Developing Topics.

Abstract

Amyloid-negative amnestic mild cognitive impairment (MCI) patients have a conversion rate to dementia of approximately 10% within 2 years. This study aimed to investigate whether brain age, calculated using quantitative data obtained from brain magnetic resonance imaging (MRI) artificial intelligence (AI) software can be an important factor in predicting the conversion of dementia in amyloid-negative amnestic MCI patients. We conducted a retrospective cohort study of patients with amyloid-negative amnestic MCI who visited the memory clinic of Asan Medical Center. All participants underwent detailed neuropsychological testing, brain MRI, and [18F]-florbetaben (FBB) positron emission tomography (PET) scan. Conversion to dementia was determined by a neurologist based on a clinical interview with a detailed neuropsychological test or a decline in the Korean version of the Mini-Mental State Examination score of more than 4 points per year combined with impaired activities of daily living. Brain age was determined through volumetric assessment of 12 distinct brain regions using commercially available segmentation software, Neurophet AQUA. During the follow-up period, 38% (35/91) of patients converted to dementia from amnestic MCI. 73% (66/91) of patients had a higher brain age than their actual chronological age. In the conversion group, all participants except three (91%, 32/35) had a brain age older than their chronological age. Conversely, the conversion rate to dementia was significantly lower in the group with a younger brain age than their actual age. The subjects were divided into eight groups based on sex, education level, and brain age. When defining the 'survival' as the non-conversion of MCI to dementia, these groups significantly differed in survival probability with a p-value of 0.036. The low-educated female group with a higher brain age than their actual age had the lowest survival rate of all groups. Our findings suggest that MRI-based brain age used in this study can contribute to predicting conversion to dementia in patients with amyloid-negative amnestic MCI.