Inclusion Criteria1. Age >18 years
2. Clinical diagnosis of ischemic stroke, stroke symptoms present for at least 30 minutes and has not significantly improved before treatment
3. No pre-stroke functional dependence (pre-stroke Modified Rankin Score ≤ 1)
4. NIHSS ≥ 8 and < 30 at the time of enrollment
5. Patient is able to be treated within 12 hours of stroke symptoms onset with minimum of one deployment of the Solitaire Device. (onset time is defined as the last time when the patient was witnessed to be at baseline)
6. Patient is confirmed to have symptomatic intracranial occlusion, based on single phase, multiphase or dynamic CTA/MRA or DSA, at one or more of the following locations: Carotid T/L, M1 MCA, or M2-MCA equivalent affecting at least 50% of MCA territory.
7. Patient or patient's legally authorized representative received information about data collection or if mandatory, has signed and dated an Informed Consent Form.
Exclusion Criteria1. Baseline non-contrast CT or DWI reveals a moderate/large core defined as extensive early ischemic changes of ASPECTS 0-6 in the territory of symptomatic intracranial occlusion or DWI lesion volume > 50ml.
2. Other confirmation of a moderate to large core defined as one of three ways:
i. On a single phase, multiphase or dynamic CTA: no or minimal collaterals in a region greater than 50% of the MCA territory when compared to pial filling on the contralateral side (multiphase/dynamic CTA preferred) OR.
ii. On CT perfusion (>8 cm coverage): a low CBV and very low CBF ASPECTS <6 in the symptomatic MCA territory OR.
iii. On CT perfusion(<8 cm coverage): a region of low CBV and very low CBF >1/3 of the CTP imaged symptomatic MCA territory.
3. Groin puncture is not possible within 70 minutes of the end of CTA/MRA acquisition.
4. Seizure at onset of stroke.
5. Prior stroke within the last 3 months.
6. Investigators thought the cause of occlusion were not atherosclerosis
7. Subject with a pre-existing neurological or psychiatric disease that would confound the neurological and functional evaluations.
8. Presumed septic embolus or suspicion of bacterial endocarditis.
9. Life expectancy of less than 90 days.
10. Known history of ICH, SAH, AVM or tumor.
11. Known disease with increased bleeding risk during the last 3 months, e.g. severe liver disease, ulcerative gastrointestinal disease, esophageal varices, hepatic failure.
12. Major surgery ,significant trauma or hemorrhagic disease in past 10 days
13. Uncompensated hypertension defined as systolic blood pressure >185 mm Hg or diastolic blood pressure ≥110 mm Hg on 3 repeated measures at least 10 minutes apart.
14. Renal Failure as defined by a serum creatinine > 2.0 or Glomerular Filtration Rate [GFR] < 30.
15. Platelet count of below 100,000/mm3.
16. Blood glucose <2.8 or >22.2 mmol/l.
17. Patients receiving oral anticoagulants, e.g. warfarin sodium, and coagulant response time (INR) >1.5.
18. Administration of heparin within the previous 48 hours and APTT time exceeding the upper limit of normal for laboratory.
19. Suspected intracranial dissection as a cause of stroke.
20. Clinical history, past imaging or clinical judgment suggests that the intracranial occlusion is chronic.
21. No femoral pulses.
22. Contraindications of DSA examination, severe contrast allergy or absolute contraindication to iodinated contrast.
23. Pregnancy; if a woman of child-bearing potential has a positive urine or serum beta HCG test.