[A case of the spontaneous dissection of the bilateral internal carotid arteries diagnosed by the transoral carotid ultrasonography (TOCU)].

A 56-year-old-man was admitted to our hospital because of acute brain infarction with symptoms of consciousness disturbance and left hemiparesis. After admission, the symptoms disappeared rapidly. MRI diffusion-weighted image on day one revealed high intensity area at the right insular cortex and MRA showed stenosis of the right middle cerebral artery. MRA on the next day demonstrated that the stenotic lesion improved, but another stenosis appeared at the petrous portion of the right internal carotid artery (ICA). Brain angiography on day eight showed improvement of the stenosis of the right ICA petrous portion and stenosis of bilateral ICAs extracranial distal portion. The transoral carotid ultrasonography (TOCU) on day nine showed clearly true lumen and false lumen at the bilateral extracranial distal ICAs, which indicated spontaneous dissection of the bilateral extracranial distal ICAs. TOCU seems very useful in evaluating the extracranial carotid arterial dissection.