Ultrasonography is a less invasive and less expensive modality which is easy to schedule and perform in an emergency situation. Sonographers can be called to perform this as an alternative to arteriography and venography, which involves injecting dye into the blood vessels so that they can be detected as X-ray images.
Duplex Ultrasound
A duplex ultrasound is a combination of tests to see how blood moves through your arteries and veins. Duplex means that two types of ultrasonography are employed: regular B-mode ultrasounds, and Doppler ultrasounds. The conventional ultrasound shows the structures of your blood vessels and Doppler shows the movement of your red blood cells through the vessels and the sound of the frequency shifts.
Doppler Ultrasound Semantics
It is interesting to note that in sonography, the word Doppler is used similar to the way the word Kleenex is. People use tissues and refer to them as Kleenex when they're not. In sonography, the word Doppler is used when true scientific Doppler is not what is really being done. It's similar, but different.
The technical point to know is that Doppler Ultrasound equipment is technically concerned with sound frequency, whereas in ultrasound applications we compare the PHASE of the sound. In what we do, Phase Shifts are more detectable and are what we measure, not frequency, but it's similar so it's referred to as Doppler sonography. Semantics!
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