Pulse-Echo Instrumentation

Question 1

Where the action originates.
It consists of a pulser; pulse delays; transmit/receive switch, amplifiers, analog-to-digital converters, echo delays, and a summer.
Functions:
-Generating voltages that drive the transducer
-determining pulse repetition frequency, coding, f, and intensity;
-scanning, focusing, and apodizing the transmitted beam;
-amplifying the returning echo voltages
-compensating for attenuation;
digitizing the echo voltage stream;
directing, focusing, and apodizing the reception beam

Answer 1

Beam Former

Question 2

Number of images that are generated each second

Answer 2

Frame Rate

Question 3

Driving voltage-pulse forms;
This accomplishes functions such as:
- multiple transmission foci;
-separation of harmonic echo Bandwidth from transmitted pulse bandwidth;
-increased penetration;
reduction of speckle with improved contrast resolution;

Answer 3

coded excitation

Question 4

The conversion of the small voltages received from the transducer elements to larger ones suitable for further processing and storage

Answer 4

Amplification

Question 5

The ratio of amplifier output to electric power input

Answer 5

Gain

Question 6

Equalizes differences in received echo amplitudes caused by different reflector depths

Answer 6

Compensation
Also called: Time Gain Compensation (TGC)
and Depth Gain Compensation

Question 7

Allows adjustment of gain laterally across the image

Answer 7

Lateral Gain Control

Question 8

The first word means ‘proportional’ and the other word means ‘in the form of discrete numbers’

Answer 8

Analog-to-digital

i.e the echo voltage has been proportional to the echo pressure

Question 9

Convert the analog voltages representing echoes to numbers for digital signal processing and storage

Answer 9

Analog-to-digital Converter

Question 10

• Determines how many shades of gray are displayed in an image;
• The ratio of the largest to the smallest amplitude or power that a system can handle;
• Demonstrates contrast or shades of gray.

Answer 10

Dynamic Range
(The higher the dynamic range the more shades of gray demonstrated;
Smaller dynamic range setting gives a higher contrast image)

Question 11

-Decreases the difference between the largest and the smallest voltages or echo amplitudes;

Answer 11

Compression

Also called Log Compression on Acuson XP or Dynamic Range on some equip

Question 12

Makes image suitable for display;
Also called Detection;
Conversion of echo voltages from radio frequency (RF) to video form;
Retains the actual amplitudes of the echo voltages;

Answer 12

Demodulation

Question 13

Scan conversion

Answer 13

Image Processor

Question 14

Image processing done before echo data are stored in image memory
Persistence
Panoramic imaging
Spatial compounding
3D processing

Answer 14

Pre Processing

Question 15

(after scan converter memory)
Gray scale
Color scale

Answer 15

Post Processing

Question 16

Enables the image data to be viewed on video monitors

Answer 16

Scan Converter

converts the acquired signals to the format needed by the video monitor

Question 17

Temporarily stores images during scanning, for viewing and recording

Answer 17

Image Memory

Question 18

Averaging of sequential frames together to get a smoother image

Answer 18

Persistence

Question 19

Averaging of frames that view anatomy from different angles

Answer 19

Spatial Compounding

Question 20

Picture Archiving and Communications Systems

Answer 20

PACS

Question 21

the ability to distinguish closely timed events as separate events; and to correctly display rapidly moving structures

Answer 21

Temporal Resolution

As frame rate increases, temporal resolution improves

Question 22

number of focuses x lines per frame x frame rate

Answer 22

PRF

Question 23

A device which takes a digital value and outputs a voltage which is proportional to the input value.

Answer 23

Digital-to-analog Converter

Question 24

An electronic circuit that has two stable states;

or as an adjective: (of a system) having two stable states

Answer 24

Bistable

Question 25

A unit of information expressed as either a 0 or 1 in binary notation.

Answer 25

Bit

Question 26

A vacuum tube generating a focused beam of electrons, the terminus of which is visible as a luminescent spot or line on a screen at the broad end of the tube: used to display images on a television receiver or computer monitor;

Answer 26

Cathode-ray tube

Question 27

Refers to the ability to distinguish between different echo amplitudes of adjacent structures.

Answer 27

Contrast Resolution

Question 28

The dynamic range of the human eye is less than 36 dB, which is equal to 64 shades of gray at the same time. The range returning signals must be compressed so we can see it. High amplitudes show up bright, no reflection is black.

Answer 28

Gray Scale&Dynamic Range

Question 29

Pixel size up-Resolution down.
Pixel size up-# of pixels down.
# of pixels up-Resolution up.

Answer 29

Pixel size & Resolution

Question 30

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

Answer 30

Pixel

Question 31

The actual time during which a process or event occurs.

Answer 31

Real-time

Question 32

Because several images can be presented per second its called…

Answer 32

Real-time Display