BACKGROUND AND PURPOSE
Intracranial collaterals influence the prognosis of patients treated with intravenous tissue plasminogen activator in acute anterior circulation ischemic stroke. We compared the methods of scoring collaterals on pre-tPA brain CT angiography for predicting functional outcomes in acute anterior circulation ischemic stroke.

MATERIALS AND METHODS
Two hundred consecutive patients with acute anterior circulation ischemic stroke treated with IV-tPA during 2010–2012 were included. Two independent neuroradiologists evaluated intracranial collaterals by using the Miteff system, Maas system, the modified Tan scale, and the Alberta Stroke Program Early CT Score 20-point methodology. Good and extremely poor outcomes at 3 months were defined by modified Rankin Scale scores of 0–1 and 5–6 points, respectively.

RESULTS
Factors associated with good outcome on univariable analysis were younger age, female sex, hypertension, diabetes mellitus, atrial fibrillation, small infarct core (ASPECTS ≥8), vessel recanalization, lower pre-tPA NIHSS scores, and good collaterals according to Tan methodology, ASPECTS methodology, and Miteff methodology. On multivariable logistic regression, only lower NIHSS scores (OR, 1.186 per point; 95% CI, 1.079–1.302; P = .001), recanalization (OR, 5.599; 95% CI, 1.560–20.010; P = .008), and good collaterals by the Miteff method (OR, 3.341; 95% CI, 1.203–5.099; P = .014) were independent predictors of good outcome. Poor collaterals by the Miteff system (OR, 2.592; 95% CI, 1.113–6.038; P = .027), Maas system (OR, 2.580; 95% CI, 1.075–6.187; P = .034), and ASPECTS method ≤5 points (OR, 2.685; 95% CI, 1.156–6.237; P = .022) were independent predictors of extremely poor outcomes.

CONCLUSIONS
Only the Miteff scoring system for intracranial collaterals is reliable for predicting favorable outcome in thrombolyzed acute anterior circulation ischemic stroke. However, poor outcomes can be predicted by most of the existing methods of scoring intracranial collaterals.