Chapter 4: Image Quality

Question 1

describes the level of detail that can be seen in an image

Answer 1

Spatial Resolution

Question 2

refers to 2 or 3 dimensions of a single image

Answer 2

Spatial domain

Question 3

most basic measurement of the resolution properties of an imaging system and it is perhaps the most intuitive

Answer 3

Point of spread function/Impulse resp fxn

Question 4

stimulate the image with a slit

Answer 4

Line fo spread function

Question 5

Uses a sharp edge to stimulate the image, useful when the spatial distribution characteristics of glare of scatter phenomenon are subject of interests

Answer 5

Edge spread function

Question 6

refers to the ability to detect very subtle changes in grey scale and distinguish them from the noise of the img

Answer 6

contrast resolution

Question 7

relates more to anatomic structures that produce small changes in signal intensity which make it difficult for radiologist to pick out that structure from a noisy background

Answer 7

contrast resolution

Question 8

results in screen film radiology where the formed img is formed by millions of silver grains attached to the clear film substrates

Answer 8

grain noise

Question 9

flow of the e- current conveys the signal at one or more parts in the imaging chain

Answer 9

electronic noise

Question 10

represent a reproducible pattern on the img that reflects the differences in the gain of individual detector elements or group of detector elements

Answer 10

structured noise

Question 11

structured noise is corrected by

Answer 11

flat field algorithm

Question 12

pattern on the img that is generated by patient anatomy that is always present but not imp for the diagnosis

Answer 12

anatomic noise

Question 13

any number of particles or objects that can be counted, such as e-, xray photons optical photons or even brush strokes on an impressionalist painting

Answer 13

quantum noise

Question 14

object size independent measure of the signal level in the presence of noise

Answer 14

contrast to noise ratio

Question 15

object size and shape is depedent in the measurement of the signal level in the noise

Answer 15

signal to noise ratio

Question 16

point inthe distribution where 50% of the observations are greater

Answer 16

median

Question 17

most frequent observation, highest point on the histogram

Answer 17

mode

Question 18

width of the distribution

Answer 18

range

Question 19

bell shaped curve characterized by the mean and standard deviation

Answer 19

normal distrubition/gaussian distribution

Question 20

the fundamental contrast that arises in the signal, after it has interacted with the patient but before it has been detected.

Answer 20

subject contrast

Question 21

the incident beam of energy from teh imaging system will eventually react the detector

Answer 21

detector contrast

Question 22

acts to modulate the subject contrast

Answer 22

displayed contrast