Motivation: Alzheimer's disease (AD) presents typically gray matter atrophy and white matter abnormalities in neuroimaging. Goal(s): Exploring gray-white matter boundary Z-score (gwBZ) and its tissue volume (gwBTV) between patients with Alzheimer’s disease (AD), amnestic mild cognitive impairment (MCI), and cognitively normal (CN) elderly participants. Approach: Three-dimensional T1-weight images of a total of 227 participants were acquired to calculate gwBZ and gwBTV, prospectively. Results: Both gwBZ and gwBTV were reduced in AD, were positively correlated with cognitive function, and could accurately discriminate AD from CN . Impact: gwBZ and gwBTV could be a useful tool for monitoring AD progression and diagnosis.