Diffusion-weighted MR imaging of bone marrow: differentiation of benign versus pathologic compression fractures.

Objective: To evaluate the usefulness of diffusion-weighted magnetic resonance (MR) imaging of bone marrow for differentiating between benign and pathologic vertebral compression fractures.

Methods: Thirty patients with 39 vertebral compression fractures were examined with MR imaging. Diffusion-weighted MR imaging was performed with a steady-state free precession sequence in 22 acute benign osteoporotic and/or traumatic fractures and 17 pathologic compression fractures. Biplanar radiographs, T1-weighted spin-echo (SE) MR images, and short inversion time inversion-recovery (STIR) MR images were available for all patients. The signal intensity characteristics were analyzed qualitatively and quantitatively (bone marrow contrast ratios and signal-to-noise ratios) for all sequences.

Results: At diffusion-weighted MR imaging, all benign vertebral compression fractures were hypo- to isointense to adjacent normal vertebral bodies. Pathologic compression fractures were hyperintense to normal vertebral bodies. Benign vertebral fractures had negative bone marrow contrast ratios at diffusion-weighted imaging, whereas pathologic vertebral fractures had positive values (P < .001). The difference in bone marrow contrast ratios for benign and pathologic compression fractures at T1-weighted SE and STIR imaging was not significant (P > .01).

Conclusions: Diffusion-weighted MR imaging provided excellent distinction between pathologic and benign vertebral compression fractures.