Clinical, molecular imaging and biomarker concordance in the diagnosis of Alzheimer’s disease and vascular dementia

Background The CSF and plasma biomarkers may help clinicians in differentiating between Alzheimer and Vascular dementia. Apart from biopsy, FDG PET, MRI Brain and clinical examination gives a reliable diagnosis of AD and VaD. Aims To evaluate the correlation of molecular imaging (FDG PET brain) with CSF Alzheimer profile and Plasma hemostatic biomarkers in Mild Cognitive Impairment (MCI), Alzheimer's disease (AD) and Vascular dementia (VaD). Methods Neuropsychological assessment, MRI brain, FDG-PET brain, CSF biomarkers of AD (Aa42 and total tau) and plasma hemostatic biomarkers (Fibrinogen and D dimer) were done for evaluation. Results FDG PET Brain, plasma fibrinogen and D dimer were done in 68 patients. CSF biomarkers were done in 46 patients. Clinical-PET discordance was found in 7 patients. One patient of MCI-VaSC had a normal PET study with elevated haemostatic biomarkers. Those with clinical diagnosis of Alzheimer's disease either had normal hemostatic biomarkers and supporting Alzheimer profile CSF biomarkers where they were done. The discordant vascular group had elevated plasma hemostatic biomarker with normal CSF profile. Even those who were reported as FTD in PET imaging had Alzheimer profile and normal hemostatic factors. Conclusion FDG PET brain findings were concordant with the CSF biomarkers (CSF Aa42, Total tau and Tau/ Aa42 ratio) in Alzheimer's disease and Haemostatic biomarkers (Plasma Fibrinogen and D dimer) in vascular dementia. In clinical and molecular imaging discordance, biomarkers help in making a reliable diagnosis which favours the clinical assessment.