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 _______.
A. rectangular, parallelogram
B. rectangular, sector
C. sector, trapezoid
D. square, re...
Understanding Ultrasound Physics - SPI Exam Review –
ARTIFACTS| 54 QUESTIONS| COMPLETE SOLUTIONS
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 _______.
A. rectangular, parallelogram
B. rectangular, sector
C. sector, trapezoid
D. square, rectangular Correct Answer: A. rectangular, parallelogram
The shape of a grayscale image using a linear sequential array is rectangular.
However, the sound beams used for Doppler are steered at an angle, creating a
parallelogram shaped region.
What is the meaning of the term "analysis" in the context of spectral analysis of
Doppler signals?
A. Building a sophisticated signal from components
B. building a simplified signal from components
C. identifying the building blocks or components of a complex signal
D. measuring a complex signal then modifying its information content Correct
Answer: C. identifying the building blocks or components of a complex signal
The term analysis defines the act of scrutinizing an object to determine what
individual components are incorporated within it. In Doppler analysis, the complex
signal is broken down into its more basic ingredients.
The analysis of Doppler Spectra using _______ is most accurate.
A. Zero crossing detectors
B. fast fourier transforms
C. time interval histograms
D. chirp Z transforms Correct Answer: B. fast fourier transforms
The fast fourier transform, or FFT, is the most accurate spectral analysis technique.
Techniques such as zero crossing, time interval histograms, and chirp Z were
,initially used to assess Doppler Spectra, but are now obsolete. Fast fourier analysis
became popular when computers were incorporated into ultrasound systems.
Spectral analysis of color flow Doppler is most commonly performed by which of
the following techniques?
A. Zero crossing detectors
B. fast fourier transforms
C. autocorrelation
D. Chirp Z transforms Correct Answer: C. autocorrelation
Autocorrelation is a technique of choice for spectral analysis of color Doppler.
Although the most accurate technique is the FFT, autocorrelation is better suited to
process the enormous amount of data acquired in a color Doppler study.
Acoustic artifacts include: (more than one answer may be correct.)
A. images of reflectors in an inappropriate position
B. Images of reflectors with improper shape
C. images of reflectors with incorrect brightness
D. images that do not correspond to anatomical structures Correct Answer: A.
images of reflectors in an inappropriate position
B. Images of reflectors with improper shape
C. images of reflectors with incorrect brightness
D. images that do not correspond to anatomical structures
An artifact is an error in imaging. All of the choices indicate a type of error, and
therefore, are artifacts.
Which of the following is not a potential cause of artifact and diagnostic imaging?
A. Operator error
B. equipment malfunction
C. Patient motion
D. Ultrasound physics
E. none of the above Correct Answer: E. none of the above
The four choices, A through D, represent the primary explanations of artifacts
commonly seen in diagnostic ultrasound.
, Ultrasound systems are designed to automatically _______ .
A. display similar structures with equal brightness, regardless of depth
B. position structures at the correct depth, regardless of the medium
C. display all reflections on a line corresponding to the main axis of the sound
beam, regardless of refraction
D. Select the optimal beam width based on the clinical application Correct Answer:
C. display all reflections on a line corresponding to the main axis of the sound
beam, regardless of refraction
Ultrasound systems assume that all reflections are created from reflectors that lie
directly along the main axis of the ultrasound beam. An artifact is created when
pulses refract and change directions.
6 distinct, equally space reflections appear on an image at ever increasing depths.
What type of artifact is this?
A. Reverberation
B. Ring down
C. Mirror imaging
D. Longitudinal Resolution Correct Answer: A. Reverberation
Reverberations are multiple , equally spaced reflections.
Which situation will commonly produce reverberation artifact?
A. Two masses that lie perpendicular to the sound beam's main axis
B. two weak reflectors that lie close to each other along the axis of the beam
C. two strong reflectors that lie along the main axis of the beam
D. a single highly reflective mass Correct Answer: C. two strong reflectors that lie
along the main axis of the beam
Reverberations are commonly produced by a pair of strong reflectors that lie along
the main axis of an ultrasound beam.
What are the characteristics of a medium that produces comet tail artifact?
A. Weak reflectors, closely spaced, low propagation speeds
B. strong reflectors, widely spaced, high propagation speeds
C. strong reflectors, closely spaced, low propagation speed
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