Focused regional FDG PET/CT detects more osseous metastases than does whole-body PET/CT

A patient with melanoma underwent FDG PET/CT for surveillance of metastatic disease. The whole-body PET/CT scan demonstrated a single FDG-avid lesion in the left ilium, suggestive of an osseous metastasis. Because there was no corresponding CT abnormality, biopsy was planned using PET/CT guidance. The PET/CT for biopsy guidance focused over a single pelvic bed position demonstrated at least 12 FDG-avid osseous metastases, which were not apparent on the original whole-body PET/CT. This case highlights the limitations of whole-body PET/CT in the detection of small metastases and suggests that a PET/CT focused over a specific body region can improve the sensitivity of detecting small metastases.