PRIMARY BONE-TUMORS - VALUE OF MR-ANGIOGRAPHY FOR PREOPERATIVE PLANNING AND MONITORING RESPONSE TO CHEMOTHERAPY

OBJECTIVE. The purposes of our study were to investigate the use of MR angiography with two- (2D) and three-dimensional (3D) displays in eva luating vascular morphology of musculoskeletal neoplasms for preoperat ive planning of limb-salvage surgery and to assess the use of MR angio graphy for monitoring changes in neovascularity and evaluating respons e to chemotherapy. SUBJECTS AND METHODS. We used MR angiography (2D ti me-of-flight) to study 13 patients with primary bone tumors (nine oste ogenic sarcomas, two Ewing's sarcomas, and two primary lymphomas of bo ne) at the time of initial presentation. Eight patients (all of whom h ad osteogenic sarcoma) also underwent MR angiography following chemoth erapy before limb-salvage surgery. Two-dimensional maximum intensity p rojections were obtained. Three-dimensional reconstructions of vascula r structures were created from the angiographic source images and were displayed simultaneously with 3D reconstructions of tumor and normal bone generated from conventional MR images. RESULTS. Two-dimensional m aximum intensity projections were useful for evaluating small Vessel n eovascularity; 3D displays demonstrated spatial relationships of tumor , feeder vessels, and normal vascular structures. Tumor encroachment o nto or encasement of normal vascular structures was shown in four pati ents on 2D maximum intensity projections and on 3D displays. The eight patients with osteogenic sarcoma who had follow-up imaging showed mar ked neovascularity prior to chemotherapy. Five patients responded to c hemotherapy (greater than or equal to 90% tumor necrosis at histology) ; MR angiography showed marked reduction in tumor neovascularity in th ese patients, Three patients did not respond to chemotherapy; MR angio graphy showed unchanged neovascularity in one and increased neovascula rity in two of these patients. CONCLUSION. MR angiography provides goo d visualization of peripheral vascular branches and tumor neovasculari ty in patients with primary bone tumors. MR angiography demonstrates e ncroachment onto and encasement of major vessels by the tumor mass and appears to be useful for assessing response to chemotherapy in osteog enic sarcoma and possibly other primary bone tumors by detecting treat ment-induced changes in tumor neovascularity.