Association Between CT Angiogram Collaterals and CT Perfusion in Delayed Time Windows for Large Vessel Occlusion...

Area of Science:

• Neurology
• Radiology
• Medical Imaging

Background:

• Endovascular trials increasingly use CT Perfusion (CTP) for large vessel occlusion (LVO) treatment selection.
• The relationship between CTP and collateral circulation in delayed time windows (6-24 hours) remains unclear.

Purpose of the Study:

• To explore the association between CT Angiogram (CTA) collateral status and CTP parameters in patients with LVO within 6-24 hours of stroke onset.
• To investigate the utility of CTA collaterals as a surrogate for CTP in delayed stroke imaging.

Main Methods:

• Retrospective analysis of 48 anterior LVO patients with CTA and CTP imaging between 6-24 hours.
• CTA collaterals were graded using the modified Tan collateral score (0-3) and dichotomized (good: 2-3, poor: 0-1).
• Automated CTP parameters including ischemic core, penumbra, and mismatch ratio were analyzed.

Main Results:

• Patients with good collaterals (n=48) had significantly smaller CTP ischemic cores (0 mL vs. 40.5 mL, p<0.001) and penumbras (83.5 mL vs. 142.5 mL, p=0.04) compared to those with poor collaterals.
• Good collaterals were associated with a larger mismatch ratio (13.7 vs. 3.1, p<0.001) and lower hypoperfusion intensity ratio (0.23 vs. 0.52, p<0.001).

Conclusions:

• In delayed LVO, good CTA collaterals correlate with smaller CTP core and penumbra, and a larger mismatch ratio.
• CTA collateral assessment may serve as a valuable surrogate for CTP, especially in centers lacking perfusion imaging capabilities.