Antiplatelet Therapy for Silent Brain Infarction

Inclusion Criteria: * cerebral infarction(s) identified by CT/MRI (≥ 3mm in diameter) * absence of signs or symptoms of neurological dysfunction ascribed to the lesion(s) * absence of PMH of neurological dysfunctions due to CNS lesion(s) Exclusion Criteria: * Age under 45 years or above 80 years * PMH of ICH within 180 days * PMH of lobar hemorrhage of anytime * Neuroimaging evidence suggesting cerebral microbleeds * High risk of bleeding (e.g. recurrent gastrointestinal or genitourinary bleeding, active peptic ulcer disease) * Anticipated requirement for long-term use (more than 28 days) of anticoagulants (e.g. recurrent deep vein thrombosis) * Prior long-term use of anticoagulants (more than 28 days) or antiplatelet agents (more than 28 days) * Prior retinal stroke/TIA (diagnosed either clinically or by imaging) * Intolerance or contraindications to aspirin (including thrombocytopenia, prolonged INR) * Prior ipsilateral carotid endarterectomy/stent * Stenosis of culprit artery ≥ 70% (detected by ultrasound, MRA, CTA or DSA) * Atrial fibrillation, or acute myocardial infarction, or acute congestive heart failure * Impaired renal function: glomerular filtration rate\<60 * Mini Mental Status Examination score\<24 (adjusted for age and education) * Medical contraindication to MRI * Pregnancy or women of child-bearing potential who are not following an effective method of contraception * Unable or unwilling to provide informed consent * Unlikely to be compliant with therapy/u…