The CIRCLE study is a single-center prospective observational study that enrolled individuals with cerebral small vessel disease (SVD), while free of known dementia or stroke (both cerebral infarction and hemorrhage). The patients will receive neuropsychological testing, retinal digital images and multimodal magnetic resonance imaging (MRI). Blood samples will also be collected. Recent small subcortical infarcts, lacunes, white matter hyperintensities, perivascular spaces, microbleeds, and brain atrophy will be evaluated on both baseline and follow-up brain MRIs. The investigators will explore the predictors of preogression of SVD and cognitive deficits.

Cerebral small vessel disease (SVD) is commonly detected in elderly individuals, and patients with stroke or neurodegenerative disease. Features seen on neuroimaging include recent small subcortical infarcts, lacunes, white matter hyperintensities, perivascular spaces, microbleeds, and brain atrophy. Previous studies indicated that SVD was associated with an increased risk of stroke and stroke recurrence, cognitive deficits, physical disabilities, and mortality. However the pathogenesis of SVD is largely unknown. Little is known about how SVD lesions contribute to neurological or cognitive symptoms, and the association with risk factors. Recent data sugessted concomitant SVDs and retinopathy is associated with a profile of vascular cognitive impairment. In this study, the investigators try to explore the new pathological mechanism of SVD, the new predictors for SVD progression, and the association with cognitive Impairment, based on digital retinal images and brain multimodal imaging technique.

Inclusion Criteria:

• Adult (≥40y; no upper limit)
• Free of known dementia or stroke (both cerebral infarction and hemorrhage)

Exclusion Criteria:

• Any MRI contraindications
• Serious head injury (resulting to loss of consciousness) or received intracranial surgery
• Suffering from cancer

Residents of certain towns