Chapter 10 Q & A Flashcards
What is the ability to accurately distinguish two structures lying close together called
resolution
the ability to distinguish two structures lying close together front to back or parallel to the sound beam is called
longitudinal
axial
range
depth resolution
axial resolution is measured with units of
distance
mm
if there are more cycles in a pulse, the numerical value of range resolution is
greater/lesser/same
greater
if a new pulsed transducer has many more cycles in its pulse, the image accuracy
improves/degrades/stays the same
degrades
high/low
frequency transducers generally have the best range resolution
high
which of the following transducers has the poorest axial resolution
A 1.7 MHz and 4 cycles/pulse
B 2.6 MHZ and 3 cycles./pulse
C 1.7 MHz and 5 cycles/pulse
D 2.6 MHz and 2 cycles/pulse
C
longest pulse
it has the lowest freq and the most ringing (more cycles/pulse)
is soft tissue a 3 cycle, 1 MHz pulse hs a poulse length equal to 4.5mm. What is the axial resolutoin
A 3mm
B 1mm
C 2.25mm
D 1.54mm
C
axial resolution is one half of the spatial pulse length
(4.5/2=2.25)
which of the following transducers has the best axial resolution
A 1.7 MHz and 4 cycles/pulse
B 2.6 MHZ and 3 cycles./pulse
C 1.7 MHz and 5 cycles/pulse
D 2.6 MHz and 2 cycles/pulse
D the shortest pulse
it has the highest freq and the least ringing (fewest cycles/pulse)
two different transducers create a sound pulse. One transducer is labeled 5 MHz and the other 3 MHz.
WHich transducer is more likely to create a more accurate image with respect to axial resolution?
Which transducer probably has a lower numerical value of axial resolution?
the 5 MHz is more likesly to create an image with better axial resolution
the higher freq transducer creates a shorter pulse and thus has a lower numerical value of axial resolution .
Lower numbers mean improved image quality
two different transducers create a sound pulse. Both create a sound pulse with a freq of 4 MHz One creates a pulse that is 6 cycles and the other is 3 cycles.
Which transducer is more likely to create a more accurate image with respect to axial resolution?
Which transducer probably has a lower numerical value of axial resolution?
the 3 cycle pulse transducer is more likely to crete an image with better axial resolution. Less ringing or fewer cycles in a pulse generall implies shorter pulses and improved axial resolution
the 3 cycle pulse has a lower numerical value of axial resolution
lower numbers mean improved image accuracy
two different transducers create a sound pulse. One transducer is labeled 5 MHz and the other 3 MHz.
The 3 MHz transducer creats a more accurate image with respect to axial resolutoin.
Explain
Axial resolutoin is determined by pulse length, SHorter pulses have better axial resolutoin. In this question the 3 MHz transducer hs the best resolution which means it must have shorter pulses.
Since the 3 MHz sound has a longer wavelength than the 5 MHz sound, the only way that the 3 MHz pulse is shorter is if the 3 MHz transducer rings less. Thus the 3 MHz pulse has fewer cycles than the 5 MHz pulse
What is the lateral resolution at a depth of 8 cm
4.5 mm
at the end of the near zone the beam diameter is one half the trasnducer diameter
what is the lateral resolution at a depth of 16 cm
9 mm
at a depth of twice the near zone the beam is as wide as the transducer
what is the best estimate for the resolution at 4 cm
A 1 cm
B 9 cm
C 5 mm
D 14 mm
C 5 mm
What is the best estimate for resolution at 7 cm
A 1 cm
B 9 cm
C 5 mm
D 14 mm
C 5 mm
What is the best estimate for the resolution at 21 cm
A 1 cm
B 9 cm
C 5 mm
D 14 mm
D 14 mm
