DifusiÓn falsamente negativa en el ictus vertebrobasilar agudo

Introduction. The new techniques of magnetic resonance imaging have produced a important advance in the early diagnosis of acute ischemic stroke. The diffusion-weighted imaging (DWI) has a high sensitivity and specificityin the acute ischemia. Case report. 70 years-old woman with previous history of hypertension and dyslipemia. The patient presented sudden vertigo with cervical neck pain and gaze problems. The physical exploration revealed right miosis, nistagmus, IX and X cranial nerve affection and ataxia. The clinical diagnosis was Wallenberg's syndrome and a medulla lateral infarction. However DWI was normal (10 hours). The neurological deficit was persistent and a repeated study disclosed a lateral infarction of the medulla. Conclusions. The sensitivity of DWI is reduced during the first 24 hours. There are false negative diagnosis mainly in small infarctions of posterior territory.