Moving From CT-First to MRI-First Paradigm in Acute Ischemic Stroke: Treatment Rates, Time Metrics, Safety, and Outcomes

Background and Purpose Neuroimaging is essential before intravenous thrombolysis (IVT) and endovascular treatment (EVT) for acute ischemic stroke (AIS). In May 2018, our center transitioned from computed tomography (CT) to magnetic resonance imaging (MRI) as the first-line imaging for suspected AIS. We aimed to assess the consequences of an MRI-based paradigm on patients’ selection, rates of acute treatment, time metrics, safety of both IVT and EVT, and clinical outcomes.Methods Using data from the Acute STroke Registry and Analysis of Lausanne (ASTRAL), we analyzed an equal number of patients from the CT-period (December 2012 to May 2018) and the subsequent MRI-period (May 2018 to August 2022). We performed univariable and multivariable analysis.Results We included 2,972 consecutive AIS patients, 1,131 undergoing IVT and 662 EVT. Compared to the CT-period, the MRI-period showed similar rates of early and late IVT and EVT. The potentially missed-IVT opportunities decreased (3.1% vs. 0.8%; Padj<0.01). Median door-to-needle time was longer in the MRI-period (43 min vs. 31 min, β-coefficientadj=15, 95% confidence interval CI=11–27, Padj<0.01), while door-to-puncture time was unchanged (β-coefficientadj=9.95, 95% CI=-2.24–22.14, Padj=0.11). Rates of symptomatic intracranial hemorrhage (SICH) were similar after IVT (5.6% vs. 3.2%, Padj= 0.99) and EVT (±IVT) (6.5% vs. 4.2%, Padj=0.52). Disability at 3 months was unaffected for both IVT and EVT patients (Padj=0.36 and Padj=0.52 respectively).Conclusion The transition from CT to MRI as the first-line imaging reduced the rates of potentially missed IVT opportunities. While door-to-needle time increased, door-to-puncture time remained stable. Safety as measured by SICH rates and 3-month disability were unaffected by the imaging paradigm shift.