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56 Cards in this Set
- Front
- Back
the critical difference between continuous and pulsed wave is
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range resolution
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the amount of time for which a transmit pulse lasts
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pulse duration (PD)
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the amount of time until a transmit pulse is repeated
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pulse repetition period (PRP)
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the number of times that a transmit pulse is sent per second
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pulse repetition frequency (PRF)
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what is the relationship between PRF and PRP
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reciprocal
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the duration of time that work is being done
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duty factor
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duty factor equation
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Duty Factor = DF/PRP
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the distance of a transmit pulse
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spatial pulse length (SPL)
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the duration and the distance of a transmit pulse
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PD and SPL respectively
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range resolution equation related to SPL
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Range Resolution =SPL/2
Also called axial, longitudinal, depth, radial resolution |
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synonyms for range resolution (5)
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LADRR
Longitudinal Axial Depth Radial Range |
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Pulse Duration (PD) equation
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period * # of cycles
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the only parameter that affects PRP and PRF
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imaging depth
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Spatial Pulse Length (SPL) equation
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λ times # of cycles
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smaller/larger numbers, in general, are better when it comes to resolution
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smaller
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synonyms for lateral resolution (5)
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Memory Aid: ATLAS
Azimuthal Transverse Lateral Angular Side-by-Side |
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any modality which turns the transmitter on and off periodically so as to reduce range ambiguity
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pulsed wave
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a single sound beam transmitted in a specific direction and its associated echoes
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acoustic line
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returning echoes
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receive line
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an image line on a screen
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display line
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general term referring to a beam
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line
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generated picture from a scan
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image
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time to transmit multiple beams
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frame time
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another name for frame frequency
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frame rate
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frequency at which signals are "viewed"
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sampling rate
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synonyms for frame time
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scan time
acoustic scan time acoustic frame time |
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modality that scans in many directions (in a plane)
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scanned modalities
(think FANNED, like a face fan) |
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name the two categories, or modalities, into which ultrasound scanning techniques are placed
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scanned, non-scanned
(think FANNED/NON-FANNED, like a face fan) |
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modality that scans only in one direction (one line)
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non-scanned
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name the scanned modalities
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2-D (B-Mode)
color flow 3D |
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name the non-scanned modalities
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CW Doppler
PW Doppler M-Mode A-Mode |
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what's the magnitude of amplitude and pulse duration in each of these modalities: 2-D, PW Doppler and CW Doppler
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2-D (amplitude highest, PD lowest)
PW Doppler (amplitude lower, PD higher) CW Doppler (amplitude lowest, PD continuous) |
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minimum acoustic line time, (PRP) equation
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PRP = 13µsec * ID (cm)
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temporal resolution is dramatically degraded with scanned/non-scanned modalities
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scanned modalities (think FANNED, like a face fan)
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the risk of thermal bioeffects is usually much greater with scanned/non-scanned modalities
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non-scanned (think NON-FANNED)
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what decreases the natural frequency of the crystal so fewer cycles are produced
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backing material
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frame time equation
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frame time = PRP * # of lines
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____ ____ is the time it takes to create a single frame or scan
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frame time
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relationship between frame rate and frame time
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frame rate * frame time = 1
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with color scans, each Color Display Line is comprised of multiple acoustic lines referred to as a ____ or an ____
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packet, ensemble
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the range of frequencies over which a device can operate
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bandwidth
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the maximum corner frequency minus the minimum corner frequency
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bandwidth
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how do you read this statement
-6dB = 4MHz |
within 6dB from maximum frequency, there's a range of 4MHz (4MHz BW)
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the bandwidth divided by the operating frequency
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fractional bandwidth (FBW)
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what is the reciprocal of FBW
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quality factor (QF)
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QF (quality factor) equation
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QF = operating frequency / bandwidth
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designed to optimize resolution and penetration
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dynamic frequency tuning (sliding receive filters)
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the transmit pulse is performed at the fundamental frequency and the receive frequency is twice the fundamental
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harmonic imaging
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receiving and processing two or more frequencies at narrower frequencies
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frequency fusion (frequency compounding)
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when is larger bandwidth not helpful
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with CW Doppler, it requires little bandwidth
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if the transducer has a short impulse response (short pulse duration), it will have a narrow/wide bandwidth
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wide
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if the transducer has a long impulse response (long pulse duration), it will have a narrow/wide bandwidth
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narrow
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another name for pulse duration (PD)
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pulse width
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name the modes, in order of importance, requiring the widest to the narrowest bandwidth
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B-Mode
color Doppler spectral PW Doppler CW spectral Doppler |
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while assembling a packet, color Doppler is scanned/non-scanned
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non-scanned
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once packets are assembled with color Doppler, it becomes scanned/non-scanned
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scanned, but not on tissue, it's essentially scanning the packets
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