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Carotid ultrasound is a low-cost, noninvasive, and accurate diagnostic imaging modality used to evaluate diseases of the carotid arteries. [2] It is most often used to diagnose carotid artery stenosis, a form of atherosclerosis, and has the capability to assess plaque morphology and characteristics. [1]
Doppler ultrasonography is medical ultrasonography that employs the Doppler effect to perform imaging of the movement of tissues and body fluids (usually blood), [1] [2] and their relative velocity to the probe. By calculating the frequency shift of a particular sample volume, for example, flow in an artery or a jet of blood flow over a heart ...
Functional transcranial Doppler sonography (fTCD) is a neuroimaging tool for measuring cerebral blood flow velocity changes due to neural activation during cognitive tasks. [8] Functional TCD uses pulse-wave Doppler technology to record blood flow velocities in the anterior, middle, and posterior cerebral arteries.
70 percent stenosis of the right internal carotid artery as seen by ultrasound. Arrow marks the lumen of the artery. CT image of a 70 percent stenosis of the right internal carotid artery. Carotid artery stenosis is usually diagnosed by color flow duplex ultrasound scan of the carotid arteries in the neck.
where P(f) is the Doppler power spectrum and is the centroid value of the Doppler frequency shift. [1] Changing flow velocity impacts the value of the standard deviation. When the difference in flow velocity becomes larger, the Doppler frequency spectrum becomes wider. As a result, the standard deviation becomes larger. [1]
To image the vessels of the neck such as common carotid, internal and external carotid arteries, AP, lateral, and 45 degrees bilateral oblique positions are taken. Contrast injection rate is 3 to 4 ml/sec with total volume of 7 to 9 ml. The frame rate of fluoroscopy is 3 to 4 frames/sec. [8]
The carotid artery is the usual site of measurement of IMT and consensus statements for carotid IMT have been published for adults [12] and children. [13] Often, carotid IMT is measured in three locations: in the common carotid artery (typically at one cm proximal to the flow divider), at the bifurcation, and in the internal carotid artery.
A Doppler ultrasound blood flow detector, commonly called Doppler wand or Doppler probe, and a sphygmomanometer (blood pressure cuff) are usually needed. The blood pressure cuff is inflated proximal to the artery in question. Measured by the Doppler wand, the inflation continues until the pulse in the artery ceases.