Unexpected Cardiac Arrest During MRI in a Patient With Acute Brainstem Infarction: A Case Report and Imaging Insights

We report the case of a 65-year-old man with a history of hypertension and diabetes who experienced cardiac arrest during MRI for acute brainstem infarction. Initial imaging revealed right vertebral artery occlusion and brainstem infarction. During follow-up MRI because of worsening symptoms, magnetic resonance angiography revealed an absence of cerebral arterial flow, and T2*-weighted imaging revealed arterial and venous engorgement, which were later recognized as early signs of cardiac arrest. Cardiopulmonary resuscitation was initiated, but hypoxic encephalopathy persisted. This case highlights the importance of continuous vital sign monitoring and real-time image evaluation during MRI, particularly in high-risk patients with stroke.