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 relatedb) directly relatedc) not related
Directly related
What 3 processes contribute to attentuation?
1) Reflection2) Scattering3) Absorption
What are the 2 forms of reflection?
Specular and Diffuse
What boundary is found with specular reflection?
Smooth boundarySound is reflected in only one direction
What boundary is found with Diffuse reflection?
Irregular surface boundarySound 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 frequencyThe number of pulses per 1 second
What is the definition of PRP?
Pulse repetition periodTime 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's100=2 1000=310,000=4
Water has low attenuationT or FTrue False
TRUE
Air has high attenuationT or FTrue False
T
As path length increases, what happens to Attenuation coefficent?a) increasesb) decreasesc) remains the same
Remains the same
When scanning a carotid artery which transducer do you choose?1) 7.02) 3.5
7
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 reflected100% 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
LateralAngularTransverseAzimuthal
What are 3 synonyms for PZT?
ElementCrystalCeramic
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 arevolume/time or distance/time
Distance/time
What are the 3 forms of blood flow?
PulsatilePhasic Steady
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?SlowConstantFast
Constant
Laminar flow isChaotic orAligned and Paralell
Alligned and Paralell
What is the Reynolds number for Laminar flow?
less than 1500
Turbulent flow is Chaotic orAligned 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 densityImproved ImageGreater 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 FTrue False
T
What are the units of Dynamic range?
dB
Slice thickness and Elevational resolution isDirectly relatedInversely relatedNot related
Directly Related
Which mode is the 1st grey scale imaging?A ModeB ModeM Mode
B Mode
Expiration increases or decreases venous flow in legs?
Increases
The difference between received and transmitted frequencies is calledDoppler FrequencyDoppler ShiftPower Doppler
Doppler Shift
Phased Array is reserved for Linear TransducerT or FTrue False
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 attenuationToo little attenuationNo 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 ModeB ModeM Mode
M Mode
What are 2 controls on video monitor that the sonographer cannot change?
Contrast and Brightness
On inspiration the DiaphragmAscendsDescendsStays the same
Descends
Reynolds number determines laminar vs turbulent flowT or FTrue False
T
Phasic flow is related to Cardiac contractionVelocityRespiration
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) Safe2) Metobolically inert3) Long lasting4) Strong reflector of U/S5) Small enough to pass through capillaries
Harmonic frequency is ________ times fundemental frequency.2310
2