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July 5, 2000

Differentiating Parkinson Disease From Multiple-System Atrophy by Measuring Cardiac Iodine-123 Metaiodobenzylguanidine Accumulation

Author Affiliations

Stephen J.LurieMD, PhD, Contributing EditorIndividualAuthor

JAMA. 2000;284(1):44-45. doi:10.1001/jama.284.1.39

To the Editor: The diagnostic differentiation of idiopathic Parkinson disease (PD) vs multiple-system atrophy (MSA) is based entirely on clinical features and the lack of other findings suggesting alternative diagnoses. However, recent studies1-4 have found a significant reduction of cardiac accumulation of iodine-123 metaiodobenzylguanidine (I-123 MIBG, a norepinephrine analog that is taken up and stored in the sympathetic nerve endings) among patients with PD. This reduction is independent of the severity or duration of disease and may be disease specific.1-4 In a small number of patients,1,3,4 there was a significant difference in I-123 MIBG accumulation between patients with PD and those with MSA, although MSA also is known to be present in patients with parkinsonism. However, the sensitivity or specificity of differentiating PD from MSA by I-123 MIBG accumulation is not known.