[Usefulness of carotid duplex ultrasonography in a patient with moyamoya disease].

The patient is a 35-year-old man who had a medical history of epilepsy in childhood. He came to our hospital because of transient disturbance of consciousness and left hemiplegia just after evacuation. At first, we thought that he had epilepsy with Todd's palsy. But we had to do a differential diagnosis for a transient ischemic attack such as paradoxical embolism, because his symptoms occurred just after evacuation. An electroencephalogram and brain computerized tomography were immediately performed, but no abnormality was detected. Hematologic studies were normal, and no deep vein thrombosis was detected in the veins of the lower extremities by duplex ultrasonography Doppler. But carotid duplex ultrasonography showed an increase in end-diastolic flow velocity and a decrease in vascular resistance in both external carotid arteries. These findings indicated that there was arteriovenous malformation such as moyamoya disease. Brain magnetic resonance imaging showed spotty high signal lesions in the subcortical areas on a fluid-attenuated inversion-recovery(FLAIR) image, and the middle cerebral artery was not visualized on magnetic resonance angiography (MRA). Cerebral angiography demonstrated moyamoya vessels in the brain and collateral circulation from the external carotid artery. Therefore, we diagnosed him as having moyamoya disease. Duplex ultrasonography of the common and, internal carotid, and vertebral arteries is a widely-used technique. Recently, cerebral angiography, MRA and transcranial Doppler have been applied to detect intracranial vascular malformation. But these results suggested that moyamoya disease could be detected by means of carotid duplex ultrasonography. Finally, we considered that carotid duplex ultrasonography was not only a noninvasive screening method but also a useful for the diagnosis of moyamoya disease.