[Imaging-based patient selection for mechanical thrombectomy based on time since symptom onset].

Area of Science:

• Neurology
• Interventional Radiology
• Emergency Medicine

Background:

• Ischemic stroke due to large vessel occlusion (LVO) requires precise patient selection for endovascular mechanical thrombectomy (MT).
• Brain imaging modalities, including computed tomography (CT) and magnetic resonance imaging (MRI), guide these critical treatment decisions.

Purpose of the Study:

• To recommend optimal imaging modalities and protocols for MT patient selection.
• To align imaging choices with specific time windows from symptom onset.

Main Methods:

• Evaluation of randomized controlled trials on imaging-based patient selection for MT.
• Analysis categorized by time intervals since symptom onset.
• Discussion of methodological aspects, advantages, and limitations of stroke imaging protocols.

Main Results:

• CT, often with CT angiography (CTA) or perfusion imaging, was predominantly used in MT trials.
• For early time windows (≤6h for MT, ≤4.5h with thrombolysis), CT with CTA is sufficient.
• Perfusion imaging is essential for patient selection in later or unknown time windows.

Conclusions:

• In early time windows, CT with CTA is adequate for MT patient selection.
• For later or unknown time windows, perfusion imaging is necessary.
• MRI is a first-line choice for unknown time windows with mild to moderate deficits; CT with perfusion imaging is preferred for severe deficits.