UST EXAM STUDY QUESTIONS 2026/2027 | Complete
Practice & Verified Answers | Pass Guaranteed - A+ Graded
SECTION 1: Ultrasound Physics & Instrumentation (Q1–Q25)
Q1: A sonographer is imaging a structure at 8 cm depth using a 5 MHz transducer. If the
propagation speed in soft tissue is 1,540 m/s, what is the approximate wavelength?
A. 0.15 mm
B. 0.31 mm [CORRECT]
C. 0.62 mm
D. 1.24 mm
Correct Answer: B
Rationale: Wavelength (λ) = propagation speed (c) / frequency (f) = 1,540 m/s ÷
5,000,000 Hz = 0.000308 m = 0.308 mm ≈ 0.31 mm. Option A uses an incorrect formula,
C doubles the value, and D quadruples it.
Q2: Which transducer type is most appropriate for imaging the liver through an
intercostal approach in a patient with a large body habitus?
A. Linear array 12 MHz
B. Phased array 2.5 MHz
C. Curved array 3.5 MHz [CORRECT]
D. Endocavitary 7.5 MHz
Correct Answer: C
Rationale: A curved (convex) array 3.5 MHz transducer provides the optimal
combination of lower frequency for deeper penetration and a wider field of view suitable
for abdominal imaging. Linear arrays lack depth penetration, phased arrays are
designed for cardiac imaging through small windows, and endocavitary probes are for
pelvic imaging.
Q3: A sonographer notices a ring-down artifact extending distal to a metallic surgical
clip in the abdomen. What is the physical mechanism producing this artifact?
,A. Refraction at a curved interface
B. Multiple internal reflections within a strong reflector [CORRECT]
C. Speed error due to high attenuation
D. Side lobe energy detection
Correct Answer: B
Rationale: Ring-down artifact occurs when ultrasound encounters a strong reflector (like
gas or metal), causing continuous resonant vibrations and multiple internal reflections
that produce a bright streak distal to the object. Refraction causes edge shadowing,
speed error causes misregistration, and side lobes create false echoes in unexpected
locations.
Q4: In pulsed-wave Doppler, which control adjustment will increase the maximum
velocity that can be measured without aliasing?
A. Decreasing the wall filter
B. Increasing the pulse repetition frequency (PRF) [CORRECT]
C. Decreasing the sample volume depth
D. Lowering the transmit frequency
Correct Answer: B
Rationale: The Nyquist limit equals PRF/2; increasing PRF raises the Nyquist limit and
allows measurement of higher velocities without aliasing. The wall filter removes
low-frequency clutter, sample volume depth affects PRF indirectly (deeper imaging
requires lower PRF), and lowering transmit frequency improves penetration but does not
directly increase the Nyquist limit.
Q5: A sonographer is performing a carotid duplex study and observes spectral
broadening with filling-in of the spectral window. What hemodynamic finding does this
indicate?
A. Laminar flow with high velocity
B. Turbulent flow with disturbed velocity profiles [CORRECT]
C. Reversed flow due to vessel occlusion
D. Pulsatile flow in a compliant vessel
Correct Answer: B
Rationale: Spectral broadening and loss of the clear spectral window indicate turbulent
flow, which occurs at stenoses, bifurcations, or distal to obstructions. Laminar flow
,produces a narrow spectral window, reversed flow appears below the baseline, and
pulsatile flow is normal in arterial systems.
Q6: The piezoelectric effect in ultrasound transducers refers to:
A. The conversion of electrical energy to mechanical energy and vice versa [CORRECT]
B. The absorption of sound energy by tissue
C. The scattering of ultrasound by small structures
D. The reflection of sound at tissue interfaces
Correct Answer: A
Rationale: Piezoelectric crystals convert electrical energy into mechanical (sound)
energy during transmission and mechanical energy back into electrical energy during
reception. Absorption, scattering, and reflection are acoustic interactions with tissue,
not transducer properties.
Q7: A sonographer adjusts the time gain compensation (TGC) to increase gain in the far
field. What is the primary purpose of this adjustment?
A. To increase lateral resolution
B. To compensate for attenuation with depth [CORRECT]
C. To reduce near-field reverberation artifact
D. To improve axial resolution
Correct Answer: B
Rationale: TGC compensates for the progressive attenuation of ultrasound as it travels
deeper into tissue, ensuring uniform brightness across the image. Lateral resolution is
improved by focusing, near-field reverberation is addressed by changing transducer
position or frequency, and axial resolution depends on spatial pulse length.
Q8: Which of the following best describes axial resolution?
A. The ability to distinguish two structures perpendicular to the ultrasound beam
B. The ability to distinguish two structures parallel to the ultrasound beam [CORRECT]
C. The ability to distinguish structures at different depths from the transducer
D. The ability to distinguish structures at the same depth but different lateral positions
Correct Answer: B
Rationale: Axial resolution is the ability to differentiate two structures along the axis of
the ultrasound beam (parallel to beam direction) and is determined by spatial pulse
, length. Lateral resolution refers to perpendicular discrimination, and the other options
describe variations of lateral or elevational resolution.
Q9: A sonographer is imaging a gallstone and observes a clean acoustic shadow
posterior to the calculus. What is the primary mechanism causing this shadow?
A. Reflection of nearly all sound energy at the stone interface [CORRECT]
B. Absorption of sound by the gallstone
C. Refraction of sound around the stone
D. Scattering of sound by the stone surface
Correct Answer: A
Rationale: Clean acoustic shadowing occurs when a strong reflector (like a calcified
gallstone) reflects or absorbs nearly all incident sound energy, preventing ultrasound
from reaching tissues distal to it. While some absorption occurs, reflection is the
dominant mechanism. Refraction causes edge shadowing, and scattering produces a
different pattern.
Q10: In color Doppler imaging, the color map displays flow toward the transducer as red
and flow away as blue. If the color scale is inverted, what will be the appearance of flow
in the hepatic veins?
A. Red (since flow is normally toward the transducer)
B. Blue (since flow is normally away from the transducer) [CORRECT]
C. Green (indicating turbulent flow)
D. Black (indicating no flow)
Correct Answer: B
Rationale: Hepatic veins normally drain toward the IVC and away from a subcostal
transducer, appearing blue on standard color maps. Inverting the scale would still show
the directional relationship correctly—flow away from the transducer would remain
coded appropriately based on the new scale orientation. Green indicates
variance/turbulence, and black indicates no flow or perpendicular flow.
Q11: The mechanical index (MI) is an indicator of:
A. The risk of thermal bioeffects
B. The risk of cavitation bioeffects [CORRECT]
C. The pulse repetition frequency
D. The axial resolution capability
Practice & Verified Answers | Pass Guaranteed - A+ Graded
SECTION 1: Ultrasound Physics & Instrumentation (Q1–Q25)
Q1: A sonographer is imaging a structure at 8 cm depth using a 5 MHz transducer. If the
propagation speed in soft tissue is 1,540 m/s, what is the approximate wavelength?
A. 0.15 mm
B. 0.31 mm [CORRECT]
C. 0.62 mm
D. 1.24 mm
Correct Answer: B
Rationale: Wavelength (λ) = propagation speed (c) / frequency (f) = 1,540 m/s ÷
5,000,000 Hz = 0.000308 m = 0.308 mm ≈ 0.31 mm. Option A uses an incorrect formula,
C doubles the value, and D quadruples it.
Q2: Which transducer type is most appropriate for imaging the liver through an
intercostal approach in a patient with a large body habitus?
A. Linear array 12 MHz
B. Phased array 2.5 MHz
C. Curved array 3.5 MHz [CORRECT]
D. Endocavitary 7.5 MHz
Correct Answer: C
Rationale: A curved (convex) array 3.5 MHz transducer provides the optimal
combination of lower frequency for deeper penetration and a wider field of view suitable
for abdominal imaging. Linear arrays lack depth penetration, phased arrays are
designed for cardiac imaging through small windows, and endocavitary probes are for
pelvic imaging.
Q3: A sonographer notices a ring-down artifact extending distal to a metallic surgical
clip in the abdomen. What is the physical mechanism producing this artifact?
,A. Refraction at a curved interface
B. Multiple internal reflections within a strong reflector [CORRECT]
C. Speed error due to high attenuation
D. Side lobe energy detection
Correct Answer: B
Rationale: Ring-down artifact occurs when ultrasound encounters a strong reflector (like
gas or metal), causing continuous resonant vibrations and multiple internal reflections
that produce a bright streak distal to the object. Refraction causes edge shadowing,
speed error causes misregistration, and side lobes create false echoes in unexpected
locations.
Q4: In pulsed-wave Doppler, which control adjustment will increase the maximum
velocity that can be measured without aliasing?
A. Decreasing the wall filter
B. Increasing the pulse repetition frequency (PRF) [CORRECT]
C. Decreasing the sample volume depth
D. Lowering the transmit frequency
Correct Answer: B
Rationale: The Nyquist limit equals PRF/2; increasing PRF raises the Nyquist limit and
allows measurement of higher velocities without aliasing. The wall filter removes
low-frequency clutter, sample volume depth affects PRF indirectly (deeper imaging
requires lower PRF), and lowering transmit frequency improves penetration but does not
directly increase the Nyquist limit.
Q5: A sonographer is performing a carotid duplex study and observes spectral
broadening with filling-in of the spectral window. What hemodynamic finding does this
indicate?
A. Laminar flow with high velocity
B. Turbulent flow with disturbed velocity profiles [CORRECT]
C. Reversed flow due to vessel occlusion
D. Pulsatile flow in a compliant vessel
Correct Answer: B
Rationale: Spectral broadening and loss of the clear spectral window indicate turbulent
flow, which occurs at stenoses, bifurcations, or distal to obstructions. Laminar flow
,produces a narrow spectral window, reversed flow appears below the baseline, and
pulsatile flow is normal in arterial systems.
Q6: The piezoelectric effect in ultrasound transducers refers to:
A. The conversion of electrical energy to mechanical energy and vice versa [CORRECT]
B. The absorption of sound energy by tissue
C. The scattering of ultrasound by small structures
D. The reflection of sound at tissue interfaces
Correct Answer: A
Rationale: Piezoelectric crystals convert electrical energy into mechanical (sound)
energy during transmission and mechanical energy back into electrical energy during
reception. Absorption, scattering, and reflection are acoustic interactions with tissue,
not transducer properties.
Q7: A sonographer adjusts the time gain compensation (TGC) to increase gain in the far
field. What is the primary purpose of this adjustment?
A. To increase lateral resolution
B. To compensate for attenuation with depth [CORRECT]
C. To reduce near-field reverberation artifact
D. To improve axial resolution
Correct Answer: B
Rationale: TGC compensates for the progressive attenuation of ultrasound as it travels
deeper into tissue, ensuring uniform brightness across the image. Lateral resolution is
improved by focusing, near-field reverberation is addressed by changing transducer
position or frequency, and axial resolution depends on spatial pulse length.
Q8: Which of the following best describes axial resolution?
A. The ability to distinguish two structures perpendicular to the ultrasound beam
B. The ability to distinguish two structures parallel to the ultrasound beam [CORRECT]
C. The ability to distinguish structures at different depths from the transducer
D. The ability to distinguish structures at the same depth but different lateral positions
Correct Answer: B
Rationale: Axial resolution is the ability to differentiate two structures along the axis of
the ultrasound beam (parallel to beam direction) and is determined by spatial pulse
, length. Lateral resolution refers to perpendicular discrimination, and the other options
describe variations of lateral or elevational resolution.
Q9: A sonographer is imaging a gallstone and observes a clean acoustic shadow
posterior to the calculus. What is the primary mechanism causing this shadow?
A. Reflection of nearly all sound energy at the stone interface [CORRECT]
B. Absorption of sound by the gallstone
C. Refraction of sound around the stone
D. Scattering of sound by the stone surface
Correct Answer: A
Rationale: Clean acoustic shadowing occurs when a strong reflector (like a calcified
gallstone) reflects or absorbs nearly all incident sound energy, preventing ultrasound
from reaching tissues distal to it. While some absorption occurs, reflection is the
dominant mechanism. Refraction causes edge shadowing, and scattering produces a
different pattern.
Q10: In color Doppler imaging, the color map displays flow toward the transducer as red
and flow away as blue. If the color scale is inverted, what will be the appearance of flow
in the hepatic veins?
A. Red (since flow is normally toward the transducer)
B. Blue (since flow is normally away from the transducer) [CORRECT]
C. Green (indicating turbulent flow)
D. Black (indicating no flow)
Correct Answer: B
Rationale: Hepatic veins normally drain toward the IVC and away from a subcostal
transducer, appearing blue on standard color maps. Inverting the scale would still show
the directional relationship correctly—flow away from the transducer would remain
coded appropriately based on the new scale orientation. Green indicates
variance/turbulence, and black indicates no flow or perpendicular flow.
Q11: The mechanical index (MI) is an indicator of:
A. The risk of thermal bioeffects
B. The risk of cavitation bioeffects [CORRECT]
C. The pulse repetition frequency
D. The axial resolution capability
