Influence of collateral circulation on cerebral oxygen metabolism assessed by MRI in acute ischemic stroke

This study aimed to investigate the relationship between cerebral collateral status and MRI-derived oxygen metabolism in acute ischemic stroke (AIS) patients undergoing mechanical thrombectomy METHODS: The HIBISCUS-STROKE cohort (CoHort of Patients to Identify Biological an Imaging markerS of CardiovascUlar Outcomes in Stroke; NCT: 03149705), a single-center observational study, enrolled AIS patients for thrombectomy following MRI triage due to anterior circulation large vessel occlusion treated with mechanical thrombectomy. Dynamic-Susceptibility Contrast perfusion (DSC perfusion), Diffusion-Weighted Imaging (DWI) and penumbral volume (Tmax ≥ 6 secs) were post-processed to generate oxygen extraction fraction (OEF) and cerebral metabolic rate of oxygen (CMRO2) maps within DWI and penumbral anomalies, compared to contralateral areas. Collateral status, assessed via pretreatment digital subtraction angiography, was categorized as poor (0-2) or good (3-4) based on ASITN/SIR collateral grading system score from Higashida.

A total of 137 patients were included (mean age 71 years; 56.2% male). The median National Institutes of Health Stroke Scale (NIHSS) score was 15 (interquartile range [IQR]: 8.0-18.0), and the median time from symptom onset to admission was 96.0 min ([IQR]: 78.0-137.0). 78 patients (57.00%) had good collaterals, while 59 patients (43.10%) had poor collaterals. Good collaterals were independently associated with a smaller baseline infarct core volume and less decrease in CMRO2 within the ischemic penumbra (respectively OR = 0.94; 95% CI: [0.92; 0.96]; (P < 0.0001), and (OR = 1.30; 95% CI: [1.06; 1.82]; P = 0.001).

Good collateral circulation was independently associated with less severe impairment of cerebral metabolic rate of CMRO2 in the penumbra.