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What is the relationship between frequency and wavelength in ultrasound?
️️Frequency and wavelength are inversely related; as frequency increases, wavelength decreases,
enhancing resolution but reducing penetration depth.
How does acoustic im...
What is the relationship between frequency and wavelength in ultrasound?
✔️✔️Frequency and wavelength are inversely related; as frequency increases, wavelength decreases,
enhancing resolution but reducing penetration depth.
How does acoustic impedance affect ultrasound imaging?
✔️✔️Acoustic impedance is the resistance to sound wave transmission; differences in impedance
between tissues cause reflections that form the ultrasound image.
What causes shadowing in ultrasound images?
✔️✔️Shadowing occurs when sound waves are heavily attenuated or absorbed by dense structures
like bone, preventing deeper structures from being visualized.
What is the purpose of the Fresnel and Fraunhofer zones in ultrasound?
✔️✔️The Fresnel zone (near field) provides better resolution close to the transducer, while the
Fraunhofer zone (far field) has reduced resolution but wider beam spread.
How does increasing the gain affect the ultrasound image?
✔️✔️Increasing gain amplifies the returning echoes, making the image appear brighter, though it may
introduce noise if set too high.
Explain the concept of lateral resolution in ultrasound.
✔️✔️Lateral resolution is the ability to distinguish two structures that are side by side and is
influenced by beam width and focusing.
What is the purpose of dynamic range adjustment in ultrasound?
✔️✔️Dynamic range adjustment controls the range of echo intensities displayed, improving contrast
and allowing differentiation between tissues of similar density.
,Describe how refraction affects ultrasound imaging.
✔️✔️Refraction is the bending of sound waves as they pass through tissues of different speeds,
potentially causing artifacts or misplacement of structures.
What is the effect of spatial compounding on an ultrasound image?
✔️✔️Spatial compounding combines multiple images taken from different angles, reducing speckle
noise and improving image clarity.
How does damping material influence the transducer’s performance?
✔️✔️Damping material reduces pulse duration and ringing, improving axial resolution and reducing
the ultrasound beam’s energy.
What is aliasing in Doppler ultrasound?
✔️✔️Aliasing occurs when the Doppler shift exceeds the Nyquist limit, causing incorrect flow direction
representation in spectral Doppler imaging.
How is frame rate affected by the number of focal zones?
✔️✔️Increasing the number of focal zones lowers frame rate because the transducer spends more
time processing multiple focal depths.
Explain the purpose of color Doppler in ultrasound.
✔️✔️Color Doppler visualizes the flow of blood within vessels, providing information on flow direction
and velocity within an area.
What is the primary factor that affects propagation speed in tissue?
✔️✔️Propagation speed is primarily affected by the density and stiffness of the tissue, with denser
tissues having higher speeds.
How does the use of a higher pulse repetition frequency (PRF) impact Doppler ultrasound?
✔️✔️A higher PRF increases the maximum measurable Doppler shift, reducing the risk of aliasing but
potentially lowering depth resolution.
,What does “echogenicity” refer to in ultrasound?
✔️✔️Echogenicity describes the ability of a tissue to reflect ultrasound waves, resulting in varying
shades of brightness on the image.
Why is the transducer face curved in some probes?
✔️✔️Curved transducer faces provide a wider field of view, which is particularly useful for imaging
large or deep structures like the abdomen.
How does scattering affect ultrasound imaging?
✔️✔️Scattering occurs when sound waves encounter small or irregular structures, leading to a
speckled image texture known as “speckle.”
What is the impact of a longer spatial pulse length on resolution?
✔️✔️A longer spatial pulse length reduces axial resolution, as it makes it harder to distinguish
between closely spaced structures.
Describe the purpose of elastography in ultrasound.
✔️✔️Elastography assesses tissue stiffness, helping to identify abnormal tissues, such as tumors,
based on their elasticity.
What role does frequency play in Doppler sensitivity?
✔️✔️Higher frequencies increase Doppler sensitivity for slow flow but may reduce penetration, while
lower frequencies allow deeper imaging.
What does “artifact” mean in ultrasound, and how can it affect imaging?
✔️✔️An artifact is an unintended structure or distortion on an ultrasound image, which may obscure
real structures or mislead interpretation.
Explain the purpose of using a phased array transducer.
, ✔️✔️A phased array transducer electronically steers the ultrasound beam, allowing for rapid imaging
of small or moving structures, like the heart.
What does power Doppler display in ultrasound?
✔️✔️Power Doppler shows the intensity of blood flow rather than its direction, useful for detecting
slow or deep blood flow.
How does increasing time-gain compensation (TGC) in the far field affect the image?
✔️✔️Increasing TGC in the far field brightens deeper structures, helping to equalize brightness across
the image depth.
Sound waves are:
a) electric
b) mechanical, transverse
c) spectral
d) longitudinal, mechanical ✔️✔️D
The speed of sound of ultrasound in soft tissue is closest to:
a) 1,540 km/sec
b) 1.54 km/sec
c) 1,500 m/s
d) 1,540 mm/sec ✔️✔️C
Which is not an acoustic variable?
a) density
b) pressure
c) distance
d) intensity ✔️✔️D
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