The Compensation Index Is Better Associated with DSA ASITN Collateral Score Compared to the Cerebral Blood Volume Index and Hypoperfusion Intensity Ratio

Background: Pretreatment CT Perfusion (CTP) parameters serve as reliable surrogates of collateral status (CS). In this study, we aim to assess the relationship between the novel compensation index (CI, Tmax > 4 s/Tmax > 6 s) and already established CTP collateral markers, namely cerebral blood volume (CBV) index and Hypoperfusion Intensity Ratio (HIR), with the reference standard American Society of Interventional and Therapeutic Neuroradiology (ASITN) collateral score (CS) on DSA. Methods: In this retrospective study, inclusion criteria were the following: (a) CT angiography confirmed anterior circulation large vessel occlusion from 9 January 2017 to 10 January 2023; (b) diagnostic CT perfusion; and (c) underwent mechanical thrombectomy with documented DSA-CS. Student t-test, Mann-Whitney-U-test and Chi-square test were used to assess differences. Spearman's rank correlation and logistic regression analysis were used to assess associations. p <= 0.05 was considered significant. Results: In total, 223 patients (mean age: 67.8 +/- 15.8, 56% female) met our inclusion criteria. The CI (rho = 0.37, p < 0.001) and HIR (rho = -0.29, p < 0.001) significantly correlated with DSA-CS. Whereas the CBV Index (rho = 0.1, p > 0.05) did not correlate with DSA-CS. On multivariate logistic regression analysis taking into account age, sex, ASPECTS, tPA, premorbid mRS, NIH stroke scale, prior history of TIA, stroke, atrial fibrillation, diabetes mellitus, hyperlipidemia, heart disease and hypertension, only CI was not found to be independently associated with DSA-CS (adjusted OR = 1.387, 95% CI: 1.09-1.77, p < 0.01). Conclusion: CI demonstrates a stronger correlation with DSA-CS compared to both the HIR and CBV Index where it may show promise as an additional quantitative pretreatment CS biomarker.

Automated summary

This study aimed to assess the relationship between the novel compensation index (CI) and already established CTP collateral markers, as well as to find a CS biomarker that demonstrates a stronger correlation with DSA-CS. The results showed that CI significantly correlated with DSA-CS, while CBV Index did not show any correlation.