6-[ ¹⁸ F]Fluorodopamine Positron Emission Tomographic (PET) Scanning for Diagnostic Localization of Pheochromocytoma

Abstract

Abstract-The diagnosis and treatment of pheochromocytoma depend critically on effective means to localize the tumor.Computed tomography and magnetic resonance imaging have good sensitivity but poor specificity for detecting pheochromocytoma, and nuclear imaging approaches such as 131 I-metaiodobenzylguanidine scintigraphy have limited sensitivity. Here we report initial results using 6-[18 F]fluorodopamine positron emission tomography (PET) scanning in the diagnostic localization of pheochromocytoma. Twenty-eight patients with known or clinically suspected pheochromocytoma underwent PET scanning after intravenous injection of 6-[18 F]fluorodopamine. Of the 28 patients, 9 had surgical confirmation of the tumor, 8 had previously diagnosed metastatic pheochromocytoma, and 11 had plasma levels of metanephrines that were within normal limits. All 9 patients with surgically proven pheochromocytoma had abnormal 6-[18 F]fluorodopamine PET scans that identified the tumors. All 8 patients with metastatic pheochromocytoma had extra-adrenal sites of 6-[18 F]fluorodopamine-derived activity. Of the 11 patients with normal plasma levels of metanephrines, 9 had negative 6-[18 F]fluorodopamine PET scans, 1 had extra-adrenal foci of 6-[ 18 F]fluorodopaminederived activity, and 1 had symmetric uptake of 6-[18 F]fluorodopamine in the region of the adrenal glands. In patients with known disease, 6-[18 F]fluorodopamine PET scanning can detect and localize pheochromocytomas with high sensitivity. In patients in whom the diagnosis of pheochromocytoma is considered but excluded because of negative plasma metanephrine results, 6-[ Key Words: fluorodopamine Ⅲ pheochromocytoma Ⅲ positron emission tomography Ⅲ metanephrines P heochromocytoma is a rare but clinically important tumor of chromaffin cells, 1 characterized by production and secretion of catecholamines and often-but not alwayshypertension. Most pheochromocytomas are benign, so that pheochromocytoma constitutes a form of surgically curable hypertension, and failure to diagnose the tumor can result in sudden, unexpected, and potentially lethal complications. Therefore, clinicians often wish to evaluate patients for pheochromocytoma, when hypertension and symptoms or signs suggest catecholamine excess.Ideally, the diagnosis of pheochromocytoma using imaging techniques requires specific localization in tumor with a high sensitivity for tumor detection. Computed tomography (CT) and magnetic resonance imaging (MRI) have good sensitivity but poor specificity, 2,3 and commonly available nuclear imaging modalities such as 131 I-metaiodobenzylguanidine scintigraphy have high specificity but limited sensitivity. 4 -8 Positron emission tomographic (PET) scanning is a physiology-based method of imaging, dependent on selective-binding or uptake and retention of radiopharmaceuticals by different tissues. The use of short-lived positronemitting radionuclides allows administration of large tracer doses, resulting in high count density and superior resolution compared with that of single photon ...

Pheochromocytomas and extra-adrenal paragangliomas detected by screening in patients with SDHD-associated head-and-neck paragangliomas

“…Nonetheless, we found the combination of MRI and 123 I-MIBG to be sufficient in most cases. Although Timmers et al (2007a) recently reported the superiority of 18 F-fluorodeoxyglucose positron emission tomography ( 18 F-FDG PET) in the evaluation of metastatic paraganglioma, one might argue that in our cohort, because most of the paragangliomas were benign, the use of 18 F-fluorodopamine or 18 F-fluoro-dihydroxyphenylalanine ( 18 F-FDOPA) PET would be more appropriate after negative MIBG imaging (Pacak et al 2001, Hoegerle et al 2002, Hoegerle et al 2003, Mackenzie et al 2007). In our study, the sensitive and specific assays for O-methylated catecholamine metabolites (metanephrine and normetanephrine) were introduced for screening only in the last few years.…”

Functional Imaging Signature of Patients Presenting with Polycythemia/Paraganglioma Syndromes

“…18 F-FDOPA targets the cell via the large amino acid transporter system (15), has previously shown good diagnostic results in other neuroendocrine tumors (15), and is currently recommended for head and neck PGL imaging as well as for metastatic disease in sporadic metastatic PGL (16). 18 F-FDA specifically enters the cell via the norepinephrine transporter and targets the catecholamine synthesis, storage, and secretion pathways (17,18). Although 18 F-FDA has shown mixed results in patients with more dedifferentiated PPGLs with underlying SDH subunit B (SDHB) mutations, it has shown a good diagnostic accuracy in primary as well as metastatic sporadic PPGLs (19)(20)(21).…”

Cardiac sympathetic denervation preceding motor signs in Parkinson disease

“…Normal follow-up plasma metanephrine, and failure of 6-[ 18 F]fluorodopamine PET to detect an adrenal or extra-adrenal focus of radioactivity, excluded pheochromocytoma. 17 At that time the concentration of 6-[ 18 F]fluorodopaminederived radioactivity was found to be markedly decreased in the left ventricular myocardium (Figure 1). …”