Pulse-Echo

Question 1

Amplification

Answer 1

Increases the strength of all electrical signals in the receiver prior to further processing
(receiver gain)

Question 2

Analog

Answer 2

relating to or using signals or information represented by a continuously variable physical quantity such as spatial position or voltage.

Question 3

Analog to digital conversion

Answer 3

A signal processing operation where the amplified voltage signal representing an ultrasound echo is converted into a binary number.

Question 4

Beam Former

Answer 4

introduces a set of times delays across the individual elements

Question 5

Bistable

Answer 5

means the system has two stable equilibrium states. Something that is bistable can be resting in either of two states. These rest states need not be symmetric with respect to stored energy.

Question 6

Cathode-Ray Tube

Answer 6

a display device

Question 7

Coded Excitation

Answer 7

creating very long sound pulses containing a wide range of frequencies, distributing energy over a broad frequency range

Question 8

Compensation

Answer 8

used to make image uniformly bright from top to bottome

Question 9

Compression

Answer 9

The phase of the wave when the molecules are pushed together

Question 10

Contrast Resolution

Answer 10

The ability of the imaging system to differentiate between body tissues and display them as different shades of gray.

Question 11

Demodulation

Answer 11

Retains the actual amplitudes of echo voltages

Question 12

Depth Gain Compensation

Answer 12

to allow for greater amplification of the weaker echos returning from deeper within the body.

Question 13

Digital-to-analog converter

Answer 13

an electronic device for converting digital signals to analog form.

Question 14

Dynamic Range

Answer 14

This allows the range of echoes or shades of gray displayed on the screen to be decreased. This will remove low-level echoes from the display and result in an image with more contrast

Question 15

Frame Rate

Answer 15

Frame rate= PRF/ lines per frame

Depends upon the PRF and the number of scan lines per image.

Question 16

Gain

Answer 16

The degree of amplication of the returning echo is called the gain. Echo or signal amplification is necessary because the returning echoes are too weak to be displayed and visualized. Echoes can be strengthened by increasing the intensity of the transmitted signal or by increasing the amplification of the returning signal.

Question 17

Gray Scale

Answer 17

allow each echoes of varying degrees of amplitude to be displayed within the same image

Question 18

Image Memory

Answer 18

Stores a number of sequentially acquired and processed static image frames every second which are rapidly sent to the display to provide dynamic real-time ultrasound.

Question 19

Image Processor

Answer 19

formats the many scan line data into form

Question 20

Persistence

Answer 20

averaging of sequential frames together to get a smoother image

Question 21

PACS

Answer 21

Picture archiving and communications system

Question 22

Pixel

Answer 22

a minute area of illumination on a display screen, one of many from which an image is composed.

Question 23

Postprocessing

Answer 23

after scan converter memory

Question 24

Preprocessing

Answer 24

Image processing done before echo data are stored in image memory

Question 25

Real-time

Answer 25

enabled the visualization of moving structures but also help speed up the examination time.

Question 26

Real-time Display

Answer 26

several images can be presented per second

Question 27

Scan Converter

Answer 27

Temporarily stores images during scanning, for viewing and recording

Performs scan conversion, enabling the image data to be viewed on video monitors

Question 28

Signal Processor

Answer 28

after the images pass through this processor they are fed into the image processor

Question 29

Spatial Compounding

Answer 29

using sonographic info from several different imaging angles to produce a single image
Only available in phased array transducers.

Question 30

Temporal resolution

Answer 30

The ability to accurately portray movement occurring within the field of view during real-time imaging.

Question 31

Time Gain Compensation

Answer 31

This is required in order to compensate for the fact that signals returning from deeper reflectors will be weaker than signals returning from more shallow reflectors, because of attenuation. Increasing TGC amplifies signals more from deeper structures than it does from shallow structures.