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Semi-quantitative Assessment Using [18F]FDG Tracer in Patients with Severe Brain Injury
Published on: November 9, 2018
The Diagnostic Role of FDG-PET in Dementias Presenting with Language and Behavioral Symptom
Objective:
This study aimed to assess the diagnostic contribution of Fluorodeoxyglucose Positron Emission Tomography (FDG-PET) in neurodegenerative dementias presenting with language-predominant symptoms, with or without accompanying behavioral changes, and to evaluate the correspondence between PET-derived metabolic patterns and cerebrospinal fluid (CSF) biomarkers.
Methods:
Sixteen patients with language-predominant onset were categorized into two groups: Alzheimer’s disease (AD) spectrum (n=8) and the frontotemporal lobar degeneration (FTLD) spectrum (n=8). All participants underwent clinical evaluation, neuropsychological testing, and FDG-PET imaging. Cerebrospinal fluid biomarkers [Amyloid Beta (Aβ42), total tau, and phosphorylated tau] were analyzed in eligible individuals (n=6). The two groups were compared across demographic, clinical, and neuroimaging parameters.
Results:
FDG-PET revealed pronounced posterior temporoparietal hypometabolism in AD-spectrum patients, whereas FTLD-spectrum patients demonstrated frontal, insular, and anterior temporal metabolic involvement. Cerebrospinal fluid biomarker profiles consistently supported Alzheimer-type pathology among AD-spectrum cases. In the FTLD group, one patient exhibited borderline-low Aβ42; however, the corresponding FDG-PET pattern was characteristic of FTLD.
Conclusion:
FDG-PET demonstrates a supportive role in differentiating AD from FTLD among patients presenting with language-predominant neurodegenerative syndromes. In scenarios where CSF biomarkers are unavailable or yield borderline values, FDG-PET-based metabolic signatures may offer additional guidance and can contribute to strengthening multimodal diagnostic frameworks in geropsychiatry settings.
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