Objective: To investigate association among brain imaging characteristics, vascular risk factors, and cognitive function in post stroke patients; to examine for risk factors of post-stroke dementia; and to evaluate interrater agreement between CT and MRI, with specific regard to white matter lesions.

Material and Method: This observational study in 100 stroke patients aged more than 15 years was conducted at Siriraj Hospital in Bangkok, Thailand. Brain imaging (CT or MRI) was performed in all patients. Cognitive and neuropsychiatric status was evaluated at 2-4 weeks after discharge and at the 6-12 month follow-up visit. Dementia was defined according to DSM IV criteria. Risk factors for and odd ratios of post-stroke dementia were analyzed.

Results: Dementia was diagnosed in 15 of 85 patients (17.6%). Vascular dementia was the most commonly observed type of dementia. Anterior circulation stroke (p = 0.033, OR: 4.5), lacunar infarction (p = 0.022, OR: 5.46), severe central atrophy (p = 0.042,OR: 14.67), and anterior white matter lucencies (p = 0.028, OR: 4.27) were all significantly different between the dementia and non-dementia groups. Risk factors associated with post-stroke dementia were educational level less than 6 years (p = 0.012, OR: 15.2), history of previous stroke (p = 0.048, OR: 3.88), and diabetes mellitus (p = 0.049, OR: 6.9). Interrater agreement for white matter lesion visual rating between CT and MRI brain was 0.637. No significant association between neuropsychiatric symptoms and brain lesion was found.

Conclusion: Prevalence of post-stroke dementia in this study was 17.6%. Combination of multiple clinical risk factors (DM, history of previous stroke, and low educational level) and brain lesion (anterior circulation, central atrophy, and anterior WML) can contribute to development of post-stroke dementia. Among brain imaging findings, severe central atrophy had the strongest association with dementia (OR: 14.7). Among evaluated risk factors, educational level less than 6 years was the strongest predictor of post-stroke dementia (OR: 15.2). CT scan of the brain was reliable, compared to MRI, for detecting white matter lesion (kappa level = 0.637, 75.5% agreement).

Keywords: post-stroke dementia, Thailand, white matter lesions