ARDMS SPI EXAM LATEST 2024-2025 UPDATE COMPREHENSIVE QUESTIONS AND CORRECT ANSWERS| ALREADY GRADED A+/PASSED 100%

Example of nonspecular reflector

red blood cells

What happens to spatial pulse length when frequency increases?

decreases

Axial resolution is dependent on?

wavelength

Lateral resolution is dependent on?

beam diameter

Where does the beam of an unfocused transducer diverge?

Fraunhofer zone

Reverberation artifacts are a result of

two or more strong reflecting surfaces

True/False: Grating lobes are essential for the proper operation of a linear phased array.

False

True/False: Electronically steered scanners always produce higher resolution images than do mechanically steered scanners.

False

True/False: An annular array scanner uses mechanical beam steering.

True

True/False: A linear sequenced array cannot be dynamically focused.

False

registration or B-mode alignment

Which AIUM test object function utilizes all the groups of wires in the AIUM 100 mm test object?

axial resolution

Which AIUM test object function utilizes the A group of wires in the AIUM 100 mm test object?

lateral resolution

Which AIUM test object function utilizes the B group of wires in the AIUM 100 mm test object?

dead zone

Which AIUM test object function utilizes the D group of wires in the AIUM 100 mm test object?

depth calibration

Which AIUM test object function utilizes the C or E groups of wires in the AIUM 100 mm test object?

What happens to axial resolution when spatial pulse length is decreased?

improves

How much will a 3.5 MHz pulse be attenuated after passing through 2 cm of soft tissue?

3.5 dB

Propagation speed errors result in

improper axial position

Enhancement is caused by

weakly attenuating structures

The Doppler shift frequency is

directly proportional to the velocity of the reflector

The number of frames per second necessary for a real-time image to be flicker free is

more than 15

True/False: The SPTA intensity will always be larger than the SATA intensity.

True

The intensity of the ultrasound beam is usually greater at the focal zone because of

the smaller beam diameter

If the amplitude is doubled, the intensity is

quadrupled

The attenuation for soft tissue is

increased with tissue thickness

The acoustic impedance of the matching layer

can be chosen to improve transmission into the body

True/False: In a pulse-echo system, the quality factor should be made as large as possible.

False

True/False: The beam diameter is constant in the near zone.

False

The operating frequency is dependent on

thickness of the crystal

The period of an ultrasound wave is

the time of one wavelength

The dynamic range of a system is

the ratio of smallest to largest power level that the system can handle

True/False: The intensity of an ultrasonic beam can be measured with radiation force balance.

True

Increasing the pulse repetition period

increases the maximum depth that can be imaged

Ultrasound bioeffects

are not confirmed below 100 mW/cm² SPTA

True/False: No refraction can occur at an interface if the media impedances are equal.

False

True/False: Smaller transducers always produce smaller beam diameters.

False

True/False: The ultrasound beam profile can be measured with a hydrophone.

True

True/False: The pulsed-Doppler system yields better depth resolution than the continuous wave (CW) system.

True

True/False: The gray-scale display was made possible when digital scan converters replaced analog scan converters.

False

True/False: Videotape recorders operating at 30 frames per second cannot be used with mechanical real-time units because the fram rate is too slow.

False

True/False: Linear phased array scanners need no form of mechanical focusing because focusing is performed electronically.

False

True/False: The fram rate of real-time scanners depends on the number of lines used to form the image.

True

True/False: It is not possible to steer an annular phased array electronically.

True

True/False: The near zone length should be kept as short as possible.

False

What percentage of intensity of an ultrasound pulse incident on an interface of 0.25 and 0.75 rayls is reflected?

25%

Axial resolution can be improved by using

higher frequency transducers

When particle motion of a medium is parallel to the direction of a wave propagation, the wave being transmitted is called a

longitudinal wave

The wavelength in a material having a wave velocity of 1500 m/s emplying a transducer frequency of 5 MHz is

0.3 mm

The factor that determines the amount of reflection at the interface of two dissimilar materials is

difference in acoustic impedances

The equation that describes the relationship among propagation, wavelength, and frequency is

λ = c/ƒ

What three things can occur when an ultrasonic beam reaches the interface of two dissimilar materials?

reflection, refraction, mode conversion

The acoustic impedance of a material is

equal to the product of density and velocity

The average velocity of ultrasonic waves in soft tissue is

1540 m/s

True/False: Receiver-angle values in CW Doppler analysis do not influence the final Doppler shift.

False

Refraction occurs because of difference in ______ across an interface between two materials

wave velocity

Reflection factor at an interface between two materials depends primarily on the change in ______ across the interface.

acoustic impedance

The velocity of sound waves is primarily dependent on

medium and mode of vibration

Increasing the frequency of an ultrasonic longitudinal wave will result in ______ in the velocity of that wave.

no change

The change in direction of an ultrasonic beam, when it passes from one medium to another, in which elasticity and density differ from those of the first medium is called

refraction

A long near zone can be obtained by

using a higher frequency transducer

If a 2 MHz frequency is used in human soft tissue, the wavelength is approximately

0.75 mm

The ratio of particle pressure to particle velocity at a given point within the ultrasonic field is

impedance

What is the following formula used to determine?

(2 × velocity of reflector × original frequency) / velocity of sound

Doppler shift frequency

The principle that states that all points on a wavefront can be considered as point sources for the production of sperical secondary wavelets was postulated by

Huygens

A 10 dB difference in signal intensity is equivalent to a _______ difference.

tenfold

The level below which signals are not transmitted through an ultrasound receiver system is the

threshold, negative, reject level

Gray-scale systems typically use _____ as a means of signal dynamic range reduction.

compression

The strength of the echo is related to the height of the deflection on the oscilloscope for the ____ display.

A-mode

What are methods of restricting the dynamic range of the signal?

suppression, rejection, compression

Most of the scan converters currently in use are of the _____ type?

digital

The fraction of time that pulsed ultrasound is actually on is the

duty factor

The ability of an imaging system to detect weak reflections is called

sensitivity

What image shape is produced by a linear sequenced array transducer?

rectangular

The major factor in determining the acoustic power output of the transducer is the

magnitude of the voltage spike

Two primary mechanisms that produce tissue biological effects are

thermal and cavitational

The _____ relates bandwidth to operating frequency.

quality factor, Q Factor

The extraneous beams of ultrasound generated from the edges of individual transducer elements and not in the direction of the main ultrasonic beam are called

side lobes

The product of the period and the number of cycles in the pulse is the

pulse duration

The substance typically used as a matrix on the imaging surface of an analog scan converter tube is

silicon oxide

Specular reflection occurs when

the reflector surface is small and smooth as compared with wavelength

The refractive index of water is slightly altered when a sound beam passes through it, thus causing compression and rarefaction of the water molecules. The phenomenon is the basis for the _____ technique of beam measurement.

Schlieren

Artifacts appearing as parallel, equally spaced lines are characteristic of

reverberation

An increase in reflection amplitude from reflectors that lie behind a weakly attenuating structure is called

enhancement

The amount of dispersion in the far field of an ultrasound beam can be decreased by

using a larger diameter transducer

Longitudinal or axial resolution is directly dependent on

spatial pulse length

The transducer _____ is equal to the ratio of the operating frequency to the frequency bandwidth.

Q factor

The technique that uses an optical system to produce a visible image of an ultrasonic beam is the _____ technique.

Schlieren

Which of the following is the least obstacle to the transmission of ultrasound?

A. MUSCLE

B. FAT

C. BONE

D. BLOOD

blood

The ratio of the largest power to the smallest power that the ultrasound system can handle is the

dynamic range

Ultrasound waves in tissues are called _____ waves.

longitudinal

axial resolution

The row of wires in the middle are used to check

scan C

Which of the diagrams shows correct arm registration?

dead zone

The row of wires on top is used to check?

call for service

While using the AIUM test object to test an articulated-arm scanner you obtain an image similar to scan A. You should

horizontal caliper check

The row of wires on the bottom is used to check for

Which of the following CANNOT be checked when the AIUM test object is scanned from the top only?

A. AXIAL RESOLUTION

B. LATERAL RESOLUTION

C. VERTICAL DISTANCE CALIBRATION

D. HORIZONTAL DISTANCE CALIBRATION

lateral resolution

What parameters CANNOT be evaluated by the AIUM test object?

gray scale, dynamic range

Scanning a test object from three sides without erasing would be used to check

registration

When using the AIUM test object, which of the following should be kept constant for comparisons?

A. OUTPUT POWER

B. TGC

C. REJECT

D. TRANSDUCER MHz & FOCUS

all the above

Which of the following type(s) of ultrasound machine can be used with AIUM test object?

A. LINEAR ARRAY

B. STATIC SCANNER

C. PHASED ARRAY

D. ANNULAR ARRAY

E. SECTOR SCANNER

all the above