Collateral Automation for Triage in Stroke: Evaluating Automated Scoring of Collaterals in Acute Stroke on Computed Tomography Scans

Iris Q. Grunwald (Lead / Corresponding author), Johann Kulikovski, Wolfgang Reith, Stephen Gerry, Rafael Namias, Maria Politi, Panagiotis Papanagiotou, Marco Essig, Shrey Mathur, Olivier Joly, Khawar Hussain, Viola Wagner, Sweni Shah, George Harston, Julija Vlahovic, Silke Walter, Anna Podlasek, Klaus Fassbender

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Computed tomography angiography (CTA) collateral scoring can identify patients most likely to benefit from mechanical thrombectomy and those more likely to have good outcomes and ranges from 0 (no collaterals) to 3 (complete collaterals). In this study, we used a machine learning approach to categorise the degree of collateral flow in 98 patients who were eligible for mechanical thrombectomy and generate an e-CTA collateral score (CTA-CS) for each patient (e-STROKE SUITE, Brainomix Ltd., Oxford, UK). Three experienced neuroradiologists (NRs) independently estimated the CTA-CS, first without and then with knowledge of the e-CTA output, before finally agreeing on a consensus score. Addition of the e-CTA improved the intraclass correlation coefficient (ICC) between NRs from 0.58 (0.46-0.67) to 0.77 (0.66-0.85, p = 0.003). Automated e-CTA, without NR input, agreed with the consensus score in 90% of scans with the remaining 10% within 1 point of the consensus (ICC 0.93, 0.90-0.95). Sensitivity and specificity for identifying favourable collateral flow (collateral score 2-3) were 0.99 (0.93-1.00) and 0.94 (0.70-1.00), respectively. e-CTA correlated with the Alberta Stroke Programme Early CT Score (Spearman correlation 0.46, p < 0.001) highlighting the value of good collateral flow in maintaining tissue viability prior to reperfusion. In conclusion, -e-CTA provides a real-time and fully automated approach to collateral scoring with the potential to improve consistency of image interpretation and to independently quantify collateral scores even without expert rater input.

Original languageEnglish
Pages (from-to)217-222
Number of pages6
JournalCerebrovascular Diseases
Issue number5-6
Early online date19 Jun 2019
Publication statusPublished - 1 Sep 2019


  • Acute stroke
  • Alberta stroke programme early CT score
  • Collateral circulation
  • Computed tomography angiography
  • e-Alberta stroke programme early CT score
  • e-Computed tomography angiography
  • Thrombectomy


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