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Total questions: 100
Worksheet time: 1hrs 26mins
What does damage to one of the elements of a phased array result in?
Complete loss of image
Partial loss of the right side image
Inconsistent or erratic beam steering and focusing
None of the above
How many elements in a phased array probe are used to create a single sound pulse?
1
All
2
0
In a phased array system, how does the pattern of electrical spikes from the ultrasound system steer the sound beam in different directions?
Each active element creates a small sound wavelet, they interfere forming a single beam
Each active element creates a large sound wavelet, they interfere forming a single beam
Each active element creates a small sound wavelet, they interfere forming two beam
Each active element creates a large sound wavelet, they interfere forming a triple beam
The electronics within the ultrasound system create these patterns is called the (a)
In a linear phased array, when a spike pattern is in a straight line, an (a) sound beam is created
The curved pattern creates a (a) sound beam during transmission in a linear phased array transducer
In a linear phased array, slope =
(a)
In a linear phased array, curvature =
(a)
A more accurate image is created when the ultrasound receiver introduces (a)
The optimal time delays used during receive focusing depends upon the (a) at which the reflection was created
True or false: The delay patterns during receive-focusing change continuously as the transducer listens for reflections
True
False
Series of concentric (round) crystal elements that are electronically focused
(a)
Appear disc like, but comprises of a multiple ring shape elements with a common center
(a)
With annular phased array transducers, ___ __ creates 2D image.
(a)
Advantage: multiple transmit focal zones (primary advantage)
(a)
An (a) has multiple focal zones that create each can line of an image
The term phased array means multi focus
True
False
The inner crystals of an annular phased array transducer creates a (a) focus beam. (small diameter)
The inner crystals of a annular phased array collects information ONLY from the (a) depths
The outer crystals aquire data from the (a) depths. (larger diameters)
If an annular array comprised 4 ringed elements, transmits 4 pulses down each scan line, would each ring have a different focal depth?
Yes
No
An __ ___ is fan or sector shaped (mechanically steered)
(a)
Each ringed element has a different focal depth. The final image is formed with echoes only from the focal zone of each crystal.
(a)
If one ring of the annular phased array does not work, how is the image affected?
A portion will be missing
The steering and focusing will be erratic
Complete loss of image
None of these
The __ __ array has a large acoustic footprint and creates rectangular images
(a)
Larger footprint (around 10 cm)
(a)
120 to 250 rectangular shaped crystal .
Larger than those in the linear phased arrays
(a)
With (a) a small group of the crystals are fired simultaneously
Width of image never larger than size of footprint
(a)
Linear sequential array focusing is achieved (a)
Just like phased arrays, electronic transmits focusing is achieved with a (a) excitation pattern
Transmit and receiving focusing using electronic delays and curved excitation patterns
(a)
Electronic steering
Image: parallelogram-shaped or rectangular
(a)
(a) is achieved dynamically by introducing electrical delays in the signals returning from the transducer
A (a) shaped image is created with a linear sequential array
What happens to the image if one element in a linear sequential array is damaged?
Total loss of image
Erratic steering and focusing
Only a portion goes missing
None of the above
Can steer sound beam electronically creating parallelogram-shaped images instead of rectangular ones.
(a)
Transmit and receiving focusing using electronic delays.
(a)
Can linear sequential array transducers steer sound beams electronically?
Yes
No
Curve line of elements
(a)
Curved or curvilinear are other names for (a) transducers
Identical to that of the linear sequential array (120 to 250 1 wavelength width elements in a bowed line
(a)
Pulses travel in different directions in a radiated manner producing a (a) -shaped image.
Some but not all of the elements are excited simultaneously.
(a)
Better fitting and entrance window
(a)
True or False: Sound beams in a convex array are parallel to each other
True
False
Larger imaged fields from a smaller entrance window
(a)
Focusing in convex arrays is achieved (a)
Multiple electronic focusing and dynamic focus of received echoes. (Curved spike line pattern)
(a)
Blunted sector shaped images are created by a (a)
How is the image impacted when one active element is damaged in a convex array?
A portion goes missing
Total loss of image
Erratic focusing and steering
None of the above
Footprint: As long as 10 cm
(a)
Image format is similar to that one from the convex array
(a)
contact surface or footprint is smaller and the top of the display is flat. (Trapezoidal)
(a)
Beam steering is abCombination of linear sequential and linear phased array
(a)
Larger apertures (more crystals firing at the time)
(a)
A (a) is designed with 120-250 rectangular shaped strips of PZT arranged side by side in a line
The electrical signals from the beam former are delayed in a slope spike line pattern as they excite a group of elements
(a)
Phasing can be applied in such a way that each pulse travels in the same direction but not straight down originating a parallel-shaped display useful in color Doppler
(a)
Electronic and dynamic receive focusing
(a)
Some but not all elements are fired simultaneously.
Electrical delays in slope: beam out in different directions
(a)
(a) images are created by a vector array
Sector shape, mechanical steering, fixed focusing
(a)
Rectangular shape, electronic steering, electronic focusing
(a)
Sector shape, electronic steering, electronic focusing
(a)
Sector shape, mechanical steering, electronic focusing
(a)
Blunted sector shape, electronic steering, electronic focusing
(a)
Trapezoidal shape, electronic steering, electronic focusing
(a)
Which two transducers are steered mechanically?
Mechanical
Annular phased
Convex
vector
Accuracy in imaging
(a)
shallow-to-deep
(a)
side-to-side
(a)
above to-below the imaging plane) Perpendicular
(a)
(a) is measured in a direction perpendicular to the imaging plane
INABILITY TO DYNAMICALLY CREATE THIN SLICES is a limitation of (a)
Active elements that are disc shaped provide the (a) ultrasound slices and the best resolution within the focal zone
Which transducers have disc shaped crystals?
Annular phased
convex
linear sequential
phased array
The elevational resolution is (a) to the lateral resolution within the disc shape active element
Elevational resolution: Narrowing improves lateral resolution but not the (a)
Is the following order correct when ranking resolution from worst to best:
1. Axial
2. Lateral
3. Thickness/Elevational
Yes
No
Phasing with phased, linear, and convex arrays improve lateral resolution BUT it does not affect slice thickness resolution
(a)
QUESTION: WHAT IS A 1 ½ DIMENSIONAL ARRAY TRANSDUCER
has few elements in the up and down direction to focus the beam in the thickness plane
improves lateral resolution
Depletes axial resolution
none of the abiove
Off axis sound Beas are called (a)
Reflections arising from within the side lobes (a) lateral resolution
Grating lobes are created by (a) transducers
True or false: Mechanical scanning produces pictures that are similar in shape to linear phased array images
True
False
True or false: Many active elements fire at almost the same time in a mechanical scanner
True
False
True or false: Many active elements fire at almost the same time in a phased array scanner
True
False
Which of the following transducers is best described as mechanically steered and fixed, single focused?
Annular phased array
Annular array
Mechanical
Linear phased
Which of the following is best described as mechanically steered and multi focus?
Annular phased array
Annular sequential
Mechanical
Linear phased
Which of the following transducers creates a rectangular shaped image?
Annular phased
Linear sequential
Mechanical
Linear phased
A linear phased array transducer has 128 crystals. How many of these crystal are fired to create a single bound beam?
1
a small group
a large group
128
A linear sequential array transducer has 128 crystals. How many of these crystals are fired to create a single sound beam?
1
a small group
a large group
128
In a linear phased array, what is the firing pattern that steers a beam to the left or right?
Electronic slope
Multi focusing
Beam diameter
Narrowing
In a linear phased array, what is the firing pattern that focuses the sound beam?
Electronic slope
Multi sloping
Electronic curvature
Narrowing
True or false: There are large time delays in the firing pattern of a linear phased array
true
false
True or false: A machine that displays A mode and two dimensional images is called a duplex scanner
True
False
Which of the following improves elevational resolution?
Matrix resolution
Linear phased
One and one half dimensional array
2D array
True or false: Side lobes degrade axial resolution
True
False
True or false: Side lobes degrade lateral resolution
True
False
