Biomarkers.

Background: Florzolotau (APN-1607) tau-PET has shown distinct patterns of binding in patients with AD and 4-repeat tauopathies. We aimed to establish disease-specific tau covariance patterns in AD and PSP/CBS and validate them as user-independent quantitative biomarkers for reference-region-free evaluation of tau-PET in an independent clinical cohort.

Method: We analyzed Florzolotau PET data from four different cohorts.

Alzheimer's Imaging Consortium.

Background: Florzolotau (APN-1607) tau-PET has shown distinct patterns of binding in patients with AD and 4-repeat tauopathies. We aimed to establish disease-specific tau covariance patterns in AD and PSP/CBS and validate them as user-independent quantitative biomarkers for reference-region-free evaluation of tau-PET in an independent clinical cohort.

Method: We analyzed Florzolotau PET data from four different cohorts.

Deformation-based morphometry applied to FDG PET data reveals hippocampal atrophy in Alzheimer's disease.

Cerebral atrophy is a key finding in patients with dementia and usually determined on MRI. We tested whether cerebral atrophy can be imaged with FDG PET by applying deformation-based morphometry (DBM). We retrospectively identified 26 patients with a biomarker-supported clinical diagnosis of Alzheimer's disease (AD) who had received FDG PET on a fully-digital PET/CT system and structural MRI and compared them to 13 healthy elderly controls (HEC).

The metabolic spatial covariance pattern of definite idiopathic normal pressure hydrocephalus: an FDG PET study with principal components analysis.

Identification of patients with idiopathic normal pressure hydrocephalus (iNPH) in a collective with suspected neurodegenerative disease is essential. This study aimed to determine the metabolic spatial covariance pattern of iNPH on FDG PET using an established technique based on scaled subprofile model principal components analysis (SSM-PCA).We identified 11 patients with definite iNPH.

Cognitive Deficits in Parkinson's Disease Are Associated with Neuronal Dysfunction and Not White Matter Lesions.

Background: Cognitive deficits considerably contribute to the patient's burden in Parkinson's disease (PD). While cognitive decline is linked to neuronal dysfunction, the additional role of white matter lesions (WML) is discussed controversially.

Objective: To investigate the influence of WML, in comparison to neuronal dysfunction, on cognitive deficits in PD.

More extensive hypometabolism and higher mortality risk in patients with right- than left-predominant neurodegeneration of the anterior temporal lobe.

Background: Left-predominant neurodegeneration of the anterior temporal lobe (ATL) and the associated syndrome termed semantic variant primary progressive aphasia (svPPA) are well characterized. Less is known about right-predominant neurodegeneration of the ATL, which has been associated with the clinical syndrome named right temporal variant of frontotemporal dementia (rtvFTD). Here, we assessed glucose metabolism across the brain, cognitive performance, and mortality in patients with right-predominant neurodegeneration of the ATL.

Nigral glucose metabolism as a diagnostic marker of neurodegenerative parkinsonian syndromes.

Parkinson's disease (PD), multiple system atrophy (MSA), and progressive supranuclear palsy (PSP) are characterized by nigrostriatal degeneration. We used [F]FDG PET to assess glucose metabolism of the substantia nigra (SN) in patients with these diseases and evaluated its ability to discriminate neurodegenerative parkinsonian syndromes (NP) from controls. We retrospectively evaluated [F]FDG PET scans of 171 patients with NP (n = 115 PD, n = 35 MSA, n = 21 PSP) and 48 controls (13 healthy controls [HC] and 35 control patients).

Neural activity of the auditory cortex predicts speech recognition of patients with asymmetric hearing loss after cochlear implantation.

Patients with asymmetric hearing loss show an asymmetry of glucose metabolism of the primary auditory cortex (PAC). We investigated whether this asymmetry could serve as an objective predictor for speech recognition with CI. Nine patients underwent FDG PET prior to CI surgery.

PET/CT background noise and its effect on speech recognition.

Positron emission tomography (PET) has been successfully used to investigate central nervous processes, including the central auditory pathway. Unlike early water-cooled PET-scanners, novel PET/CT scanners employ air cooling and include a CT system, both of which result in higher background noise levels. In the present study, we describe the background noise generated by two state-of-the-art air-cooled PET/CT scanners.

DAT SPECT Predicts Survival in Patients Assessed for Differential Diagnosis of Dementia.

Background: Dopamine transporter (DAT) SPECT is an established diagnostic procedure in dementia diagnostics, yet its prognostic value is currently unknown.

Objective: We evaluated the prognostic value of DAT SPECT in patients assessed for differential diagnosis of dementia.

Methods: We included all patients who had received DAT SPECT for differential diagnosis of dementia from 10/2008 to 06/2016 at our site and whose survival status could be obtained in 09/2019.

Cognitive impairment and altered cerebral glucose metabolism in the subacute stage of COVID-19.

During the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic, neurological symptoms increasingly moved into the focus of interest. In this prospective cohort study, we assessed neurological and cognitive symptoms in hospitalized coronavirus disease-19 (COVID-19) patients and aimed to determine their neuronal correlates. Patients with reverse transcription-PCR-confirmed COVID-19 infection who required inpatient treatment primarily because of non-neurological complications were screened between 20 April 2020 and 12 May 2020.

Slow but Evident Recovery from Neocortical Dysfunction and Cognitive Impairment in a Series of Chronic COVID-19 Patients.

Cognitive impairment is a frequent complaint in coronavirus disease 2019 (COVID-19) and can be related to cortical hypometabolism on F-FDG PET at the subacute stage. However, it is unclear if these changes are reversible. We prospectively assessed the Montreal Cognitive Assessment scores and F-FDG PET scans of 8 COVID-19 patients at the subacute stage (once no longer infectious) and the chronic stage (˜6 mo after symptom onset).

Validation of the Alzheimer Disease Dementia Conversion-Related Pattern as an ATN Biomarker of Neurodegeneration.

Objective: To determine whether the Alzheimer disease (AD) dementia conversion-related pattern (ADCRP) on [F]FDG PET can serve as a valid predictor for the development of AD dementia, the individual expression of the ADCRP (subject score) and its prognostic value were examined in patients with mild cognitive impairment (MCI) and biologically defined AD.

Methods: A total of 269 patients with available [F]FDG PET, [F]AV-45 PET, phosphorylated and total tau in CSF, and neurofilament light chain in plasma were included. Following the AT(N) classification scheme, where AD is defined biologically by in vivo biomarkers of β-amyloid (Aβ) deposition ("A") and pathologic tau ("T"), patients were categorized to the A-T-, A+T-, A+T+ (AD), and A-T+ groups.

Brain activation patterns during visuomotor adaptation in motor experts and novices: An FDG PET study with unrestricted movements.

Background: Speed of performance improvements and the strength of memory consolidation in humans vary with movement expertise. Underlying neural mechanisms of behavioural differences between levels of movement expertise are so far unknown.

New Method: In this study, PET with [F]fluorodeoxyglucose (FDG) was proposed as a powerful novel methodology to assess learning-related brain activity patterns during large non-restricted movements (ball throwing with a right hand).

Differential diagnosis of parkinsonism: a head-to-head comparison of FDG PET and MIBG scintigraphy.

[F]fluorodeoxyglucose (FDG) PET and [I]metaiodobenzylguanidine (MIBG) scintigraphy may contribute to the differential diagnosis of neurodegenerative parkinsonism. To identify the superior method, we retrospectively evaluated 54 patients with suspected neurodegenerative parkinsonism, who were referred for FDG PET and MIBG scintigraphy. Two investigators visually assessed FDG PET scans using an ordinal 6-step score for disease-specific patterns of Lewy body diseases (LBD) or atypical parkinsonism (APS) and assigned the latter to the subgroups multiple system atrophy (MSA), progressive supranuclear palsy (PSP), or corticobasal syndrome.

Intrinsic Alertness Is Impaired in Patients with Nigrostriatal Degeneration: A Prospective Study with Reference to [123I]FP-CIT SPECT and [18F]FDG PET.

Background: Variations in alertness and attention are common in Lewy body diseases (LBD) and among the core features of dementia with Lewy bodies (DLB). Dopamine transporter SPECT is an accurate biomarker of nigrostriatal degeneration (NSD) in LBD.

Objective: The present study investigated performance on a computerized alertness test as a potential measure of attention in patients with NSD compared to patients without NSD.

Amyloid biomarkers as predictors of conversion from mild cognitive impairment to Alzheimer's dementia: a comparison of methods.

Background: Amyloid-β (Aβ) PET is an established predictor of conversion from mild cognitive impairment (MCI) to Alzheimer's dementia (AD). We compared three PET (including an approach based on voxel-wise Cox regression) and one cerebrospinal fluid (CSF) outcome measures in their predictive power.

Methods: Datasets were retrieved from the ADNI database.

Impact of age and sex correction on the diagnostic performance of dopamine transporter SPECT.

Purpose: The specific binding ratio (SBR) of I-FP-CIT (FP-CIT) in the putamen decreases with age by about 5% per decade and most likely is about 10% higher in females. However, the clinical utility of age and sex correction of the SBR is still a matter of debate. This study tested the impact of age and sex correction on the diagnostic performance of the putamen SBR in three independent patient samples.

Principal-Component Analysis-Based Measures of PET Data Closely Reflect Neuropathologic Staging Schemes.

Voxel-based principal-component analysis allows for an identification of patterns of glucose metabolism and amyloid deposition related to the conversion from mild cognitive impairment (MCI) to Alzheimer disease (AD). The present study aimed to validate these AD conversion-related patterns (ADCRPs) against neuropathologic findings. We included patients from the Alzheimer's Disease Neuroimaging Initiative who underwent autopsy and for whom F-FDG PET (30 AD, 6 MCI, 2 cognitively normal) and amyloid-β (Aβ) PET (17 AD, 3 MCI, 2 cognitively normal) were available.

[123I]FP-CIT SPECT in Clinically Uncertain Parkinsonism Predicts Survival: A Data-Driven Analysis.

Background: Dopamine transporter SPECT is an established method to investigate nigrostriatal integrity in case of clinically uncertain parkinsonism.

Objective: The present study explores whether a data-driven analysis of [123I]FP-CIT SPECT is able to stratify patients according to mortality after SPECT.

Methods: Patients from our clinical registry were included if they had received [123I]FP-CIT SPECT between 10/2008 and 06/2016 for diagnosis of parkinsonism and if their vital status could be determined in 07/2017.

Whole-brain irradiation with hippocampal sparing and dose escalation on metastases: neurocognitive testing and biological imaging (HIPPORAD) - a phase II prospective randomized multicenter trial (NOA-14, ARO 2015-3, DKTK-ROG).

Background: Whole brain radiation therapy (WBRT) is the standard therapy for multiple brain metastases. However, WBRT has a poor local tumor control and is associated with a decline in neurocognitive function (NCF). Aim of this trial is to assess the efficacy and safety of a new treatment method, the WBRT with hippocampus avoidance (HA) combined with the simultaneous integrated boost (SIB) on metastases/resection cavities (HA-WBRT+SIB).

Automated voxel- and region-based analysis of gray matter and cerebrospinal fluid space in primary dementia disorders.

Purpose: Previous studies showed voxel-based volumetry as a helpful tool in detecting pathologic brain atrophy. Aim of this study was to investigate whether the inclusion of CSF volume improves the imaging based diagnostic accuracy using combined automated voxel- and region-based volumetry.

Methods: In total, 120 individuals (30 healthy elderly, 30 frontotemporal dementia (FTD), 30 Alzheimer's dementia (AD) and 30 Lewy body dementia (LBD) patients) were analyzed with voxel-based morphometry and compared to a reference group of 360 healthy elderly controls.

FDG Uptake in the Basal Forebrain as Measured by Digital High-Resolution PET Is a Promising Marker of Basal Forebrain Degeneration in the Lewy Body Disease Spectrum: A Pilot Study.

Purpose: Cognitive decline in diseases of the Lewy body spectrum (LBS) is linked to dysfunction/degeneration of the basal forebrain (BF). Assessment of glucose metabolism in the BF by FDG PET is hampered by the small size of the BF and limited spatial resolution of conventional PET. This pilot study tested the feasibility of assessing BF glucose metabolism by high-resolution digital PET (dPET).