Defining the prognostic performance of multiphase CT-angiography in ischemic stroke patients

Background The prognostic performance of multiphase CT-angiography (mCTA) in ischemic stroke patients undergoing endovascular treatment (EVT) in the early and late treatment window remains poorly characterized. Methods Data derived from two prospective EVT registries. The primary outcome was functional independence (90-day modified Rankin Scale ≤2). Secondary outcomes included excellent prognosis (90-day mRS ≤ 1), 90-day ordinal mRS, and follow-up infarct volume (FIV) on 24-hour non-contrast CT. Associations between mCTA collateral status and outcomes were assessed with binary, ordinal, or linear logistic regression analyses as appropriate. The prognostic performance was evaluated with the c-statistic. The optimal cutoff for mCTA collaterals, assessed using the Menon grading system (0–5), was identified using the Youden Index. The same analyses were conducted in subgroups based on reperfusion status, CT-reperfusion time, and treatment windows. Results 1220 patients were included: median age was 74 years [IQR = 67–84], 647 (53.0%) were females, and 593 (48.6%) achieved functional independence. Functional independence was associated with mCTA collaterals (adjusted odds ratio [aOR] 2.09 [95%CI = 1.75–2.50] per each 1-point score increase). The c-statistic of mCTA collaterals for predicting functional independence was 0.68 (95%CI = 0.65–0.71). The optimal cutoff value for mCTA collaterals in predicting functional independence was ≥ 4. Collaterals evaluated by mCTA, per each 1-point increase, were associated with excellent outcome (aOR 1.87 [95%CI = 1.54–2.26]), ordinal mRS (acOR 0.60 [95%CI = 0.51–0.69]), and FIV (aß −20.25 [95%CI=-(26.46;14.05)]. Results were consistent in subgroup analyses. Conclusion Collateral status evaluated by mCTA was strongly associated with clinical outcomes and FIV, and a specific cutoff of 4 was shown to predict functional independence.