Imaging modality	Purpose	Study findings at presentation	Changes consistent with good response to induction chemotherapy
Plain-film radiography	Differential diagnosis Estimate effects of chemotherapy Detect pulmonary metastasis	Most commonly, mixed Chest nodules or “cannonball”lesions	Increased ossification Periosteal thickening and new bone formation Increased sclerosis of tumor border Decreased size of soft tissue mass
MRI	Determine extent of tumor Detect soft tissue mass or skip lesion Determine relationship of tumor to neurovascular bundle	Length of bone affected Size of soft tissue mass No findings specifically characteristic of osteosarcoma	Not accurate; however, the MRI study may show a thick, dark rim around the tumor, which is consistent with periosteal new bone formation.
CT of affected extremity	Determine extent of tumor, especially in the presence of excessive tumoral edema Visualize vessels (using contrast medium)	Mixed sclerotic and lytic lesion	Increased ossification Rim of calcification surrounding tumor Reduction in size of soft tissue mass
CT of chest	Detect pulmonary metastasis	Small nodules or large cannonball lesions (late stage)	Increased ossification Decrease in size or disappearance of tumor nodules
Bone scintigraphy	Determine sites of bone metastasis Detect intraosseous extension	Increased bony uptake	Not accurate; new bone formation may yield increased uptake. Flow study shows decreased vascularity.
Thallium scintigraphy	Monitor effects of chemotherapy Detect local recurrence of tumor	Increased uptake in tumor	Complete disappearance in uptake
Angiography	Determine vascularity of tumor Detect vascular displacement and determine relationship of vessels to the tumor Identify vascular anomalies Estimate effects of chemotherapy	Neovascularization Tumor blush Vascular anomalies	Complete disappearance of neovascularity and tumor blush