Related Experiment Video
Updated: Jan 2, 2026
Optimized Management of Endovascular Treatment for Acute Ischemic Stroke
Published on: January 18, 2018
Imaging Triage of Patients with Late-Window (6-24 Hours) Acute Ischemic Stroke: A Comparative Study Using Multiphase
M A Almekhlafi1,2,3, W G Kunz4, R A McTaggart5
1From the Department of Clinical Neurosciences (M.A.A., M.N., M.D.H., A.M.D., M.G., B.K.M.).
Insights
Multiphase CT angiography (CTA) effectively identifies patients for endovascular thrombectomy in the late window, comparable to CT perfusion (CTP). This collateral imaging approach aids in selecting appropriate candidates for stroke treatment beyond six hours.
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.
Background And Purpose:
The role of collateral imaging in selecting patients for endovascular thrombectomy beyond 6 hours from onset has not been established. To assess the comparative utility of collateral imaging using multiphase CTA in selecting late window patients for EVT.
Materials And Methods:
We used data from a prospective multicenter observational study in which all patients underwent imaging with multiphase CT angiography as well as CTP. Two blinded reviewers evaluated patients' eligibility for endovascular thrombectomy using published collateral imaging (multiphase CTA) criteria compared with CTP using the selection criteria of the Clinical Mismatch in the Triage of Wake Up and Late Presenting Strokes Undergoing Neurointervention with Trevo (DAWN) and Endovascular Therapy Following Imaging Evaluation for Ischemic Stroke 3 (DEFUSE-3) trials. CTP images were processed using automated commercial software. The outcomes of patients eligible for endovascular thrombectomy according to multiphase CTA, DAWN, or DEFUSE-3 criteria were compared using multivariable logistic regression modeling. Model characteristics were compared using the C-statistic for the receiver operating characteristic curve, the Akaike information criterion, and the Bayesian information criterion.
Results:
Eighty-six patients presented beyond 6 hours from onset/last known well (median, 9.6 hours; interquartile range, 4.1 hours). Thirty-five patients (40.7%) received endovascular thrombectomy, of whom good functional outcome (90-day mRS, 0-2) was achieved in 16/35 (47%). Collateral-based imaging paradigms significantly modified the treatment effect of endovascular thrombectomy on 90-day mRS 0-2 (P interaction = .007). The multiphase CTA-based regression model best fit the data for the 90-day outcome (C-statistic, 0.86; 95% CI, 0.77-0.94) and was associated with the least information loss (Akaike information criterion, 95.7; Bayesian information criterion, 114.9) compared with CTP-based models.
Conclusions:
The collateral-based imaging paradigm using multiphase CTA compares well with CTP in selecting patients for endovascular thrombectomy in the late time window.
