Transcranial Ultrasonography Plays An Important Role In Therapeutic Decision-Making
Ultrasound provides human tissue and blood flow velocity information with real-time processing. This technique has relatively limited field of view and it is technically not viable to use in 10 per cent cases. However, the information gathered is being widely accepted because of its relevance in therapeutic decision-making in the prevention and management of stroke.
Doppler ultrasound or transcranial color-coded duplex is relatively less expensive, ensures excellent safety and tolerability. However, this imaging technique provides inferior spatial and anatomical detail in comparison to angiographic techniques.
Transcranial ultrasound imaging technique enables doctors to capture real-time images of blood flow in the major basal intracranial arteries. It is widely used in for haemodynamically significant intracranial stenoses or vessel occlusions because of its accuracy.
To gather information about brain anatomy, a sensor is placed at the anterior and superior attachment site of the upper ear in adults. This is because the human skull prevents the disclosure of brain anatomy. By means of transcranial sonography system, doctors can visualize the shape of the skull and brain surface from any point to examine skull fracture and brain disease such as cerebral atrophy and epidural or subdural hematoma.
Velocity of the blood flow is recorded by emitting a high-pitched sound wave from the ultrasound probe. A particular frequency, usually a multiple of 2 MHz is used. The speed of the blood causes a phase shift in relation to the probe and as a result the frequency changes. The frequency change with respect to the blood flow is recorded electronically for further analysis.