Utility of thallium-201 and iodine-123 metaiodobenzylguanidine in the scintigraphic detection of neuroendocrine neoplasia

Abstract

Metaiodobenzylguanidine (MIBG) is a specific marker for neuroendocrine tumours, such as phaeochromocytoma, neuroblastoma, medullary thyroid cancer (MTC) and paraganglioma, but it suffers in some cases (especially in MTC) from a lack of sensitivity. Thallium is a well-known marker of cellularity with a great sensitivity and a lack of specificity. In order to determine whether the association of these two markers is able to improve the detection of neuroendocrine lesions, 137 scintigraphic examinations using MIBG and thallium were performed in 101 patients referred for suspicion or follow-up of neuroendocrine tumours. Thallium chloride was first injected (1 MBq/kg), images being acquired about 20 min after injection; 123I-MIBG (4 MBq/kg) was then injected and images acquired 5 and 24 h later. In patients with phaeochromocytoma or neuroblastoma, thallium scintigraphy appeared of little help since no tumoural site was discovered by thallium accumulation alone. In contrast, thallium examination seemed of interest in the detection of paraganglioma and MTC, the association of the two radiopharmaceuticals increasing the number of detected sites.

Advances in the diagnostic imaging of pheochromocytomas

“…The highest sensitivity was obtained in a study consisting only of PC patients. 61 The lowest sensitivity was 75%, 62 which may be due to a large proportion of PGL. Some of these patients may have been parasympathetic head and neck PGL with a documented low sensitivity (44%).…”

“…Some of these patients may have been parasympathetic head and neck PGL with a documented low sensitivity (44%). 61,63 In a recent prospective, multicenter trial, where masked readers evaluated the images, the overall sensitivity was 81%-88% and specificity was 75%-84% for 123 I-MIBG scintigraphy of primary and metastatic PC/PGL (Table 3). 64 Recently, SPECT/CT is used more commonly and has the advantage of simultaneous acquisition of both morphological and functional data.…”

123I-Meta-Iodobenzylguanidine Scintigraphy for the Detection of Neuroblastoma and Pheochromocytoma: Results of a Meta-Analysis

“…Of the 15 articles included in the review (26,(43)(44)(45)(46)(47)(48)(49)(50)(51)(52)(53)(54)(55)(56), 11 contributed data to the analysis of sensitivity and eight to the determination of specificity. Sensitivity ranged between 75 and 100% for the individual studies (395 total subjects) and 96% (95% CI, 94 -98%) for all studies combined (Table 1 and Fig.…”