Automated advanced imaging in acute ischemic stroke. Certainties and uncertainties

Area of Science:

• Neuroradiology
• Stroke Imaging
• Interventional Neurology

Background:

• Advanced imaging techniques like computed tomography perfusion (CTP) and diffusion/perfusion-weighted imaging (PWI/DWI) are crucial for selecting acute ischemic stroke (AIS) patients for endovascular treatment (EVT).
• These methods aim to quantify infarct core and ischemic penumbra, defining 'target mismatch' criteria for optimal patient selection in the late time window (6-24 hours).

Purpose of the Study:

• To review the benefits and drawbacks of advanced imaging in selecting AIS patients for EVT, focusing on the late time window.
• To discuss the role of target mismatch criteria, including core volume, penumbra volume, and mismatch ratio, in patient selection.

Main Methods:

• Review of advanced imaging techniques (CTP, DWI, PWI) and their application in AIS patient selection for EVT.
• Analysis of target mismatch parameters, automated software calculations, and their limitations.
• Comparison of advanced imaging with conventional imaging (e.g., ASPECTS, CT angiography collaterals).

Main Results:

• Advanced imaging can quantify infarct core and ischemic penumbra, aiding in target mismatch identification.
• Automated software for advanced imaging analysis presents limitations, including technical artifacts and vendor-dependent variability, leading to potential misclassification.
• The accuracy of advanced imaging in detecting infarct core can be variable, leading to over- or underestimation.
• Current selection criteria for EVT using advanced imaging may be suboptimal, resulting in high rates of futile reperfusion and overselection.
• Debate exists on whether advanced imaging is superior to conventional imaging for EVT selection, with some studies suggesting comparable outcomes with conventional methods.

Conclusions:

• While advanced imaging offers valuable insights, its limitations in automated analysis and accuracy necessitate careful consideration.
• The optimal selection of AIS patients for EVT, particularly in the late window, remains challenging.
• Combining conventional and advanced imaging approaches may offer improved criteria for selecting patients eligible for EVT.