The need of standardization and of large clinical studies in an emerging indication of [18F]FDG PET: the autoimmune encephalitis

Morbelli, Silvia; Arbizu, Javier; Booij, Jan; Chen, Ming Kai; Chételat, Gaël; Cross, Donna; Djekidel, Mehdi; Drzezga, Alexander; Ekmekçioğlu, Özgül; Garibotto, Valentina; Hesse, Swen; Ishii, Kazunari; Saraf, Lida Jafari; Lammertsma, Adriaan A.; Law, Ian; Mathews, Dana; Minoshima, Shinsei; Mosci, Karina; Pagani, Marco; Pappatà, Sabina; Silverman, Daniel; Giessen, Elsmarieke van de; Villemagne, Victor L.; Barthel, Henryk

doi:10.1007/s00259-016-3589-9

Cited by 45 publications

(29 citation statements)

References 29 publications

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“…Not only larger validation studies are needed, but also more objective semi-quantitative measures. As outlined by the European Association of Nuclear Medicine [33], these specific semi-automated approaches to analyze FDG-PET data were developed for Alzheimer's disease and therefore are not equally suitable for identifying hypermetabolic areas. Likewise, they pointed out that some voxel-based approaches, depending on the choice of the reference region for intensity normalization, may lead to biased hypermetabolic areas.…”

Section: Discussionmentioning

confidence: 99%

18F-FDG-PET Imaging Patterns in Autoimmune Encephalitis: Impact of Image Analysis on the Results

et al. 2020

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Brain positron emission tomography imaging with 18Fluorine-fluorodeoxyglucose (FDG-PET) has demonstrated utility in suspected autoimmune encephalitis. Visual and/or assisted image reading is not well established to evaluate hypometabolism/hypermetabolism. We retrospectively evaluated patients with autoimmune encephalitis between 2003 and 2018. Patients underwent EEG, brain magnetic resonance imaging (MRI), cerebrospinal fluid (CSF) sampling and autoantibodies testing. Individual FDG-PET images were evaluated by standard visual reading and assisted by voxel-based analyses, compared to a normal database. For the latter, three different methods were performed: two based on statistical surface projections (Siemens syngo.via Database Comparison, and 3D-SSP Neurostat) and one based on statistical parametric mapping (SPM12). Hypometabolic and hypermetabolic findings were grouped to identify specific patterns. We found six cases with definite diagnosis of autoimmune encephalitis. Two cases had anti-LGI1, one had anti-NMDA-R and two anti-CASPR2 antibodies, and one was seronegative. 18F-FDG-PET metabolic abnormalities were present in all cases, regardless of the method of analysis. Medial–temporal and extra-limbic hypermetabolism were more clearly depicted by voxel-based analyses. We found autoantibody-specific patterns in line with the literature. Statistical surface projection (SSP) methods (Neurostat and syngo.via Database Comparison) were more sensitive and localized larger hypermetabolic areas. As it may lead to comparable and accurate results, visual analysis of FDG-PET studies for the diagnosis of autoimmune encephalitis benefits from voxel-based analysis, beyond the approach based on MRI, CSF sample and EEG.

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Section: Discussionmentioning

confidence: 99%

18F-FDG-PET Imaging Patterns in Autoimmune Encephalitis: Impact of Image Analysis on the Results

et al. 2020

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“…Recently, the clinical importance of FDG-PET in autoimmune encephalitis, including anti-LGI1 antibody encephalitis, has been emphasized (22). Although whether hypermetabolism itself is due to inflammation or epileptic activity is controversial, FDG-PET has been considered to be more sensitive than MRI in terms of detecting inflammation (11-15).…”

Section: Discussionmentioning

confidence: 99%

Hashimoto's Encephalopathy Presenting with Smoldering Limbic Encephalitis

et al. 2019

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Hashimoto's encephalopathy (HE) is a steroid-responsive autoimmune encephalopathy associated with Hashimoto thyroiditis. We herein report a case of HE manifesting “smoldering” limbic encephalitis with persisting symptoms and abnormalities on examinations. Although our patient experienced partial clinical remission after treatment, hippocampal hypermetabolism on [ 18 F] fluorodeoxyglucose positron emission tomography (FDG-PET) and subclinical seizures on video electroencephalography persisted. Hypermetabolism on FDG-PET was improved by additional prednisolone therapy. Thus, as with other autoimmune limbic encephalitis cases, HE can take a course of “smoldering” encephalitis. FDG-PET and electroencephalogram findings can reflect the disease activity degree in such patients, although with certain neurophysiological and biochemical distinctions.

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“…A number of studies indicate that these PET findings (in the limbic system and extra-limbic regions) were associated with clinical symptoms and active disease status more strongly than the MRI findings [7,36]. A recent Editorial emphasized the importance of harmonized brain 18 F-FDG-PET protocols, making PET findings consistent and comparable between different centers [37]. Combining the strength of both MRI and PET in a single temporal as well as spatial domain, as well as facilitating a one-stop-shop examination, by means of cerebral and whole-body imaging, the aim of our study was to investigate the according morphologic and metabolic changes in patients with LE while ruling out potential causes for paraneoplastic limbic encephalitis.…”

Section: Discussionmentioning

confidence: 99%