Aims and methods: The aim of this prospective study was to compare the diagnostic value of [¹⁸F]FDOPA-PET and [¹¹¹In]pentetreotide-SPECT somatostatin receptor scintigraphy (SRS) in patients with nonmetastatic extra-adrenal paragangliomas (PGLs). Twenty-five consecutive unrelated patients who were known or suspected of having nonmetastatic extra-adrenal PGLs were prospectively evaluated with SRS and [¹⁸F]FDOPA-PET. ¹³¹I-MIBG and [¹⁸F]FDG-PET were added to the work-up in patients with a personal or familial history of PGL, predisposing mutations, abdominal PGLs, metanephrine hypersecretion and abdominal foci on SRS and/or [¹⁸F]FDOPA-PET.
Results: SRS correctly detected 23/45 lesions of which 20 were head or neck lesions (H&N) and 3 were abdominal lesions. [¹⁸F]FDOPA-PET detected significantly more lesions than SRS (39/45, P < 0·001). Both SRS and ¹⁸F-DOPA-PET detected significantly more H&N than abdominal lesions (66·7% vs 20%, P = 0·003 and 96·7% vs 67%, P = 0·012, respectively). In two patients with the succinate dehydrogenase D (SDHD) mutation, [¹⁸F]FDOPA-PET missed five abdominal PGLs which were detected by the combination of SRS, [¹³¹I]MIBG and [¹⁸F]FDG-PET. A lesion-based analysis using a forward stepwise logistic regression model demonstrates that size ≤ 10 mm (P = 0·002) and abdominal lesions (P = 0·031) were independently associated with "[¹⁸F]FDOPA-PET diagnosis only". In turn, a previous history of surgery and/or the presence of germline mutation was associated with lower lesion size (P = 0·001).
Conclusions: The sensitivity of SRS for localizing parasympathetic PGLs is lower than originally reported, and [¹⁸F]FDOPA-PET is better than SRS for localizing small lesions. SRS should be replaced by [¹⁸F]FDOPA-PET as the first-line imaging procedure in H&N PGL, especially in patients at risk of multifocal disease (predisposing mutations and or previous history of surgery).
© 2010 Blackwell Publishing Ltd.