Vertebral compression fractures in multiple myeloma. Part II. Assessment of fracture risk with MR imaging of spinal bone marrow.

PURPOSE: To determine the utility of bone marrow magnetic resonance (MR) imaging in the assessment of risk of vertebral compression fractures in patients with multiple myeloma. MATERIALS AND METHODS: In 50 patients with stage III multiple myeloma, 280 MR examinations of the thoracolumbar spine obtained at diagnosis and during treatment (mean follow-up, 28 months) were analyzed to determine MR patterns of bone marrow involvement before treatment and the occurrence of vertebral compression fracture at follow-up. Four MR patterns of marrow involvement were determined: A, normal marrow appearance; B, fewer than 10 focal lesions; C, more than 10 focal lesions; and D, diffuse infiltration. Fracture-free survival was compared according to these patterns. RESULTS: During follow-up, 131 vertebral compression fractures appeared in 37 patients. Patients with pattern A (n = 10) or B (n = 16) had significantly longer fracture-free survival before occurrence of the first, second, and third fractures than those with pattern C or D (P < 10(-5)). Relative risks of first, second, and third fracture occurrence for patients with pattern C or D compared with those with pattern A or B were 6.2, 9.1, and 11.0, respectively. CONCLUSION: Determination of MR patterns of spinal bone marrow involvement is a potential relevant factor to predict the risk of vertebral fractures in patients with stage III multiple myeloma.