Pheochromocytomas: Imaging with 2-[fluorine-18] fluoro-2-deoxy-D-glucose PET

PURPOSE: To assess the sensitivity of positron emission tomography (PET) wi th 2-[fluorine-18]fluoro-2-deoxy-D-glucose (FDG) in pheochromocytomas and, secondarily, to compare images obtained with FDG PET to those obtained with metaiodobenzylguanidine (MIBG) scintigraphy. MATERIALS AND METHODS: Twenty-nine patients with one or more known or subse quently proved pheochromocytomas underwent FDG PET (35 scans) and MIBG scin tigraphy (35 scans). Tumor uptake of FDG was quantified on positive PET sca ns. RESULTS: Tumor uptake of FDG was detected in 22 of 29 patients. Most benign (seven of 12 patients) and most malignant (15 of 17 patients) pheochromocy tomas and their metastases avidly concentrated FDG. In four patients whose pheochromocytomas failed to accumulate MIBG, uptake of FDG in the tumors wa s intense. For the majority of the 16 patients whose tumors concentrated bo th agents, however, ratings for MIBG images compared to FDG PET images for delineation of the tumor in comparison to background and normal organ accum ulation were superior for nine patients (56%) and as good or better for 14 (88%). CONCLUSION: Most pheochromocytomas accumulate FDG. Uptake is found in a gre ater percentage of malignant than benign pheochromocytomas. FDG PET is espe cially useful in defining the distribution of those pheochromocytomas that fail to concentrate MIBG.