The purpose of this study was to evaluate the role of (68)Ga-labeled DOTANOC PET/CT for baseline evaluation of patients with head and neck paragangliomas (HNPs).
Methods: The data for 26 patients (mean age ± SD, 34.3 ± 10.4 y; 50% men) with known or suspected HNPs who underwent (68)Ga-DOTANOC PET/CT for staging were retrospectively analyzed. PET/CT was performed after intravenous injection of 132-222 MBq of (68)Ga-DOTANOC. The images were evaluated by 2 experienced nuclear medicine physicians in consensus, both qualitatively and quantitatively. The PET/CT findings were grouped as HNPs, paraganglioma at other sites (non-HNPs), and metastatic disease. The size and maximum standardized uptake values (SUVmax) were measured for all lesions. All of the patients also underwent whole-body (131)I-metaiodobenzylgunanidine ((131)I-MIBG) scintigraphy and conventional imaging (CT/MR imaging) of the head and neck region. Their results were compared with those of (68)Ga-DOTANOC PET/CT.
Results: (68)Ga-DOTANOC PET/CT findings were positive in all 26 patients, and 78 lesions were detected. PET/CT imaging demonstrated 45 HNPS, 10 non-HNPs, and 23 metastatic sites. Fifteen patients (57.6%) had more than one site of disease on PET/CT. Among 45 HNPs, 26 were carotid body tumors (CBTs), 15 glomus jugulare, 3 glomus tympanicum, and 1 laryngeal paraganglioma. A positive correlation was seen between size and SUVmax of HNPs (ρ = 0.323; P = 0.030). The SUVmax of the CBTs was higher than that of jugulotympanic paragangliomas (P = 0.026). No correlation was seen between size and SUVmax (ρ = 0.069; P = 0.854) of non-HNPs. The size and SUVmax of non-HNPs were significantly less than those of HNPs (P = 0.029 and 0.047, respectively). (131)I-MIBG scintigraphy showed only 30 of the 78 lesions and was inferior to PET/CT (P < 0.0001). Conventional imaging (CT/MR imaging) was positive for 42 of 49 head and neck lesions and was inferior to PET/CT on direct comparison (P = 0.015). A combination of CT/MR imaging and (131)I-MIBG scintigraphy detected only 53 of 78 (67.9%) lesions and was also inferior to PET/CT (P < 0.0001).
Conclusion: (68)Ga-DOTANOC PET/CT is useful for the baseline evaluation of patients with HNPs and can demonstrate synchronous paragangliomas at other sites and distant metastases. It is superior to (131)I-MIBG scintigraphy and conventional imaging (CT/MR imaging) for this purpose.
Keywords: 131I-MIBG; 68Ga-DOTANOC; PET/CT; head and neck paraganglioma; staging.