68Ga-DOTATATE PET/CT in the Localization of Head and Neck Paragangliomas Compared with Other Functional Imaging Modalities and CT/MRI

Abstract

Pheochromocytomas/paragangliomas overexpress somatostatin receptors, and recent studies have already shown excellent results in the localization of sympathetic succinate dehydrogenase complex, subunit B, mutation-related metastatic pheochromocytomas/paragangliomas using (68)Ga-DOTATATE PET/CT. Therefore, the goal of our study was to assess the clinical utility of this functional imaging modality in parasympathetic head and neck paragangliomas (HNPGLs) compared with anatomic imaging with CT/MRI and other functional imaging modalities, including (18)F-fluorohydroyphenylalanine ((18)F-FDOPA) PET/CT, currently the gold standard in the functional imaging of HNPGLs.

Methods: (68)Ga-DOTATATE PET/CT was prospectively performed in 20 patients with HNPGLs. All patients also underwent (18)F-FDOPA PET/CT, (18)F-FDG PET/CT, and CT/MRI, with 18 patients also undergoing (18)F-fluorodopamine ((18)F-FDA) PET/CT. (18)F-FDOPA PET/CT and CT/MRI served as the imaging comparators.

Results: Thirty-eight lesions in 20 patients were detected, with (18)F-FDOPA PET/CT identifying 37 of 38 and CT/MRI identifying 23 of 38 lesions (P < 0.01). All 38 and an additional 7 lesions (P = 0.016) were detected on (68)Ga-DOTATATE PET/CT. Significantly fewer lesions were identified by (18)F-FDG PET/CT (24/38, P < 0.01) and (18)F-FDA PET/CT (10/34, P < 0.01).

Conclusion: (68)Ga-DOTATATE PET/CT identified more lesions than other imaging modalities. With the results of the present study, and the increasing availability and use of DOTA analogs in the therapy of neuroendocrine tumors, we expect that (68)Ga-DOTATATE PET/CT will become the preferred functional imaging modality for HNPGLs in the near future.

Keywords: 18F-FDOPA; 68Ga-DOTATATE; head and neck paraganglioma.

Figure 1

Patient 5 with SDHD mutation-related HNPGLs. [⁶⁸Ga]-DOTATATE PET/CT (A) demonstrates a lobulated finding in the CB region on the left side, additional lesions in the GV region on both sides, and in the JT region on the left side. The findings in the JT region are not visible on [¹⁸F]-FDOPA PET/CT (B). [¹⁸F]-FDG PET/CT (C) demonstrates the left CB and very faintly the GV and part of the JT lesions on the left side. The black arrow points to uptake in the vocal cord. [¹⁸F]-FDA PET/CT (D) is completely negative. The white arrow on the MRI (E) points to the CB lesion on the left side.

Figure 2

Patient 18 with SDHD mutation-related HNPGLs. [⁶⁸Ga]-DOTATATE PET/CT (A) demonstrates a big mass in the GV region on the right side and an additional lesion in the CB region on the right. The finding in the CB region is not visible on [¹⁸F]-FDOPA PET/CT (B). The [¹⁸F]-FDG PET/CT (C) and [¹⁸F]-FDA PET/CT (D) scans are completely negative. The arrow on the MRI (E) points to the GV lesion on the right side.

Figure 3

(A) Common sites of HNPGLs (black). (B) Localization of lesions detected only on [⁶⁸Ga]-DOTATATE in our study (green). Abbreviations: ACC: common carotid artery, ACE: external carotid artery, ACI: internal carotid artery; CBP: carotid body paraganglioma, FC: carotid foramen, FJ: jugular foramen, JTP: jugulotympanic paraganglioma, VP: vagale paraganglioma.