Axial Resolution Flashcards
Axial resolution describes the accuracy related to visualizing two structures that are ____ to a sound beam’s main axis.
a. parallel
b. perpendicular
c. oblique
d. normal
a. parallel
You are purchasing a diagnostic ultrasound system. System X has axial resolution of 0.7 mm whereas System D’s is 0.4 mm. Based on this information, which system will produce the better quality picture?
a. System X
b. System D
c. they have the same quality
d. cannot be determined
b. System D
The axial resolution of an imaging system is reported to be 0.85 mm at the beam’s focus. What is the closest estimate of the system’s radial resolution at a location that is 5 cm deeper than the focus?
a. less than 0.85 mm
b. equal to 0.85 mm
c. greater than 0.85 mm
b. equal to 0.85 mm
Two systems are undergoing evolution. System A has 1,000,000 pixels, each with 4 bits. System B has 750,000 pixels, each with 12 bits. Which system has the best longitudinal resolution?
a. System A
b. System B
c. both are the same
d. cannot be determined
d. cannot be determined
True or False?
The lower the numerical value of the longitudinal resolution, the worse the picture.
False
True or False?
One way that a sonographer can alter the axial resolution achieved during an exam is to adjust the maximum imaging depth.
False
True or False?
With a specific ultrasound system and transducer, the system’s axial resolution is invariant, and the sonographer can do nothing to improve.
True
True or False?
The shorter the pulse duration, the better the picture.
True
An ultrasonic pulse has a pulse repetition period of 1.2 msec, a spatial pulse length of 2.0 mm, and a wavelength of 0.4 mm. What is the axial resolution of the system?
a. 2.0 mm
b. 1.0 mm
c. 0.4 mm
d. 1.8 mm
b. 1.0 mm
True or False?
The more there are in a pulse, the greater the detail that will be visualized in the ultrasound scan.
False
Two ultrasound systems produce acoustic pulses. A pulse from System 1 has a wavelength of 0.5 mm, 4 cycles per pulse, and a pulse repetition period of 1.2 msec. The pulses from System 2 have a wavelength of 1.0 mm, 2 cycles per pulse, and a pulse repetition period of 1.8 msec. Which ultrasound system will have a lower numerical value of axial resolution?
a. System 1
b. System 2
c. both are the same
d. cannot be determined
c. both are the same
Which transducer has the best axial resolution?
a. 2 cycles/pulse, 4 MHz
b. 4 cycles/pulse, 4 MHz
c. 4 cycles/pulse, 2 MHz
d. 2 cycles/pulse, 2 MHz
a. 2 cycles/pulses, 4 MHz
Which transducer has the worst axial resolution?
a. 2 cycles/pulse, 4 MHz
b. 4 cycles/pulse, 4 MHz
c. 4 cycles/pulse, 2 MHz
d. 2 cycles/pulse, 2 MHz
c. 4 cycles/pulse, 2 MHz
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 radial resolution?
a. 0.4 usec system
b. 0.2 usec system
c. they are the same
d. cannot be determined
b. 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?
a. higher frequency
b. shorter wavelength
c. fewer cycles per pulse
d. less ringing
e. all of the above
e. all of the above
