RT Journal Article SR Electronic T1 Clot Burden Score and Collateral Status and Their Impact on Functional Outcome in Acute Ischemic Stroke JF American Journal of Neuroradiology JO Am. J. Neuroradiol. FD American Society of Neuroradiology SP 42 OP 48 DO 10.3174/ajnr.A6865 VO 42 IS 1 A1 I. Derraz A1 M. Pou A1 J. Labreuche A1 L Legrand A1 S. Soize A1 M. Tisserand A1 C. Rosso A1 M. Piotin A1 G. Boulouis A1 C. Oppenheim A1 O. Naggara A1 S. Bracard A1 F. Clarençon A1 B. Lapergue A1 R. Bourcier, A1 on behalf of the ASTER and the THRACE Trials Investigators YR 2021 UL http://www.ajnr.org/content/42/1/42.abstract AB BACKGROUND AND PURPOSE: Collateral status and thrombus length have been independently associated with functional outcome in patients with acute ischemic stroke. It has been suggested that thrombus length would influence functional outcome via interaction with the collateral circulation. We investigated the individual and combined effects of thrombus length assessed by the clot burden score and collateral status assessed by a FLAIR vascular hyperintensity–ASPECTS rating system on functional outcome (mRS).MATERIALS AND METHODS: Patients with anterior circulation acute ischemic stroke due to large-vessel occlusion from the ASTER and THRACE trials treated with endovascular thrombectomy were pooled. The clot burden score and FLAIR vascular hyperintensity score were determined on MR imaging obtained before endovascular thrombectomy. Favorable outcome was defined as an mRS score of 0–2 at 90 days. Association of the clot burden score and the FLAIR vascular hyperintensity score with favorable outcome (individual effect and interaction) was examined using logistic regression models.RESULTS: Of the 326 patients treated by endovascular thrombectomy with both the clot burden score and FLAIR vascular hyperintensity assessment, favorable outcome was observed in 165 (51%). The rate of favorable outcome increased with clot burden score (smaller clots) and FLAIR vascular hyperintensity (better collaterals) values. The association between clot burden score and functional outcome was significantly modified by the FLAIR vascular hyperintensity score, and this association was stronger in patients with good collaterals, with an adjusted OR = 6.15 (95% CI, 1.03–36.81).CONCLUSIONS: The association between the clot burden score and functional outcome varied for different collateral scores. The FLAIR vascular hyperintensity score might be a valuable prognostic factor, especially when contrast-based vascular imaging is not available.AISacute ischemic strokeCBSclot burden scoreEVTendovascular thrombectomyFVHFLAIR vascular hyperintensityIVTintravenous thrombolysismTICImodified TICI score