Cognitive Outcomes in BAD-related Stroke

Branch atheromatous disease (BAD) is a distinct subtype of ischemic stroke that is particularly prevalent among Chinese and other Asian populations. Patients with BAD are prone to early neurological deterioration and poor functional outcomes, and BAD is increasingly recognized as an independent disease entity. However, the association between BAD and cognitive impairment remains unclear. This nationwide, multicenter, prospective observational study will prospectively collect epidemiological, clinical, neuroimaging, functional, and cognitive outcome data from patients with BAD. The study aims to investigate the occurrence of cognitive impairment after BAD and identify the clinical and neuroimaging characteristics associated with cognitive impairment. In particular, the relationship between early neurological deterioration (END) and cognitive impairment will be investigated. As an exploratory objective, this study will further explore the potential brain network mechanisms underlying cognitive impairment associated with END events.

Inclusion Criteria: 1. Age: 18-80 years. 2. Time from onset to enrollment: 8-14 days; if onset time is unknown, time from last known normal to enrollment must be 8-14 days. 3. Meet the following imaging inclusion criteria: 3\. 1 DWI infarct: single (isolated) deep (subcortical) infarct 3.2 The culprit vessel is the lenticulostriate artery, and the DWI lesion meets at least one of the following criteria (A/B): A. comma-shaped infarct expanding fan-wise from bottom to top on coronal view; or B. involvement of ≥3 axial slices (slice thickness 5-7 mm) 3.3 No ≥50% stenosis of the ipsilateral middle cerebral artery (confirmed by MRA, CTA, or DSA) 4. Informed consent form signed by the patient or their legally authorized representative. Exclusion Criteria: 1. Baseline imaging showing intracranial hemorrhagic disease, vascular malformation, space-occupying lesion, or other non-ischemic intracranial pathology. 2. Transient ischemic attack or stroke mimics. 3. Cardioembolic causes: including atrial fibrillation, valvular heart disease, infective endocarditis, etc. 4. Tandem extracranial vascular stenosis ≥50% ipsilateral to the infarct lesion. 5. Prior diagnosis of dementia (Alzheimer's disease, frontotemporal dementia, or Lewy body dementia) or significant cognitive decline (IQCODE \> 3.38). 6. Contraindications to photon-counting CT or 5T-MRI. 7. Pregnancy or lactation. 8. Life expectancy \< 1 year.