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Carla Palleis

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3 papers

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YNICL Journal 2026 Journal Article

Additive value of early-phase β-Amyloid-PET for the differential diagnosis of non-Alzheimer’s disease dementia

Sebastian Eckenweber
Friederike Völter
Nicolai Franzmeier
Carla Palleis
Olivia Wagemann
Endy Weidinger
Sabrina Katzdobler
Elisabeth Wlasich

PURPOSE: F]FDG-PET, indicating the potential of early-phase β-amyloid-PET as a surrogate biomarker of neuronal injury. We therefore aimed to investigate the additive value of early-phase β-amyloid-PET for the differential diagnosis of non-Alzheimer's disease dementia syndromes in clinical routine. MATERIALS AND METHODS: F]flutemetamol-PET scans (n = 379) performed between July 2013 and July 2021 were analyzed for their amyloid status and the presence of a neurodegenerative hypoperfusion pattern using visual assessment and z-score maps. In patients visually rated as amyloid-negative/neurodegeneration-positive (A-N+), the most likely diagnosis based on perfusion patterns was compared to the final clinical diagnosis, i.e. frontotemporal dementia or psychiatric disorders, suspected 4R-tauopathy, and suspected non-Alzheimer pathophysiology. Logistic regression models based on a data-driven selection of cerebral regions of hypoperfusion by principal component analysis were used to predict neurodegenerative disease and clinical diagnoses. Diagnostic accuracy was compared between visual assessment and the regression models. RESULTS: Neurodegeneration status was correctly identified in 78.8% (119/151) of amyloid-negative patients through visual rating, compared to 67.5% (102/151) using logistic regression. Visual assessment assigned 75.3% (67/89) of A-N+ patients to the correct diagnostic category. In contrast, the regression model classified 69.7% (62/89) of patients. CONCLUSIONS: The current study demonstrates an additive value of early-phase β-amyloid-PET for the differential diagnosis of dementia syndromes. While visual assessment of early-phase β-amyloid-PET already provides substantial diagnostic accuracy, a data-driven analysis approach could aid in cases of uncertainty.

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YNICL Journal 2023 Journal Article

Symptomatology in 4-repeat tauopathies is associated with data-driven topology of [18F]-PI-2620 tau-PET signal

Sonja Schönecker
Carla Palleis
Nicolai Franzmeier
Sabrina Katzdobler
Christian Ferschmann
Sebastian Schuster
Anika Finze
Maximilian Scheifele

In recent years in vivo visualization of tau deposits has become possible with various PET radiotracers. The tau tracer [18F]PI-2620 proved high affinity both to 3-repeat/4-repeat tau in Alzheimer’s disease as well as to 4-repeat tau in progressive supranuclear palsy (PSP) and corticobasal syndrome (CBS). However, to be clinically relevant, biomarkers should not only correlate with pathological changes but also with disease stage and progression. Therefore, we aimed to investigate the correlation between topology of [18F]PI-2620 uptake and symptomatology in 4-repeat tauopathies. 72 patients with possible or probable 4-repeat tauopathy, i. e. 31 patients with PSP-Richardson’s syndrome (PSP-RS), 30 with amyloid-negative CBS and 11 with PSP-non-RS/CBS, underwent [18F]PI-2620-PET. Principal component analysis was performed to identify groups of similar brain regions based on 20–40 min p. i. regional standardized uptake value ratio z-scores. Correlations between component scores and the items of the PSP Rating Scale were explored. Motor signs like gait, arising from chair and postural instability showed a positive correlation with tracer uptake in mesial frontoparietal lobes and the medial superior frontal gyrus and adjacent anterior cingulate cortex. While the signs disorientation and bradyphrenia showed a positive correlation with tracer uptake in the parietooccipital junction, the signs disorientation and arising from chair were negatively correlated with tau-PET signal in the caudate nucleus and thalamus. Total PSP Rating Scale Score showed a trend towards a positive correlation with mesial frontoparietal lobes and a negative correlation with caudate nucleus and thalamus. While in CBS patients, the main finding was a negative correlation of tracer binding in the caudate nucleus and thalamus and a positive correlation of tracer binding in medial frontal cortex with gait and motor signs, in PSP-RS patients various correlations of clinical signs with tracer binding in specific cerebral regions could be detected. Our data reveal [18F]PI-2620 tau-PET topology to correlate with symptomatology in 4-repeat tauopathies. Longitudinal studies will be needed to address whether a deterioration of signs and symptoms over time can be monitored by [18F]PI-2620 in 4-repeat tauopathies and whether [18F]PI-2620 may serve as a marker of disease progression in future therapeutic trials. The detected negative correlation of tracer binding in the caudate nucleus and thalamus with the signs disorientation and arising from chair may be due to an increasing atrophy in these regions leading to partial volume effects and a relative decrease of tracer uptake in the disease course. As cerebral regions correlating with symptomatology differ depending on the clinical phenotype, a precise knowledge of clinical signs and symptoms is necessary when interpreting [18F]PI-2620 PET results.

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YNICL Journal 2021 Journal Article

Cognitive reserve hypothesis in frontotemporal dementia: A FDG-PET study

Leonie Beyer
Johanna Meyer-Wilmes
Sonja Schönecker
Jonas Schnabel
Julia Sauerbeck
Maximilian Scheifele
Catharina Prix
Marcus Unterrainer

BACKGROUND AND OBJECTIVE: F]-fluorodeoxyglucose positron-emission-tomography (FDG-PET) hypometabolism in FTD. METHODS: Sixty-six FTD subjects (age 67 ± 8 years) and twenty-four cognitively healthy controls (HC) were evaluated. Brain regions with FTD-related glucose hypometabolism in the contrast against HC and brain regions that correlate with the cognitive function were defined by a voxel-based analysis and individual FDG-PET values were extracted from all frontotemporal brain areas. Linear regression analysis served to test if education is associated with residualized cognitive performance and regional FDG-PET hypometabolism after controlling for global cognition. RESULTS: Compared to healthy controls, patients with FTD showed glucose hypometabolism in bilateral frontal and temporal brain areas whereas cognition was only associated with deteriorated glucose metabolism in the left temporal lobe. The education level was significantly correlated with the residualized cognitive performance (residuals from regression analysis between hypometabolism and cognitive function as a quantitative index of reserve) and also negatively correlated with left temporal FDG-PET hypometabolism after controlling for cognition. CONCLUSIONS: In patients with FTD, the education level predicts the existing left temporal FDG-PET hypometabolism at the same cognition level, supporting the cognitive reserve hypothesis in FTD.

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