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Discordant localization of 2-[18F]-fluoro-2-deoxy-D-glucose in 6-[18F]-fluorodopamine- and [(123)I]-metaiodobenzylguanidine-negative metastatic pheochromocytoma sites
Although the majority of pheochromocytomas (PHEO) are benign, a subset is malignant. Computed tomography (CT) and magnetic resonance imaging (MRI) localize PHEO with high sensitivity but, because of limited specificity, [(131)I]- or [(123)I]-metaiodobenzylguanidine ([(131)I]- or [(123)I]-MIBG) is often used as a complementary agent. 6-[18F]-fluorodopamine ([18F]-DA) has been developed as a radiopharmaceutical for the targeting of noradrenergic pathways, and has been shown to result in a better detection rate of PHEO sites than MIBG; however, [18F]-DA has shown a lack of accumulation in some patients with metastatic PHEO.
Five patients with widespread metastatic PHEO who had CT and MRI evidence of metastatic disease (one man and four women; age range, 25-64 years), and who underwent imaging with [(123)I]-MIBG, [18F]-DA and 2-[18F]-fluoro-2-deoxy-D-glucose ([18F]-FDG), were evaluated retrospectively. Tomographic imaging was performed and positron emission tomography (PET) images were inspected visually and quantitatively.
All five patients had [(123)I]-MIBG scans that grossly underestimated the extent of disease when compared with conventional CT and MRI. All lesions seen on [(123)I]-MIBG scans were detected on [18F]-DA scans, which also detected additional lesions. Nonetheless, [18F]-DA also failed to detect numerous lesions seen on CT and MRI. In all of these cases, [18F]-FDG PET showed lesions that were not detected on either [(123)I]-MIBG or [18F]-DA scans.
When [(123)I]-MIBG or [18F]-DA fails to localize lesions seen on conventional imaging studies, [18F]-FDG may be recommended as an ancillary test for the diagnosis and localization of metastatic PHEO. This is particularly important in patients with aggressive PHEO
Evaluation of Biologic End Points and Pharmacokinetics in Patients With Metastatic Breast Cancer After Treatment With Erlotinib, an Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitor
Staging and functional characterization of pheochromocytoma and paraganglioma by 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography.
Item does not contain fulltextBACKGROUND: Pheochromocytomas and paragangliomas (PPGLs) are rare tumors of the adrenal medulla and extra-adrenal sympathetic chromaffin tissues; their anatomical and functional imaging are critical to guiding treatment decisions. This study aimed to compare the sensitivity and specificity of (18)F-fluorodeoxyglucose positron emission tomography with computed tomography ((18)F-FDG PET/CT) for tumor localization and staging of PPGLs with that of conventional imaging by [(123)I]-metaiodobenzylguanidine single photon emission CT ((123)I-MIBG SPECT), CT, and magnetic resonance imaging (MRI). METHODS: A total of 216 patients (106 men, 110 women, aged 45.2 +/- 14.9 years) with suspected PPGL underwent CT or MRI, (18)F-FDG PET/CT, and (123)I-MIBG SPECT/CT. Sensitivity and specificity were measured as endpoints and compared by the McNemar test, using two-sided P values only. RESULTS: Sixty (28%) of patients had nonmetastatic PPGL, 95 (44%) had metastatic PPGL, and 61 (28%) were PPGL negative. For nonmetastatic tumors, the sensitivity of (18)F-FDG was similar to that of (123)I-MIBG but less than that of CT/MRI (sensitivity of (18)F-FDG = 76.8%; of (123)I-MIBG = 75.0%; of CT/MRI = 95.7%; (18)F-FDG vs (123)I-MIBG: difference = 1.8%, 95% confidence interval [CI] = -14.8% to 14.8%, P = .210; (18)F-FDG vs CT/MRI: difference = 18.9%, 95% CI = 9.4% to 28.3%, P < .001). The specificity was 90.2% for (18)F-FDG, 91.8% for (123)I-MIBG, and 90.2% for CT/MRI. (18)F-FDG uptake was higher in succinate dehydrogenase complex- and von Hippel-Lindau syndrome-related tumors than in multiple endocrine neoplasia type 2 (MEN2) related tumors. For metastases, sensitivity was greater for (18)F-FDG and CT/MRI than for (123)I-MIBG (sensitivity of (18)F-FDG = 82.5%; of (123)I-MIBG = 50.0%; of CT/MRI = 74.4%; (18)F-FDG vs (123)I-MIBG: difference = 32.5%, 95% CI = 22.3% to 42.5%, P < .001; CT/MRI vs (123)I-MIBG: difference = 24.4%, 95% CI = 11.3% to 31.6%, P < .001). For bone metastases, (18)F-FDG was more sensitive than CT/MRI (sensitivity of (18)F-FDG = 93.7%; of CT/MRI = 76.7%; difference = 17.0%, 95% CI = 4.9% to 28.5%, P = .013). CONCLUSIONS: Compared with (123)I-MIBG SPECT and CT/MRI, both considered gold standards for PPGL imaging, metastases were better detected by (18)F-FDG PET. (18)F-FDG PET provides a high specificity in patients with a biochemically established diagnosis of PPGL
Comparison of 18F-Fluoro-L-DOPA, 18F-Fluoro-Deoxyglucose, and 18F-Fluorodopamine PET and 123I-MIBG Scintigraphy in the Localization of Pheochromocytoma and Paraganglioma
Context: Besides 123I-metaiodobenzylguanidine (MIBG), positron emission tomography (PET) agents are available for the localization of paraganglioma (PGL), including 18F-3,4-dihydroxyphenylalanine (DOPA), 18F-fluoro-2-deoxy-d-glucose (18F-FDG), and 18F-fluorodopamine (18F-FDA)