Calculating the frequency shift of a particular sample volume, such a blood flow through an artery in the neck. Each major vein has a characteristic blood flow which can be recorded. If a narrowing of the artery is present, blood flow increases which can be detected by a hissing sound during the examination. Blood flow in pre and post stenotic veins can also have directional changes which affect the patient. Blockage in the blood flow also changes the profile. The artery itself cannot be visually examined.
Blood flow in the following arteries can be examined:
Existing constriction or blockage of neck arteries
Image: Medical machine. Transcranial Doppler sonography allows for the study of collateral circulation in the throat arteries as well as the reserve capacity as a sign of impairment of the cerebral blood flow.
Typical Question Areas: Acute narrowing or blockage of the cerebral arteries, formation of collateral circulation of the throat arteries
Using Duplex, throat arteries as well as cerebral arteries can be examined. This machine has 2 functions: just like the Doppler sonography and transcranial Doppler sonography, it can show blow flood through the arteries as well as other major veins.
The following arteries can be examined:
Arteria cerebri media, Arteria cerebri anterior
Arteria cerebri posterior, Arteria vertebralis
Artera basilaris, Arteria carotis interna (distal)
Definite proof of constriction or blockage of throat and cerebral arteries, proof of plaque in throat area