Hypoperfusion Intensity Ratio Correlates with CTA Collateral Status in Large-Vessel Occlusion Acute Ischemic Stroke

Area of Science:

• Neurology
• Radiology
• Medical Imaging

Background:

• Collateral blood supply is crucial for outcomes in large-vessel occlusion acute ischemic stroke.
• Current collateral scoring systems using CT angiography (CTA) are subjective and require specialized training.

Purpose of the Study:

• To evaluate the association between the CTP-derived hypoperfusion intensity ratio and CTA collateral status.
• To determine if a hypoperfusion intensity ratio threshold can predict poor CTA collaterals.

Main Methods:

• Retrospective review of imaging and clinical data from 52 patients with large-vessel occlusion acute ischemic stroke.
• Collateral scoring using single-phase and multiphase CTA (Tan, Maas, Calgary/Menon methods).
• CT perfusion (CTP) analysis using RAPID software to calculate the hypoperfusion intensity ratio.

Main Results:

• Multiphase CTA scoring demonstrated superior interrater agreement (κ = 0.813) compared to single-phase CTA.
• The hypoperfusion intensity ratio showed a significant correlation with multiphase CTA collateral scores (r = -0.55, P ≤ .001).
• A hypoperfusion intensity ratio threshold of >0.45 effectively predicted poor multiphase CTA collateral status (AUC = 0.86).

Conclusions:

• The hypoperfusion intensity ratio is a reliable, automated, and quantitative measure associated with CTA collateral status in large-vessel occlusion stroke.
• This CTP-derived ratio serves as a valuable alternative to subjective CTA collateral scoring in clinical practice and stroke trials.