[MRI in osteoporotic and metastatic vertebral compressions: apropos of 60 cases]

Magnetic resonance imaging (MRI) was performed in 60 patients with vertebral compression fractures caused by either bone metastasis (BM) or osteoporosis (OP). In the BM group (20 patients, 62 BM with 22 compression fractures), the signal was decreased on T1-weighted images in all cases and was usually increased on T2 sequences, in the whole vertebral body or in patchy areas. The vertebral body showed a diffuse posterior bulging in 85% of patients; malignant infiltration often involved pedicles, posterior arch or soft tissues. In the OP group (40 patients, 160 vertebral fractures): a significant recession of one of the corners of the vertebral body, different from metastatic bulging, was observed in 37% of patients; the spinal cord signal depended on the stage: during the first 4 months, the signal was low on T1 and high on T2 sequences, with a characteristic band disposition, which may involve most of the vertebral body even in mild fractures; the modifications extended to the pedicles in 5 cases; after 6 months, the signal was normal. MRI specificity was 92% between malignant versus benign compression fractures. MRI had a better sensitivity than bone scan for depicting vertebral BM. In OP, MRI signal modifications disappeared several months before increased uptake of technetium. This study emphasizes the value of MRI for the diagnosis of osteoporotic versus metastatic vertebral compression fractures when morphological and chronological parameters are added to the signal intensity analysis.