Evaluation of cerebral infarction using B-mode ultrasonic and doppler flowmeter

Abstract

We report results of B-mode ultrasonic and doppler flowmetric studies on patients with various forms of cerebral infarction. The subjects of this study consist of 49 patients with cerebral infarction (thrombosis; 38 and embolism; 11) and 15 control patients without cerebral infarction or risk factors for cerebrovascular accidents. Atherosclerotic lesions in the extracranial carotid arteries were found in 77% of the patients with large artery thrombosis, in 58% of those with lacunar infarction, in 11% with Binswanger-type infarction, 12% with infarction in the vertebrobasilar territory, and 18% of those with cerebral embolism.
Incidence of these atherosclerotic lesions among the patients with cerebral thrombosis was much higher than that among those with cerebral embolism. The sensitivity of the B-mode ultrasonography in detecting these atherosclerotic changes was much higher than that of intravenous disital subtraction carotid angiography. In addition, the magnitude of carotid stenosis and occlusion was more precisely evaluated by the doppler flowmetry than angiography. The velocity of the carotid blood flow was significantly increased in the stenotic portion as compared with the contralateral side. On the other hand, the end-diastolic blood flow velocity was decreased in the acute stage of the patients with cerebral embolism. In contrast, that of those with cerebral thrombosis was unchanged. Thus, this may be used as an indicator to differentiate embolism from thrombosis. In conclusion, B-mode ultrasonic and doppler flowmetric evaluation of extracranial carotid arteries is an useful and noninvasive method for patients with cerebral infarction.