Resolution

Question 1

3 aspects of resolution

Answer 1

detail (spatial)
contrast
temporal

Question 2

detailed resolution can be further divided into

Answer 2

axial
lateral
elevational

Question 3

axial resolution is the ability to

Answer 3

separate reflectors along the path of the beam

Question 4

axial resolution dependent on

Answer 4

SPL

Question 5

axial resolution calculated by

Answer 5

1/2 SPL

Question 6

increase f = ____ SPL = ____ axial res

Answer 6

decrease
increase

Question 7

5 things relating to better axial resolution

Answer 7

higher f probes
decreased wavelength
wide bandwidths
low Q factor
increased damping

Question 8

wide bandwidths = ____ pulse

Answer 8

shorter

Question 9

axial resolution AKA and what to remember it as

Answer 9

LARD

longitudinal
range
depth

Question 10

lateral resolution is the ability to

Answer 10

separate reflectors perpendicular to the path of the beam

Question 11

lateral resolution is dependent on the ______, therefore it ___is/is not___ constant with depth

Answer 11

width of the beam
is not

Question 12

near zone = _____ (con/divergent) = ____ lat resolution

Answer 12

convergent
increased

Question 13

what area has the best lat resolution

Answer 13

focal zone

Question 14

far zone = _____ (con/divergent) = ______ lat resolution

Answer 14

divergent
decreased

Question 15

increase focus = ______ divergence in far field = ____ lat res

Answer 15

increase
decrease

Question 16

lateral resolution is directly related to the ____ of the beam

Answer 16

width

Question 17

beam width decreased = ______ lateral resolution

Answer 17

increases

Question 18

5 things relating to better lateral resolution

Answer 18

distance from probe
amount of focusing
size of aperture
higher the f
NZL

Question 19

increase focus by increasing delay = ____ NZL

Answer 19

decrease

Question 20

NZL affected by (3)

Answer 20

aperture
f
amount of focusing

Question 21

lateral resolution AKA and how to remember it by

Answer 21

LATA

angular
transverse
azimuthal

Question 22

decrease NZL = ____ lat resolution for NZ/focal point, ____ lat resolution in far field

Answer 22

increase
decrease

Question 23

increase aperture = _____ NZL = _____ lat resolution in far field

Answer 23

increase
increase

Question 24

elevational resolution is what

Answer 24

the ability to separate reflectors perpendicular to the image plane of the beam

Question 25

elevational resolution is dependent on the ___ of the ____ but in the ___ axis

Answer 25

width beam Z-axis

Question 26

beam width in. the z-axis ____ = increased elevational resolution

Answer 26

decreases

Question 27

4 things relating to better elevational resolution

Answer 27

distance from probe higher the f NZL amount of focusing in Z plane

Question 28

elevational res AKA (2)

Answer 28

slice thickness section thickness

Question 29

contrast resolution is the ability

Answer 29

to distinguish subtle differences in tissue gray scale

Question 30

contrast resolution is related to the systems ____

Answer 30

bit depth

Question 31

higher bit depth = ____ shades of grey

Answer 31

more

Question 32

more shades of grey gives the operator more control over the ____

Answer 32

dynamic range

Question 33

reducing dynamic range = ____ the ability to distinguish subtle differences in grayscale

Answer 33

increase

Question 34

temporal resolution is the ability to

Answer 34

appreciate moving structures in real time (or moving probe)

Question 35

temporal res is related to the systems ____

Answer 35

frame rate

Question 36

frame rate increases = ____ temporal resolution

Answer 36

increases

Question 37

temp resolution is defined by FR and FR is related to the _____

Answer 37

PRF

Question 38

PRF formula for temp resolution

Answer 38

PRF (Hz) = n x LPF x FR (Hz) n= number of foci LPF = lines per frame FR = framte rate or frames/s

Question 39

____ of the sound plays an important role in the PRF as well

Answer 39

penetration

Question 40

penetration (cm) x n x LPF x F ≤ _____

Answer 40

77 000 cm/s

Question 42

why is 77 000 cm/s used

Answer 42

it represents half of the average speed of sound in soft tissue (154000cm/s)

Question 43

temp res related to 5 things

Answer 43

depth of penetration number of foci sector width number of lines per frame frame rate

Question 44

deeper = _____ pulses per second = ____ temp res

Answer 44

less decreased

Question 45

more foci = ____ temp res

Answer 45

decrease

Question 46

2 foci = _____ time = ____ temp res

Answer 46

double 1/2

Question 47

less scan lines = _____ interpolation

Answer 47

increases

Question 48

decrease sector width = _____ temp res

Answer 48

increase