Ultrasound physics final review

When a renal calcification is detected, the appearance using ColorFlow is called…

twinkle artifact

If color flow is aliasing in a vessel you would adjust:

Scale (PRF)

When newly generated echoes are displayed along with echoes coming from deep tissue, the resulting artifact is called a…

range ambiguity artifact

An artifact in ultrasound is

anything that isn’t real.

What type of artifact is produced by the crystals buried in the gallbladder wall?

comet tail

A surgical clip will most likely demonstrate which of the following artifacts?

comet tail

In Color Flow imaging, what do we look for to determine if aliasing is occurring?

shades of red and blue separated by a thin black interface

One strategy for removing the aliasing involves:

Decreasing the transducer frequency

When sound waves meet destructively, it means that ….

Two waves are out-of-phase with each other

A strong attenuator, located in the beam path, will most likely create

shadow artifact

The speed at which sound travels depends on the

Medium

A mass lies between the transducer and the diaphragm. The propagation speed of the mass is 1865 cm/sec. The diaphragm distal to the mass would be displaced…

toward the transducer

Edge-shadow results from…

refraction

What part of the ultrasound beam is found at 1NZL?

The Focal point

The artifact produced by gas bubbles in the beam path, is referred to as

ring-down

A mass located near the diaphragm may produce a copy of itself that is shown deep to the diaphragm, this called a _____

mirror image artifact

Cystic structures are most likely to produce _____ artifacts.

enhancement

When echoes bounce between two reflectors, the artifact produced is

reverberation

When multiple, low-amplitude images are combined with the fundamental image of a curvilinear transducer, the result is

grating lobe artifact

What region of the beam has the best lateral resolution?

The focal point

The analysis of Doppler spectra using ___________ is most accurate.

Fast Fourier Transform

One strategy for removing the aliasing involves:

Decreasing the transducer frequency

Wall filters…

eliminate low-frequency Doppler shifts

Doppler does not always provide a valid estimate of the speed of blood cells because the shift is related to the _______ of the angle between the direction of the beam and the direction of blood flow.

Cosine

1. The highest Doppler frequency without the appearance of aliasing is called the _________ and is equal to ________.

Nyquist limit, half of the emitted PRF

In the picture below, would you increase or decrease the wall filter?

increase

All of the following are related to pulsed wave Doppler transducer EXCEPT:

High velocities

An advantage of PW doppler is…

It can detect velocities at specific sites

An advantage of Doppler Packets are

increased sensitivity to flow

A duplex ultrasound system displays ______ information

Two-dimensional image and Doppler

A negative Doppler shift means _______

red blood cells move away from the transducer

Which of the following is present in this Doppler wave form?

Aliasing

True or False: Power Doppler is color flow that shows blood flow direction and velocity

False

Use the color Doppler image to answer the question regarding the direction of flow in a rectangular image with a steered box

right to left

All of the following are associated with CW Doppler transducer except:

backing material