Diverse Vascular Contributions to Cognitive Impairment and Dementia (VCID): Improving Meaningful Diagnosis for People at Risk for Dementia. Vascular Contributions to Cognitive Impairment and Dementia (VCID) is defined as memory or thinking problems due to vascular disease.  Our blood circulatory systems affect our brain health. Cerebrovascular disease (vascular disease affecting the brain) reduces blood flow, causes abnormal signals in the white matter of the brain called white matter hyperintensities, and small holes in the brain called infarcts.  MRI can detect these changes. These changes can affect memory and thinking skills, and when severe, can lead to higher risk of developing dementia, including Alzheimer's. We use vascular contributions to cognitive impairment or dementia (VCID) as a term to indicate problems with memory and thinking that result from vascular brain injury.