Ultrasound Terminology Flashcards
Acoustic impedence
Density of tissues times the speed of sound in tissue. Sound is reflected back when it reaches the border between two structures with different acoustic impedance
Acoustic enhancement
An increase in echoes distal to fluid when sound travels through a fluid-filled structure
Amplitude
Strength or height of a wave
Measured in decibels
Anechoic
Without echoes, echo-free (but not necessarily cystic)
Attenuation
Weakening of sound as it travels through tissue, caused by scatter, absorption and reflection
Complex
A structure that contains both fluid and solid components
Cycle
The frequency at which an ultrasound transducer crystal vibrates
per second;
One complete wave or one area of compressed molecules and one area of less dense molecules
Cyst
Fluid filled structure that has well-defined borders, transmits sound well and displays acoustic enhancement
Cystic
Used to describe a fluid-filled structure ; can refer to normal structures that are fluid filled (ex. Gal bladder)
Decibel
Intensity of the amplitude of a sound wave;
Ratio of acoustic power
Duplex
Simultaneous display of B-scan image and Doppler waveform
Triplex
Simultaneous display of B-scan, Doppler waveform and color Doppler
Dynamic range
The range of echo intensity (shades of gray) that the system can display
Echogenic
A structure that produces echoes;
Each structure in the body has a particular pattern of echoes it produces
Frequency
Number of times a sound wave is repeated per second;
Number of cycles that pass a certain point in tissue in one second
(2.25mHz - 20mHz)
Gain
Regulates the degree of echo amplification
Hertz (Hz)
Standard unit of frequency equal to 1 cycle per second
Heterogenous
Mixed composition;
Echo pattern is not uniform
Homogenous
Uniform composition of body tissues or structures
Hyperechoic
More echoes, more echogenic (whiter)
Hypoechoic
Fewer echoes, less echogenic
Interface
Strong echoes marking the border between structures, caused by the difference in sound impedance between the 2 structures
Isoechoic
Of the same echogenicity as a neighboring structure
Piezoelectric effect
Effect caused by crystals changing in shape when an electric current in applied or when mechanically stressed;
Allows an electrical impulse to generate sound and sound to generate an electrical impulse
Power
Quantity of energy generated by a transducer
Measured in watts
Resolution
Two types?
The ability of the ultrasound equipment to distinguish between two structures
-lateral resolution- distinguishes between 2 structures side by side at the same depth ••
-axial resolution- distinguishes two structures along the axis of the sound beam (at different depths in the same spot)•
•
Reverberation
An artifact resulting from strong echoes returning from a large surface or interface
Ring down
Extreme form of reverberation which is a long series of echoes and reverberations seen from a strong interface
Shadowing
An artifact created when an object transmits sound completely so that no echoes return, such as gallstones or bone sound travels over 4000m/sec and continues without echoes returning. Structures behind these objects will not be seen
Sonologist
A physician trained in and who specializes in interpreting sonographic images
Sonogram
An image or “picture” produced with sound
Sonographer
A allied health professional that performs diagnostic ultrasound imaging
Sonolucent
Without echoes, but not necessarily cystic
Hypoechoic
Texture
The echo pattern of an organ
TGC, DGC
Control that allows operator to compensate for the attenuation if sound as it travels through tissue
Transducer
A device capable of converting energy from one form into another
Velocity
Speed of sound, depending of structure density or tissue
What is the average speed of sound in [human soft tissue] the body?
1540 m/sec
Wavelength
The distance a wave travels in 1 sec;
Higher the frequency = shorter the wavelength, shorter the distance it travels
