A 55-year-old female is evaluated after a recent hospital admission for ischemic stroke. She presented with mild right-sided hemiparesisbut it completely resolved after the second hospital day. An electrocardiogram (EKG)transthoracic echocardiogram (TTE)and carotid ultrasound were normal. Transesophageal echocardiogram (TEE) was normal. What is the most likely etiology of the patient's transient ischemic attack (TIA)?
a) Atrial fibrillation
b) Carotid artery stenosis
c) Patent foramen ovale (PFO)
d) Large vessel atherosclerosis
