Efficacy Study of Cilostazol and Aspirin on Cerebral Small Vessel Disease

Inclusion Criteria: * 50 to 85 years of age * He/She can walk to the hospital (walker or cane is permissible). * Cerebral small vessel disease is observed on brain MRI. 1\) presence of one or more lacunar infarction and 2) moderate or severe confluent leukoaraiosis (defined as grade 2 or 3 on a modified Fazekas scale): periventricular WMCs with cap or rims lager than 5mm and deep subcortical WMCs \>10 mm in maximum diameter * written informed consent Exclusion Criteria: * Any patient with contraindication of antiplatelets * Any patient with cardioembolic source * Carotid bruit or large cerebral artery stenosis \>50% * Cortical infarction or subcortical infarction lager than 1.5 cm * bleeding tendency * chronic liver disease (AST or ALT \>100 IL/L) * chronic renal disease (Creatinine \>3.0mg/dL) * active gastrointestinal ulcer * any patients with any severe or unstable medical disease that may prevent them from completing study requirements (i.e., unstable or severe asthma) * Anemia (Hb \<10g/dL) or thrombocytopenia * Cardiac pacemaker or contraindication to MRI * Pregnancy or breast-feeding * drug or alcohol addiction * Any other white matte disease (i.e., Multiple sclerosis, sarcoidosis, or brain irradiation, etc) or brain tumor * Parkinson's disease, Alzheimer's disease or any other neurodegenerative disease * any hearing or visual impairment that can disturb the efficient evaluation of the patient * recent cerebral infarction with 3 months