The factors and symptomatology associated with different types of hyperintensity lesions on MRI were investigated. The study population consisted of 139 subjects who were recruited from 450 outpatients who had a neurological diagnosis in 1994. The subjects underwent brain magnetic resonance imaging between 1994 and 1995 and were divided into three groups (control, asymptomatic, and symptomatic) on the basis of T-2 hyperintensity lesions, as well as a history of or neurological signs of stroke, or both. The demographic characteristics and risk factors were studied, and the T-2 hyperintensity lesions were analysed semi-quantitatively. Results showed that: (1) the control and asymptomatic groups did not differ in terms of risk factors and demographic characteristics with the exception of age; (2) the symptomatic group was characterized by a significantly higher incidence of hypertension and electrocardiographic abnormalities, as well as significantly more numerous risk factors when compared with the other two groups; (3) the symptomatic patients also had higher proportion of men and higher levels of systolic blood pressure and blood glucose than the control patients, and more frequent hypertriglyceridaemia and higher triglyceride level than the asymptomatic patients; (4) the symptomatic group had a greater lesion distribution in the posterior basal ganglia-internal capsule and the infratentorial regions than did the asymptomatic group. We concluded that the asymptomatic and symptomatic groups should not be considered identical entities.