Differentiation of benign versus metastatic vertebral body compression fractures

Summary

Six patients with benign fractures showed a sharply demarcated vertical band of preserved bone marrow along the dorsal one-third of the compressed vertebral body, while the anterior two-thirds showed decreased signal intensity (SI) with a T1-weighted sequence. This “posterior band sign” seen in benign, and not seen in metastatic, fractures correlates well with the biochemical theory of the “three column spine”. The latter defines compression fracture by an intact “middle column” which includes the dorsal one-third of the vertebral body, posterior annulus fibrosus, and posterior longitudinal ligament. Metastatic fractures showed either complete or irregular bone marrow replacement of multiple vertebral bodies and of posterior elements. Other benign patterns included a horizontal band of low SI adjacent to the superior or inferior vertebral endplate, isointense or increased SI of the vertebral body in images with a T1-weighted sequence. Two fractures were indeterminate.