Prospective comparison of Ga-68-DOTATATE and F-18-FDOPA PET/CT in patients with various pheochromocytomas and paragangliomas with emphasis on sporadic cases

Purpose Pheochromocytomas/paragangliomas (PHEOs/PGLs) overexpress ă somatostatin receptors and recent studies have already shown excellent ă results in the localization of these tumors using Ga-68-labeled ă somatostatin analogs (Ga-68-DOTA-SSA), especially in patients with ă germline succinate dehydrogenase subunit B gene (SDHB) mutations and ă head and neck PGLs (HNPGLs). The value of Ga-68-DOTA-SSA has to be ă established in sporadic cases, including PHEOs. Thus, the aim of this ă study was to compare Ga-68-DOTATATE PET/CT, F-18-FDOPA PET/CT, and ă conventional imaging in patients with various PHEOs/PGLs with a special ă emphasis on sporadic cases, including those located in the adrenal ă gland. ă Design Ga-68-DOTATATE, F-18-FDOPA PET/CT, and conventional imaging ă (contrast-enhanced CT and MRI with MR angiography sequences) were ă prospectively performed in 30 patients (8 with SDHD mutations, 1 with a ă MAX mutation and 21 sporadic cases) with PHEO/PGL at initial diagnosis ă or relapse. ă Results The patient-based sensitivities were 93 % (28/30), 97 % ă (29/30), and 93 % (28/30) for Ga-68-DOTATATE PET/CT, F-18-FDOPA PET/CT, ă and conventional imaging, respectively. The lesion-based sensitivities ă were 93 % (43/46), 89 % (41/46), and 76 % (35/46) for Ga-68-DOTATATE ă PET/CT, F-18-FDOPA PET/CT, and conventional imaging respectively (p = ă 0.042). Ga-68-DOTATATE PET/CT detected a higher number of HNPGLs (30/30) ă than F-18-FDOPA PET/CT (26/30; p = 0.112) and conventional imaging ă (24/30; p = 0.024). Ga-68-DOTATATE PET/CT missed two PHEOs of a few ă millimeters in size and a large recurrent PHEO. One lesion was ă considered false-positive on Ga-68-DOTATATE PET/CT and corresponded to a ă typical focal lesion of fibrous dysplasia on MRI. Among the 11 lesions ă missed by conventional imaging, 7 were detected by conventional imaging ă with knowledge of the PET results (4 HNPGLs, 2 LNs, and 1 recurrent ă PHEO). ă Conclusion Ga-68-DOTATATE PET/CT is the most sensitive tool in the ă detection of HNPGLs, especially SDHD-related tumors, which may be very ă small and fail to concentrate sufficient F-18-FDOPA. The present study ă further expands the use of Ga-68-DOTATATE for all patients with HNPGLs, ă regardless of their genotype. Ga-68-DOTATATE PET/CT may be inferior to ă F-18-FDOPA PET/CT in the detection PHEOs.