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WorksheetsInstrumentation Physic Prep
Total questions: 97
Worksheet time: 49mins
In A-mode ultrasound, which axes show echo strength and depth?
z-axis strength, y-axis depth
y-axis strength, x-axis depth
x-axis strength, y-axis depth
x-axis strength, z-axis depth
Which statement best describes the output of A-mode?
A set of vertical spikes showing amplitude and depth
A color map of velocity vectors
A gray-scale image with different dot brightness
A 3D rendering of tissue surfaces
In B-mode imaging, what determines the brightness of each dot?
Depth compensation by the system
Probe frequency
Strength of the return echo
Speed of sound in tissue
Which term describes a structure that appears nearly white on B-mode, and why?
Hypoechoic, due to weak reflectors
Hyperechoic, due to strong reflectors
Isoechoic, due to equal echoes
Anechoic, due to no echoes
Which comparison between A-mode and B-mode is accurate?
A-mode forms images; B-mode lacks images
B-mode shows velocity; A-mode shows displacement
A-mode uses spikes; B-mode uses brightness dots
Both plot amplitude along the x-axis
In B-mode, amplitude is mapped along which axis?
x-axis of the displayed frame
y-axis of the displayed frame
t-axis representing time
z-axis representing brightness
A fluid-filled cyst appears black on B-mode. What is the correct term and reason?
Isoechoic, because echoes match surrounding
Anechoic, because echoes are absent
Hypoechoic, because echoes are moderate
Hyperechoic, because echoes are strong
Which parameter is needed to place echo dots at the correct depth on an ultrasound screen?
Beam frequency of the transducer
Time for sound to go and return
Amplitude of the returning echoes
Angle of insonation to the target
Which variables does the range equation use to calculate distance to a reflector?
Power and pulse duration
Propagation speed and round‑trip time
Frequency and wavelength
Attenuation and gain settings
What does the 13 microsecond rule mean in ultrasound for soft tissue?
Sound travels 1 cm one way in 13 µs
Sound travels 0.5 cm one way in 13 µs
Sound travels 1 cm round trip in 13 µs
Sound travels 2 cm round trip in 13 µs
How long is the echo round-trip time for a reflector 3 cm deep in soft tissue?
52 µs
39 µs
26 µs
13 µs
Which display mode is shown in the image?
A‑mode amplitude mapping
D‑mode Doppler spectral
B‑mode brightness imaging
M‑mode motion tracing
In M‑mode, what is shown on the x‑axis and y‑axis?
Amplitude and depth
Velocity and time
Depth and time
Time and depth
Which clinical application most commonly uses M‑mode?
Cardiac and obstetric viability
Musculoskeletal tendon imaging
Vascular stenosis quantification
Hepatic lesion characterization
If round-trip time doubles and soft tissue speed stays the same, what happens to the calculated depth?
Depth halves
Depth doubles
Depth unchanged
Depth becomes zero
If a system assumes a speed faster than soft tissue, how does the displayed depth of a reflector change?
Displayed too shallow
Displayed unchanged
Displayed as moving
Displayed too deep
Which statement best describes a nonlinear behavior?
High-pressure peaks slow while troughs speed up in tissue
Beam generates harmonics only at the surface
Wave remains perfectly sinusoidal throughout travel
Wave shape deforms into nonsinusoidal with depth
What are tissue harmonics in ultrasound?
Added frequencies generated by patient tissues
Original transmitted fundamental frequency only
Noise artifacts from superficial structures
Echoes created solely by the transducer hardware
Where are harmonic signals mainly produced in the body?
At the skin surface
As the beam goes deeper in tissue
Equally at all depths
Only in the transducer crystal
Which harmonic is most commonly used for imaging?
Fourth harmonic, four times the fundamental
First harmonic, equal to the fundamental
Second harmonic, two times the fundamental
Third harmonic, three times the fundamental
When harmonic imaging is used with a 2 MHz beam, which signal is usually displayed?
4 MHz narrow second harmonic signal
3 MHz intermediate harmonic signal
2 MHz broad fundamental signal
5 MHz wideband artifact-prone signal
Why does harmonic imaging improve lateral resolution?
Harmonic beams are narrower than fundamental
Surface reverberations broaden the beam
It increases axial resolution only
Frequency filtering widens the main lobe
How does harmonic imaging reduce superficial artifacts?
By generating harmonics mainly at the surface
By ignoring all echoes from deep tissue
By processing only deep-generated harmonic signals
By lowering the transmitted acoustic power
Which component controls the voltage amplitude to transducer elements and sets pulse repetition?
Beam former with delay control
Pulser acting as transmitter
Master synchronizer unit
Receiver gain amplifier
Increasing output power in ultrasound most directly affects which characteristic?
Wave strength entering tissue
Beam width uniformity
Center frequency stability
Echo timing accuracy
What is the main safety concern when increasing output power during scanning?
Shorter pulse repetition period
Higher risk of image artifacts
Greater chance of patient bioeffects
Reduced signal-to-noise ratio
Which statement best reflects the ALARA principle in ultrasound?
Prioritize image brightness over patient exposure
Use highest power for fastest imaging
Keep power and scan time as low as reasonable
Favor long scans to improve averaging
What does the beam former mainly control in array transducers?
Post‑processing dynamic range
Mechanical movement of elements
Timing delays for steering and focus
Amplitude equalization only
Apodization, controlled by the beam former, mainly reduces which artifact?
Side lobes near the focus
Grating lobes from arrays
Speckle from interference
Reverberations from surfaces
What does the master synchronizer do during pulse‑echo operation?
Compensates for attenuation with TGC
Amplifies weak returning echoes
Assigns dynamic receive focusing
Controls echo timing and range determination
Why should a new transmit pulse not be sent before previous echoes return?
To ensure maximum lateral resolution
To prevent range ambiguity errors
To avoid thermal index elevation
To maintain constant PRF across depths
A sonographer increases output power to improve signal‑to‑noise ratio. Which action best maintains ALARA?
Use wider beam and slower frame rate
Increase power and lengthen scan time
Keep power fixed and raise receiver gain
Increase power and reduce scan duration
Which receiver function changes the strength of all returning echoes equally?
Rejection thresholding
Amplification (overall gain)
Compensation (TGC)
Compression of amplitudes
What is the main purpose of Compensation (TGC) in ultrasound?
Reduce dynamic range differences
Boost near-field echoes only
Equalize brightness by depth
Discard low-amplitude noise
Which control applies compensation across depth?
Reject filter toggle
TGC sliders curve
Overall gain knob
Dynamic range menu
Compression in the receiver mainly affects which signal property?
Transducer element sensitivity
Echo travel time
Beam steering
Difference between largest and smallest amplitudes
Dynamic range, as managed by compression, refers to the range of what?
Acoustic power output levels
Transducer operating frequencies
Image pixel spatial resolution
Signal amplitudes within the signal
Demodulation makes signals easier for machines to handle. Which pair are its components?
Filtering and interpolation
Rectification and smoothing
Clamping and dithering
Modulation and averaging
What does rectification do in demodulation?
Compresses the dynamic range of the image
Eliminates low-amplitude signals below threshold
Amplifies all echoes equally across depth
Turns negative voltages into positive voltages
What does smoothing do to the signal during demodulation?
Converts analog data to digital samples
Increases gain for deeper echoes
Sharpens high-frequency components
Wraps an envelope to make it less bumpy
Which receiver function removes signals below a set threshold to reduce noise?
Smoothing
Amplification
Compensation
Rejection
If deeper structures look darker than superficial ones due to attenuation, which adjustment should be made first?
Apply additional rectification
Raise overall gain uniformly
Increase TGC slope and far gain
Lower the reject threshold
Which receiver setting helps remove weak noise but keeps important echoes?
Rejection threshold level
Compression knee position
Demodulation smoothing depth
Overall gain control
Strong echoes fill the display, but weak echoes are hard to see. Which option best restores balance?
Increase compression to reduce dynamic range
Decrease TGC to lower far-field gain
Reduce rectification to keep voltages negative
Raise rejection to remove strong signals
What is the main function of a scan converter in medical imaging?
Stores image data and enables gray-scale display
Generates ultrasound echoes from tissue interfaces
Performs Doppler analysis of blood flow velocities
Controls transducer frequency and beam focusing
What key feature did analog storage in early scan converters provide?
Error-correcting codes for unstable signals
Fixed memory addresses per matrix element
Infinite signal amplitudes allowing many gray shades
Discrete binary levels limited to black and white
Which complication was commonly associated with analog scan converters?
Aliasing from under-sampling rates
Image flicker, fade, and instability
Quantization noise and bit depth limits
Latency due to large buffer queues
What number system do digital scan converters use for storage?
Hexadecimal system using digits and letters
Ternary system using three distinct states
Decimal system using digits zero to nine
Binary system using zeroes and ones
In ultrasound digital representation, what do 0 and 1 indicate?
Off black echo and on white echo
Minimum intensity pixel and maximum
Low amplitude echo and high amplitude
Noise floor level and peak signal
Before gray-scale imaging, displays were bistable. What does bistable mean?
Adaptive contrast based on gain
Variable hue with color saturation
Multiple gray levels across continuum
Purely black and white with two states
What is a pixel in a digital image?
Average intensity across a region
Largest addressable block in memory
Temporary cache used for buffering
Smallest picture element in a display
How does increasing the number of pixels on a display affect image quality?
Improves spatial resolution
Reduces dynamic range
Increases color saturation
Decreases frame rate
What is a bit in digital imaging memory?
Smallest amount of computer memory possible
Single pixel coordinate on the matrix
Analog voltage representing gray level
Compression unit used for file storage
If n is the number of bits per pixel, what does n determine in gray-scale imaging?
Number of possible shades of gray
Number of pixels per column
Amount of beamformer delay taps
Total dynamic range in decibels
Which statement correctly matches bit depth to gray shades?
Eight bits give 1024 gray shades
Eight bits give 128 gray shades
Five bits give 64 gray shades
Five bits give 32 gray shades
Which image matrix gives better spatial resolution for the same field of view?
256 × 256 pixels matrix
32 × 32 pixels matrix
128 × 128 pixels matrix
64 × 64 pixels matrix
Which component assigns shades of gray to ultrasound signal amplitudes?
PACS archiving system component
Display monitor processing component
Digital-to-analog converter component
Analog-to-digital converter component
Preprocessing changes occur when the image is in which state?
Stored in memory
Sent to PACS archive
Converted to analog output
Live real-time acquisition
Postprocessing starts after which event in the scan converter workflow?
Assignment of gray levels event
Beam formation in the receiver event
Transmission from transducer event
Storage of the image frozen event
What does a digital-to-analog (D-to-A) converter do?
Magnifies pixels
Converts digital data to analog
Stores images
Converts analog signals to digital
Which zoom method increases pixel density by redrawing the image?
Write zoom preprocessing method
Linear interpolation display method
Monitor zoom hardware method
Read zoom postprocessing method
When should write zoom be performed on an image?
Frozen and stored in memory condition
Live and being acquired condition
Displayed and archived to PACS condition
Converted back to analog output condition
Read zoom mainly magnifies the image by which action?
Increasing pixel density
Redrawing the sampled region
Reassigning gray levels
Stretching existing pixels
Which statement best compares write zoom and read zoom effects on image quality?
Both methods equally improve resolution quality
Write zoom improves, read zoom degrades quality
Read zoom improves, write zoom degrades quality
Neither method changes resolution quality
Which sequence shows the correct path of the ultrasound signal?
Transducer to PACS, monitor, then memory
Receiver to D-to-A, memory, then A-to-D
PACS to memory, A-to-D, then D-to-A
Receiver to A-to-D, memory, then D-to-A
A sonographer freezes an image and then magnifies a lesion. What type of zoom is used?
Read zoom postprocessing type
Beamformer magnification type
A-to-D converter zoom type
Write zoom preprocessing type
Which statement best describes coded excitation in ultrasound?
It relies on continuous-wave transmission
It averages frames to reduce noise
It sends a long pulse per scan line
It uses encoded pulse sequences for one scan line
What is the main imaging benefit of coded excitation?
Higher color Doppler frame rates only
Lower axial resolution in deep tissues
Better speckle reduction and contrast resolution
Improved temporal resolution only
How is the final image created in frequency compounding?
By averaging images from different frequencies
By choosing the highest frequency
By adding raw RF data from one transducer element
By removing all low-frequency echoes
What is the typical result of frequency compounding in soft tissue imaging?
Less penetration with more aliasing
Better contrast resolution and less speckle
Sharper edges but more electronic noise
More speckle and less contrast
What is the main purpose of frame averaging in scan conversion?
Increase frame rate to reduce motion blur
Improve signal-to-noise ratio without bioeffects
Reduce signal-to-noise ratio without bioeffects
Increase transmit power for better penetration
Which list correctly identifies types of frame averaging?
Spatial compounding and frequency compounding
Time gain compensation and persistence filters
Temporal compounding and analog averaging only
Harmonic imaging and coded aperture methods
Fill-in interpolation in ultrasound imaging is:
Replacing missing pixels with zeros
Discarding frames with missing data
Estimating missing pixels using nearby grayscale
Increasing pixel size to cover gaps
A patient's scan showed heavy speckle. Which technique best reduces speckle while keeping contrast?
Apply frequency compounding across multiple bands
Switch to continuous-wave Doppler mode
Use single-pulse excitation and increase gain
Disable averaging to maintain native texture
Which statement best distinguishes interlaced CRT imaging from non-interlaced LCD imaging?
CRT builds frames from two fields
LCD forms images using odd lines
CRT draws frames as one image
LCD composes frames from two fields
On a CRT display, what is the time to produce one frame from two fields?
1/30 second per frame
1/60 second per frame
1/15 second per frame
1/45 second per frame
A CRT at 30 Hz shows how many frames per second?
15 frames per second
60 frames per second
45 frames per second
30 frames per second
Which part controls if light passes through an LCD display?
Twisting of liquid crystals
Strength of magnetic tape
Velocity of electron gun
Charge of phosphor screen
In a CRT’s interlaced scan, which lines are placed first?
Odd-numbered lines
All lines together
Even-numbered lines
Center-to-edge lines
Which system uses a computer network and DICOM software to manage medical images?
CD/DVD burner
PACS system
VHS recorder
MO cartridge
Which list correctly groups storage media for medical imaging outside PACS?
Phosphor screen, LCD panel, CRT
Odd field, even field, refresh rate
Film, VHS tape, CD/DVD, MO
Ethernet cable, DICOM header, PACS
Which statement best defines ultrasound artifacts?
Echoes not representing actual anatomy
Noise from machine power supply
Echoes representing true anatomy
Shadows caused by patient motion
Pixels created by post-processing
Which machine assumption states sound travels in a straight line to and from the transducer?
Mirror return principle
Linear path assumption
Reverberation hypothesis
Side lobe doctrine
Beam width theorem
What speed does ultrasound assume for soft tissue?
1480 m/s
1500 m/s
1540 m/s
1600 m/s
1650 m/s
Which assumption places all returning echoes along the transmitted beam path?
Apodization constraint
Speckle modeling assumption
On-axis reflection assumption
Time-gain compensation rule
Beamformer coherence law
What does the slice thickness assumption say about the imaging plane?
It is thicker near focus
It is elliptical shaped
It is 5 mm thick
It varies with depth
It is razor thin
According to machine assumptions, what should echogenicity represent?
Beam intensity profile
Transducer heating level
Ambient noise in room
Operator gain settings only
Structure’s true echogenicity
Mirror image artifact places a duplicated structure where?
Within the focal zone only
Shallower, near the transducer
Inside acoustic shadow regions
Deeper, across a strong reflector
Lateral to the true structure
Propagation speed error causes structures to be shown at which incorrect property?
Wrong frame rate
Wrong lateral position
Wrong depth location
Wrong Doppler frequency
Wrong echogenicity level
If tissue speed is less than 1540 m/s, how will depth appear?
Too shallow
Lateralized
Correct depth
Too deep
Randomized
Acoustic shadowing is mainly caused by which physical effect?
Strong attenuation behind a reflector
Phase cancellation in beamformer
Time-gain overcompensation
Velocity mismatch across tissues
Edge refraction of side lobes
Through-transmission (enhancement) is most prominent behind which type of structure?
Bone cortex
Highly attenuating mass
Cyst with low attenuation
Calcified plaque
Gas-filled bowel
Grating lobes are caused by which transducer feature?
Array element spacing
Single crystal design
Excessive TGC slope
Short pulse duration
Low center frequency
Which control reduces grating lobes by lowering outer element contributions?
Apodization settings
Color gain control
Dynamic range control
Rejection threshold
Persistence averaging
Which scenario is most likely to produce a mirror image artifact?
Beam passing through homogeneous liver
Beam transmitted through muscle
Beam reflecting off diaphragm
Beam focused within a cyst
Beam crossing a curved vessel
A hypoechoic band deep to a gallstone is which artifact?
Mirror image from diaphragm
Enhancement due to low attenuation
Shadowing due to strong absorption
Speed error in fatty tissue
Grating lobe sidelobe energy
Echoes under a simple cyst are brighter than nearby tissues. What artifact causes this?
Mirror image duplication
Grating lobe reflection
Reverberation between walls
Propagation speed error
Acoustic enhancement
