History Of Ultrasound Flashcards
Infrasound
Below 20H (whales)
Audible sound
20-20000H
Ultrasound
More than 20000 (bats)
Diagnostic ultrasound vs
therapeutic
1-30 MHz
1-3 MHz
Low frequency for high frequency for
Low: Penetration
High: Resolution
Who discovered piezoelectric effect
The Currie brothers
What is the piezoelectric effect
Applying pressure waves to crystal causes electrical pulses (voltage)
Reverse piezoelectric effect
Electricity sent to Crystal causing them to vibrate (producing ultrasound)
What was ultrasound first used for
To check for icebergs/submarines
Metal flaw detectors
A mode first used for
To see brain tumor, then gallstones
Father of obstetrical ultrasound
Ian Donald
Three things Ian donals did
Father of obstetrical ultrasound (identified gestational sac)
Developed biparietal diameter measurement (BDM)
Developed first compound scanner
Real time scanning
Single frame/image is created several times to give appearance of movement
Ultrasound modes (5)
A mode: amplitude (metal/brain tumor)
B mode: brightness (dots)
M mode: motion (fetal HR)
Real time mode: view of baby
Doppler (spectral and colour)
Ultrasound modes (5)
A mode: amplitude (metal/brain tumor)
B mode: brightness (dots)
M mode: motion (fetal HR)
Real time mode: view of baby
Doppler (spectral and colour)
A mode
Most basic method
Amplitude shown on graph based on echo strength
A mode
Most basic method
Amplitude shown on graph based on echo strength
B mode
displays intensity (amp) by varying the brightness of a dot, compound dots to get 2 d image
brighter dot=stornger echo
bi-stable
b mode image with only black or white dots
no soft tissue differentiation
uses cathode ray tube for display
gray scale
b mode image that has many shades of gray
uses scan converter
real time
b mode pictures captured at a rate fast enough to mimic physiological imaging
probe is firing and listening constantly
m mode
motion
series of b mode dots displayed on a moving time base to see motion of structure
doppler
uses the Doppler equation to determine the velocity of blood flow or frequency of blood
static scanning AKA
B-scan
articulated arm scan
contact scanning
transducer touches patient (instead of scanning though water)
The rapid succession of acquired frames of gray scale data
real time
A mode of ultrasound where the amplitude of the reflector is represented as a vertical spike along a time axis?
a mode
A mode of ultrasound that displays the movement of reflectors over time.
m mode
An image that that utilizes two shades of gray with the highest possible contrast.
bistable
A mode of ultrasound that displays the effect of reflector motion relative to the transducer.
doppler
A mode of ultrasound that displays several scan lines of gray scale amplitudes in a single frame.
static scan
A mode of ultrasound in which the reflector amplitude is represented as a shade of gray.
b mode
The conversion of mechanical forces into a electrical current.
piezoelectric effect
