The cost of a Doppler test ranges from$100-$150 depending on the level of the hospital. Cerebral Doppler examination is often used to detect malformations of the cerebral blood vessels and atherosclerosis of the cerebral blood vessels. Cerebral blood vessels are divided into two circulatory systems: the anterior circulation supplies blood to the first two thirds of the cerebral hemispheres and is mainly divided into the middle cerebral artery and the anterior cerebral artery. The posterior circulation supplies blood to the posterior third of the brain, and is mainly composed of the two vertebral arteries and the basilar artery. The anterior and posterior circulations are connected in the skull by the Willis ring. For cerebrovascular disease, after infarction or hemorrhage, the cerebrovascular system is compensated for by the Willis ring, and the patient may have neurological deficits that are not particularly severe. In the treatment of cerebrovascular disease, it is possible to promote collateral circulation, which has a very good effect on the recovery of cerebrovascular disease. Cerebral Doppler examination can assess the improvement of atherosclerosis and the opening of collateral branches of the patient.