Ultrasound Physics - 15\storage

Front 1

A glass vacuum tube shaped like a funnel, sometimes used to display ultrasound images, is called what?

Back 1

Cathode Ray Tube (CRT)

Front 2

The narrow end of a CRT contains a/an ___ that shoots out a stream of ___ containing video information

Back 2

Electron Gun / Electrons

Front 3

The interior surface of the CRT is coated with ___ which glow when struck by electrons

Back 3

Phosphors

Front 4

The odd-numbered lines (1-525) which the electron beam writes across the CRT screen first, are called what?

Back 4

Odd Field

Front 5

The even-numbered lines (2-524) which the electron beam writes across the CRT screen last, are called what?

Back 5

Even Field

Front 6

A combination of one odd field and one even field is called what?

Back 6

Frame

Front 7

How much time is required to make a single frame? thus making CRT fame rate what?

Back 7

1/30 sec (1/60 + 1/60)
30 Hz

Front 8

When a CRT screen is written by alternating between the odd field and the even field, what is this called?

Back 8

Interlaced

Front 9

At what Hz can human no longer detect an interlaced display?

Back 9

60 Hz

Front 10

This type of image consists of only two colors: black & white

Back 10

Bistable Images/Display

Front 11

This type of image consists of multiple levels of brightness. Different amplitudes are assigned to different shades

Back 11

Grayscale Images/Display

Front 12

What two user controls alter display characteristics?

Back 12

1) Brightness
2) Contrast

Front 13

This user control determines the range of brilliancies within displayed images

Back 13

Contrast

Front 14

This user control determines the brilliance of the displayed image

Back 14

Brightness

Front 15

This system component converts the sound beam spoke patterns into a digital, interlaced pattern suitable for display

Back 15

Digital Scan Converter

Front 16

This type of number can have an unlimited and continuous range of values, and are found in everyday lives

Back 16

Analog Numbers

Front 17

This type of number have a limited range of discrete values, and are frequently associated with computer devices

Back 17

Digital Numbers

Front 18

For what four reasons are analog scan converters obsolete today?

Back 18

1) Image Fade
2) Image Flicker
3) Instability
4) Deterioration

Front 19

Using computer technology to convert images into numbers is called what?

Back 19

Digitizing

Front 20

What are five advantages of digital scan converters today?

Back 20

1) Uniformity
2) Stability
3) Durability
4) Speed
5) Accuracy

Front 21

What is the smallest building block of a digital picture?

Back 21

Pixel
(PICture ELement)

Front 22

The number of picture elements per square inch is called what?

Back 22

Pixel Density

Front 23

The following factors define what?
- lower spatial resolution
- less detailed image
- larger pixels
- few pixels/inch

Back 23

Low Pixel Density

Front 24

The following factors define what?
- higher spatial resolution
- more detailed image
- smaller pixels
- many pixels/inch

Back 24

High Pixel Density

Front 25

What is the smallest amount of computer memory called?

Back 25

Bit
(BInary digiT)

Front 26

What digits are binary numbers based on? Decimal numbers?

Back 26

Binary: 0 - 1
Decimal: 0 - 9

Front 27

A group of eight bits of computer memory

Back 27

Byte

Front 28

The computer memory made up of 2 bytes (or 16 bits)

Back 28

Word

Front 29

When an image displays many shades of gray, it is said to have this

Back 29

Superior Contrast Resolution

Front 30

The following factors define what?
- fewer shades of gray
- degraded contrast resolution

Back 30

Fewer Bits/Pixel

Front 31

The following factors define what?
- more shades of gray
- improved contrast resolution

Back 31

More Bits/Pixel

Front 32

How do we determine the number of shades of gray?

Back 32

Multiply 2 by itself, the same number of times as there are bits

Front 33

What is the number of shades that can be represented by 3 bits?

Back 33

2 x 2 x 2 = 8 shades of gray

Front 34

What is the number of shades that can be represented by 8 bits?

Back 34

256 shades of gray

Front 35

How many bits are needed to store:
- 10 shades of gray?
- 11 shades of gray?
- 15 shades of gray?

Back 35

4 bits

Front 36

What is the primary advantage of digital over analog?

Back 36

Digital is less susceptible to signal contamination

Front 37

The FIRST step in converting analog signals to digital, involves converting the electrical signals received by the transducer to strings of 0s and 1s. This is performed by what?

Back 37

Analog-to-Digital (A-to-D) Converter

Front 38

The SECOND step in converting analog signals to digital, involves processing of the reflected signals before storage. This is called what?

Back 38

Pre-Processing

Front 39

The THIRD step in converting analog signals to digital, involves processing after storage. This is called what?

Back 39

Post-Processing

Front 40

The FOURTH step in converting analog signals to digital, involves translating stored digital signals back to analog for display on analog CRT (televisions). This is performed by what component?

Back 40

Digital-to-Analog (D-to-A) Converter

Front 41

The FIFTH step in converting analog signals to digital, involves writing the newly converted analog signals to the CRT. This is called what?

Back 41

Video Display

Front 42

The manipulation of image data before storage in the scan converter. This manipulation cannot be reversed

Back 42

Pre-Processing

Front 43

The manipulation of image data after storage in the scan converter. This manipulation can be reversed

Back 43

Post-Processing

Front 44

The following are handled when?
- TGC
- Log Compression
- Write Magnification
- Fill-In Interpolation

Back 44

Pre-Processing

Front 45

The following are handled when?
- any change after freeze frame
- Black/White Inversion
- Read Magnification
- Contrast Variation

Back 45

Post-Processing

Front 46

The following are handled when?
- Persistence
- Frame Averaging
- Edge Enhancement
- Smoothing

Back 46

Either Pre- or Post-Processing

Front 47

Zoom can also be called what?

Back 47

Magnification

Front 48

Image visualization can be improved by enlarging a portion to fill the entire screen. This is called what?

Back 48

Magnification

Front 49

This form of magnification occurs after image storage in the scan converter. It consists of 3 steps:
- anatomy scan
- conversion & storage
- region of interest selected and only the original data that pertains to that region is displayed (no rescan)

Back 49

Read Magnification

Front 50

Read magnification can be used on a frozen image, and thus is considered what?

Back 50

Post-Processing

Front 51

This form of magnification occurs during data acquisition, before storage in the scan converter. It consists of 4 steps:
- anatomy scan
- conversion & storage
- region of interest selected
- rescans only the region of interest

Back 51

Write Magnification

Front 52

If the number of pixels or scan lines in the region of interest is greater than in the original image (improved spatial resolution), name the form of magnification used

Back 52

Write Magnification

Front 53

If the number of pixels or scan lines in the region of interest is the same as the original image (same spatial resolution), name the form of magnification used

Back 53

Read Magnification

Front 54

Write nagnification cannot be used on a frozen image and thus is considered what?

Back 54

Pre-Processing

Front 55

The following describes what kind of magnificaiton?
- uses old data
- post-processing
- larger pixel size
- same # pixels as original ROI
- unchanged spatial resolution
- unchanged temporal resolution

Back 55

Read Magnification

Front 56

The following describes what kind of magnificaiton?
- acquires new data
- pre-processing
- identical pixel size
- more pixels than original ROI
- improved spatial resolution
- possible improved temporal resolution

Back 56

Write Magnification

Front 57

Name the storage media:

ADVANTAGES: portability, requires no device to read

DISADVANTAGE: bulky, hard to store, difficult to copy, cannot display dynamic images

Back 57

Paper Media

Front 58

Name the storage media:

ADVANTAGES: can store large amounts of info efficiently, can store and play dynamic images, can record color

DISADVANTAGE: Can be erased by strong magnetic fields

Back 58

Magnetic Media

Front 59

Name the storage media:

ADVANTAGES: High resolution, accepted in the medical community, can produce color images

DISADVANTAGE: bulky, difficult to store and retrieve, requires chemical processing, artifacts can arise from dirt or chemical contamination

Back 59

Chemically Mediated Photographs

Front 60

Name the storage media:

ADVANTAGES: can store huge amounts of data, inexpensive, not erased by exposure to magnetic fields

DISADVANTAGE: Requires a display system, no standardized format for image display and storage

Back 60

Optical Media

Front 61

This describes the digital ultrasound lab in which images and reports are digitized and stored on a large computer network

Back 61

PACS - Picture Archiving and Communications System

Front 62

What are three advantages of PACS?

Back 62

1) Instant access to archived studies
2) No degradation of data
3) Electronically transmit images and reports to remote sites

Front 63

This describes a form of storage based on a combination of magnetic and optical technology, which is often used by PACS

Back 63

Magneto-Optical (MO) Storage

Front 64

What are two advantages of magneto-optical storage?

Back 64

1) can store large amounts of data on a single disc
2) high degree of security (cannot be erased by strong magnetic fields)

Front 65

All of the following are true of ordinary CRTs, except:
A. It contains large vacuum tubes with a phosphor-coated screen
B. Electrons are emitted by a gun and swept across the screen by varying magnetic fields
C. There are 600 horizontal scan lines from top to bottom, painted in order from 1 to 600
D. There are 60 fields generated each second that combine into 30 fames per second

Back 65

C (525 lines, interlaced format)

Front 66

Which of the following correctly describes a typical television display?
A. interlaced
B. progressive scan
C. bistable
D. non-interlaced

Back 66

A

Front 67

Which electronic component is required for grayscale imaging?
A. VCR
B. non-interlaced display
C. computer memory
C. scan converter

Back 67

D

Front 68

All of the following are disadvantages of analog scan converters except:
A. image fade
B. low-resolution image
C. image flicker
D. deterioration

Back 68

B

Front 69

Which of the following scan converters will provide the best spatial resolution?
A. digital with 256x256 pixels
B. digital with 512x512 pixels
C. digital with 128x128 pixels
D. analog with 1000x1000 array

Back 69

D

Front 70

Which of these statements regarding a bit of computer memory is false?
A. it is the smallest element of an image
B. it is bistable
C. eight bits combine to make a byte
D. it is a component of a digital scan converter

Back 70

A

Front 71

How many gray shades can be represented by a group of 4 bits? 2 bits?

Back 71

16 shades
4 shades
(multiply 2 by itself as many times as there are bits)

Front 72

Which of the following statements regarding a pixel is false?
A. smallest part of a digitized image
B. a collection of bits, assigned to each pixel, stores the shad of gray
C. it displays up to 3 gray shades simultaneously
D. image quality is improved when the number of pixels is high

Back 72

C

Front 73

Are the following procedures usually pre- or post-processing?
A. modifyng a frozen image
B. read zoom
C. write zoom
D. adjusting the brightness of the CRT
E. increasing the receiver gain

Back 73

A. post-processing
B. post-processing
C. pre-processing
D. post-processing
E. pre-processing

Front 74

Are the following forms of information usually digital or analog?
A. signal from the transducer to the receiver
B. input signal to the digital-to-analog converter
C. output signal from the analog-to-digital converter
D. input signal to the analog-to-digital converter
E. output signal from the digital-to-analog converter
F. typical video signal

Back 74

A. analog
B. digital
C. digital
D. analog
E. analog
F. analog

Front 75

All of the following are characteristics of write magnification except:
A. pre-processing function
B. more pixels in the ROI
C. identical regions stored in the scan converter before and after zooming
D. it is the preferred method of image magnification

Back 75

C

Front 76

What is the primary disadvantage of video tape and computer disc storage?
A. cost
B. vulnerable to erasure by strong magnetic fields
C. only low resolution images are stored
D. only black and white images are stored

Back 76

B

Front 77

All of the following are advantages of PACS systems except:
A. data will not deteriorate over time
B. images can be delivered to distant locations
C. studies can be reviewed easily
D. images have a higher resolution that what appears on the display

Back 77

D