Chapter 10-11 quiz Flashcards
Which of the following transducers has the poorest axial resolution?
- 7 MHz and 4 cycles/pulse
- 6 MHz and 3 cycles/pulse
- 7 MHz and 5 cycles/pulse
- 6 MHz and 2 cycles/pulse
1.7 MHz and 5 cycles
The ability to distinguish between two structures lying closely together front-to-back or parallel to the sound beam is called _________.
Axial resolution
____ frequency transducers generally have the best range resolution.
High
Axial resolution is measures in units of _______.
Distance (mm)
The more cycles in a pulse, the ________ the numerical value of the range resolution is.
Greater
If a new pulsed transducer has many cycles in its pulse, the image accuracy _______.
Degrades
Two different transducers create sound pulses. One transducer is labeled 5 MHz and the other, 3 MHz. Which transducer is more likely to create a more accurate image with relation to axial resolution?
5 MHz
Which of the following transducers has the best axial resolution?
- 7 MHz and 4 cycles/pulse
- 6 MHz and 3 cycles/pulse
- 7 MHz and 5 cycles/pulse
- 6 MHz and 2 cycles/pulse
2.6 MHz and 2 cycles/pulse
Axial resolution describes the accuracy related to visualizing two structures that are _______ to a sound beam’s main axis.
Parallel
T or F. The lower the numerical value of the longitudinal resolution, the worse the picture.
False
You are purchasing a diagnostic ultrasound system. System X has axial resolution of 0.7 mm while system D’s is 0.4 mm. Based on this information, which system will produce the better quality picture?
System D
Two ultrasound systems produce pulses. One pulse is 0.4 usec in duration and the other is 0.2 usec long. Which pulse is most likely to provide the best radical resolution?
0.2 usec system
A sonographer is performing a study on a patient and desires superior depth resolution. Which of the following changes would create such a system? Higher frequency Shorter wavelength Fewer cycles per pulse Less ringing All of the above
All of the above
Which transducer has the worst axial resolution? 2 cycles/pulse, 4 MHz 4 cycles/pulse, 4 MHz 4 cycles/pulse, 2 MHz 2 cycles/pulse, 2 MHz
4 cycles/pulse, 2 MHz
T or F. The shorter the pulse duration, the better the picture.
True
T or F. One way that a sonographer can alter the axial resolution achieved during an exam is to adjust the maximum imaging depth.
False
The lateral resolution of an ultrasound system is primarily determined by the _________.
Width of the sound pulse
or
Width of the sound beam
T or F. When using standard ultrasonic imaging instrumentation, the lateral resolution has a higher numerical value than the axial resolution.
True
Two ultrasound systems have near zone lengths of 8 cm. At the focus. system G’s lateral resolution is 3.0 mm, while system P’s is 5.0 mm. Which system will produce higher quality pictures at their foci?
System G
Two ultrasound systems have near zone lengths of 8 cm. At the focus. system S’s lateral resolution is 3.0 mm, while system C’s is 5.0 mm. Which system is most likely to appropriately display two small body structures that lie, one in front of the other, at depths of 8.6 and 9.0 mm?
Cannot be determined
What will lower the value of an ultrasound system’s lateral resolution?
Use an acoustic lens
Two ultrasound systems have a near zone of 8 cm. At their foci, system Q’s lateral resolution is 3.0 mm and system H’s is 5.0 mm. Which system will correctly display two small structures at a depth of 8 cm? The objects are side by side and are 0.4 cm part?
System Q
T or F. When using an instrument typical of today’s diagnostic imaging devices, a higher frequency transducer is likely to improve the axial resolution.
True
The lateral resolution of an US system is 4mm. Two structures are separated by 3 mm and lie side by side in relation to the sound beam’s main axis. What will most likely appear on the display of the system?
One echo
T or F. When using an instrument typical of today’s imaging devices, a higher frequency transducer is likely to mildly improve the system’s lateral resolution.
True
The diameter of a disc-shaped, unfocused piezoelectric crystal is 1 cm. What is the best estimate for the minimum lateral resolution of the ultrasound system?
5 mm
Which mode provides the foundation for real-time, gray scale anatomic imaging?
Brightness mode
With B-mode, which axis is related to the strength of the reflection?
Z-axis
Which imaging mode accurately displays reflector depth?
Amplitude mode
What is the only display mode that provides information regarding reflector motion with respect to time?
Motion mode
With M-mode, what does the Y-axis display?
Depth
Which imaging modality places dots of dissimilar grayscale on the display?
Amplitude-mode
With B-mode, on which axis of a CRT is the strength of the reflection input?
Z-axis
To which of the following do the X-axis of a B-mode, the y axis of an M-mode and the x-axis of an A-mode all relate?
Time of flight
Which imaging modality places time-of-flight information on the axis and echo-amplitude on the y-axis?
A-mode
