Chapter 2: Ultrasound Principles Flashcards
(216 cards)
echoes on the image that were not caused by actual reflectors in the body
artifacts
ultrasound has the ability to cause changes to the tissue if proper settings are not used
bioeffects
principle of constantly transmitting a sound wave into the patient to obtain a spectral Doppler waveform
continuous wave
Tool for measuring blood flow quantitatively or qualitatively using pulsed-wave or continuous-wave techniques
Doppler
Principle of sending in a small group of sound waves and then waiting for that pulse to come back so that an image can be displayed. Also used for spectral and color Doppler.
pulsed wave
the part of the ultrasound machine that transmits and receives sound via an array of piezoelectric elements
transducer
pressure/mechanical waves
sound waves
a series of reflectors along one vertical line
scan line
all the scan lines displayed on the screen
frame
propagative of wave is parallel to the movement of molecules within the medium
longitudinal wave
simplest unit of a wave
cycle
can be measure by height, length, and other parameters
cycle
the number of cycles that occur in 1 second
frequency
the frequency of a pulsed wave transducer is determined primarily by:
thickness of piezoelectric element
other names for frequency
operating frequency
center frequency
resonating frequency
units for frequency
Hz
typical range of frequency in ultrasound
2-20 MHz
time taken for one cycle to occur in milliseconds
period
speed at which sound moves through a medium
propagation speed
What is propagation speed determined by?
only by the medium through which sound is traveling
What is the average propagation speed of soft tissue?
1540 m/s
length in (mm) of one cycle of sound, from the beginning of the wave to the end of the wave
wavelength
What is wavelength determined by?
propagation speed divided by the operating frequency
height of a cycle, from the baseline to the peak of the cycle
amplitude