Radiologic imaging of osteosarcoma: role in planning surgical treatment.

We reviewed radiographic studies of 50 central osteosarcomas to assess their accuracy and contributions to surgical treatment planning. Accurate anatomic delineation was especially important when limb-sparing tumor resection was considered. The plain roentgenograms yielded most of the diagnostic information, and often showed large masses located so that major neurovascular involvement was inevitable. Conventional tomography added little. Computed tomography (CT) usually was accurate in showing tumor extent and relationships to major nerves and vessels. However, CT was less useful when vessels were not seen, when edema and hemorrhage (especially after biopsy) blurred tumor margins, or when tumor margin and soft tissue planes blended together without clear definition. Angiography was essential when vascular relationships were unclear on CT. Scintigraphy occasionally revealed subtle intra-marrow tumor extension, but nonspecific increased uptake beyond the true tumor limits was more common than occult tumor spread.