This study evaluates the accuracy and feasibility of a portable low-field MRI (Hyperfine) device in patients presenting to the emergency department with suspected acute stroke. All enrolled patients undergo standard clinical imaging (CT, CT angiography, CT perfusion) and additionally receive a low-field MRI scan. Low-field MRI findings are compared to routine CT imaging and final clinical diagnosis. The study aims to determine whether low-field MRI can reliably detect acute ischemic stroke (including lacunar and large vessel occlusion), hemorrhagic stroke, and stroke mimics in the acute setting. Secondary outcomes include feasibility measures such as scan time, completion rate, patient satisfaction, and adverse events.

Inclusion Criteria:

• Age ≥ 18 years
• Presentation with suspected acute stroke (stroke code activation by ambulance paramedics)
• Symptom onset < 12 hours prior to presentation
• Admission to the emergency department of the Leiden University Medical Center (LUMC) during office hours
• Undergoing standard-of-care head CT imaging at the emergency department
• Ability to provide informed consent (written or verbal in the acute setting, with deferred written consent if applicable)

Exclusion Criteria:

• Imminent death
• Severe claustrophobia preventing MRI
• Presence of MRI-incompatible implanted devices (e.g., pacemaker, cochlear implant, insulin pump)
• Known intra-ocular metallic foreign body or intracranial metallic clip/device identified on admission CT
• Pregnancy
• Acute life-threatening or disabling condition requiring immediate intervention that precludes study procedures
• Any study-related delay that could interfere with time-critical stroke treatments (intravenous thrombolysis or endovascular thrombectomy)

Adult patients presenting to the emergency department of a tertiary academic hospital (LUMC) with suspected acute stroke (stroke code activation) within 12 hours of symptom onset. The study population includes patients with ischemic stroke (large vessel occlusion and lacunar), hemorrhagic stroke, and stroke mimics, reflecting real-world acute stroke diagnostics.

Due to the limited sample size, the single-centre design, and privacy considerations under GDPR, there is no plan to share individual participant data. Aggregate results will be published in peer-reviewed journals and presented at scientific meetings.