Chapter 18

Question 1

Resolution

Answer 1

The ability to image fine detail

Question 2

____ resolution is better

Answer 2

Smaller

Tinier details can be discerned

Question 3

If two reflectors are not seperated sufficiently they produce

Answer 3

Overlapping echoes

Question 4

Axial resolution aka

Answer 4

Longitudinal, radial, depth and range

Question 5

Axial resolution is

Answer 5

Minimum reflector seperation along scan line to produce separate echoes

Question 6

Axial resolution = ____ mm

Answer 6

2mm

Question 7

Structures place 1 mm apart will be seen as a

Answer 7

Single structure

Question 8

Axial resolution equation

Answer 8

AR= SPL/2

Question 9

The smaller the AR the

Answer 9

Better

Question 10

To improve AR we need to

Answer 10

Reduce SPL

Question 11

Lateral resolution aka

Answer 11

Angular, transverse, azimuthal

Question 12

Lateral resolution is

Answer 12

Minimum reflector seperation perpendicular to scan line to produce separate echoes

Question 13

Lateral resolution occurs when _____=____

Answer 13

LR=Wb

Lateral resolution = width of beam

Question 14

LR=3mm

Answer 14

Reflector seperation is less than Wb

Question 15

LR=1mm

Answer 15

BEAM IS NARROWER THAN REFLECTOR SEPERATION

Question 16

WHAT IS BETTER SMALL OR LARGE LR

Answer 16

Smaller

Question 17

LR is improved by

Answer 17

Reducing the wb

Question 18

Elevation resolution

Answer 18

Minimum reflector separation perpendicular to scan plane to produce separate echoes

Operates in 3 dimension

Question 19

Elevational resolution has ____

Answer 19

Slice thickness aka section thickness / elevational plane

Question 20

Elevational resolution can preoduce

Answer 20

Section thickness artifact aka partial volume artifact

Can fill in cysts or other anechoic structures

Question 21

Poor elevation resolution will show

Answer 21

Echoes from outside the intended scan plane

Especially within anechoic structures

Question 22

HOW DO WE FIX elevational resolution artifact

Answer 22

THI—> narrower and thinner beam

Less likely to pick up echoes from other plane

Spatial compounding

Question 23

AR is less than _____mm to distinguish two seperate objects

Answer 23

1mm

Question 24

Temporal resolution

Answer 24

Being able to separate echoes in time

Poor temporal resolution is visualized as lag

Question 25

Contrast resolution

Answer 25

Being able to separate two different shades of grey

Question 26

Usefull frequency range

Answer 26

2 to 20 MHz

Question 27

Higher freq increase _____ and decrease ________

Answer 27

Resolution Max imaging depth

Question 28

Up to _____ Mhz can be used for ophthalmologic, dermatologic, and intravascular imaging

Answer 28

50 MHz

Question 29

Focus can be achieved in the third dimension by

Answer 29

Lens or curved elements

Question 30

What is third dimension

Answer 30

Perpendicular to the scanning plane

Question 31

How many rows of elements needed for phasing to be applied to focus the third dimension electronically

Answer 31

At least three

Question 32

Electronic focusing eliminates the need for

Answer 32

A lens or curved elements

Question 33

2D arrays have the ability to _____ and _____ in two dimensions

Answer 33

Steer and focus

Question 34

1D array =

Answer 34

2D imaging

Question 35

2D array ->

Answer 35

3D imaging

Question 36

3D imaging aka

Answer 36

Volume imaging | Volumetric scanning

Question 37

3D imaging mainly used for

Answer 37

OBSTETRICS AND BREAT

Question 38

4D imaging =

Answer 38

3D imaging + time

Question 39

Echoes arriving to the transducer can be ________ as well

Answer 39

Delayed or phased

Question 40

Reception steering

Answer 40

Listening from a particular direction

Question 41

Dynamic focusing

Answer 41

Continual change of the focus with increasing depth

Question 42

Dynamic aperture

Answer 42

As the focus continues to change during echo reception, the aperture will increase to maintain a constant focus with

Question 43

Annular arrays

Answer 43

Concentric rings Piezoelectric material carved out in rings Go from smallest to largest Not used anymore