Basics of Scanning Flashcards
High frequency transducer for superficial imaging that provides a rectangular image
Linear transducer
Compensates for the loss of energy in the reflected signal due to attenuation
Time Gain Compensation
Controlled through slide pods or a 3-knob control
Time Gain Compensation
Transducer that produces sector images
Curvilinear array transducer
An increase or decrease of the intensity by 3 dB will multiply or divide the intensity by
2
What artifact is a result of sound bouncing between two strong reflectors?
Reverberation artifact
Not a true magnification of the image. The pixels are simply enlarged
Read zoom
What artifact occurs when sound reflects off a strong reflector and is redirected toward a second structure which causes a second copy of the image to be seen?
Mirror image
What is power output measured in?
Decibels
Which artifact violates the assumption that sound returns directly to the transducer?
Reverberation artifact
Curvilinear probe freqeuncy
2-5 MHz
Phased array probe frequency
2-5 MHz
What is produced when closely spaced reverberations merge?
Ring down (comet tail) artifacts
Linear probe frequency
5-10+ MHz
Controls the strength or intensity of the sound wave
Power output
The average speed of a sound wave through a human body is:
1540m/s
What improves image quality particularly in obese patients?
Tissue harmonics imaging (THI))
Decreases the overall frame rate but when set at the level of the desired structure enhances that image
Focal zone
ALARA means
As Low As Reasonable Achievable
The degree of amplification of the returning sound
Gain
Occurs when the sound beam hits a strong reflector and the sound beam is completely or nearly completely reflected back to the transducer
Shadowing
What can be used to minimize shadowing and posterior enhancement?
Compound imaging
True magnification of the desired area. The pixels are reallocated
Write zoom
Contains elements in the transducer head that are pulsed as a complete group with a slight time delay
Phased array
What artifact occurs when a sound beam passes through a fluid-filled structure?
Posterior enhancement
