Pulsed Echo Instrumentation

Question 1

anything not properly indicative of anatomy or motion imaged

Answer 1

artifact

Question 2

group of bits

Answer 2

binary number

Question 3

binary digit; smallest amount of computer memory

Answer 3

bit

Question 4

group of 8 bits of computer memory

Answer 4

byte

Question 5

imaging display ehere the strength of the electron beam determines the brightness

Answer 5

cathode ray tube (CRT)

Question 6

an independent signal path consisting of a transducer element, delay, and other electronic components

Answer 6

channel

Question 7

storage of the last several real time frames

Answer 7

cine loop

Question 8

a series of pulses and gaps allowing multiple focal zones and harmonic frequencies

Answer 8

code excitation

Question 9

a series of closely spaced reverberation echoes behind a strong reflector

Answer 9

comet tail

Question 10

the ratio of the largest to smallest amplitude that the ultrasound system can handle

Answer 10

dynamic range

Question 11

loss in intensity from bending of the sound beam at a curved surface

Answer 11

edge shadowing

Question 12

the increase in reflection amplitude from structures that lie behind a weakly attenuating structure

Answer 12

enhancement

Question 13

displayed image of the returning echoes

Answer 13

feild of view

Question 14

a complete scan of the ultrasound beam; individual image composed of multiple scan lines

Answer 14

frame

Question 15

the number of complete scans (images) displayed per second

Answer 15

frame rate

Question 16

holding and displaying one frame of the real time sequence

Answer 16

freeze frame

Question 17

ration of amplifier output to input of electric power

Answer 17

gain

Question 18

secondary sound beams produced by a multielement transducer

Answer 18

grating lobes

Question 19

number of scan lines per fram; scan line density

Answer 19

line density

Question 20

denotes the rows and colums of pixels in a digital image

Answer 20

matrix

Question 21

storage of echo information

Answer 21

memory

Question 22

an artifactual gray scale, color flow, or doppler signal appearing on the opposite side of a strong reflector

Answer 22

mirror image

Question 23

the path toward and away from a reflector are different

Answer 23

multipath

Question 24

disturbance that reduces the clarity of the signal

Answer 24

noise

Question 25

the minimum number oof samples required to avoid aliasing; doppler shift frequency above which aliasing occurs

Answer 25

nyquist limit

Question 26

an expanded immage display beyond the normal limits of the transducer

Answer 26

panoramic image

Question 27

picture element; smalles portion of a digital image

Answer 27

pixel

Question 28

number of picture elements per inch

Answer 28

pixel density

Question 29

assigning a brightness value to a missing pixel

Answer 29

pixel interpolation

Question 30

a harmonic imaging technique using two pulses per scan line where the second pulse is an inverse of the first one

Answer 30

pulse inversion

Question 31

the number of voltage pulses sent to the transducer each second

Answer 31

pulse rep frequency

Question 32

time from the beginning of one pulse to the start of the next

Answer 32

pulse rep period

Question 33

allows access of stored data in an unsystematic order

Answer 33

random access memory (RAM)

Question 34

produced when echoes are placed too superficially because a second pulse was emitted before all reflections have returned from the first pulse

Answer 34

range ambiguity

Question 35

stored data that cannot be modified

Answer 35

read only memory (ROM)

Question 36

two dimensional imaging of the motion of moving structures

Answer 36

real time imaging

Question 37

portion of the sound reflected from the boundary of a medium

Answer 37

reflection

Question 38

change of sound direction on passing from one medium to another

Answer 38

refraction

Question 39

multiple reflections between a structure and the transducer or within a structure

Answer 39

reverberation

Question 40

redirection of sound in several directions on encountering a rough surface

Answer 40

scattering

Question 41

reduction of reflective amplitude from reflectors that lie behind a strongly reflecting or attenuating structure

Answer 41

shadowing

Question 42

comparision of meaningful information in an image (signal) to the amount of signal disturbance (noise)

Answer 42

signal to noise ratio

Question 43

averging of frames that view anatomy from different angles

Answer 43

spatial compounding

Question 44

large, flat, smooth surface

Answer 44

specular

Question 45

the smallest distinguishable part of a 3 dimensional image

Answer 45

voxel

Question 46

A-mode

Answer 46

amplitude mode 1-d displays amplitude on y-axis and distance on x-axis

Question 47

B-mode

Answer 47

brightness mode 2D imaging y axis = increasing depth x axis = side to side or superior to inferior aspects of body the stronger the reflection the brighter the pixel

Question 48

M-Mode

Answer 48

motion mode 1d y axis = reflector depth x axis = time