Usefulness of standardized uptake values for distinguishing adrenal glands with pheochromocytoma from normal adrenal glands by use of 6-18F-fluorodopamine PET.

Contains fulltext : 51650timmers.pdf (publisher's version ) (Closed access)6-(18)F-Fluorodopamine ((18)F-FDA) PET is a highly sensitive tool for the localization of pheochromocytoma (PHEO). The aim of this study was to establish cutoff values for pathologic and physiologic adrenal gland tracer uptake. METHODS: (18)F-FDA PET with CT coregistration was performed in 14 patients (10 men and 4 women; age [mean +/- SD], 42.9 +/- 13.3 y) with unilateral adrenal gland PHEO and in 13 control subjects (5 men and 8 women; age, 51.7 +/- 12.5 y) without PHEO. Standardized uptake values (SUVs) were compared between adrenal glands with PHEO and normal left adrenal glands in control subjects. RESULTS: (18)F-FDA accumulation was observed in all adrenal glands with PHEO and in 6 of 13 control adrenal glands (P = 0.02). The SUV was higher in adrenal glands with PHEO (mean +/- SD, 16.1 +/- 6.1) than in (18)F-FDA-positive control adrenal glands (7.7 +/- 1.4) (P = 0.005). SUV cutoffs for distinguishing between adrenal glands with PHEO and normal adrenal glands were 7.3 (100% sensitivity) and 10.1 (100% specificity). CONCLUSION: The SUVs of adrenal foci on (18)F-FDA PET facilitate the distinction between adrenal glands with PHEO and normal adrenal glands

The effects of carbidopa on uptake of 6-18F-Fluoro-L-DOPA in PET of pheochromocytoma and extraadrenal abdominal paraganglioma.

Contains fulltext : 51455timmers.pdf (publisher's version ) (Closed access)6-(18)F-fluoro-l-3,4-dihydroxyphenylalanine ((18)F-DOPA) PET is a useful tool for the detection of certain neuroendocrine tumors, especially with the preadministration of carbidopa, an inhibitor of DOPA decarboxylase. Whether carbidopa also improves (18)F-DOPA PET of adrenal pheochromocytomas and extraadrenal paragangliomas is unknown. The aim of this study was to investigate the sensitivity of (18)F-DOPA PET in the detection of paraganglioma and its metastatic lesions and to evaluate whether tracer uptake by the tumors is enhanced by carbidopa. METHODS: Two patients with nonmetastatic adrenal pheochromocytoma, and 9 patients with extraadrenal abdominal paraganglioma (1 nonmetastatic, 8 metastatic), underwent whole-body CT, MRI, baseline (18)F-DOPA PET, and (18)F-DOPA PET with oral preadministration of 200 mg of carbidopa. The dynamics of tracer uptake by these lesions and the physiologic distribution of (18)F-DOPA in normal tissues were recorded. RESULTS: Seventy-eight lesions were detected by CT or MRI, 54 by baseline (18)F-DOPA PET (P = 0.0022 vs. CT/MRI), and 57 by (18)F-DOPA PET plus carbidopa (P = 0.0075 vs. CT/MRI, not statistically significant vs. baseline). In reference to findings on CT and MRI, the sensitivities of baseline (18)F-DOPA PET were 47.4% for lesions and 55.6% for positive body regions, versus 50.0% (lesions) and 66.7% (regions) for (18)F-DOPA PET plus carbidopa (neither is statistically significant vs. baseline). Compared with baseline, carbidopa detected additional lesions in 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 physiologic (18)F-DOPA uptake, which may mask adrenal pheochromocytoma, is blocked by carbidopa. CONCLUSION: Carbidopa enhances the sensitivity of (18)F-DOPA PET for adrenal pheochromocytomas and extraadrenal abdominal paragangliomas by increasing the tumor-to-background ratio of tracer uptake. The sensitivity of (18)F-DOPA PET for metastases of paraganglioma appears to be limited

Role of positron emission tomography and bone scintigraphy in the evaluation of bone involvement in metastatic pheochromocytoma and paraganglioma: specific implications for succinate dehydrogenase enzyme subunit B gene mutations.

Contains fulltext : 71093timmers.pdf (publisher's version ) (Closed access)We performed a retrospective analysis of 71 subjects with metastatic pheochromocytoma and paraganglioma (30 subjects with mutation of succinate dehydrogenase enzyme subunit B (SDHB) gene and 41 subjects without SDHB mutation). Sixty-nine percent presented with bone metastases (SDHB +/-: 77% vs 63%), 39% with liver metastases (SDHB +/-: 27% vs 47%), and 32% with lung metastases (SDHB +/-: 37% vs 29%). The most common sites of bone involvement were thoracic spine (80%; SDHB+/-: 83% vs 77%), lumbar spine (78%; SDHB +/-: 78% vs 75%), and pelvic and sacral bones (78%; SDHB +/-: 91% vs 65%, P=0.04). Subjects with SDHB mutation also showed significantly higher involvement of long bones (SDHB +/-: 78% vs 30%, P=0.007) than those without the mutation. The best overall sensitivity in detecting bone metastases demonstrated positron emission tomography (PET) with 6-[(18)F]-fluorodopamine ([(18)F]-FDA; 90%), followed by bone scintigraphy (82%), computed tomography or magnetic resonance imaging (CT/MRI; 78%), 2-[(18)F]-fluoro-2-deoxy-d-glucose ([(18)F]-FDG) PET (76%), and scintigraphy with [(123/131)I]-metaiodobenzylguanidine (71%). In subjects with SDHB mutation, imaging modalities with best sensitivities for detecting bone metastases were CT/MRI (96%), bone scintigraphy (95%), and [(18)F]-FDG PET (92%). In subjects without SDHB mutations, the modality with the best sensitivity for bone metastases was [(18)F]-FDA PET (100%). In conclusion, bone scintigraphy should be used in the staging of patients with malignant pheochromocytoma and paraganglioma, particularly in patients with SDHB mutations. As for PET imaging, [(18)F]-FDG PET is highly recommended in SDHB mutation patients, whereas [(18)F]-FDA PET is recommended in patients without the mutation