Single-phase CT angiography predicts ASPECTS decay and may help determine when to repeat CT before thrombectomy

Area of Science:

• Neurology
• Radiology
• Emergency Medicine

Background:

• Time is a critical factor in large-vessel occlusion acute ischemic stroke (LVO-AIS).
• Inter-hospital transfer from primary to comprehensive stroke centers is common for LVO-AIS patients.
• The Alberta Stroke Program Early CT Score (ASPECTS) can decay over time, potentially affecting treatment decisions.

Purpose of the Study:

• To evaluate the rate of ASPECTS decay in LVO-AIS patients transferred between stroke centers.
• To identify predictors of ASPECTS decay.
• To determine which patients would benefit from a repeat computed tomography (CT) scan before mechanical thrombectomy.

Main Methods:

• Retrospective cohort study of 663 anterior circulation LVO-AIS transferred patients.
• ASPECTS decay rate calculated as (PSC-ASPECTS - CSC-ASPECTS)/hours between scans.
• CT angiography (CTA) used to assess collateral circulation at the primary stroke center (PSC).

Main Results:

• 37% of patients repeated CT at a comprehensive stroke center (CSC).
• Median ASPECTS decay rate was 0.4/h.
• Absent collateral circulation was associated with a higher decay rate (1.51/h).
• Collateral score, age, NIHSS, and initial ASPECTS predicted the usefulness of repeat CT scans.

Conclusions:

• CTA collateral score can predict ASPECTS decay rate in LVO-AIS patients.
• This prediction aids in selecting patients who would benefit from repeat CT assessment upon arrival at the CSC.
• Optimizing imaging protocols can improve patient selection for thrombectomy.