Demonstrating the pathophysiological link between Left Atrial (LA) and Left Atrial Appendage (LAA) pathology and embolic strokes in non-Atrial Fibrillation (AF) individuals represents a major advance in stroke prevention strategies. Instead of relying on non-specific criteria for stroke risk assessment, the investigators propose to identify individuals with high-risk of embolic stroke using imaging criteria that reflect the underlying pathophysiology of embolic stroke of cardiac origin. the investigators can therefore lay the groundwork for future anticoagulation strategies for stroke prevention beyond AF.