Emergency MRI as the First Imaging Modality in Acute Stroke: Effect on Diagnostic Performance and Outcomes.

Area of Science:

• Neurology
• Radiology
• Emergency Medicine

Background:

• The optimal initial imaging strategy for acute stroke remains debated.
• Computed tomography (CT) is traditionally used, but magnetic resonance imaging (MRI) offers higher sensitivity for certain stroke types.

Purpose of the Study:

• To evaluate the impact of an "MRI-first" paradigm on diagnosis, workflow, and clinical outcomes in acute stroke care.
• To compare the effectiveness of MRI-first versus CT-first approaches in a comprehensive stroke center.

Main Methods:

• Retrospective analysis of a prospective observational cohort of patients with acute stroke or transient ischemic attack (TIA).
• Comparison of diagnostic performance, workflow metrics, and 3-month modified Rankin Scale (mRS) between CT-first and MRI-first paradigms.
• Inclusion of patients admitted within 24 hours of symptom onset.

Main Results:

• The MRI-first paradigm demonstrated improved stroke diagnosis concordance (95.9% vs. 91.2%).
• Fewer "stroke mimics" were treated with thrombolysis under the MRI-first approach, despite slightly longer door-to-needle times.
• MRI-first was associated with favorable 3-month mRS shifts for all stroke/TIA patients (aOR 0.65) and specifically for cerebral ischemia (aOR 0.61).

Conclusions:

• Implementing MRI as the initial imaging modality for emergency stroke assessment is feasible.
• The MRI-first approach is linked to improved diagnostic accuracy and favorable clinical outcomes, particularly for cerebral ischemia.