Assessment of muscular activity by positron emission tomography using [¹¹C]acetate

The purpose of the present study is to investigate exercise-related changes in skeletal muscle of rodents and humans with PET and [11C]acetate. A pre-clinical and a clinical protocol were implemented, the veterinary experiment involving the application of kinetic analysis to investigate the metabolism of skeletal rat muscle and its comparison to more conventional quantitation approaches. Osteoarthritis represents a chronic disease that causes significant burdens to patients and there is now increasing evidence in literature as well as from clinical practice, that muscle weakness probably plays a contributory role in the onset and progression of osteoarthritis. PET allows the study of tissue metabolism in vivo in a non-invasive way, enabling to quantitatively characterise physiologic processes. To the best of our knowledge, just a few studies in literature investigated the metabolic fate of acetate in the skeletal muscle at rest and after exercise using PET monitoring and kinetic analysis

[¹¹C]acetate and PET/CT assessment of muscle activation in rat studies

The purpose of the present study is to apply kinetic analysis to investigate exercise-related changes in the metabolism of the skeletal muscle of the rat hindlimb by [[Formula: see text]]acetate positron emission tomography and computed tomography (PET/CT)

Education-Adjusted Normality Thresholds for FDG-PET in the Diagnosis of Alzheimer Disease

Background: A corollary of the reserve hypothesis is that what is regarded as pathological cortical metabolism in patients might vary according to education. Objective: The aim of this study is to assess the incremental diagnostic value of education-adjusted over unadjusted thresholds on the diagnostic accuracy of FDG-PET as a biomarker for Alzheimer disease (AD). Methods: We compared cortical metabolism in 90 healthy controls and 181 AD patients from the Alzheimer Disease Neuroimaging Initiative (ADNI) database. The AUC of the ROC curve did not differ significantly between the whole group and the higher-education patients or the lower-education subjects. Results: The threshold of wMetaROI values providing 80% sensitivity was lower in higher-education patients and higher in the lower-education patients, compared to the standard threshold derived over the whole AD collective, without, however, significant changes in sensitivity and specificity. Conclusion: These data show that education, as a proxy of reserve, is not a major confounder in the diagnostic accuracy of FDG-PET in AD and the adoption of education-adjusted thresholds is not required in daily practice

Hybrid PET-MRI in Alzheimer's Disease Research

Multiple factors, namely amyloid, tau, inflammation, metabolic, and perfusion changes, contribute to the cascade of neurodegeneration and functional decline occurring in Alzheimer's disease (AD). These molecular and cellular processes and related functional and morphological changes can be visualized in vivo by two imaging modalities, namely positron emission tomography (PET) and magnetic resonance imaging (MRI). These imaging biomarkers are now part of the diagnostic algorithm and of particular interest for patient stratification and targeted drug development.In this field the availability of hybrid PET/MR systems not only offers a comprehensive evaluation in a single imaging session, but also opens new possibilities for the integration of the two imaging information. Here, we cover the clinical protocols and practical details of FDG, amyloid, and tau PET/MR imaging as applied in our institutions

Basal forebrain metabolism in Alzheimer's disease continuum: relationship with education

We analyzed education, as a proxy of cognitive reserve, and the cholinergic pathway in Alzheimer's disease (AD), to test the hypothesis that education might modulate the relationship between clinical symptoms and metabolic and structural changes in AD. We included 84 subjects and compared between diagnostic groups and different educational levels the glucose metabolism of basal forebrain (BFM) and volume of the basal forebrain, the major cholinergic structure, and hippocampus (HM) (and hippocampal volume), a relevant projection site for the basal forebrain. Correlations with the global cognitive status and education in the whole sample were also performed. Patients with AD dementia showed reduced basal forebrain volume, hippocampal volume, and HM compared with controls. In the whole group, the global cognitive status was positively correlated with BFM and HM. Among high-educated subjects, mild cognitive impairment showed higher BFM and HM in comparison to other diagnostic groups. Our results suggest that in mild cognitive impairment subjects with a higher educational level, cholinergic activity is upregulated and this appears to have a compensatory effect, which may be lost in later symptomatic stages

Imagerie cérébrale de la maladie d'Alzheimer : état de l'art et perspectives pour le clinicien

To improve the clinical detection of Alzheimer's disease (AD) new diagnostic criteria have been proposed, based on biomarkers of synaptic dysfunction, AD-related neurodegeneration, and Aβ cerebral amyloidosis. Magnetic resonance imaging (MRI) and position emission tomography (PET) neuroimaging can be configured as powerful means for the detection of medial-temporal atrophy, reduced uptake of 18F-FDG PET or and increased retention of Aβ amyloid protein by amyloïd-PET. In this review, we will discuss these promising techniques that allow assessing in vivo AD pathology and help clinicians to better diagnose and follow-up patients, particularly in clinical trials using disease-modifying treatments

L'atrophie du lobe temporal mésial détectée par IRM en tant que biomarqueur de la maladie d'Alzheimer

Significant progresses have been made in the understanding of the pathological mechanisms of Alzheimer's disease (AD) and in developing tools enabling to detect its stages and its progression in vivo. At present, we know that the changes in AD pathophysiology occur many years before its clinical manifestations. Atrophy of the medial temporal lobe - containing anatomical structures essential for declarative memory, mostly impaired in AD - is one of the biomarkers detectable by magnetic resonance which can help us to predict the progression to dementia in patients with mild cognitive impairment. The atrophy assessment of the posterior cingulate cortex and the precuneus, other key hubs of the declarative memory network, can also be a useful complement