Transcranial Doppler is a non-invasive test that focuses on intracranial vascular conditions. Transcranial Doppler is a non-invasive test for cerebrovascular disease that utilizes the Doppler effect in ultrasound. The Doppler effect means that when a sound-emitting object moves in the direction of the receiver of the sound, the receiver of the sound receives an increase in the pitch of the sound, and when it moves in the opposite direction, the receiver of the sound receives a decrease in the pitch of the sound. Transcranial Doppler exams utilize this property to examine the blood flow rate of each artery in the intracerebral arterial ring, and can assist in the diagnosis of intracranial artery-related diseases. It is recommended that patients undergo a transcranial Doppler examination under the supervision of a physician, and that if abnormalities are detected, they should follow the physician’s instructions for active intervention and treatment.