MRI-based Quantitative Collateral Assessment in Acute Stroke : A Comparison with Single-phase CTA in Drip-and-ship...

Area of Science:

• Neurology
• Radiology
• Medical Imaging

Background:

• Acute ischemic stroke with large-vessel occlusion (LVO) requires accurate collateral assessment.
• Single-phase computed tomography angiography (CTA) may underestimate pial collateral supply in LVO patients.
• Quantitative collateral mapping using time-resolved MRI offers a potential alternative.

Purpose of the Study:

• To compare quantitative collateral mapping with time-resolved MRI (CVI_PWI) against conventional collateral imaging with CTA.
• To evaluate the association of these collateral measures with stroke severity, infarct volume, and early functional outcome in LVO patients.

Main Methods:

• Retrospective analysis of 6 years of data from drip-and-ship LVO patients.
• MRI-based collateral assessment using T2*-weighted time series from perfusion-weighted imaging (PWI) to compute CVI_PWI.
• Comparison of CVI_PWI with CTA-based collateral scores (Tan and Maas) and their relationships with clinical outcomes.

Main Results:

• No significant relationship was found between MR-based CVI_PWI and CT-based collateral scores.
• CTA-based collateral scores did not correlate with stroke severity or infarct volume.
• MR-based CVI_PWI was independently associated with favorable early functional outcome, while CTA scores were not.

Conclusions:

• Single-phase CTA collateral scores do not accurately reflect infarct progression or reliably predict functional outcome in LVO.
• CVI_PWI derived from time-resolved MRI is a robust imaging parameter for collateral supply.
• CVI_PWI is independently associated with favorable functional outcomes in LVO patients.