Differential Diagnosis in Alzheimer’s Disease and Dementia with Lewy Bodies via VMAT2 and Amyloid ImagingVillemagne V.L.a, d · Okamura N.e · Pejoska S.d · Drago J.b, c · Mulligan R.S.d · Chételat G.d, f · O’Keefe G.d · Jones G.d · Kung H.F.g · Pontecorvo M.h · Masters C.L.a · Skovronsky D.M.g, h · Rowe C.C.d
aMental Health Research Institute, bHoward Florey Institute, and cCentre for Neuroscience, University of Melbourne, and dDepartment of Nuclear Medicine and Centre for PET, Austin Health, Melbourne, Vic., Australia; eDepartment of Pharmacology, Tohoku University School of Medicine, Sendai, Japan; fInserm-EPHE-Université de Caen/Basse-Normandie, Unité U923, GIP Cyceron, CHU Côte de Nacre, Caen, France; gRadiology, University of Pennsylvania, and hAvid Radiopharmaceuticals Inc., Philadelphia, Pa., USA
Background: The noninvasive evaluation of nigrostriatal dopaminergic integrity by PET can provide useful information for the differential diagnosis between dementia with Lewy bodies (DLB) and Alzheimer’s disease (AD). Objectives: To evaluate the diagnostic potential of imaging striatal monoaminergic terminal integrity with the novel vesicular monoamine transporter type 2 (VMAT2) radioligand [18F]AV-133 and PET to distinguish DLB from AD. Methods: Fifty participants [9 DLB, 11 AD, 20 Parkinson’s disease (PD) and 10 healthy age-matched control subjects (HC)] underwent [18F]AV-133 PET studies. Additionally, 20 participants underwent amyloid imaging PET scans with either [11C]PiB or 18F-florbetaben. VMAT2 density was calculated through normalized tissue uptake value ratios (RT) at 120–140 min after injection using the primary visual or the cerebellar cortex as reference region. Comparison of the RT for [18F]AV-133 was done between the different clinical diagnostic groups. Results: Significantly lower striatal VMAT2 densities were observed in DLB and PD when compared to AD and HC, especially in the posterior putamen. In contrast to PD and DLB, no reductions were observed in AD patients when compared to HC. Conclusions: [18F]AV-133 allows assessment of nigrostriatal degeneration in Lewy body diseases. In contrast to amyloid imaging, VMAT2 imaging with [18F]AV-133 can robustly detect reductions of dopaminergic nigrostriatal afferents in DLB patients, assisting in the differential diagnosis from AD.
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