We assessed the severity of amyloid-β accumulation and white matter lesions (WML) in the brain, and their association with cognitive decline, in patients (n = 47) with Alzheimer's disease (AD). The mean cortical standardized uptake value ratio (mcSUVR) was derived from amyloid positron emission tomography, while the percentage of WML area relative to brain parenchymal area was determined using magnetic resonance imaging. Cognitive decline was positively correlated with WML severity (