Vertebral fractures in multiple myeloma: first results of assessment of fracture risk using dynamic contrast-enhanced magnetic resonance imaging

Abstract.

The objective of this study was to evaluate dynamic contrast-enhanced magnetic resonance imaging (d-MRI) as a prognostic indicator of lumbar vertebral fractures in patients with multiple myeloma. d-MRI of the lumbar spine was performed in ten patients with multiple myeloma. A fast gradient echo sequence (turbo fast low-angle shot, two-dimensional) was used, together with controlled bolus injection of gadolinium diethylenetriaminepentaacetic acid (Gd-DTPA). The maximum increase in signal intensity [amplitude (A), arbitrary units (a.u.)] was assessed for each lumbar vertebra. About half a year later (median: 6.2 months) magnetic resonance imaging was repeated to detect new fractures. Amplitudes of vertebrae which fractured after the initial d-MRI were compared with amplitudes of vertebrae which did not fracture during follow-up. Six of ten patients (7 of 50 lumbar vertebrae) showed new fractures. Five patients fractured one vertebra each, whereas one patient had several vertebrae involved. The initial d-MRI showed significantly higher amplitudes (p<0.0001) in those vertebrae that subsequently fractured (A: 33.1±8.1 vs 16.7±4.2). On retrospective analysis, a cutoff level of 25 a.u. discriminated without overlap between vertebrae that fractured during follow-up and those which did not. The maximum increase in signal intensity (the amplitude) on d-MRI appears to be a prognostic marker capable of predicting vertebral fractures of the lumbar spine in patients with multiple myeloma. d-MRI may therefore be helpful in identifying patients who might benefit from localized radiation therapy or surgical intervention.