Magnetic resonance imaging or metaiodobenzylguanidine scintigraphy for the demonstration of paragangliomas?

Abstract

Paragangliomas are tumours arising from paraganglionic tissue dispersed from the base of the skull to the pelvic diaphragm. These tumours produce symptoms by secreting catecholamines (functioning tumours) or by local tumour expansion. They can be part of several hereditary disorders. The introduction of magnetic resonance (MR) imaging and metaiodobenzylguanidine (MIBG) scintigraphy has provided new insights into paragangliomas and has tremendously changed the topographic diagnosis of paragangliomas. Both techniques have proven to be adequate in localising paragangliomas. In this report, the performance of these two noninvasive imaging methods in the examination of paragangliomas is compared and the merits and deficits of the two techniques are discussed. Both techniques produce comparable results in the detection of functioning paragangliomas. MR imaging, however, also demonstrates tumours that do not take up MIBG. MR imaging does not involve the use of ionising radiation and is not hampered by medication. Moreover, MR imaging has a higher spatial resolution. Because of these merits it is concluded that for demonstration of paragangliomas, wholebody MR imaging is the preferred and initial method of investigation. MIBG scintigraphy, on the other hand, continues to be a reliable method for non-invasive detection of functioning paragangliomas. At present it is clearly faster in whole-body imaging than MRI and it is definitely patient-friendly (no claustrophobia). It could be reserved for cases where a strong suspicion of a functioning paraganglioma persists, despite normal MR imaging findings, and for cases where doubt exists about the functional activity of one or more multicentric tumours. MIBG scintigraphy must be used in the evaluation of patients referred for iodine-131 MIBG treatment.

A meta-iodobenzylguanidine scintigraphic scoring system increases accuracy in the diagnostic management of pheochromocytoma

“…CT or MRI represent the first diagnostic step in the localization of phaeochromocytoma (Van Gils et al 1994), but frequently the nature of the identified adrenal mass remains to be clarified (Berglund et al 2001). Furthermore, the functional meaning of suspected paragangliomas or metastatic malignant masses can be difficult to obtain with CT or MRI and it has been demonstrated that when postoperative changes are present (Pacak et al 2001) the sensitivity of both MRI and CT decreases.…”

“…In this group of patients, it is worth noticing how functional data may be useful in distinguishing between a normal adrenal and a pheochomocytoma. Many studies have compared the accuracy of CT, MRI and 131 I-MIBG scintigraphy in the diagnosis of suspected pheochromocytomas (Maurea et al 1993, 1996, Van Gils et al 1994, Elgazzar et al 1995, Freitas 1995. Others have reported results with 123 I-MIBG, which enjoys the advantages of having an energy more suitable for the g camera, a shorter half-life than 131 I and the absence of b emission (Maurea et al 1995).…”

18F-DOPA positron emission tomography for the detection of glomus tumours

“…A variety of morphological [computed tomography, magnetic resonance imaging (MRI)] and metabolic methods [metaiodobenzylguanidine (MIBG) scintigraphy, somatostatin receptor scintigraphy] have been used for diagnostic imaging of glomus tumours [9,10,11,12,13,14,15,16]. A metabolic method that has not been described thus far is 18 F-DOPA whole-body positron emission tomography (PET).…”

Case Report: Patient with Multiple Paragangliomas Treated with Long Acting Somatostatin Analogue

“…According to WHO classification all tumors of the paraganglion system are called paraganglioma. Paragangliomas occurring in the head and neck region (from the carotid and vagal body, from the glomus jugulare and glomus tympanicum) are called chemodectomas or glomus tumors [1,2]. They are in general rare, solitary and slow growing tumors of neuroendocrine origin [3].…”