[Ultrasonic assessment of cerebrovascular disease]

The aim of this paper of the symposium of the 36th Scientific Meeting of Japanese Society of Neurology is to clarify the general status of ultrasonic assessment in the imaging modality of cerebrovascular disease (CVD). Although there are many ultrasonic techniques, we want to address the carotid ultrasonography and transcranial ultrasonography. Cervical carotid atherosclerosis is known to be a major cause of brain infarction and Duplex ultrasonography is the best imaging tool. This method made it possible to visualize the living human arterial wall and to visualize the intraplaque characters. This was most advantage among several modalities. Few and really disadvantages of this method are examiner dependent results and narrow visual window. On the basis of these ultrasonic data, many investigations of nature of stroke have been performed. Transcranial ultrasonography have been accepted as a new method for non-invasive intracranial vascular imaging. There are the transcranial Doppler, transcranial tomography and the transcranial color flow imaging. Using these transcranial methods, we can evaluate the intracranial lesions. Transcranial color flow imaging made it possible to obtain real images of major arteries of circle of Willis. In conclusion, ultrasonic modality is a useful tool for assessing the risk of cerebrovascular disease or atherosclerosis, especially in chronic situations.