Role of SPECT in differentiating malignant from benign lesions in the lower thoracic and lumbar vertebrae.

The authors categorized 125 spinal lesions in cancer patients and 127 lesions in patients with back pain according to their location in the vertebra on single photon emission computed tomographic (SPECT) images. Forty-four lesions were metastases, all in patients with known malignancy. Lesions in the apophyseal joints were all benign. Lesions manifesting as abnormal uptake projecting beyond the vertebral body surface were osteophytes. Thirty-seven percent of the lesions detected in cancer patients were categorized in either of these two benign categories. Lesions showing focal or diffuse uptake in the body were usually benign (96% and 87%, respectively). Lesions showing uptake in the body and pedicle were usually metastases (83%). When abnormal uptake was seen in both the body and posterior elements but with an intervening normal pedicle, benign disease was the most common cause (93%). It was concluded that the location of lesions on tomographic images provides useful information for differentiation between malignant and benign lesions in the vertebrae.