Patients suspected of having symptomatic ICAD at admission will be enrolled. All patients will receive a thorough evaluation to determine the cause of their ischemic event (TIA or ischemic stroke), including carotid duplex, transcranial Doppler, echocardiography, electrocardiogram, computed tomography (CT), CT angiography, MRI, magnetic resonance angiography (MRA), or digital subtraction angiography DSA.