HIGH-DOSE GD-DTPA-BMA (GADODIAMIDE) FOR D IAGNOSTIC-IMAGING AND THERAPY MONITORING OF MALIGNANT BONE-TUMORS

Purpose: To evaluate the efficacy of high-dose Gd-DTPA-BMA (gadodiamid e, Omniscan) as a contrast for magnetic resonance imaging of malignant bone tumors and the use of high-dose dynamic studies for predicting t he response to preoperative chemotherapy. Materials and methods: Exami nations were performed in 22 patients with suspected malignant bone tu mor on a 1.5 T system. In 8 cases a follow-up examination was done aft er preoperative chemotherapy. Static studies included Pd- and T2-weigh ted spin-echo sequences as well as T1-weighted spin-echo sequences, ob tained pre- and post-contrast. Dynamic studies were performed using a FLASH 2D-gradient-echo sequence (TR 40 ms/TE 10 ms, 90 degrees flip an gle) every 20 s after intravenous bolus injection of Gd-DTPA-BMA (0.3 mmol/kg body weight). MR images were evaluated qualitatively by visual assessment of conspicuity size, extraosseous delineation and structur e of the lesion and quantitatively by measurement of the signal intens ities and calculation of the relative increase in signal intensity. Re sults. Qualitative image analysis showed best demonstration of the les ions on contrast-enhanced T1-weighted images, Comparison of T1-weighte d pre- and postcontrast spin-echo sequences revealed significantly bet ter assessment of tumor structure after administration of contrast med ia. After preoperative chemotherapy, all responders showed a markedly stronger reduction in relative increase in signal intensity in dynamic studies com pared to nonresponders. Conclusion: Gd-DTPA-BMA is effect ive for magnetic resonance imaging of musculoskeletal lesions and impr oves assessment of the tumor structure. Dynamic studies may help to pr edict the response to preoperative chemotherapy.