Ch.15 Physics: Displays and Image Processing Flashcards
_________ is essential because what we see ultimately determines what we conclude.
Display monitor
_________ images are only black and white, High contrast, Narrow dynamic range and Poor contrast resolution
Bistable
_________ shows multiple levels of brightness, Low contrast,
Wide dynamic range, and Good contrast resolution
Gray scale
What Determines the range of brilliancies within the image, has High contrast results in bistable and Low contrast contains many shades of grey?
Contrast
Determines the brilliance of the displayed image
Brightness
Grayscale imaging is made possible by using a __________.
Scan converter
What first stores ultrasound information (write) and then displays it on the monitor (read)?
Scan converter
How is Ultrasound information obtained?
from pulses in a spoke pattern
What are numbers that are real world numbers and May contain an unlimited and continuous range of values?
Ex: a person’s weight or length of an object
Analog
What are numbers that are associated with computer devices and Only have discrete values?
Ex: could be a person’s weight on a digital scale only representing whole pounds
Digital
First type used to create gray scale images
analog scan converters
A funnel shaped vacuum tube with an electron gun located within its smaller end and Each electron stored is read to retrieve the image information.
Analog scan converter
The __________ (image detail) of an analog scan converter is excellent because of the larger number of storage elements
spatial resolution
What are the Limitations of analog converters?
Image fade
Image flicker
Instability
Deterioration
Computer technology converts images into numbers through digitizing and The image is stored in computer memory as a series of 0’s and 1’s
Digital scan converter
What are the Two important elements of digital scan converters?
pixel
bits
What are the Advantages of digital converters?
Uniformity
Stability
Durability
Speed
Accuracy
the smallest building block of a digital picture and derived from the term picture element
Pixel
the number of pixels per inch of an image
Pixel density
__________ = higher pixel density = improved spatial resolution = better image detail
smaller pixels
_________ = Low pixel density = lower spatial resolution = poor image detail
Larger pixels
smallest amount of computer memory and Comes from the term binary digit
Bit
What is a group of bits and is a Series of zeroes and ones.
Binary numbers
____________ = more shades of gray = improved contrast resolution
More bits per pixel
____________ = fewer shades of gray = degraded contrast resolution
fewer bits per pixel
is a group of eight bits of computer memory
byte
_____ of computer memory consists of two bytes, or 16 bits
word
How do you calculate the shades of gray?
By multiplying the number 2 itself with however many bits.
how many shades of gray can be displayed with 5 bits of memory?
2 x 2 x 2 x 2 x 2 = 32 shades of gray (max)
is the manipulation of image data before it is stored in the scan converter
Preprocessing
is the manipulation of image data after storage in the scan converter
Postprocessing
Preprocessing is changing the …..?
write magnification
Postprocessing is altering the …..?
read magnification
What is performed on live images during real-time scanning?
Preprocessing or postprocessing
preprocessing
What Consists of any change after freeze frame such as Black/White Inversion and 3D Rendering?
preprocessing or postprocessing
Postprocessing
Also called zoom, the sonographer can improve visualization of anatomic detail by enlarging a portion of an image.
Magnification
The selected part of the image is known as the …..?
region of interest (ROI)
What are the two different forms of magnification?
Write magnification - preprocessing
read maginification - postprocessing
Applied during data acquisition, before the image data
has been stored in the scan converter.
Write magnification
Zooming in on a ROI after the image data has been stored
in the scan converter.
Read magnification
What creates a very long sound pulse with a wide range of frequencies?
Coded excitation
What are the benefits of coded excitation?
Higher signal-to-noise ration
Improved axial, spatial, and contrast resolution
Deeper penetration
A method of using sonographic information from several different imaging angles to produce a single image.
Spatial compounding
True or false:
Spatial compounding is available to all transducers.
False
only with phased array transducers
What is one benefit of spatial compounding?
the reduction of angle-dependent artifacts (speckle, granular appearance, and shadowing).
What divides the reflected signal into different groups based on frequency? Each of these groups is added together reducing the overall noise level.
Frequency compounding
An image processing method that makes pictures look sharper by the computer identifying and emphasizes sharp edge boundaries between two media with different gray scale levels.
Edge enhancement
Defines the boundary between two different tissues and It accomplishes this by increasing the contrast at the interface of different tissues.
Edge enhancement
Also known as persistence, or temporal averaging and this technique continues to display information from older images.
Temporal compounding
For temporal compounding, how is a smoother image produced?
Reduced noise
Higher signal-to-noise ratio
Improved image quality
How is temporal compounding most effective with slow moving structures?
the primary limitation of persistence is reduced temporal resolution.
What uses a program to predict and display missing data (shades of gray) between scan lines based on neighboring pixels?
Fill in interpolation
Fill in interpolation is a form of what?
preprocessing
A technique that produces images called elastograms, based on tissue deformity when force is applied. It identifies tissues of different stiffness through ultrasonic palpation, what is this?
Elastography
This estimates tissue stiffness
Elastogrpahy
What creates the tissue deformation on the ultrasound?
Force of the sound beam
True or false:
Elastogrpahy can be combined with grayscale images and Doppler to add to the diagnostic value of the exam.
(benign vs. malignant tumor)
True
True or false:
Elastography can be combined with color doppler.
True
What are the meanings of the color scale for tissue stiffness?
Red
Green/yellow
Blue
Red- Very stiff
Green/yellow- intermediate
Blue- Low stiffness
The digital archiving system that stores diagnostic images and medical information.
PACS -Picture Archiving and Communications System
Capable of electronically transmitting images and reports remotely
PACS
“Set of rules” that allows imaging system components to communicate with a network.
DICOM
When an ultrasound system adheres to DICOM standards, it can connect to a __________ medical information network.
PACS
Sharing, managing, and distributing images among many manufactures is simplified by the acceptance of________ standards.
DICOM
