staticnrg Posted October 3, 2007 Report Share Posted October 3, 2007 Pheochromocytoma and Extraadrenal Abdominal Paraganglioma Henri J.L.M. Timmers1,2, Mohiuddin Hadi3, Jorge A. Carrasquillo3, Clara C. Chen3, Lucia Martiniova1, Millie Whatley3, Alexander Ling4, Graeme Eisenhofer5, Karen T. Adams1 and Karel Pacak1 1 Reproductive Biology and Medicine Branch, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland; 2 Department of Endocrinology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands; 3 Nuclear Medicine Department, Warren G. Magnuson Clinical Center, National Institutes of Health, Bethesda, Maryland; 4 Department of Diagnostic Radiology, Warren G. Magnuson Clinical Center, National Institutes of Health, Bethesda, Maryland; and 5 Clinical Neurocardiology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland Correspondence: For correspondence or reprints contact: Karel Pacak, MD, PhD, DSc, Reproductive Biology and Medicine Branch, National Institute of Child Health and Human Development, 10 Center Dr., Bldg. 10, CRC, RM 1-E 3140, MSC 1109, Bethesda, MD 20892-1109. E-mail: email@example.com 6-18 F-fluoro-L-3,4-dihydroxyphenylalanine (18F-DOPA) PET isa useful tool for the detection of certain neuroendocrine tumors,especially with the preadministration of carbidopa, an inhibitorof DOPA decarboxylase. Whether carbidopa also improves 18F-DOPAPET of adrenal pheochromocytomas and extraadrenal paragangliomasis unknown. The aim of this study was to investigate the sensitivityof 18F-DOPA PET in the detection of paraganglioma and its metastaticlesions and to evaluate whether tracer uptake by the tumorsis enhanced by carbidopa. Methods: Two patients with nonmetastaticadrenal pheochromocytoma, and 9 patients with extraadrenal abdominalparaganglioma (1 nonmetastatic, 8 metastatic), underwent whole-bodyCT, MRI, baseline 18F-DOPA PET, and 18F-DOPA PET with oral preadministrationof 200 mg of carbidopa. The dynamics of tracer uptake by theselesions and the physiologic distribution of 18F-DOPA in normaltissues were recorded. Results: Seventy-eight lesions were detectedby CT or MRI, 54 by baseline 18F-DOPA PET (P = 0.0022 vs. CT/MRI),and 57 by 18F-DOPA PET plus carbidopa (P = 0.0075 vs. CT/MRI,not statistically significant vs. baseline). In reference tofindings on CT and MRI, the sensitivities of baseline 18F-DOPAPET were 47.4% for lesions and 55.6% for positive body regions,versus 50.0% (lesions) and 66.7% (regions) for 18F-DOPA PETplus carbidopa (neither is statistically significant vs. baseline).Compared with baseline, carbidopa detected additional lesionsin 3 (27%) of 11 patients. Carbidopa increased the mean (?SD)peak standardized uptake value in index tumor lesions from 6.4? 3.9 to 9.1 ? 5.6 (P = 0.037). Pancreatic physiologic18F-DOPA uptake, which may mask adrenal pheochromocytoma, isblocked by carbidopa. Conclusion: Carbidopa enhances the sensitivityof 18F-DOPA PET for adrenal pheochromocytomas and extraadrenalabdominal paragangliomas by increasing the tumor-to-backgroundratio of tracer uptake. The sensitivity of 18F-DOPA PET formetastases of paraganglioma appears to be limited. Link to comment Share on other sites More sharing options...
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