Patient description: An 8-year-old boy fell from his bike striking his left temple on the pavement. There was no immediate loss of consciousness, and a brief examination at the scene noted his pupils were symmetrical, reactive to the light, and he was moving all four limbs. Half an hour after the fall the child became drowsy, pale, and vomited. He was transferred to the emergency department. Upon arrival the heart rate was 52/min, blood pressure of 155/98. The Glasgow Coma Scale (GCS) was 6/15, the pupils were asymmetrical and movement of the right upper and lower extremities was impaired. The neurosurgical team advised deferring the CT scan in favor of initiating immediate treatment.

Clinical trial eligibility criteria: eligible ages (years): 30.0-80.0,  Intracranial Arterial Stenosis Intracranial Atherosclerosis Ischemic Stroke Cerebral Angiogenesis TIA or non-severe stroke within 30 days of enrollment attributed to 70% to 99% stenosis* of a major intracranial artery (carotid artery or MCA) *May be diagnosed by TCD, MRA, or CTA to qualify, but must be confirmed by catheter angiography as per usual clinical practice Modified Rankin scale score of ≤3 Target area of stenosis in an intracranial artery that has a normal diameter of 2.00 mm to 4.50 mm Target area of stenosis is ≤14 mm in length Age ≥30 years and ≤80 years * Patients 30 to 49 years of age are required to meet at least 1 additional (i-vi) provided below to qualify for the study. This additional requirement is to increase the likelihood that the symptomatic intracranial stenosis in patients 30 to 49 years is atherosclerotic: i. Insulin-dependent diabetes for at least 15 years ii. At least 2 of the following atherosclerotic risk factors: hypertension (BP ≥ 140/90 mm Hg or on antihypertensive therapy); dyslipidemia (LDL ≥130 mg/dL or HDL ≤40 mg/dL or fasting triglycerides ≥150 mg/dL or on lipid lowering therapy); smoking; non-insulin-dependent diabetes or insulin-dependent diabetes of <15 years duration; family history of any of the following: myocardial infarction, coronary artery bypass, coronary angioplasty or stenting, stroke, carotid endarterectomy or stenting, and peripheral vascular surgery in parent or sibling who was < 55 years of age for men or < 65 for women at the time of the event iii. History of any of the following: myocardial infarction, coronary artery bypass, coronary angioplasty or stenting, carotid endarterectomy or stenting, or peripheral vascular surgery for atherosclerotic disease iv. Any stenosis of an extracranial carotid or vertebral artery, another intracranial artery, subclavian artery, coronary artery, iliac or femoral artery, other lower or upper extremity artery, mesenteric artery, or renal artery that was documented by noninvasive vascular imaging or catheter angiography and is considered atherosclerotic v. Aortic arch atheroma documented by noninvasive vascular imaging or catheter angiography vi. Any aortic aneurysm documented by noninvasive vascular imaging or catheter angiography that is considered atherosclerotic Negative pregnancy test in a female who has had any menses in the last 18 months Patient is willing and able to return for all follow-up visits required by the protocol  Tandem extracranial or intracranial stenosis (70-99%) or occlusion that is proximal or distal to the target intracranial lesion Bilateral intracranial vertebral artery stenosis of 70% to 99% and uncertainty about which artery is symptomatic (e.g., if patient has pontine, midbrain, or temporal occipital symptoms) Stenting, angioplasty, or endarterectomy of an extracranial (carotid or vertebral artery) or intracranial artery within 30 days before the expected enrollment date Previous treatment of target lesion with a stent, angioplasty, or other mechanical device, or plan to perform staged angioplasty followed by stenting of target lesion Plan to perform concomitant angioplasty or stenting of an extracranial vessel tandem to an intracranial stenosis Presence of intraluminal thrombus proximal to or at the target lesion Any aneurysm proximal to or distal to the stenotic intracranial artery Intracranial tumor (including meningioma) or any intracranial vascular malformation Computed tomographic or angiographic evidence of severe calcification at target lesion Thrombolytic therapy within 24 hours before enrollment