UNDERSTANDING ULTRASOUND PHYSICS
FOURTH EDITION EDELMAN
COMPREHENSIVE STUDY GUIDE 2026
FULL ANSWERS GRADED A+
⩥ is axial resolution constant at different depths. Answer: yes
- axial resolution is ONLY dependent on SPL
⩥ Objects closer than _____ will NOT be resolved.. Answer: 1/2 spatial
pulse length (SPL)
⩥ the ability of the system to resolve objects in a direction perpendicular
to the beam direction =_____. Answer: lateral resolution
⩥ is lateral resolution constant at different depths. Answer: no
- changes with convergence and divergence of the ultrasound beam
⩥ where is lateral resolution the best?. Answer: at the focal zone (where
the beam is most narrow)
⩥ Lateral resolution is (better/worse) in the deeper field?. Answer:
worse
,- is bad in the near field (close to transducer) and far field
⩥ does increasing gain improve the lateral resolution?. Answer: NO
- increasing gain will widen the beam
- you want a nice, narrow beam for best lateral resolution
⩥ (T/F) elevation resolution is usually the worst measure of resolution.
Answer: True
- it is a source of volume averaging before and after the focal zone (near
and far fields)
⩥ what is elevation resolution dependent on. Answer: transducer
element height
⩥ how can you improve axial resolution (3). Answer: - shorter pulses
(smaller SPL)
- greater dampening (Low Q -- shorter pulses --> smaller SPL)
- higher frequency (shorter wavelength --> smaller SPL)
⩥ how can lateral resolution be improved (4). Answer: - narrowing the
beam in proximal field (add acoustic lens)
- minimize gain (gain widens the beam)
- phased array with multiple focal zones (put what you want to see in the
focal zone)
, - increase the line density (lines per cm)
⩥ how can you improve elevation resolution (2). Answer: -use fixed
focal length across the entire surface of the array
-minimize slice thickness
⩥ axial resolution is depent on. Answer: SPL
⩥ lateral resolution is dependent on. Answer: transducer element width
⩥ elevation resolution is dependent on. Answer: transducer element
height
⩥ what are 2 beam related artifacts. Answer: - side lobe artifact
- beam width artifact
⩥ Side Lobe artifact:. Answer: Beam related artifact:
- off axis beams at the edge of US beam bounces of strong reflector and
goes back to the transducer
- incorrectly placed as if the echo originated from the main beam
⩥ side lobe artifacts occur more with what type of transducer. Answer:
linear array transducers
FOURTH EDITION EDELMAN
COMPREHENSIVE STUDY GUIDE 2026
FULL ANSWERS GRADED A+
⩥ is axial resolution constant at different depths. Answer: yes
- axial resolution is ONLY dependent on SPL
⩥ Objects closer than _____ will NOT be resolved.. Answer: 1/2 spatial
pulse length (SPL)
⩥ the ability of the system to resolve objects in a direction perpendicular
to the beam direction =_____. Answer: lateral resolution
⩥ is lateral resolution constant at different depths. Answer: no
- changes with convergence and divergence of the ultrasound beam
⩥ where is lateral resolution the best?. Answer: at the focal zone (where
the beam is most narrow)
⩥ Lateral resolution is (better/worse) in the deeper field?. Answer:
worse
,- is bad in the near field (close to transducer) and far field
⩥ does increasing gain improve the lateral resolution?. Answer: NO
- increasing gain will widen the beam
- you want a nice, narrow beam for best lateral resolution
⩥ (T/F) elevation resolution is usually the worst measure of resolution.
Answer: True
- it is a source of volume averaging before and after the focal zone (near
and far fields)
⩥ what is elevation resolution dependent on. Answer: transducer
element height
⩥ how can you improve axial resolution (3). Answer: - shorter pulses
(smaller SPL)
- greater dampening (Low Q -- shorter pulses --> smaller SPL)
- higher frequency (shorter wavelength --> smaller SPL)
⩥ how can lateral resolution be improved (4). Answer: - narrowing the
beam in proximal field (add acoustic lens)
- minimize gain (gain widens the beam)
- phased array with multiple focal zones (put what you want to see in the
focal zone)
, - increase the line density (lines per cm)
⩥ how can you improve elevation resolution (2). Answer: -use fixed
focal length across the entire surface of the array
-minimize slice thickness
⩥ axial resolution is depent on. Answer: SPL
⩥ lateral resolution is dependent on. Answer: transducer element width
⩥ elevation resolution is dependent on. Answer: transducer element
height
⩥ what are 2 beam related artifacts. Answer: - side lobe artifact
- beam width artifact
⩥ Side Lobe artifact:. Answer: Beam related artifact:
- off axis beams at the edge of US beam bounces of strong reflector and
goes back to the transducer
- incorrectly placed as if the echo originated from the main beam
⩥ side lobe artifacts occur more with what type of transducer. Answer:
linear array transducers
