Q.1 What is the primary factor that determines the axial resolution of an ultrasound system?
Pulse length
Transducer frequency
Sound speed in tissue
Beam width
Explanation - Axial resolution depends on the distance between two points along the beam that can be distinguished. It is directly related to the spatial pulse length, which is the product of pulse duration and sound speed.
Correct answer is: Pulse length
Q.2 Which type of transducer geometry is most commonly used for cardiac imaging?
Linear array
Curved array
Phased array
Sector array
Explanation - Phased array transducers allow electronic steering and focusing, which is essential for imaging the heart through narrow acoustic windows.
Correct answer is: Phased array
Q.3 In B-mode imaging, what does the brightness of a pixel represent?
Time of flight
Echo amplitude
Depth
Frequency shift
Explanation - Brightness is proportional to the reflected echo amplitude, which is converted into grayscale values.
Correct answer is: Echo amplitude
Q.4 Which of the following best describes the Doppler shift equation for ultrasound?
f' = f * (c + v) / (c - v)
f' = f * (c - v) / (c + v)
f' = f * (c - v) / (c - v)
f' = f * (c + v) / (c + v)
Explanation - The Doppler shift for moving blood towards the transducer increases the frequency by the factor (c+v)/(c-v).
Correct answer is: f' = f * (c + v) / (c - v)
Q.5 What is the typical range of mechanical index (MI) allowed in diagnostic ultrasound to avoid cavitation?
0.1–0.3
0.7–1.0
1.1–1.5
2.0–3.0
Explanation - Diagnostic ultrasound guidelines limit MI to 1.0 or below, with most clinical machines operating around 0.7–1.0.
Correct answer is: 0.7–1.0
Q.6 Which imaging artifact is caused by signal reflections between the probe and the patient's skin?
Side lobe artifact
Mirror image artifact
Shadowing artifact
Comet-tail artifact
Explanation - The mirror artifact occurs when echoes reflect off a strong reflector and re-enter the transducer, producing an image behind it.
Correct answer is: Mirror image artifact
Q.7 The attenuation of ultrasound in soft tissue increases primarily with which of the following?
Frequency
Temperature
Depth
Probe size
Explanation - Higher frequencies experience greater attenuation due to increased absorption and scattering in tissue.
Correct answer is: Frequency
Q.8 What is the function of a delay line in an ultrasound phased array?
Amplify the received signal
Control the transmit beam orientation
Filter out noise
Convert analog to digital
Explanation - Delay lines adjust the timing of each element, allowing electronic steering of the beam without moving the probe.
Correct answer is: Control the transmit beam orientation
Q.9 Which of the following is NOT a component of an ultrasound signal chain?
Transmit amplifier
Band-pass filter
Digital-to-analog converter
Motion detector
Explanation - Ultrasound signal chains consist of transmit, receive, amplification, filtering, digitization, and display, but not motion detectors.
Correct answer is: Motion detector
Q.10 What does the term 'spatial resolution' refer to in ultrasound imaging?
Ability to distinguish two points at different depths
Ability to distinguish two points in the same depth
Maximum depth penetration
Signal-to-noise ratio
Explanation - Spatial resolution is the minimum distance between two points that can be resolved, usually referring to lateral resolution.
Correct answer is: Ability to distinguish two points in the same depth
Q.11 Which of the following best describes harmonic imaging?
Using a higher transmit frequency than the receive frequency
Using a lower transmit frequency than the receive frequency
Using the same frequency for transmission and reception
Using multiple frequencies simultaneously
Explanation - Harmonic imaging transmits at a fundamental frequency and receives at its harmonic, improving image quality and reducing artifacts.
Correct answer is: Using a higher transmit frequency than the receive frequency
Q.12 What is the typical speed of sound in human soft tissue used in ultrasound calculations?
1400 m/s
1540 m/s
1700 m/s
2000 m/s
Explanation - The standard assumed speed is 1540 meters per second, used for depth calculations and time-of-flight.
Correct answer is: 1540 m/s
Q.13 Which safety standard regulates the maximum permissible exposure of ultrasound energy to the eye?
IEC 60601-2-2
ISO 9001
ASTM F2261
FDA 510(k)
Explanation - IEC 60601-2-2 provides safety limits for diagnostic ultrasound, including exposure limits for ocular tissues.
Correct answer is: IEC 60601-2-2
Q.14 In Doppler ultrasound, what does the color map represent?
Velocity magnitude and direction
Depth
Signal strength
Temperature
Explanation - Color Doppler assigns colors (e.g., red/blue) to indicate flow direction relative to the transducer and magnitude to intensity.
Correct answer is: Velocity magnitude and direction
Q.15 What is the purpose of using a low-frequency transducer in abdominal imaging?
Higher resolution
Greater depth penetration
Reduced cost
Faster scanning speed
Explanation - Lower frequencies travel farther with less attenuation, enabling imaging of deeper structures like the liver.
Correct answer is: Greater depth penetration
Q.16 Which parameter is most directly affected by increasing the focal zone size?
Axial resolution
Lateral resolution
Depth penetration
Signal-to-noise ratio
Explanation - A larger focal zone spreads the beam laterally, decreasing the system’s lateral resolution.
Correct answer is: Lateral resolution
Q.17 Which of the following is a characteristic of a linear array transducer?
Curved field of view
Electrically steered beam
High frequency for superficial imaging
Multiple elements for 3D imaging
Explanation - Linear arrays are used for high‑frequency, superficial imaging such as musculoskeletal or obstetric scans.
Correct answer is: High frequency for superficial imaging
Q.18 In a color Doppler spectrum, what does a vertical line indicate?
Maximum velocity
Zero velocity
Time delay
Signal strength
Explanation - A vertical line in the spectrum corresponds to blood moving parallel to the transducer, showing no velocity component.
Correct answer is: Zero velocity
Q.19 What is the main advantage of 3‑D ultrasound over 2‑D ultrasound?
Higher spatial resolution
Faster data acquisition
Volumetric imaging without manual sweep
Lower cost
Explanation - 3‑D provides volumetric data sets, allowing post‑processing and better anatomical understanding.
Correct answer is: Volumetric imaging without manual sweep
Q.20 Which of the following is NOT a typical source of ultrasound attenuation?
Absorption
Scattering
Reflection
Diffraction
Explanation - Diffraction does not cause attenuation; it causes beam spreading. Attenuation arises from absorption, scattering, and reflection.
Correct answer is: Diffraction
Q.21 What is the function of a matching layer on a piezoelectric transducer?
Enhance electrical conductivity
Improve acoustic coupling
Reduce mechanical vibrations
Increase mechanical strength
Explanation - The matching layer reduces acoustic impedance mismatch between transducer and tissue, increasing transmission efficiency.
Correct answer is: Improve acoustic coupling
Q.22 Which type of imaging modality uses acoustic waves reflected from tissues?
MRI
CT
Ultrasound
X‑ray
Explanation - Ultrasound imaging relies on detecting reflected sound waves; MRI uses magnetic fields, CT uses X‑rays.
Correct answer is: Ultrasound
Q.23 Which of the following best describes the term 'gain' in ultrasound imaging?
Signal amplification
Pulse repetition frequency
Depth of focus
Bandwidth
Explanation - Gain controls the amplification of the received signal, affecting brightness and noise levels.
Correct answer is: Signal amplification
Q.24 Why is a standoff pad used in ultrasound imaging of superficial structures?
To reduce acoustic impedance mismatch
To increase transducer temperature
To improve resolution
To shield the patient
Explanation - The pad provides a coupling medium to minimize reflection at the skin interface, improving image quality.
Correct answer is: To reduce acoustic impedance mismatch
Q.25 Which parameter determines the depth of penetration of an ultrasound beam?
Beam width
Transducer frequency
Gain
Bandwidth
Explanation - Lower frequency waves penetrate deeper because they are less attenuated in tissue.
Correct answer is: Transducer frequency
Q.26 In color Doppler imaging, what does a blue color usually represent?
Blood flowing away from the transducer
Blood flowing towards the transducer
No blood flow
High velocity
Explanation - Color convention: red = away, blue = towards; this may vary but is commonly used.
Correct answer is: Blood flowing towards the transducer
Q.27 Which of the following is a common cause of reverberation artifacts?
Strong reflectors with high impedance
Low pulse repetition frequency
Thin layers of tissue
Wide beam width
Explanation - Strong reflectors send multiple back‑to‑back echoes that repeat, creating reverberation artifacts.
Correct answer is: Strong reflectors with high impedance
Q.28 What is the role of an ADC in an ultrasound system?
Amplify transmitted signals
Digitize received analog signals
Filter out noise
Control probe motion
Explanation - The analog‑to‑digital converter (ADC) samples the amplified analog echo and converts it to digital for processing.
Correct answer is: Digitize received analog signals
Q.29 Which imaging modality is particularly good for evaluating fetal anatomy in the first trimester?
MRI
Ultrasound
CT
X‑ray
Explanation - Ultrasound is the standard, safe, and cost‑effective modality for early pregnancy imaging.
Correct answer is: Ultrasound
Q.30 Which of the following is a common limitation of ultrasound imaging?
Ionizing radiation
High cost
Limited depth in large patients
Poor spatial resolution
Explanation - Ultrasound attenuation limits imaging depth, especially in larger body habitus patients.
Correct answer is: Limited depth in large patients
Q.31 In a phased array system, how is the beam steered electronically?
By changing the transmit frequency
By altering the delay applied to each element
By moving the probe physically
By adjusting the gain settings
Explanation - Electronic steering uses time delays to shift the constructive interference direction of the beam.
Correct answer is: By altering the delay applied to each element
Q.32 Which of the following best describes 'bandwidth' of a transducer?
Range of frequencies it can transmit
Depth of field
Signal amplification factor
Spatial resolution
Explanation - Bandwidth refers to the frequency range over which the transducer can efficiently transmit and receive.
Correct answer is: Range of frequencies it can transmit
Q.33 What does a higher mechanical index indicate?
Higher safety margin
Lower potential for cavitation
Increased acoustic energy
Reduced imaging depth
Explanation - Mechanical index is proportional to acoustic pressure; a higher MI means more energy that can cause cavitation.
Correct answer is: Increased acoustic energy
Q.34 Which component is responsible for forming the B‑mode image from raw RF data?
Beamformer
Envelope detector
Display processor
Transmit amplifier
Explanation - The beamformer combines the delayed signals from each element to create a coherent image line.
Correct answer is: Beamformer
Q.35 In contrast‑enhanced ultrasound, microbubbles are used primarily to:
Increase tissue attenuation
Act as a source of higher frequency harmonics
Provide a fluorescent marker
Reduce patient discomfort
Explanation - Microbubbles produce strong nonlinear responses that enhance contrast via harmonic imaging.
Correct answer is: Act as a source of higher frequency harmonics
Q.36 Which of the following is a non‑linear ultrasound imaging technique?
Conventional B‑mode
Harmonic imaging
M‑mode
Doppler
Explanation - Harmonic imaging exploits the non‑linear behavior of tissues and contrast agents to generate second‑harmonic signals.
Correct answer is: Harmonic imaging
Q.37 Why is a high PRF (pulse repetition frequency) used in Doppler imaging?
To increase penetration depth
To avoid aliasing in fast blood flow
To enhance image resolution
To reduce power consumption
Explanation - High PRF allows sampling of high velocity flows without aliasing, but limits penetration.
Correct answer is: To avoid aliasing in fast blood flow
Q.38 What is the typical bandwidth of a 5‑MHz linear array transducer?
0.5–1 MHz
2–3 MHz
3.5–6 MHz
7–10 MHz
Explanation - Bandwidth is roughly 70‑80% of center frequency, so for 5‑MHz it is about 3.5–6 MHz.
Correct answer is: 3.5–6 MHz
Q.39 Which of the following is a contraindication for using ultrasound contrast agents?
Pregnancy
Kidney disease
Heart failure
All of the above
Explanation - Contrast agents are typically contraindicated in pregnancy, severe renal insufficiency, and some cardiac conditions.
Correct answer is: All of the above
Q.40 What is the main advantage of using a convex transducer for abdominal imaging?
Higher resolution
Greater depth penetration
Wider field of view
Faster scan time
Explanation - Convex transducers provide a larger view area, useful for surveying abdominal organs.
Correct answer is: Wider field of view
Q.41 Which phenomenon causes the shadowing artifact in ultrasound imaging?
Strong reflection
Absorption and scattering
Refraction
Diffraction
Explanation - Tissues with high attenuation absorb or scatter the beam, creating a dark region beyond them.
Correct answer is: Absorption and scattering
Q.42 The time‑of‑flight of an ultrasound pulse is used to calculate:
Velocity of blood
Depth of a reflecting interface
Frequency shift
Signal amplitude
Explanation - Depth = (sound speed × time)/2, where time is the echo travel time.
Correct answer is: Depth of a reflecting interface
Q.43 In M‑mode imaging, what does the horizontal axis represent?
Time
Depth
Velocity
Angle
Explanation - M‑mode records depth over time, with depth on the vertical axis and time on the horizontal.
Correct answer is: Depth
Q.44 Which component of the ultrasound signal chain is primarily responsible for reducing electronic noise?
Pre‑amplifier
Band‑pass filter
Beamformer
Display processor
Explanation - Band‑pass filtering removes out‑of‑band noise before digitization.
Correct answer is: Band‑pass filter
Q.45 The term 'spatial pulse length' (SPL) is defined as:
Pulse duration × speed of sound
Number of cycles × wavelength
Bandwidth × center frequency
Pulse repetition frequency × depth
Explanation - SPL = pulse length in meters, calculated by pulse duration times sound speed.
Correct answer is: Pulse duration × speed of sound
Q.46 Which of the following best describes the function of a transducer's backing material?
Improve acoustic impedance matching
Provide mechanical damping to reduce ringing
Act as a power source
Increase electrical conductivity
Explanation - Backing material absorbs residual vibrations, shortening the transducer's ringing period.
Correct answer is: Provide mechanical damping to reduce ringing
Q.47 Which of the following is a key difference between conventional B‑mode and harmonic imaging?
Harmonic imaging uses two transducers
Harmonic imaging transmits at a higher frequency
Harmonic imaging receives at a higher frequency
Harmonic imaging has lower resolution
Explanation - Harmonic imaging transmits at the fundamental frequency and receives at its harmonic, improving image clarity.
Correct answer is: Harmonic imaging receives at a higher frequency
Q.48 What is the main purpose of the beamforming process in ultrasound imaging?
To convert RF data to grayscale
To focus the acoustic energy and combine echoes
To filter out unwanted frequencies
To amplify the transmitted pulse
Explanation - Beamforming steers and focuses the beam and coherently sums the received echoes.
Correct answer is: To focus the acoustic energy and combine echoes
Q.49 Which of the following best describes the term 'apodization' in ultrasound?
Adjusting beam width
Shaping the transmit pulse
Applying a weighting function to array elements
Changing transducer frequency
Explanation - Apodization reduces side lobes by applying a tapering window to the array element excitations.
Correct answer is: Applying a weighting function to array elements
Q.50 Which parameter is increased to reduce the noise floor in an ultrasound image?
Gain
PRF
Beam width
Bandwidth
Explanation - Increasing gain amplifies received signals but also raises noise; proper calibration reduces noise floor.
Correct answer is: Gain
Q.51 What is the primary reason for using a lower frequency transducer in vascular imaging?
Higher resolution
Lower attenuation and deeper penetration
Faster scanning
Higher safety index
Explanation - Lower frequencies penetrate deeper, which is essential for imaging larger vessels.
Correct answer is: Lower attenuation and deeper penetration
Q.52 In a Doppler spectrum, what does an 'aliasing' pattern indicate?
Very slow blood flow
Fast blood flow beyond the Nyquist limit
No blood flow
Strong tissue attenuation
Explanation - Aliasing occurs when flow velocity exceeds half the PRF, causing the spectrum to fold.
Correct answer is: Fast blood flow beyond the Nyquist limit
Q.53 Which of the following is a typical range for the transmit PRF in a standard diagnostic ultrasound scanner?
10–100 Hz
200–500 Hz
1–10 kHz
20–30 kHz
Explanation - Diagnostic ultrasound typically uses PRFs from about 1 to 10 kHz, balancing penetration and Doppler resolution.
Correct answer is: 1–10 kHz
Q.54 Which type of artifact appears as a bright image directly behind a strong reflector?
Shadowing artifact
Reverberation artifact
Mirror image artifact
Comet-tail artifact
Explanation - A mirror image artifact shows a bright echo behind a strong reflector due to double reflection.
Correct answer is: Mirror image artifact
Q.55 What is the typical purpose of a digital beamformer in modern ultrasound?
To provide analog gain control
To process received signals in real‑time using digital algorithms
To reduce the cost of transducers
To increase the acoustic output power
Explanation - Digital beamformers use DSP or FPGA to calculate delays and sum signals electronically, improving flexibility.
Correct answer is: To process received signals in real‑time using digital algorithms
Q.56 Which of the following best describes 'virtual source imaging' (VSI) in ultrasound?
Creating images by scanning a phantom
Using software to simulate tissue properties
Reconstructing images from multiple transducer positions
Combining B‑mode with Doppler data
Explanation - VSI uses multiple transducer positions to synthesize a larger field of view, similar to tomography.
Correct answer is: Reconstructing images from multiple transducer positions
Q.57 Which component of the ultrasound system primarily determines the system’s overall electrical noise figure?
Transmit amplifier
Beamformer
Pre‑amplifier
Display processor
Explanation - The pre‑amplifier is closest to the transducer and sets the noise floor for the entire chain.
Correct answer is: Pre‑amplifier
Q.58 Which of the following statements is true regarding the relationship between transducer element size and field of view?
Larger elements increase field of view
Smaller elements increase field of view
Element size has no effect
Field of view is determined by frequency alone
Explanation - Smaller elements produce more beams over a given angle, expanding the field of view.
Correct answer is: Smaller elements increase field of view
Q.59 What is the primary benefit of using a 'soft' gel pad for coupling in ultrasound?
It improves acoustic impedance matching
It provides a high‑temperature environment
It reduces probe wear
It decreases patient discomfort
Explanation - Gel pads fill gaps and provide a uniform coupling medium, minimizing reflections at the skin interface.
Correct answer is: It improves acoustic impedance matching
Q.60 Which of the following is NOT a parameter used to assess a patient’s risk for ultrasound-induced thermal injury?
Thermal index (TI)
Mechanical index (MI)
Beam width
Exposure time
Explanation - Thermal index and exposure time relate to heat buildup; beam width does not directly influence temperature rise.
Correct answer is: Beam width
Q.61 Which of the following is a typical application of Doppler ultrasound?
Detecting bone fractures
Measuring blood flow velocity
Assessing bone density
Diagnosing infections
Explanation - Doppler imaging is used to quantify blood flow and detect vascular abnormalities.
Correct answer is: Measuring blood flow velocity
Q.62 In 3‑D ultrasound imaging, how is the volume data typically acquired?
By rotating a single transducer
By scanning multiple 2‑D planes
By using a 3‑D transducer array
Both b and c
Explanation - 3‑D data can be captured by acquiring successive 2‑D slices or using a 3‑D array that samples volume directly.
Correct answer is: Both b and c
Q.63 Which of the following is a primary source of electronic noise in an ultrasound system?
Ambient room temperature
Transducer crystal material
Electromagnetic interference
Patient motion
Explanation - External EM sources can couple into the signal chain, increasing noise.
Correct answer is: Electromagnetic interference
Q.64 The 'time‑gain compensation' (TGC) curve primarily compensates for:
Variation in tissue speed
Depth‑dependent attenuation
Beam steering errors
Mechanical index changes
Explanation - TGC increases gain for deeper echoes to counteract signal loss due to attenuation.
Correct answer is: Depth‑dependent attenuation
Q.65 In a transducer, the term 'resonant frequency' refers to:
The frequency where the transducer is most efficient
The frequency at which the transducer fails
The lowest possible transmit frequency
The frequency of the backing material
Explanation - Resonant frequency is where the piezoelectric element has maximum transduction efficiency.
Correct answer is: The frequency where the transducer is most efficient
Q.66 Which of the following best describes the function of a 'matching layer' in a piezoelectric transducer?
Matches acoustic impedance to reduce reflection
Reduces mechanical vibrations
Increases electrical conductivity
Acts as a heat sink
Explanation - The matching layer reduces the impedance mismatch between the transducer and tissue, enhancing transmission.
Correct answer is: Matches acoustic impedance to reduce reflection
Q.67 Which type of ultrasound imaging is particularly useful for assessing fetal movement and viability?
M‑mode
Doppler
B‑mode
Harmonic imaging
Explanation - M‑mode records motion along a single line, useful for fetal cardiac assessment.
Correct answer is: M‑mode
Q.68 What is the primary limitation of ultrasound imaging in detecting lung tissue abnormalities?
High attenuation by air-filled cavities
Low mechanical index
Poor beam steering
High frequency requirements
Explanation - Air strongly reflects ultrasound, preventing deep imaging into the lungs.
Correct answer is: High attenuation by air-filled cavities
Q.69 Which of the following is a major safety concern associated with high MI ultrasound?
Radiation exposure
Heat generation
Cavitation
Electrical shock
Explanation - High MI can produce gas bubbles (cavitation) that may damage tissues.
Correct answer is: Cavitation
Q.70 In a Doppler ultrasound system, the Nyquist limit is defined as:
Half the PRF
One-fourth the PRF
The PRF itself
Double the PRF
Explanation - The Nyquist limit equals 0.5 × PRF, beyond which aliasing occurs.
Correct answer is: Half the PRF
Q.71 Which of the following is a key benefit of using harmonic imaging in obstetrics?
Reduced depth penetration
Lower acoustic output
Improved contrast between fetal tissue and amniotic fluid
Increased mechanical index
Explanation - Harmonic imaging suppresses clutter and improves differentiation of soft tissues.
Correct answer is: Improved contrast between fetal tissue and amniotic fluid
Q.72 Which component in an ultrasound system is responsible for generating the raw RF data?
Transmit amplifier
Beamformer
Transducer
Display processor
Explanation - The transducer emits and receives the acoustic waves, producing the raw RF echoes.
Correct answer is: Transducer
Q.73 The term 'aperture size' in a transducer array refers to:
The number of elements in the array
The total length of the array
The width of each element
The distance between elements
Explanation - Aperture size is defined by the count of elements that can be independently driven.
Correct answer is: The number of elements in the array
Q.74 Which of the following best describes the term 'bandwidth efficiency'?
Fraction of usable bandwidth relative to center frequency
The ability to transmit at multiple frequencies simultaneously
The range of frequencies over which the transducer operates effectively
The speed of beam steering
Explanation - Bandwidth efficiency is the bandwidth divided by the center frequency, indicating transducer performance.
Correct answer is: Fraction of usable bandwidth relative to center frequency
Q.75 Which of the following is an example of a non‑linear imaging technique that can reduce artifacts?
Envelope detection
Non‑linear beamforming
Harmonic imaging
Linear array scanning
Explanation - Harmonic imaging uses the non‑linear response of tissues, which can reduce clutter and improve image quality.
Correct answer is: Harmonic imaging
Q.76 Which parameter directly affects the penetration depth of an ultrasound beam?
Transducer voltage
Sound speed
Frequency
Bandwidth
Explanation - Lower frequencies are less attenuated and therefore penetrate deeper.
Correct answer is: Frequency
Q.77 What is the main function of the envelope detector in an ultrasound system?
To convert analog signals to digital
To extract the amplitude envelope of the RF signal
To adjust the beam focusing
To modulate the transmit pulse
Explanation - The envelope detector demodulates the RF signal to produce a baseband signal for display.
Correct answer is: To extract the amplitude envelope of the RF signal
Q.78 Which of the following best explains the 'shadowing artifact' in ultrasound?
Strong reflection from a high‑impedance object
Absorption of the ultrasound beam by an attenuating structure
Multiple reflections between two surfaces
Signal processing errors
Explanation - Shadowing occurs when a structure absorbs or scatters the beam, creating a dark region beyond it.
Correct answer is: Absorption of the ultrasound beam by an attenuating structure
Q.79 Which component is responsible for steering the ultrasound beam in a phased array?
Beamformer
Transducer array
Delay lines
Display processor
Explanation - Delay lines introduce time offsets to each element, enabling electronic steering of the beam.
Correct answer is: Delay lines
Q.80 Which of the following is a typical application of Doppler ultrasound in obstetrics?
Measuring fetal heart rate
Assessing placenta perfusion
Detecting bone fractures
Imaging the brain
Explanation - Doppler can evaluate blood flow in the placenta, important for fetal health assessment.
Correct answer is: Assessing placenta perfusion
Q.81 What does the term 'SNR' (signal‑to‑noise ratio) represent in the context of ultrasound?
Ratio of transmit power to received power
Ratio of echo amplitude to background noise
Ratio of depth to beam width
Ratio of PRF to bandwidth
Explanation - SNR indicates how well the echo stands out above noise, affecting image quality.
Correct answer is: Ratio of echo amplitude to background noise
Q.82 Which of the following is a major difference between linear array and convex array transducers?
Linear arrays have a wider field of view
Convex arrays focus on a single line
Linear arrays produce a uniform plane wave
Convex arrays provide a curved field of view
Explanation - Convex arrays form a curved imaging plane, useful for abdominal scans.
Correct answer is: Convex arrays provide a curved field of view
Q.83 Which parameter is increased to improve depth penetration while sacrificing lateral resolution?
Frequency
Beam width
Pulse length
Gain
Explanation - A wider beam penetrates deeper but blurs lateral details.
Correct answer is: Beam width
Q.84 What does the term 'beamwidth' refer to in ultrasound imaging?
The vertical dimension of the beam
The horizontal spread of the beam at its focal point
The depth of field
The time duration of the pulse
Explanation - Beamwidth indicates how narrowly the beam is focused laterally.
Correct answer is: The horizontal spread of the beam at its focal point
Q.85 Which of the following is a common type of contrast agent used in ultrasound?
Microbubbles
Dyes
Radioisotopes
Photons
Explanation - Microbubble contrast agents enhance backscatter and are used in cardiovascular imaging.
Correct answer is: Microbubbles
Q.86 Which of the following best describes the concept of 'aperture' in a transducer array?
Total number of elements
The physical width of each element
The spacing between elements
The electrical impedance of the array
Explanation - Aperture refers to the overall size of the transducer, determined by how many elements it has.
Correct answer is: Total number of elements
Q.87 Which of the following is a characteristic of a 'curved array' transducer?
High-frequency, small field of view
Wide field of view, used in abdominal scans
Provides 3‑D imaging capability
Only used in obstetrics
Explanation - Curved arrays give a larger view area, ideal for abdominal imaging.
Correct answer is: Wide field of view, used in abdominal scans
Q.88 Which of the following statements about the Doppler spectrum is true?
It displays the velocity of flow over time
It displays depth versus brightness
It displays temperature distribution
It displays the frequency shift only
Explanation - The Doppler spectrum is a velocity vs. time plot of blood flow.
Correct answer is: It displays the velocity of flow over time
Q.89 What is the main benefit of using a higher bandwidth transducer?
Improved axial resolution
Greater penetration depth
Higher mechanical index
Lower cost
Explanation - A wider bandwidth leads to shorter pulses, which improves axial resolution.
Correct answer is: Improved axial resolution
Q.90 Which component of an ultrasound system is most responsible for adjusting the echo amplitude to compensate for depth attenuation?
Gain control
TGC (time‑gain compensation)
PRF control
Bandwidth setting
Explanation - TGC increases gain as depth increases to counteract signal loss.
Correct answer is: TGC (time‑gain compensation)
Q.91 Which of the following best describes the term 'harmonic signal' in ultrasound?
Signal at the fundamental frequency
Signal at a multiple of the fundamental frequency
Signal at a lower frequency
Signal caused by noise
Explanation - Harmonics are integer multiples of the transmitted frequency, generated by non‑linear tissue response.
Correct answer is: Signal at a multiple of the fundamental frequency
Q.92 Which imaging modality is used primarily to visualize the structure of soft tissue organs at high resolution?
MRI
CT
Ultrasound
X‑ray
Explanation - Ultrasound provides real‑time, high‑resolution imaging of soft tissues.
Correct answer is: Ultrasound
Q.93 Which of the following is NOT a typical characteristic of a phased array transducer?
Electronic steering
Wide field of view
Large element size
Multiple element elements
Explanation - Phased arrays use many small elements to enable electronic steering.
Correct answer is: Large element size
Q.94 What does the 'pulse repetition frequency' (PRF) affect in an ultrasound system?
Maximum depth penetration
Maximum Doppler velocity without aliasing
Axial resolution
Transducer impedance
Explanation - Higher PRF reduces aliasing but limits depth penetration.
Correct answer is: Maximum Doppler velocity without aliasing
Q.95 Which of the following best describes the function of an 'apodization window'?
Increase beam width
Reduce side lobes in the beam pattern
Adjust transducer frequency
Control mechanical index
Explanation - Apodization applies a weighting function to reduce side lobes and improve image quality.
Correct answer is: Reduce side lobes in the beam pattern
Q.96 Which of the following is a commonly used method to reduce speckle noise in ultrasound images?
Harmonic imaging
High gain
Low frequency
Large transducer size
Explanation - Harmonic imaging reduces speckle due to its non‑linear response and narrow beam pattern.
Correct answer is: Harmonic imaging
Q.97 In which type of ultrasound scan is a 'curved array' most typically used?
Obstetric imaging
Musculoskeletal imaging
Head ultrasound
Abdominal imaging
Explanation - Curved arrays provide a wide field of view for abdominal structures.
Correct answer is: Abdominal imaging
Q.98 Which of the following best describes the term 'echo' in ultrasound imaging?
Sound that passes through tissue without reflection
Reflected sound returning to the transducer
Sound generated by the transducer
Noise generated by electronics
Explanation - Echoes are sound waves reflected from tissue interfaces, captured by the transducer.
Correct answer is: Reflected sound returning to the transducer
Q.99 Which of the following is a major safety metric used to limit acoustic exposure in ultrasound?
Mechanical index (MI)
Thermal index (TI)
Sound pressure level (SPL)
All of the above
Explanation - MI, TI, and SPL are used to ensure patient safety during ultrasound exams.
Correct answer is: All of the above
Q.100 Which of the following is a primary function of the analog‑to‑digital converter in an ultrasound system?
Amplify the echo signal
Filter the received signal
Convert analog signals to digital for processing
Transmit the pulse
Explanation - The ADC digitizes the amplified analog echo, allowing digital signal processing.
Correct answer is: Convert analog signals to digital for processing
Q.101 Which type of imaging artifact is caused by the interference of echoes from a single strong reflector?
Reverberation artifact
Shadowing artifact
Comet-tail artifact
Mirror image artifact
Explanation - Reverberation results from multiple reflections between a strong reflector and the transducer.
Correct answer is: Reverberation artifact
Q.102 Which of the following best describes the term 'resolution' in ultrasound imaging?
Ability to distinguish between two points in depth
Ability to distinguish between two points laterally
Both a and b
None of the above
Explanation - Resolution refers to both axial (depth) and lateral (horizontal) distinguishing capabilities.
Correct answer is: Both a and b
Q.103 Which component is primarily responsible for providing the power to drive the transducer elements?
Transmit amplifier
Beamformer
Pre‑amplifier
Display processor
Explanation - The transmit amplifier supplies the necessary voltage to excite the piezoelectric elements.
Correct answer is: Transmit amplifier
Q.104 Which of the following is a typical application of 3‑D ultrasound in obstetrics?
Fetal head circumference measurement
Visualization of fetal anatomy in three dimensions
Assessment of fetal heart rate
Measuring blood flow velocity
Explanation - 3‑D ultrasound allows volumetric imaging of the fetus, improving anatomical assessment.
Correct answer is: Visualization of fetal anatomy in three dimensions
Q.105 What is the main advantage of using a 'curved array' transducer over a linear array for abdominal imaging?
Higher resolution
Better depth penetration
Larger field of view
Lower cost
Explanation - Curved arrays produce a curved imaging plane, covering more area in one sweep.
Correct answer is: Larger field of view
Q.106 Which of the following is a common cause of the 'comet-tail artifact' in ultrasound?
Strongly reflecting interface
Acoustic shadow
Weak tissue interfaces
Large element size
Explanation - Comet-tail artifact is caused by multiple echoes from a highly reflective interface, creating a tapering signal.
Correct answer is: Strongly reflecting interface
Q.107 Which component of an ultrasound system is primarily used to adjust the time delay of each transducer element during beamforming?
Beamformer
Pre‑amplifier
Transmit amplifier
Display processor
Explanation - The beamformer calculates and applies the required delays for constructive interference.
Correct answer is: Beamformer
Q.108 What is the primary purpose of the 'gain' setting in ultrasound imaging?
Adjust the acoustic output
Control the depth of the image
Adjust the amplification of received echoes
Set the Doppler sensitivity
Explanation - Gain amplifies the received signal, affecting image brightness and noise.
Correct answer is: Adjust the amplification of received echoes
Q.109 Which of the following is a typical feature of a phased array transducer?
Large aperture size
Electronic steering
High frequency
Single element design
Explanation - Phased arrays steer the beam electronically using time delays.
Correct answer is: Electronic steering
Q.110 Which of the following best describes the 'time‑gain compensation' (TGC) function?
Adjusts gain for each depth
Adjusts gain for each frequency
Adjusts gain for each transducer element
Adjusts gain for each PRF
Explanation - TGC increases gain for deeper echoes to compensate for attenuation.
Correct answer is: Adjusts gain for each depth
Q.111 In Doppler ultrasound, which of the following is used to measure blood flow velocity?
Time of flight
Frequency shift
Echo amplitude
Beam width
Explanation - Doppler measures frequency shift to calculate blood flow velocity.
Correct answer is: Frequency shift
Q.112 Which of the following is a key benefit of using harmonic imaging in obstetric ultrasound?
Increased depth penetration
Reduced speckle
Higher mechanical index
Lower cost
Explanation - Harmonic imaging reduces speckle, improving clarity of fetal images.
Correct answer is: Reduced speckle
Q.113 What is the typical range of the mechanical index (MI) for diagnostic ultrasound?
0.0–0.3
0.4–0.6
0.7–1.0
1.1–1.5
Explanation - Diagnostic ultrasound typically limits MI to 1.0 or below, with common values around 0.7–1.0.
Correct answer is: 0.7–1.0