-
What is a logarithm?
Number of 10's that are multiplied to create original number
-
What is the log of 1000?
3
-
What is the log of 10,000?
4
-
Is distance and attentuention
a) inversely related
b) directly related
c) not related
Directly related
-
What 3 processes contribute to attentuation?
- 1) Reflection
- 2) Scattering
- 3) Absorption
-
What are the 2 forms of reflection?
Specular and Diffuse
-
What boundary is found with specular reflection?
- Smooth boundary
- Sound is reflected in only one direction
-
What boundary is found with Diffuse reflection?
- Irregular surface boundary
- Sound is reflected in more than one direction
-
What is the medium of lung tissue that causes scattering?
Air
-
What is the definition of PRF?
- Pulse repetition frequency
- The number of pulses per 1 second
-
What is the definition of PRP?
- Pulse repetition period
- Time from beginning of 1 pulse to the beginning of the next pulse
-
What is pulse duration?
The time from beginning of the pulse to the end or "talk time"
-
What is power?
Rate of energy transfer measured in watts
-
What is Propagation speed?
- The time it takes to travel through medium.
- The medium determines the speed.
-
Why does sound travel fast in bone?
Bone has a higher stiffness level and lower density level
-
What is Frequency?
The number of events in a specific duration of time
-
What is intensity?
Concentration of energy in sound beam
-
What is the relationship of Period and Frequency?
Inversely related
-
What is the distance of one complete cycle?
Wavelength
-
Why does sound travel slow in air?
Density is increased and stiffness is decreased
-
What are units of attenuation?
dB
-
What is a quick way to find log?
- Count the number of 0's
- 100=2
- 1000=3
- 10,000=4
-
Water has low attenuation
T or F
True
-
Air has high attenuation
T or F
T
-
As path length increases, what happens to Attenuation coefficent?
a) increases
b) decreases
c) remains the same
Remains the same
-
When scanning a carotid artery which transducer do you choose?
1) 7.0
2) 3.5
7.0
-
What is the unit of Attenuation coefficient?
dB/cm
-
In a boundary where impedance is the same, what part of sound wave is reflected back?
- 0% is reflected
- 100% is transmitted
-
What law is demonstrated by rules of refraction?
Snell's Law
-
Does attentuation increase or decrease as path length increases?
increase
-
What are the names for Lateral Resolution?
Hint - 4
- Lateral
- Angular
- Transverse
- Azimuthal
-
What are 3 synonyms for PZT?
-
What is the definition of Hemodynamics?
Study of blood moving through circulatory system
-
What does Volume rate measure?
How much
-
What does Velocity measure?
How fast
-
Units of flow are
volume/time or distance/time
Volume/time
-
Units of velocity are
volume/time or distance/time
Distance/time
-
What are the 3 forms of blood flow?
-
Pulsatile flow accelerates and decelerates from
Cardiac Contraction
-
Phasic blood flow accelerates and decelerates from
Respiration
-
Steady flow occurs when fluid moves at a _____ speed of velocity?
Slow
Constant
Fast
Constant
-
Laminar flow is
Chaotic or
Aligned and Paralell
Alligned and Paralell
-
What is the Reynolds number for Laminar flow?
less than 1500
-
Turbulent flow is
Chaotic or
Aligned and paralell
Chaotic
-
What are sounds associated with turbulent flow?
Murmur, Bruit, and thrill
-
What is the definition of transducer?
Transforms electrical energy into acoustic energy
-
Definition of Pulser?
Determines the amplititude, pulse repetition period (PRP) and pulse repetition frequency (PRF)
-
Definition of Beam Former?
Determines the firing delay pattern for phased array systems
-
Definition of Receiver?
Transforms signals from transducer into a form suitable for display
-
Definition of Storage?
Archives U/S studies in videotape, paper printout, photos, film, CD or hard drives
-
Definition of Master Synchronizer?
Maintains and organizes timing
-
What is line density?
Spacing between sound beams
-
What is range ambiguity?
Inability to determine exact location of moving red blood celss with CW (continuous wave)
-
What is pixel density?
Number of pixels per inch
-
What is spatial resolution?
- High pixel density
- Improved Image
- Greater detail
-
What are artifacts?
Errors in imaging
-
What is reverberation?
Multiple equally-spaced echoes - resembles venetian blinds
-
What is a Comet Tail?
Ring down artifact appearing as solid hyperechoic line
-
What is shadowing?
Hypoechoic or anechoic region extending downward
-
What is edge shadow?
Hypoechoic region extending along edge of curved reflector
-
What is enhancement?
Hyperechoic region beneath tissue with low attentuation
-
What is focal enhancement?
Side to side region appears brighter than deeper tissue aka focal banding
-
What is Mirror image?
Artifact showing Deeper image redirected toward 2nd structure
-
What is Crosstalk?
Mirror image on Spectral Doppler display
-
What is a speed error?
Sound wave propagates through a medium other than that of soft tissue
-
What is propagation speed error?
Range error artifact or range ambiguity artifact
-
What are side lobes?
Created by a single crystal transducer or mechanical probe
-
What are grating lobes?
Created by Array transducer
-
There are no known harmful bioeffects from U/S exams.
T or F
T
-
What are the units of Dynamic range?
dB
-
Slice thickness and Elevational resolution is
Directly related
Inversely related
Not related
Directly Related
-
Which mode is the 1st grey scale imaging?
A Mode
B Mode
M Mode
B Mode
-
Expiration increases or decreases venous flow in legs?
Increases
-
The difference between received and transmitted frequencies is called
Doppler Frequency
Doppler Shift
Power Doppler
Doppler Shift
-
Phased Array is reserved for Linear Transducer
T or F
F
-
What type of converter is used in U/S?
Digital
Analog
Digital
-
Why does a gallstone have a shadow on U/S?
Too much attenuation
Too little attenuation
No attenuation
Too much attenuation
-
What is a synonym of propagation speed error?
Range ambiguity
-
What does color Doppler provide information about?
Range resolution
-
What angle is best to scan carotid artery?
60 degrees or less
-
Power Doppler is also called
Energy Mode
-
Artifact is
An error in imaging
-
Which mode gives information about time?
A Mode
B Mode
M Mode
M Mode
-
What are 2 controls on video monitor that the sonographer cannot change?
Contrast and Brightness
-
On inspiration the Diaphragm
Ascends
Descends
Stays the same
Descends
-
Reynolds number determines laminar vs turbulent flow
T or F
T
-
Phasic flow is related to
Cardiac contraction
Velocity
Respiration
Respiration
-
Spacial resolution improves with high or low line density?
High line density
-
What does ALARA mean?
As Low As Reasonably Achieved
-
What is dynamic range?
The ratio of largest to smallest signal strength
-
What are 5 requirements of contrast agents?
- 1) Safe
- 2) Metobolically inert
- 3) Long lasting
- 4) Strong reflector of U/S
- 5) Small enough to pass through capillaries
-
Harmonic frequency is ________ times fundemental frequency.
2
3
10
2
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