Abstract
<title>Abstract</title> <p> <underline> <bold>BACKGROUND:</bold> </underline> Early differentiation between Alzheimer’s disease (AD) and fronto-temporal dementia (FTD) remains challenging due to overlapping clinical features and structural MRI findings. Functional MRI techniques such as arterial spin labelling (ASL) and proton magnetic resonance spectroscopy (¹H‑MRS) offer non‑invasive assessment of cerebral perfusion and metabolism that may precede overt structural changes. <underline> <bold>OBJECTIVE:</bold> </underline> To evaluate the role of ASL and ¹H‑MRS in early detection and differentiation of AD and FTD, and distinguishing these entities from age-related changes. <underline> <bold>METHODS:</bold> </underline> Fifteen patients each with AD, FTD and healthy controls underwent 3D-Pseudocontinous ASL-MRI and MRS in addition to routine imaging on 3T MRI system. Visual rating scales were used for assessment of regional atrophy. Regional cerebral blood flow (CBF) was quantified using ASL, and metabolite ratios (NAA/Cr, mI/Cr, NAA/mI) were assessed in the anterior and posterior cingulate gyri using MRS. Diagnostic performance was evaluated using receiver operating characteristic (ROC) analysis. <underline> <bold>RESULTS:</bold> </underline> FTD demonstrated predominant frontal and anterior temporal atrophy with corresponding hypoperfusion, while AD showed parietotemporal and posterior cingulate involvement. Mean CBF in the anterior cingulate gyrus differentiated FTD from controls with a sensitivity of 86.6% and specificity of 80% at cut‑off of 31.91 ml/100 g/min. Posterior cingulate hypoperfusion differentiated AD from controls with a sensitivity of 86.6% and specificity of 73.3% at cut‑off of 38.29 ml/100 g/min. On MRS, NAA/mI ratio was significantly decreased in anterior cingulate gyrus in FTD compared to both AD and controls at cut-off value of 8.56 in controls with a specificity and sensitivity of 86.6 % and 83.3% respectively, whereas in AD patients, cutoff value was 14.75 with sensitivity and specificity of 86.6% each. <underline> <bold>CONCLUSION:</bold> </underline> The use of functional neuroimaging techniques as an adjunct to conventional MRI can provide unique insights into the changes seen in neurodegenerative diseases in the form of disease-specific patterns of differences in perfusion and metabolism. </p>