Chapter 21 Flashcards
When creating an ultrasound image, all of the following assumptions are made except:
All structures create reflections of equal magnitude
Which statement regarding axial resolution is incorrect?
Axial resolution artifact is related to beam diameter
An ultrasound pulse has a width of 4 mm, a length of 2 mm, and is produced by a transducer 3,000 times per second. What is the best estimate of the system’s axial resolution?
1 mm
Which of the following statements is true about lateral resolution?
It can be improved by focusing
All of the following artifacts result in the placement of too many echoes on the image except:
Shadowing
Which of the following determines the spatial resolution of a display?
Number of lines on the display
Which of the following determines the spatial resolution of a digital display?
Pixel density
Which artifact produces an image with an incorrect number of reflectors?
Side lobes
T or F. Mirror image artifacts always appear deeper than the true anatomy.
True
Which artifact is unrelated to the dimensions of an ultrasound pulse?
Refraction
T or F. It is common to visualize artifacts when the dimension of the sound beam is larger than the reflector’s dimension.
True
Two reflections, one true and one artifact, are displayed on an ultrasound image. In the body, only one anatomic structure is present. The correct reflection and the artifact are found side by side. What is the most likely cause of this artifact?
Grating lobe
Two distinct reflections are observed on an image, but they actually arise from a single anatomic structure. The artifact is positioned deeper than the correct reflection. What is the most likely cause of this artifact?
Mirror image
Which one of these artifacts does not result from multiple reflections?
Enhancement
