Imaging of Malignant Bone Involvement by Morphologic, Scintigraphic, and Hybrid Modalities*

Detection of accompanying epidural mass by ¹⁸F-FDG PET/CT in patient with lymphoma. Top row, transaxial images; bottom row, sagittal images. From left to right: CT image, ¹⁸F-FDG PET image, and fused image. Tumor is marked by arrows. Based on fusion with CT, increased ¹⁸F-FDG uptake is detected in right aspect of L4 and in accompanying epidural component. Soft-tissue epidural mass appears to displace the thecal sac laterally, on CT.

Multiple myeloma assessment by ¹⁸F-fluoride PET/CT. (A) Maximum-intensity-projection image detecting multiple lesions. (B) From left to right: CT image, ¹⁸F-fluoride PET image, and fused image. Increased uptake is detected in well-defined margins (arrows) of large lytic lesion detected on CT in head of right humerus.

Disease progression of multiple myeloma on ¹⁸F-FDG PET. (A) Two maximum-intensity-projection images 5 mo apart. Baseline study (left) was performed in patient with monoclonal gammopathy of undetermined significance who presented with vertebral plasmocytoma and spinal compression fracture. In addition to increased uptake at known spinal lesion, increased ¹⁸F-FDG uptake was also detected in ribs, which appeared normal on CT data of PET/CT, probably reflecting early malignant involvement in other sites (B). Spinal lesion was treated by radiotherapy. Five months later, numerous new lesions (arrow) were identified on a repeated study, indicative of tumor progression.