Is Nuclear Imaging Important in the Management of Head and Neck Paragangliomas?

Nuclear medical imaging is indicated in most, but not all, patients with suspected paragangliomas of the head and neck. Advances technology somatostatin receptor analogs have improved selectivity sensitivity this imaging. Paragangliomas are uncommon tumors neck that contain membrane-bound type 2 receptors (SSTR-2), making them easy to detect radiolabeled peptide Some these may present a typical fashion can be identified conventional such as CT or MRI. There classic signs associated seen on standard “lyre sign” which internal external carotid arteries splayed vascular mass promontory middle ear. “Salt pepper” appearance contrast MRI T1 weighted images also strongly suggestive paraganglioma. other situations where nuclear medicine will an important tool surgeon's arsenal. multifocal, familial, recurrent, metastatic. All evaluated via medicine, taking advantage SSTR-2 their affinity for analogs.1 Treatment planning multiple recurrent challenging knowledge location all paraganglioma tissue critical. Familial syndrome at high risk early onset multifocality. If person harbor familial tumor (family member paraganglioma, vagal age detection, sites) ruling out sites paraganglionic necessary. The succinate dehydrogenase subunit B (SDHB) variant higher degree malignancy. genetic pedigree determined SDHB, looking metastases (Figure 1A, B) highly recommended. purpose article review current demonstrate scenarios its use would most advisable. For more than 50 years, metaiodobenzylguanidine (MIBG) labeled 131I, later 123I, has been used image treat neuroendocrine tumors, tumors' utilization norepinephrine analog. Unfortunately, only about 45% accumulate sufficient material routine whole-body 111In-pentetreotide, analog, was introduced over 30 years ago. It SSTR receptors, combination planar scintigraphic SPECT hybrid identify 85% paragangliomas. More recently, departments switched from pentetreotide Dotatate PET (positron emission tomography).2 DOTA moiety links octreotate, analog even positron emitters 68Ga 64Cu beta-emitters like 177Lu therapy.3 From diagnostic perspective, better resolution overall greater when compared radionuclide imaging, after considering fusion characteristics CT.4 several advantages performed 1 h injection, meaning patient's entire procedure takes less 2–3 h. Pentetreotide requires least two sets images, usually one being 4 initial injection second set following day. Secondly, needs followed by especially localization paramount importance treatment Lastly, diminishing 111In agents (in particular, indium oxine labeling white blood cells) means cost risen dramatically.5 At time, although still regularly available, now exceeds Dotatate. In summary, expensive use, logistically image, poorer either products. One limitation very short half-life, some areas, limit availability material, account continued pentetreotide. recent introduction 64Cu-Dotatate 13-h half-life significantly mitigates issue. recommended multifocality syndromes (SDHB SDHD) frequently necessarily simultaneously. Knowledge bilateral ipsilateral locations necessary plan safe 1C). common tumors. surgery contemplated, smaller operated first. Frequently, detected With possessing incidence malignant potential, known SDHB mutations, detecting adenopathy metastasis essential. Finally, require determine site(s) disease affect local therapy. Once identified, site-specific dedicated define characteristics. This includes morphologic data, size, proximity vessels, distant metastasis. Additionally, masses do possess distinguished diagnosis variants, malignant, potentially multifocal. presentations sporadic tympanic routinely nature make large prospective studies difficult perform. These recommendations based level 3 evidence (nonconsecutive studies), (case series), 5 (expert opinion).