Brain MRI Biomarkers to Predict Cognitive Decline in Older People with Alzheimer's Disease

Background: Structural magnetic resonance imaging markers predicting symptomatic progression at the individual level can be highly beneficial for early intervention and treatment planning for Alzheimer's disease (AD). However, the correlation between baseline MRI findings and AD progression has not been fully established. Objective: To explore the correlation between baseline MRI findings and AD progression. Methods: Brain volumetric measures were applied to differentiate the patients at risk of fast deterioration in AD. We included 194 AD patients with a 24-month follow-up: 65 slow decliners, 63 normal decliners, and 66 fast decliners categorized by changes in Alzheimer's Disease Assessment Scale-Cognitive Subscale (ADAS-Cog). ANOVA analyses were used to identify baseline brain atrophy between groups. Logistic regressions were further performed to explore the relative merits of AD resemblance structural atrophy index (AD-RAI) and individual regional volumetric measures in prediction of disease progression. Results: Atrophy in the temporal and insular lobes was associated with fast cognitive decline over 24 months. Smaller volumes of temporal and insular lobes in the left but not the right brain were associated with fast cognitive decline. Baseline AD-RAI predicted fast versus slow progression of cognitive decline (odds ratio 3.025 (95% CI: 1.064-8.600), high versus low, AUC 0.771). Moreover, AD-RAI was significantly lower among slow decliners when compared with normal decliners (p = 0.039). Conclusion: AD-RAI on MRI showed potential in identifying clinical AD patients at risk of accelerated cognitive decline.