Evaluating the Ceretrieve Device for Treating Acute Ischemic Stroke

Inclusion Criteria:

1. Age ≥18 years of age
2. Clinical signs consistent with acute ischemic stroke
3. Subject is able to be treated within 24 hours of stroke symptom onset.
4. Pre-stroke modified Rankin Score of 0 or 1
5. NIHSS \> 6 at the time of screening
6. If intravenous thrombolysis (IVT) is indicated, initiation of IVT should be administered as soon as possible and no later than 4.5 hours of onset of stroke symptoms (onset time is defined as the last time when the patient was witnessed to be at baseline neurologic status), with investigator verification that the subject has received/is receiving the correct IVT dose for the estimated weight.
7. Intracranial occlusion defined as Modified Thrombolysis in Cerebral Infarction (mTICI) 0-1 flow confirmed by angiography that is accessible to the mechanical thrombectomy device in the following locations:

1\. Intracranial internal carotid artery 2. M1 and/or M2 segment of the MCA 3. Vertebral artery 4. Basilar artery Note: M1 segment of the MCA is defined as the arterial trunk from its origin at the ICA to the first bifurcation or trifurcation into major branches neglecting the small temporo-polar branch.

8\. A valid completed informed consent in accordance with the local ethics committee regulations.

Exclusion Criteria:

1. Female who is pregnant or lactating or has a positive pregnancy test at time of admission.
2. Rapid neurological improvement prior to study enrolment suggesting resolution of signs/symptoms of stroke
3. Known serious sensitivity to radiographic contrast agents
4. Known sensitivity to nickel, titanium metals, or their alloys
5. Subjects already enrolled in other investigational studies that would interfere with study endpoints
6. Known hereditary or acquired hemorrhagic diathesis, coagulation factor deficiency. (A subject without history or suspicion of coagulopathy does not require INR or prothrombin time lab results to be available prior to enrolment.)
7. Life expectancy of less than 90 days
8. Clinical presentation suggests a subarachnoid hemorrhage, even if the initial CT or MRI scan is normal.
9. Suspicion of aortic dissection
10. Subject with a comorbid disease or condition that would confound the neurological and functional evaluations or compromise survival or ability to complete follow-up assessments.
11. Known to currently use or abuses alcohol (defined as regular or daily consumption of more than four alcoholic drinks per day).
12. Known arterial condition (e.g., proximal vessel stenosis or pre-existing stent) that would prevent the device from reaching the target vessel and/or preclude safe recovery of the device
13. Subject who requires balloon angioplasty or stenting of the carotid artery at the time of the index procedure
14. Angiographic evidence of carotid dissection
15. Imaging exclusion criteria:

    * CT or MRI evidence of hemorrhage on presentation
    * CT or MRI evidence of mass effect or intra-cranial tumor (except small meningioma)
    * CT or MRI evidence of cerebral vasculitis
    * CT or MRI-DWI showing ASPECTS 0-5 (or pc-ASPECTS 0-6 in the posterior circulation). Alternatively, if automated core volume assessment software is used, MRI-DWI or CTP core \> 70cc.
    * CT/MRI shows evidence of carotid dissection or complete cervical carotid occlusion requiring a stent
    * Any imaging evidence that suggests, in the opinion of the investigator, that the subject is not appropriate for mechanical thrombectomy intervention while utilizing an aspiration approach (e.g. inability to navigate to the target lesion, moderate/large infarct with poor collateral circulation, etc.).
16. Occlusions in multiple vascular territories (e.g., bilateral anterior circulation, or anterior/posterior circulation) as confirmed by angiography, or clinical evidence of bilateral strokes or strokes in multiple territories.