Validation of Cerebral Collaterals on Vascular Imaging in Acute Anterior Ischemic Stroke in Relation to Functional Outcome

Abstract

Background

Outcome variability in anterior circulation acute ischemic stroke is partly attributable to differences in collateral perfusion. The adequacy of leptomeningeal collateral recruitment influences infarct progression and neurological recovery. We evaluated whether computed tomography angiography (CTA)-based collateral assessment can serve as a prognostic indicator of functional status in this population.

Aim

To determine the proportion of patients achieving a favorable functional outcome in acute anterior circulation ischemic stroke using CTA collateral grading systems and to compare the predictive performance of different collateral scoring scales.

Materials and Methods

This observational analytical study included consecutive patients presenting within 48 h of symptom onset with imaging-confirmed anterior circulation ischemic stroke. Collateral circulation was graded using multiple established CTA scoring systems. Each scale was analyzed for its ability to predict functional independence at 3 months.

Results

A total of 206 patients were studied. Most patients (68%) were aged 41-70 years, and 69% were male. The mean baseline National Institutes of Health Stroke Scale (NIHSS) score was 8.64 ± 6.58. Hypertension was the most frequent vascular risk factor (58.3%). Alcohol intake and tobacco chewing were significantly associated with unfavorable outcomes. Among the evaluated grading systems, the multiphase CTA (mCTA) and Miteff scales demonstrated the highest sensitivity (93%) for predicting a favorable 3-month functional outcome. The mCTA scale achieved an overall accuracy of 71.36%. The Maastricht Acute Stroke Assessment Scale (MAAS) scale showed greater specificity but comparatively lower sensitivity. Functional independence (Modified Rankin Scale (mRS) <2) at 3 months was observed in 74.8% of patients with good collateral grades.

Conclusion

CT angiographic collateral grading provides meaningful prognostic information in acute anterior circulation ischemic stroke. Among the assessed systems, the mCTA scale demonstrated superior overall predictive performance. Favorable collateral status was strongly associated with good functional recovery at 3 months.