Clinical utility of FDG PET in Parkinson’s disease and atypical parkinsonism associated with dementia

Abstract

PurposeThere are no comprehensive guidelines for the use of FDG PET in the following three clinical scenarios: (1) diagnostic work-up of patients with idiopathic Parkinson’s disease (PD) at risk of future cognitive decline, (2) discriminating idiopathic PD from progressive supranuclear palsy, and (3) identifying the underlying neuropathology in corticobasal syndrome.MethodsWe therefore performed three literature searches and evaluated the selected studies for quality of design, risk of bias, inconsistency, imprecision, indirectness and effect size. Critical outcomes were the sensitivity, specificity, accuracy, positive/negative predictive value, area under the receiving operating characteristic curve, and positive/negative likelihood ratio of FDG PET in detecting the target condition. Using the Delphi method, a panel of seven experts voted for or against the use of FDG PET based on published evidence and expert opinion.ResultsOf 91 studies selected from the three literature searches, only four included an adequate quantitative assessment of the performance of FDG PET. The majority of studies lacked robust methodology due to lack of critical outcomes, inadequate gold standard and no head-to-head comparison with an appropriate reference standard. The panel recommended the use of FDG PET for all three clinical scenarios based on nonquantitative evidence of clinical utility.ConclusionDespite widespread use of FDG PET in clinical practice and extensive research, there is still very limited good quality evidence for the use of FDG PET. However, in the opinion of the majority of the panellists, FDG PET is a clinically useful imaging biomarker for idiopathic PD and atypical parkinsonism associated with dementia.

Metabolic patterns across core features in dementia with lewy bodies

“…26,27 Instead, the relatively preserved metabolism in bilateral MTL was less affected by the severity of cognitive impairment, was not affected by the region used as reference for intensity normalization, and thus may retain diagnosis utility at all stages. Again, this pattern shows some similarity with the one already highlighted in patients with PD and mild cognitive impairment, [33][34][35] as well as the so-called PD cognitive-related pattern described also in cognitively unimpaired PD patients. 1 Similarly, relatively increased striatal metabolism was previously described early in the disease course in Parkinson disease (PD) patients but not in atypical parkinsonian syndromes.…”

“…35,49 The present study improves our understanding of pathophysiology and clinical-imaging correlation in DLB, paving the path toward optimization of the use of FDG PET in this clinical setting. Recently, the joined recommendations of the European Academy of Neurology and of the EANM have defined FDG PET as a highly relevant tool in clinical practice, allowing discernment of different patterns of hypometabolism among the main neurodegenerative diseases from prodromal stages, including DLB.…”

“…Recently, the joined recommendations of the European Academy of Neurology and of the EANM have defined FDG PET as a highly relevant tool in clinical practice, allowing discernment of different patterns of hypometabolism among the main neurodegenerative diseases from prodromal stages, including DLB. 35,49 The present study improves our understanding of pathophysiology and clinical-imaging correlation in DLB, paving the path toward optimization of the use of FDG PET in this clinical setting.…”

European Association of Nuclear Medicine and European Academy of Neurology recommendations for the use of brain 18F‐fluorodeoxyglucose positron emission tomography in neurodegenerative cognitive impairment and dementia: Delphi consensus

“…Quantitative assessments of the discrimination accuracy of patterns of hypometabolism in this condition are not available [29]. A consensual recommendation was achieved in Delphi Round IV, with five panellists voting for clinical use.…”

Diagnostic utility of FDG-PET in the differential diagnosis between different forms of primary progressive aphasia

“…Panelists also mentioned that solving standardization issues (e.g., for scan reading or normality threshold) may overcome some of the current heterogeneity in FDG-PET diagnostic performance [16, 17], as did also the other literature reviews within the EANM-EAN Initiative [18–23]. …”