FDG-PET in the Staging Work-Up of Patients with Suspected Intracranial Metastatic Tumors

OBJECTIVE: To evaluate the role of positron emission tomography with 2-[18F] fluoro-2-deoxy-D-glucose (FDG-PET) in 31 patients with evidence of intracranial metastatic disease. MATERIALS AND METHODS: PET was used to evaluate the intracranial lesions for glucose hypermetabolism to suggest malignancy, mutiplicity of intracranial lesions, and extracranial foci or sources of disease. Patients with proven malignant intracranial lesions subsequently underwent further corroborative radiologic tests and histologic examination to confirm staging and primary location. RESULTS: PET identified focal hypermetabolic abnormalities in 19 of 22 intracranial metastases, 2 hypometabolic lesions, and 1 renal cell tumor embolism that hemorrhaged (hypometabolic lesion). It also identified 82% of extracranial primary tumor sites, of which 55% were found only on PET and not on conventional diagnostic tests. CONCLUSION: FDG-PET may prove valuable in the initial work-up of patients with suspected intracranial metastases.