The price of Doppler B-ultrasound examination ranges from 100-150 RMB, and the current fees in tertiary hospitals are relatively higher. Brain Doppler examination is mainly able to find out the general condition of intracranial blood vessels, anterior cerebral, middle cerebral, internal carotid artery terminal, bilateral posterior cerebral, and double vertebral and basilar arteries, and also anterior and posterior communicating arteries can be evaluated by Doppler examination, and generally the stenosis of blood vessels, elastic shadow of blood vessels can be found. It can be assessed by beat index and blood flow velocity, and whether the patient has vascular spasm and cerebral blood supply deficiency can be detected by cerebral Doppler examination. Clinically, there is also the possibility of blood theft due to heavy atherosclerosis, and the clinical abnormalities in the direction of blood flow can be detected, more commonly in the subclavian artery, which can also be detected by cerebral Doppler examination.