Clinical Relevance of Computed Tomography Perfusion-Estimated Infarct Volume in Acute Ischemic Stroke Patients within the 6-h Therapeutic Time Window

Abstract

Introduction: Although the estimated infarct volume on baseline computed tomography perfusion (CTP) can identify patients who are likely to benefit from endovascular thrombectomy (EVT) in late time window strokes, the role of CTP imaging in early time windows has not been established. We assessed the clinical impact of CTP-estimated infarct volume on long-term prognosis after EVT, particularly in patients with early time window stroke. Methods: We retrospectively reviewed patients who underwent pretreatment CTP and EVT for large vessel occlusion in the anterior circulation within 6 h after symptom onset between March 2014 and February 2019. The infarct volume at baseline CTP was estimated using commercially available software (RAPID, iSchemaView, Menlo Park, CA, USA) with a cerebral blood flow threshold <30% of the normal brain. Risk factors for poor outcome after EVT were evaluated, and a receiver operating characteristic (ROC) curve analysis was used to identify CTP-estimated infarct volumes that optimally predicted the development of symptomatic intracranial hemorrhage (sICH) and poor outcomes (modified Rankin Scale [mRS] 3–6) at 90 days. Results: Of 120 patients, successful recanalization was achieved in 89 (74.2%) patients, while 61 (50.8%) showed poor outcomes at 90 days. Among 89 patients with successful recanalization after EVT, age, diabetes, clinical stroke severity, CTP-estimated infarct volume, and sICH development were independently associated with 90-day clinical outcomes. ROC analysis identified infarct volumes of ≥88.5 mL and ≥74 mL as the optimal thresholds for predicting poor outcome and development of sICH, respectively. Patients with large infarct volumes showed poorer outcomes (odds ratio [OR], 7.704; 95% confidence interval [CI], 1.528–38.839) and higher rates of sICH development (OR, 10.857; 95% CI, 1.835–64.235). Among patients with large infarction volumes (≥88.5 mL), the 90-day mRS demonstrated a shift toward better outcomes in patients with successful recanalization. Conclusion: Larger initial infarct volumes are significantly associated with worse clinical outcomes in patients who underwent EVT because of early time window stroke. Furthermore, our study of 6-h data demonstrated that an initial infarction of more than a certain volume might be an independent risk factor for sICH development and poor outcomes even in patients with successful recanalization. However, we still observed benefits of EVT in patients with large ischemic cores. The CTP-estimated infarct volume might be an important prognostic factor after EVT rather than a biomarker predicting treatment effectiveness.

Risk factors of hemorrhagic transformation in acute ischaemic stroke: A systematic review and meta-analysis

“…Improved imaging technology in recent years, particularly the advent of CT perfusion, have shown great potential to enhance patient selection by more accurately characterizing infarct core and penumbra. For example, CT perfusion-based predictors including those measuring infarct core volume ( 19 , 53 , 183 , 184 ) and blood-brain-barrier permeability ( 6 , 142 , 185 – 188 ) haven been reported in previous work, and novel CT perfusion-based parameters such as net water uptake ( 189 ) continue to emerge. These techniques have largely emerged in tandem with EVT and indeed have enabled its application in the extended therapeutic window, meaning that the majority of published randomized trial data charactering HT has EVT as a focus.…”