Abstract
Objective: The absence of markers for ante-mortem diagnosis of idiopathic Parkinson's disease (IPD), multiple system atrophy (MSA), and progressive supranuclear palsy (PSP) results in these disorders being commonly mistaken for each other, particularly in the initial stages. We aimed to investigate annualized whole-brain atrophy rates (a-WBAR) in these disorders to aid in the diagnosis between IPD vs. PSP and MSA.Methods: Ten healthy controls, 20 IPD, 39 PSP, and 41 MSA patients were studied using Structural Imaging Evaluation with Normalization of Atrophy (SIENA). SIENA is an MRI-based algorithm that quantifies brain tissue volume and does not require radiotracers. SIENA has been shown to have a low estimation error for atrophy rate over the whole brain (0.5%).Results: In controls, the a-WBAR was 0.37% ± 0.28 (CI 95% 0.17–0.57), while in IPD a-WBAR was 0.54% ± 0.38 (CI 95% 0.32–0.68). The IPD patients did not differ from the controls. In PSP, the a-WBAR was 1.93% ± 1.1 (CI 95% 1.5–2.2). In MSA a-WBAR was 1.65% ± 0.9 (CI 95%1.37–1.93). MSA did not differ from PSP. The a-WBAR in PSP and MSA were significantly higher than in IPD (p < 0.001). a-WBAR 0.6% differentiated patients with IPD from those with PSA and MSA with 91% sensitivity and 80% specificity.Conclusions: a-WBAR within the normal range is unlikely to be observed in PSP or MSA. a-WBAR may add a potential retrospective application to improve the diagnostic accuracy of MSA and PSP vs. IPD during the first year of clinical assessment.
Highlights
Multiple system atrophy (MSA) and progressive supranuclear palsy (PSP)—sometimes designated as “Parkinson plus syndromes”—are debilitating neurodegenerative disorders with heterogeneous presentation, inexorable progression, and a median survival of between 5 and 10 years
PSP and MSA can be misdiagnosed as idiopathic Parkinson’s disease (IPD), especially in early stages, as these disorders share some common clinical features, such as bradykinesia and rigidity and even initial response to levodopa treatment, making the diagnosis, which is initially based on clinical presentation only, rather uncertain
We aimed to explore the retrospective application of aWBAR to differentiate IPD from MSA and PSP, after 1 year from the baseline assessment and before 5 years of the disease course
Summary
Multiple system atrophy (MSA) and progressive supranuclear palsy (PSP)—sometimes designated as “Parkinson plus syndromes”—are debilitating neurodegenerative disorders with heterogeneous presentation, inexorable progression, and a median survival of between 5 and 10 years. Whole brain atrophy rates (WBAR) from magnetic resonance imaging (MRI) data may be an informative way to quantify disease progression in an unbiased fashion This approach reduces inter- individual variability in brain size and morphology when baseline scans are used as reference point so that the subject acts as his or her own control. In six autopsy-confirmed PSP cases (Josephs et al, 2006), the a-WBAR [measured using the boundary shift integral (BSI; Freeborough et al, 1997), a (semi-) automated technique] was 1.3% In another five proven PSP cases, this figure was 1% (Josephs et al, 2006; Whitwell et al, 2007); in another study, using BSI, a-WBAR estimates were approximately 1% for both PSP and MSA based on 17 PSP cases and 9 cases with MSA-P (Paviour et al, 2006)
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