Quantification of Collateral Supply with Local-AIF Dynamic Susceptibility Contrast MRI Predicts Infarct Growth

Area of Science:

• Neurology
• Medical Imaging
• Biomedical Engineering

Background:

• Leptomeningeal collaterals are crucial in ischemic stroke, supplying blood to at-risk tissue and influencing treatment outcomes.
• Accurate quantification of collateral blood supply is vital for understanding stroke progression and therapeutic response.

Purpose of the Study:

• To test the hypothesis that a local arterial input function (AIF) is necessary for accurate quantification of collateral blood supply in ischemic stroke.
• To compare the efficacy of a local AIF versus a global AIF in assessing collateral perfusion.

Main Methods:

• Seven pre-clinical experiments utilized a middle cerebral artery occlusion model.
• Dynamic susceptibility contrast (DSC) MRI was employed to generate cerebral blood flow maps.
• A novel local AIF, sensitive to retrograde flow, was compared against a traditional global AIF.

Main Results:

• The local AIF demonstrated a strong correlation with collateral recruitment (R²=0.81) compared to the global AIF (R²=0.05).
• Quantitative perfusion using the local AIF was significantly correlated with reduced infarct growth (R²=0.79), unlike the global AIF (R²=0.02).

Conclusions:

• Local AIF-based DSC perfusion is more accurate for evaluating leptomeningeal collateralization and tissue status in ischemic stroke.
• These findings support the use of a local AIF for quantitative perfusion assessment in occlusive cerebrovascular diseases.