Chapter 12 quiz Flashcards
The minimum number of active elements in a mechanical transducer is:
1
T or F. Many active elements fire at almost the same time in a phased array scanner.
True
Which of the following transducers is best describes as mechanically steered and fixed, single focused?
Mechanical
Which of the following is best described as mechanically steered and multi-focus?
Annular phased array transducer
Which of the following transducers creates a rectangular shaped image?
Linear sequential array
A linear phased array transducer has 128 crystals. How many of these crystals are fired to create a single sound beam?
128 (All of them)
A linear sequential array transducer has 128 crystals. How many of these crystals are fired to create a single sound beam?
A small group
In a linear phased array, what is the firing pattern that steers a beam up or down?
Slope
In a linear phased array, what is the firing pattern that focuses a sound beam?
Curve
T or F. There are large time delays in the firing pattern that focuses a sound beam.
False
T or F. A machine that displays A-mode and two-dimensional images is called a duplex scanner.
False
When looking at image produce by these transducer systems, which one can be distinguished from all the others? Linear phased array Linear switched array Annular phased array Mechanical transducer
Linear switched array
T or F. All phased array transducer systems direct ultrasound pulses in many directions to create a two-dimensional image.
True
What is true of the electrical pulses that excite the active elements of an annular phased array transducer?
They arrive at each PZT crystal at different times microseconds apart
The pattern of electrical signals exciting the PZT crystals of a linear phased array transducer ________.
Typically changes from one acoustic pulse to the next
How are PZT crystals excited when using an ultrasound system with sequential linear array transducer?
In a specific order
How are the PZT crystal of a linear phased array transducer fired?
At almost exactly the same time
T or F. The “curvature pattern” of delays in the electrical spikes used in linear phase array transducer focuses the beam during transmission.
True
Which of the following forms of focusing is different that the others? Lens Mirror Phased Dynamic recieve
Mirror
T or F. The “curved pattern” of delays in the electrical spikes used in linear phase array transducer focuses the beam during reception.
False
Which two of the following terms are associated with phased array transducer?
Adjustable
Multi-focus
What helps to determine the frequency of the sound produced by the transducer of a continuous wave ultrasound system?
Ultrasound system electronics
What is the shape of the elements in an annular phased array transducer?
Circles
Which best describes the element in a linear phased array transducer? Rectangular, 1/4 wavelength thick Rectangular, 1/2 to 1/4 wavelength wide Circular Squares, 1/2 wavelength thick
Rectangular, 1/2 to 1/4 wavelength wide
Which best describes the element in a linear sequential array transducer? Rectangular, 1/4 wavelength thick Rectangular, 1/2 to 1/4 wavelength wide Circular Squares, 1/2 wavelength thick
Circular
What image is created with a two-dimensional array transducer?
3D real time image
All of the following describe dynamic receive focusing except:
Delay pattern change continuously throughout reception
May be used by single crystal transducers
Focusing occurs at many depths
Automatically performed by system
May be used by single crystal transducer
Which transducer possesses the best slice thickness resolution?
1 1/2 dimensional arrays
While using a linear sequential array transducer during a color doppler exam, the shape of the grayscale image is most often _________, whereas the shape of the color doppler portion of the image is __________.
Rectangular
Parallelogram
Numerical value is higher in _______ and lower in _______.
Axial resolution
Lateral resolution
Lateral resolution has to do with _______.
Width
