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. 2023 Jun;33(2):353-359.
doi: 10.1007/s00062-022-01216-4. Epub 2022 Sep 26.

Collateral Capacity Assessment : Robustness and Interobserver Agreement of Two Grading Scales and Agreement with Quantitative Scoring

Wenjin Yang  1 , Jazba Soomro  2 , Ivo G H Jansen  3 , Aashish Venkatesh  3 , Albert J Yoo  2 , Demetrius Lopes  4 , Ludo F M Beenen  5 , Bart J Emmer  5 , Charles B L M Majoie  5 , Henk A Marquering  5   6
Affiliations

Collateral Capacity Assessment : Robustness and Interobserver Agreement of Two Grading Scales and Agreement with Quantitative Scoring

Wenjin Yang et al. Clin Neuroradiol. 2023 Jun.

Abstract

Background and purpose: Intracranial collateral capacity is conducive to imply parenchymal perfusion of affected territory after acute vessel occlusion. The Tan collateral score is commonly used to assess the intracranial collateral capacity; however, this score is coarsely grained and interobserver agreement is low, which reduces prognostic value and clinical utility. We introduce and evaluate an alternative extended Tan score based on the conventional Tan scale and assess the agreement with a quantitative score.

Methods: We included 100 consecutive patients with a proven acute single large vessel occlusion of the proximal anterior circulation. Collaterals were graded with the conventional and extended Tan score and an automated quantitative score. The extended Tan score is a finer 6‑scale manual score based on the conventional 4‑point Tan scale. The quantitative score is calculated by an automatic software package (StrokeViewer). Interobserver agreement of the manual scores was assessed with the weighted kappa. The Spearman correlation coefficient was calculated to determine the agreement between the manual and automated collateral scores.

Results: The interobserver agreement was higher for the extended score than for the conventional score with a weighted kappa of 0.70 and 0.65, respectively. For the extended and conventional score, the Spearman correlation coefficient for the agreement with the automated score was 0.78 and 0.76, respectively.

Conclusion: Because of the good interobserver agreement and good agreement with quantitative assessment, the extended collateral score is a strong candidate to improve prognostic value of collateral assessment and implementation in clinical practice.

Keywords: Automated quantitative score; Correlation coefficient; Interobserver agreement; Intracranial collateral capacity; Manual Tan score.

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Conflict of interest statement

C.B.L.M. Majoie, H.A. Marquering and I.G.H. Jansen are shareholders of Nico-lab. A.J. Yoo holds stock options in Nico-lab and reports grants from Medtronic, Cerenovus, Penumbra, Stryker, and Genentech, and is a consultant for Vesalio, Cerenovus, Penumbra, and Philips, all outside the submitted work. C.B.L.M. Majoie reports grants from CVON/Dutch Heart Foundation, TWIN Foundation, European Commission, Health Evaluation Netherlands, and Stryker outside the submitted work (all paid to institution). W. Yang, J. Soomro, A. Venkatesh, D. Lopes, L.F.M. Beenen and B.J. Emmer declare that they have no competing interests.

Figures

Fig. 1
Fig. 1
a Maximum intensity projection (MIP) of a patient with a left-sided M1 occlusion. Automated collateral score was 93%. Consensus was grade 2 and 2B for the conventional and extended Tan scores, respectively. b MIP of patient with right-sided M1 occlusion. Automated score was 1%, consensus was grade 1 and 1A. c MIP of a patient with right-sided M1 occlusion. Automated score was 38%, consensus was grade 1 and 1B. The occlusion location as detected by StrokeViewer is depicted with a blue rectangle
Fig. 2
Fig. 2
a Distribution of the automated collateral score per consensus collateral grade for the conventional Tan score with 4‑point scale, ranging from absent collaterals to good collaterals. b Distribution of the automated collateral score per consensus collateral grade for the extended Tan score with 6‑point scale, ranging from absent collaterals to good collaterals
See this image and copyright information in PMC

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