[MRI diagnosis of vertebral metastasis]

To study MRI changes of vertebral metastasis and their value in differential diagnosis.

MR films of 103 patients with vertebral metastasis confirmed clinically or pathologically were reviewed with all features recorded and analyzed.

338 vertebrae were involved in 103 patients, including 82 in vertebral body only, 3 in appendix only and 253 in both. According to the shape of vertebral body and the characteristic abnormality, 335 vertebrae with body involved were divided into 4 types: Type I (97) with one single focus in the vertebral body, type II (102) with multiple foci with clear margin in the vertebral body, type III (16) with abnormal signal in the whole vertebral body and type IV (120) with abnormal signal in the whole or most part of vertebral body complicated with compression fracture. Among all these lesions, 114 showed concave superior and/or inferior edges and 116 protruding posterior and/or anterior borders. In 256 vertebrae with abnormal appendix, 238 showed abnormal pedicle of vertebral arch involving neighbouring part of vertebral body and 235 showed enlarged pedicle and other parts of the appendix. Soft tissue mass was showed around 133 vertebrae, with the center at the involved vertebrae on sagittal image. 130 pieces of these masses extended cranio-caudally within or a little beyond the width of a vertebral body.

Vertebral metastasis is characterized by involving multiple vertebrae. Its diagnosis and differential diagnosis can be made definite in most patients according to the lesions distribution, change in vertebral shape and the characteristics of the soft tissue mass.