めまいで発症し超急性期MRIで異常を認めなかった脳梗塞例

抄録

Imaging diagnosis using magnetic resonance imaging (MRI) is indispensable for the diagnosis of acute cerebrovascular disturbances. Diffusion-weight imaging (DWI) MRI, in particular, has improved the diagnostic accuracy in acute ischemic stroke. However, some patients with acute stroke show no abnormal signals on DWI, despite the presence of an infarction. We present herein on a case of a hyperacute large ischemic stroke that was not detected on the initial DWI. A 85-year-old female with acute vertigo and vomiting was admitted to our hospital. In the neuro-otological examination, she had evoked direction fixed horizontal gaze and left-sided positional nystagmus. DWI examined within 2 hours after onset showed no ischemic findings. Twelve hours after onset, she developed consciousness disturbance and follow-up DWI demonstrated a large infarction on the brainstem, cerebellum and cerebrum.
False-negative findings demonstrated on DWI are sometimes observed in the case of brainstem or cerebellar infarction. Careful observation of neurological findings and follow-up MR imaging are useful for closer investigation of false-negative findings in the patients with suspected as having suffered an ischemic stroke.