Imaging Selection for Mechanical Thrombectomy

Initial Imaging Requirements

• The American Heart Association recommends that noncontrast CT head must be performed immediately to exclude hemorrhage and assess ASPECTS score, and CT angiography (CTA) should be obtained simultaneously to identify large vessel occlusion 1, 4
• The American College of Radiology suggests that these studies should not delay IV alteplase if the patient is within 4.5 hours 1

Time-Based Advanced Imaging Requirements

• In the early window (0-6 hours from last known well), the American College of Radiology states that CTP is not necessary for thrombectomy decision-making, and noncontrast CT plus CTA is sufficient if ASPECTS ≥6, NIHSS ≥6, and large vessel occlusion is confirmed 5, 6
• In the extended window (6-24 hours from last known well), the American Heart Association recommends that CTP or DW-MRI with perfusion is required to determine eligibility, and must demonstrate sizable mismatch between ischemic core and hypoperfusion area 1, 2, 3, 7
• The American Stroke Association states that strict adherence to DAWN or DEFUSE-3 criteria is mandatory when selecting patients beyond 6 hours, which used perfusion imaging as eligibility criteria 1, 2, 3, 8

Laboratory Requirements

• The American College of Cardiology recommends that aPTT and INR should be obtained but must not delay reperfusion therapy, and only blood glucose measurement must precede IV alteplase 1, 4, 7, 8