Early Identification and Diagnosis of BAD-related Stroke

Prior treatment

• Participation in another clinical study within 3 months before informed consent or current participation in another clinical study that may interfere with this study.
  • Additional criteria that preclude classification as BAD-related stroke:

Other illness

• Intracranial hemorrhage, vascular malformation, aneurysm, brain abscess, malignant intracranial mass, or other non-ischemic intracranial lesion on baseline CT, MRI, MRA, CTA, or DSA.
• Pre-stroke modified Rankin Scale score ≥2.
• Definite cardioembolic source, including atrial fibrillation, myocardial infarction, clinically significant valvular heart disease, dilated cardiomyopathy, infective endocarditis, atrioventricular conduction disease, or heart rate \<50 beats/min as defined in the protocol.
• Receipt of or planned acute-phase endovascular treatment after stroke onset.
• Stroke due to other determined causes, such as moyamoya disease, arterial dissection, or vasculitis.

Other

• General exclusion criteria for all participants:
• Life expectancy ≤6 months.
• Unable to tolerate MRI examination.
• Pregnancy or breastfeeding.
• Ipsilateral extracranial tandem artery stenosis ≥50%.

• Age 18 to 80 years.
• Diagnosis of acute ischemic stroke.
• Time from symptom onset to enrollment ≤ 1 week; if the onset time is unknown, time from last known well to enrollment ≤ 1 week.
• Availability of required baseline clinical and neuroimaging assessments according to the study protocol.
• Written informed consent provided by the participant or legally authorized representative.
  • Participants will be classified into the BAD-related stroke cohort if they meet all predefined BAD-related stroke diagnostic criteria, including:
• A single isolated deep subcortical infarct on diffusion-weighted imaging.
• The presumed culprit perforating artery is the lenticulostriate artery or the paramedian pontine artery.
• For lenticulostriate artery territory infarction: a comma-shaped lesion extending from inferior to superior direction on coronal DWI or involvement of ≥3 axial DWI slices with 5-7 mm slice thickness.
• For paramedian pontine artery territory infarction: a lesion extending from the deep pons to the ventral surface of the pons on axial DWI.
• No ≥50% stenosis of the corresponding parent artery, confirmed by MRA, CTA, or DSA.
  • Participants with acute ischemic stroke who do not meet BAD-related stroke criteria will be classified into the non-BAD acute ischemic stroke cohort.