Transcranial Doppler and carotid ultrasound are tests for two different areas and cannot be simply compared for accuracy. Transcranial Doppler evaluates the intracranial arteries to understand the blood supply of intracranial arteries, including the anterior cerebral artery, middle cerebral artery, posterior cerebral artery, and ophthalmic artery. However, transcranial Doppler is a blind probe, and the accuracy of the examination depends on the physician’s proficiency as well as professionalism, and there may be missed diagnosis. Carotid ultrasound mainly probes the blood vessels in the neck and reflects the condition of the blood vessels in the neck, including the common carotid artery, internal carotid artery and vertebral artery. Carotid ultrasound has a lower rate of leakage because there is no bone in the way and the ultrasound can directly probe the blood vessels and visualize the condition of these blood vessels more intuitively. Transcranial Doppler and carotid ultrasound have their own advantages and are tests of two different areas, so you cannot simply compare which is more accurate. However, the two tests can be combined together to assess the condition with greater accuracy. In addition, the blood vessels in the head and neck can be examined by angiography, which has a higher diagnostic value. If you experience discomfort in the blood vessels of the head and neck, it is recommended that you go to the hospital in a timely manner and choose the appropriate test after evaluating your condition under the guidance of your doctor.