Inclusion Criteria:

Groups 1-2

• Stroke in one of the pre-defined categories for Groups 1-2.
• Signed informed consent from participant or legally authorized representative (LAR).
• Stroke onset to enrollment window 60 days: this time window allows for completion of potential acute inpatient rehabilitation, as it is difficult to arrange transport from an inpatient facility to outpatient MRI.
• Age ≥65 years

Groups 3-4

• Controls without stroke – without or with atrial fibrillation, matched, respectively, with Groups 1 and 2 (without and with atrial fibrillation).
• Matching criteria are: Age (±5 years); Sex; Race/Ethnicity; and CHA₂DS₂-VASc Score (excluding stroke).
• Signed informed consent from participant.

Exclusion Criteria:

• Patients not discharged to home or acute inpatient rehabilitation: patients discharged to a nursing home or assisted living facility may have difficulty returning for cardiac MRI. 
• Contraindications to cardiac MRI, including MRI-incompatible metallic implants, implanted electronic devices (i.e. pacemaker/defibrillator, neurostimulators, cochlear implants), other potentially mobile ferromagnetic material (i.e. shrapnel, magnetic aneurysm clips) and morbid obesity, and those with severe claustrophobia or who are unable to lie flat for 30-60 minutes. In a previous stroke imaging study (Romano JG, Prabhakaran S, Nizam A, et al. Infarct recurrence in intracranial atherosclerosis: Results from the MyRIAD Study. J Stroke Cerebrovasc Dis. 2021;30:105504), we identified that only 4% of our ischemic stroke population had MRI contraindication. Of note, implantable loop recorders are not contraindicated as they are MRI compatible. 
• Women who are pregnant, breast-feeding or intend to become pregnant.
• Anticipated life expectancy <1 year, as we anticipate minimum cardiac rhythm monitoring of 1 year and repeat cardiac MRI in a proportion of participants.
• Participation in other clinical trial involving investigational devices as these may not be MRI compatible and may interfere with cardiac rhythm monitoring.
• Patent foramen ovale (PFO) felt to be pathogenic as the cause of stroke: these individuals may be referred for PFO closure; it is unclear how this affects MRI 4D flow imaging.

Note: Other protocol defined Inclusion/Exclusion Criteria may apply.

Eligibility last updated 08/23/2024. Questions regarding updates should be directed to the study team contact.