spin-echo and STIR sequences. For data analysis, the entire skeleton was divided into 61 regions per patient. Image evaluation was performed in a consensus reading by two radiologists blinded to the patients' history, with separate evaluation of each technique. The patients were staged by MRI and MDCT data separately according to the Durie and Salmon PLUS staging system. RESULTS. On MRI, 15 patients showed no involvement. In 26 patients, 975 regions were affected: 21 patients were stage I, two were stage II, and 18 were stage III. On MDCT, 19 patients showed no involvement. In 22 patients, 462 regions were affected. For the detection rate, MRI was statistically superior to MDCT (p < 0.001, Wilcoxon's signed rank test). According to MDCT, 25 patients were stage I, seven were stage II, and nine were stage III. In 21 patients with involvement detected on both methods, MRI showed more extensive disease than MDCT. Eleven patients were understaged with MDCT compared with MRI, which was statistically significant (p < 0.001, chi-square test). CONCLUSION. Whole-body MDCT leads to a significantly lower detection rate and staging in patients with multiple myeloma.