Collateral score on CT angiography in patients with acute ischemic stroke - A retrospective study.

Objective: Clinically assessing the status of cerebral collaterals is thought to provide invaluable diagnostic and prognostic data in managing acute ischemic stroke (AIS) patients. In this study we present a report, based on commonly used collateral grading system, assessing the correlation between the collateral status seen on CT angiography and patients’ functional outcome at Day 90 in our institution. Method: Patients presenting to the Emergency Department within 6 hours of onset of stroke from January 2010 until December 2014 were chosen for the study. CT angiography source images were retrospectively reviewed and given a “collateral score” (CS) by a radiologist who was blinded to the patient’s clinical information on presentation, as well as the clinical outcomes at 90 days. Patients’ mRS score at 90 days was obtained retrospectively and compared against the “collateral score”. Results: 87 patients were enrolled into this study, of which 60 (69%) were male and 27 (31%) were female with a mean age of 60.3 years. In this study, 56 (64.4%) patients had a collateral score (CS) ? 2 and 31 (35.6%) patients had a CS < 2. Out of 56 patients who had a CS ? 2, 51 of them (91%) had good clinical outcome with a mRS ? 2. All the patients who had CS < 2 showed poor clinical outcome with a mRS > 2. The collateral score predicts accurately the clinical outcome with an area under the curve (ROC) of 0.75 (95% CI, 0.675-0.871, P=0.001). There is significant Spearman correlation between CS and the clinical outcome at Day 90, in patients with AIS during CTA analysis. Conclusion: Our data supports the potential use of CS analysis in predicting clinical outcome of patients with AIS. Nevertheless, further study on a larger scale is strongly suggested to verify the reliability and reproducibility of CS assessment in CTA analysis prior to reperfusion in AIS patients.