A case report of lateral medullary infarction detected as false negative by initial MRI

Abstract

We report a case of lateral medullary infarction that was not detected on the initial magnetic resonance imaging (MRI). A 49-year-old female with acute vertigo and vomiting presented to the emergency room. Although she complained of both vertigo and sensory disorder in the right arm and leg, abnormal findings were not noted on the initial MRI scan, which was examined 2 hours 45 minutes after symptom onset. Since dysbasia and paralysis of left soft palate and vocal cord were detected by otolaryngologist, a follow-up MRI performed 7 hours after symptom onset. This MRI showed lateral medullary infarction and she was admitted to a neurosurgery department for treatment. False-negative findings on MRI are sometimes observed in the case of brainstem infarction. Physicians should keep in mind the importance to neurological examinations and a second MRI examination, if needed, to rule out the diagnosis of brainstem infarction.