1. Tau-PET and multimodal imaging in clinically atypical multiple system atrophy masquerading as progressive supranuclear palsy
- Author
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Arenn F. Carlos, Hiroaki Sekiya, Shunsuke Koga, Nha Trang Thu Pham, Farwa Ali, Hugo Botha, Heather M. Clark, Elizabeth A. Coon, Val Lowe, J. Eric Ahlskog, Jorge A. Trejo-Lopez, Dennis W. Dickson, Jennifer L. Whitwell, and Keith A. Josephs
- Subjects
Parkinson Disease ,Multiple System Atrophy ,Magnetic Resonance Imaging ,Multimodal Imaging ,Article ,Diagnosis, Differential ,Levodopa ,Parkinsonian Disorders ,Neurology ,Fluorodeoxyglucose F18 ,Humans ,Supranuclear Palsy, Progressive ,Neurology (clinical) ,Geriatrics and Gerontology - Abstract
INTRODUCTION: Multiple system atrophy (MSA) typically presents with parkinsonism, ataxia and/or autonomic dysfunction. Occasionally, clinically atypical (ca-MSA) cases masquerade as progressive supranuclear palsy (PSP). We aimed to investigate whether different neuroimaging modalities could facilitate differentiation and whether histopathologic characteristics could explain the atypical presentation. METHODS: We identified 3 neuropathologically-defined ca-MSA patients with clinically diagnosed PSP who underwent various antemortem brain imaging: MRI and PET imaging using (11)C-Pittsburgh compound B, (18)F-flortaucipir, and (18)F-fluorodeoxyglucose. We compared clinical features, brainstem planimetry, and radiotracer standardized uptake value ratios in ca-MSA to 10 autopsy-confirmed PSP patients and 10 healthy controls (imaging only). We also compared histologic count of neuronal loss, iron deposition and α-synuclein-immunoreactive glial cytoplasmic inclusion burden to 10 autopsy-confirmed MSA-parkinsonism (MSA-P) cases. RESULTS: Ca-MSA had better PSP Saccadic Impairment Scale scores (p=0.003) and more frequent good levodopa response (p=0.061) than PSP. Ca-MSA showed higher midbrain-to-pons ratio and lower Magnetic Resonance Parkinsonism Index than PSP (each, p=0.036) and exhibited lower glucose metabolism in the putamen and globus pallidus versus PSP (p=0.017) and controls (p=0.007). These same regions showed higher flortaucipir uptake in ca-MSA than PSP (p=0.007 for putamen, p=0.049 for pallidum) and controls (p=0.012). Lower flortaucipir retention was observed in the subthalamic nucleus versus PSP (p=0.007). The putamen-to-subthalamic ratio distinguished ca-MSA from PSP. No histopathological differences were observed for ca-MSA versus typical MSA-P. CONCLUSION: Severity of saccadic impairment, levodopa responsiveness, MRI planimetric measurements, and different patterns of fluorodeoxyglucose and flortaucipir uptake can help improve antemortem differentiation of MSA masquerading as PSP from true PSP.
- Published
- 2022
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