Value of Gd-DTPA-enhanced MR imaging in assessment of the response to therapy of spinal metastases

This preliminary report evaluates the utility of Gd-DTPA-enhanced-MR imaging in assessing the response to therapy of spinal metastases. Sixteen patients (36 affected vertebral bodies) with metastasis to the spine were evaluated before and after therapy (irradiation, chemotherapy, or hormonal therapy) with Gd-DTPA-enhanced MR imaging (1.5-T, General Electric Signa). Sagittal pre- and postcontrast T1-weighted (600/20) images were obtained. The signal intensities of the lesions and the marrow of the adjacent normal vertebral bodies were measured on pre- and postcontrast T1-weighted images. The enhancement ratios (ERs) ([postcontrast intensity - precontrast intensity]/precontrast intensity) were compared before and after treatment. Prior to therapy, the ER was 40.1 ± 6.9 for metastatic foci and 7.5 ± 4.2 for normal vertebral bodies, for a statistically significant difference. After therapy, patients were divided into two groups: group 1 included 12 responders; group 2, four nonresponders. In group 1, the ER diminished to 8.7 ± 4.1. These patients remain clinically asymptomatic for 2-6 months. The ER was 25.3 ± 8.6 in group 2. There was a statistically significant difference in posttreatment ER between groups 1 and 2. Gd-DTPA-enhanced-MR imaging may be useful in assessing the effectiveness of therapy for spinal metastasis