To investigate the relationships among cerebrospinal fluid (CSF) levels of t-Tau, p-Tau and Aβ1-42 amyloid peptide and 18F-FDG brain distribution in a population with Alzheimer’s disease (AD).
The study included 81 newly diagnosed AD patients according to the NINCDS-ADRDA criteria. The mean (SD) age of the patients was 70 (± 6) years, 44 males and 37 females. All subjects underwent a CSF assay and a Magnetic Resonance before 18F-FDG PET scanning. The relationships were evaluated by means of Statistical Parametric Mapping (SPM8).
An increased 18F-FDG uptake in BA 18,19 and in right cerebellum is related to low CSF levels of Aβ1-42. Increased t-Tau CSF levels are related to a reduced glucose consumption in a wide portion of right frontal lobe (BA 47) and limbic lobe bilaterally (BA 31,32) while no areas of increased 18F-FDG uptake related to t-Tau levels have been detected. Elevated p-Tau concentrations in CSF are related to an increased glucose consumption in both right and left limbic lobe and in left frontal lobe (BA 32 and 8).
The results of our study suggests that reduced Aβ1-42 CSF concentrations are related to a wide cortical dysfunction while t-Tau and p-Tau are related to more selective cortical metabolic patterns that mainly involves the cingulate cortex.