Carotid Doppler machine
A carotid Doppler machine (the same ultrasound machine used to evaluate the fetus in pregnant women) is a device which can be used to measure blood flow velocities within the cervical carotid arteries, as well as the vertebral arteries and sometimes the subclavian arteries by means of non-invasive ultrasonic scanning in which the Doppler effect is utilized. This can be useful for estimating the effects of atherosclerotic disease on the lumen in late stages; specifically the level of compromise in blood flow caused by reduction in arterial lumen diameter.
Using B-mode scanning (imaging) and very careful technique, the same ultrasound machine can also be used to measure the arterial wall thickening within segments of the carotid arteries non-invasively. This can be useful for detecting and tracking atherosclerotic disease in early stages. This has been used in clinical research since the early 1990s and is occasionally used by some clinicians.