¹²³I‐2β‐carbomethoxy‐3β‐(4‐iodophenyl)‐<i>N</i>‐(3‐fluoropropyl) nortropane single photon emission computed tomography and ¹²³I‐metaiodobenzylguanidine myocardial scintigraphy in differentiating dementia with lewy bodies from other dementias: A comparative study

<jats:sec><jats:title>Objective</jats:title><jats:p>To compare the diagnostic value of striatal <jats:sup>123</jats:sup>I‐2β‐carbomethoxy‐3β‐(4‐iodophenyl)‐<jats:italic>N</jats:italic>‐(3‐fluoropropyl) nortropane (<jats:sup>123</jats:sup>I‐FP‐CIT) single photon emission computed tomography (SPECT) and <jats:sup>123</jats:sup>I‐metaiodobenzylguanidine (<jats:sup>123</jats:sup>I‐MIBG) myocardial scintigraphy in differentiating dementia with Lewy bodies (DLB) from other dementia types.</jats:p></jats:sec><jats:sec><jats:title>Methods</jats:title><jats:p>This prospective longitudinal study included 30 patients with a clinical diagnosis of DLB and 29 patients with non‐DLB dementia (Alzheimer disease, n = 16; behavioral variant frontotemporal dementia, n = 13). All patients underwent <jats:sup>123</jats:sup>I‐FP‐CIT SPECT and <jats:sup>123</jats:sup>I‐MIBG myocardial scintigraphy within a few weeks of clinical diagnosis. All diagnoses at each center were agreed upon by the local clinician and an independent expert, both unaware of imaging data, and re‐evaluated after 12 months. Each image was visually classified as either normal or abnormal by 3 independent nuclear physicians blinded to patients' clinical data.</jats:p></jats:sec><jats:sec><jats:title>Results</jats:title><jats:p>Overall, sensitivity and specificity to DLB were respectively 93% and 100% for <jats:sup>123</jats:sup>I‐MIBG myocardial scintigraphy, and 90% and 76% for <jats:sup>123</jats:sup>I‐FP‐CIT SPECT. Lower specificity of striatal compared to myocardial imaging was due to decreased <jats:sup>123</jats:sup>I‐FP‐CIT uptake in 7 non‐DLB subjects (3 with concomitant parkinsonism) who had normal <jats:sup>123</jats:sup>I‐MIBG myocardial uptake. Notably, in our non‐DLB group, myocardial imaging gave no false‐positive readings even in those subjects (n = 7) with concurrent medical illnesses (diabetes and/or heart disease) supposed to potentially interfere with <jats:sup>123</jats:sup>I‐MIBG uptake.</jats:p></jats:sec><jats:sec><jats:title>Interpretation</jats:title><jats:p><jats:sup>123</jats:sup>I‐FP‐CIT SPECT and <jats:sup>123</jats:sup>I‐MIBG myocardial scintigraphy have similar sensitivity for detecting DLB, but the latter appears to be more specific for excluding non‐DLB dementias, especially when parkinsonism is the only “core feature” exhibited by the patient. Our data also indicate that the potential confounding effects of diabetes and heart disease on <jats:sup>123</jats:sup>I‐MIBG myocardial scintigraphy results might have been overestimated. Ann Neurol 2016;80:368–378</jats:p></jats:sec>