Imaging Triage of Patients with Late-Window (6-24 Hours) Acute Ischemic Stroke: A Comparative Study Using Multiphase...

Area of Science:

• Neurology
• Radiology
• Medical Imaging

Background:

• The established role of collateral imaging in patient selection for endovascular thrombectomy (EVT) beyond 6 hours from stroke onset remains unclear.
• Assessing the utility of multiphase CT angiography (CTA) for collateral imaging is crucial for optimizing EVT in late-window stroke patients.

Purpose of the Study:

• To compare the effectiveness of multiphase CTA in selecting patients for EVT in the late time window against CT perfusion (CTP).
• To evaluate collateral imaging's role in determining eligibility for EVT in extended timeframes.

Main Methods:

• A prospective, multicenter observational study included 86 patients presenting beyond 6 hours from stroke onset.
• Patient eligibility for EVT was assessed by blinded reviewers using multiphase CTA collateral criteria and CTP criteria from DAWN and DEFUSE-3 trials.
• Multivariable logistic regression models compared outcomes, with model fit assessed using C-statistic, AIC, and BIC.

Main Results:

• Of 86 patients, 35 (40.7%) received EVT, with 47% achieving good functional outcomes (90-day mRS 0-2).
• Collateral imaging paradigms significantly influenced the treatment effect of EVT on functional outcomes (P interaction = .007).
• The multiphase CTA model demonstrated superior data fit (C-statistic=0.86) and less information loss compared to CTP-based models.

Conclusions:

• Multiphase CTA serves as a viable collateral-based imaging paradigm for selecting patients for EVT in the late time window.
• The findings suggest multiphase CTA is comparable to CTP in identifying suitable candidates for late-window EVT.