Thallium-201 SPECT in Differentiating Bone Infarction From Metastatic Lesions in Osteosarcoma

The authors present a case of bone infarction in the proximal epiphysis of the right tibia, which was caused by preoperative intraarterial chemotherapy for osteosarcoma. MR imaging revealed that suspected metastases had inhomogeneous signal intensity similar to that of the primary tumor, which made a metastatic lesion difficult to exclude. On Tl-201 SPECT, no accumulation was found in the lesions, confirming that they were not osseous metastases. Consequently, this enabled limb salvage surgery to be performed with joint preservation. Intraoperative biopsy revealed no viable tumor cells in the lesion, and bone infarction was suspected. Tl-201 SPECT was very useful, not only in differentiating bone infarction from tumor progression, including metastatic lesions, but also in the determination of the operative technique.