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ARDMS- Sonography Principles And
Instrumentation
What is the Standard protocol for digital imaging that allows for compatibility and communication between computers, workstations, and network hardware provided by various manufactures of CT, MRI and Ultrasound equipment? - ANSWER ✔️ DICOM - Digital Imaging and Communication in Medicine
The spatial pulse length decreases - ANSWER ✔️ with higher frequency
Axial resolution is improved by - ANSWER ✔️ damping ......(because it INCREASES the frequency)
Think SHORT and HIGH! Like Axl Rose from Guns n Roses- just google him.
Lateral resolution is improved by - ANSWER ✔️ decreasing the beam diameter **Tested at point BandE on the phantom
The beam of an unfocused transducer diverges where? - ANSWER ✔️ In the Fraunhofer zone
Reverberation artifacts are a result of - ANSWER ✔️ The presence of two or more strong reflecting surfaces
Recommendations for reducing the potential for bioeffects using the ALARA principal is to - - ANSWER ✔️ Increase receiver gain, decrease output power
What technique can be employed to reduce grating side lobes? - ANSWER ✔️ Apodization, harmonics, subdicing "grate off that Ahs!" think skinny..
Presence of grating lobe and side lobe artifacts are what type of resolution issue? - ANSWER ✔️ Lateral resolution
A technique that uses an ensemble of pulses to improve penetration and contrast resolution - ANSWER ✔️ CE - Coded excitation
If a patient is wheeled over from the ER(other dept.) without an ID band, but is a STAT for r/o DVT- - ANSWER ✔️ Send them back for appropriate identification measures and tagging. Trust NO ONE! Patients Lie/have altered mental status, nurses are rushed. Just send them back for it to be done correctly.
Decreasing the spatial pulse length improves - ANSWER ✔️ axial resolution
How much will a 3.5 MHz pulse be attenuated after passing through 2 cm of soft tissue? - ANSWER ✔️ 3.5 dB (freq / 2) x path length cm = total attenuation dB/cm
Which of the following is the role of the pulse? A. voltage generation to drive the transducer B. gain adjustment for the receiver C. beam focusing D. beam steering - ANSWER ✔️ Voltage generation to drive the transducer
A long near zone can be obtained by - - ANSWER ✔️ using a higher frequency transducer
What is the first step required prior to starting any procedure? - ANSWER ✔️ Verify Name, DOB, and medical record number. Those are the 3 basic required identifiers every time.
The operating frequency depends on - ANSWER ✔️ the thickness of the crystal. Thickness = 1/2 the wavelength
The period of an ultrasound wave is - ANSWER ✔️ time to complete one cycle (Just like a lady..)
The dynamic range of a system - ANSWER ✔️ is the ratio of smallest to largest power level that the system can handle
The digital imaging system that allows MRI, CT, ultrasound and xray to store images electronically and viewed remotely- - ANSWER ✔️ PACS
Increasing the pulse repetition period - ANSWER ✔️ increases the maximum depth that can be imaged-(decreases PRF) *Includes increasing listening time, thus spaced out pulses, lower frequency.
Ultrasound bioeffects with an unfocused beam are not confirmed below : - ANSWER ✔️ 100 mW/cm^2 spatial peak temporal average (SPTA)
When can an informed consent be revoked? - ANSWER ✔️ at any time
When should ultrasound probes be disinfected? - ANSWER ✔️ Before and after each use.
Don't be gross. Clean it like your hands.
Define autocorrelation - ANSWER ✔️ mathematical process that analyzes the change in doppler shift over a short time
Stable cavitation refers to - ANSWER ✔️ microbubbles that oscillate without collapsing with variations in sound pressure
Which is the least likely to cause Bio-effects? A. Power Output B. Thermal Index C. Exam Time D. High-Frequency Transducer E. Mechanical Index - ANSWER ✔️ High Frequency Transducer
Harmonic Frequencies are derived from - ANSWER ✔️ non- linear or asymmetrical wave propagation
Propagation speed is determined by - ANSWER ✔️ Tissue Medium only - density and stiffness
What is the equivalent to the prefix giga - ANSWER ✔️ 10^
What % of intensity of an ultrasound pulse incident on an interface of 0.25 and 0.75 rayls is reflected? - ANSWER ✔️ 25% Reflection%= { (z2-z1) / (z2+z1) } squared x 100
Axial resolution can be improved by - ANSWER ✔️ shorten the spatial pulse length shorten pulse duration higher frequency transducers (damping)
What is the average velocity of ultrasonic waves in soft tissue - ANSWER ✔️ 1540 m/s 154,000 cm/s 1.54mm/microsec one mile per second
Convert mm to cm 80 mm =? cm - ANSWER ✔️ move decimal 1 place to the left 80mm = 8 cm
When a soundwave strikes a boundary between two tissues with a normal incidence, what other condition must be present in order for reflection to occur? - ANSWER ✔️ A difference in acoustical impedances
Ultrasound transducers convert - ANSWER ✔️ electrical energy into mechanical energy (acoustic,pressure) and vice versa
The velocity of sound waves is primarily dependent on - ANSWER ✔️ The medium (tissue) and mode of vibration determine propagation speed (aka velocity) Faster in solids, slower in gasses.
Increasing the frequency of an ultrasonic longitudinal wave will result in ______ in the velocity of that wave. - ANSWER ✔️ No change.
Refraction - ANSWER ✔️ The bending of a wave as it passes at an angle from one medium to another
Rarefaction - ANSWER ✔️ The part of a longitudinal wave where the particles of the medium are far apart
Reflection - ANSWER ✔️ The bouncing back of a wave when it hits a surface through which it cannot pass.
Compression - ANSWER ✔️ The part of a longitudinal wave where the particles of the medium are close together.
Change in direction of the ultrasound beam when passing from one medium to another with a different density and elasticity? - ANSWER ✔️ Refraction
A long near zone can be obtained by - ANSWER ✔️ using a higher frequency transducer
If a 2MHz transducer is used in human soft tissue the wavelength is aproximately? - ANSWER ✔️ 0.75mm 1.54cm /2MHZ= wavelength
What is the ratio of particle pressure to particle velocity at a given point within the ultrasound field? - ANSWER ✔️ Impedance
2 X velocity of reflector X original frequency Velocity of sound is the - ANSWER ✔️ Shift in frequency caused by the doppler effect
Huygen's Principle - ANSWER ✔️ Every point on any wave front can be regarded as a new point source for the production of spherical secondary wavelets. (spherical=hugs &waves=huygens -- like a group hug, one leads to many!)
What system performance parameter can be assessed using a phantom to determine the minimum echo amplitude detectible? - ANSWER ✔️ Sensitivity
The image shape produced by a linear sequenced array real-time transducer - ANSWER ✔️ Rectangle
The major factor in determining the acoustic power output of the transducer is the - ANSWER ✔️ Magnitude of the pulser voltage spike
What 2 scan parameters are used to determine potential for biological effects - ANSWER ✔️ Thermal Index (TI) and Mechanical index (MI)
Which of the following are acoustic variables:
- frequency
- pressure
- propagation speed
- wavelength
- voltage
- intensity
- motion of particles in the wave
- density - ANSWER ✔️ Pressure, particle motion, density
All of the following are True about sound waves EXCEPT:
- they are mechanical
- they are transverse
- they carry energy from place to place
- they generally travel in a straight line - ANSWER ✔️ They are transverse (they are actually longitudinal)
What are the units of a pressure measurement of an acoustic wave? - ANSWER ✔️ Atmosphere (atm), pascals (Pa), millimeters of mercury (mm Hg), pounds/ sq in (lb/in^2)
Waves that exist at the same location and time will combine. What is this called? - ANSWER ✔️ interference
Two waves arrive at the same location and interfere. The resultant sound wave is smaller than either of the two original waves. What is this called? - ANSWER ✔️ Destructive Interference
A pair of waves are in phase. What occurs when these waves interfere? - ANSWER ✔️ Constructive Interference
With standard ultrasonic imaging, what happens to the period of a wave as it propagates? - ANSWER ✔️ It remains the same (Period and frequency of a wave typically remain constant as the sound wave propagates)
What determines the period of an ultrasound wave? - ANSWER ✔️ The transducer (sound source)
Which units are appropriate to describe the period of an acoustic wave? - ANSWER ✔️ Minutes, microseconds
What term describes the number of cycles that an acoustic variable completes in a second? - ANSWER ✔️ Frequency = aka "how fast" High frequency= fast /more waves, but weak/shallow. Low frequency = slow/less waves, but strong/deep.
Artifacts in parallel, equally spaced lines - ANSWER ✔️ Reverberation
Slice thickness artifact - ANSWER ✔️ Artifactual echoes seen within anechoic structures due to the wide beam width. A resolution, propagating artifact. Occurs when the beam dimension is greater than the reflector size AKA section thickness or partial volume artifact.
comet tail - ANSWER ✔️ Sound wave between two very closely spaced reflectors that merge and generate a series of closely spaced, discrete echoes · usually caused by small calcifications / metal objects /air bubbles *more often when the reflectors are located in a medium with high propagation speed
Highly attenuating structure or reflective structure causes what posterior artifact? - ANSWER ✔️ Posterior shadowing
An increase in reflection amplitude from reflectors that lie behind a weakly attenuating structure is called - ANSWER ✔️ enhancement
The amount of dispersion in the far field of an ultrasound beam can be decreased by - ANSWER ✔️ A Larger diameter transducer
Axial (longitudinal) resolution is directly dependent on - ANSWER ✔️ Spatial pulse length
Various terms for axial resolution = - ANSWER ✔️ LARRD= Longitudinal, Axial , Range, Radial or Depth resolution.
A linear sequence and phased array combined transducer that produces a trapezoidal shaped image - ANSWER ✔️ Vector array
What is the least attenuating material for ultrasound transmission? a. Liver b. kidney c. bone d. muscle e. urine f. blood - ANSWER ✔️ Urine - ultrasound travels best with less resistance, in liquids. Blood is a liquid but has more viscosity than urine (thicker). AKA blood is thicker than water!
The ratio of largest power to smallest power that an ultrasound system can handle is the - ANSWER ✔️ Dynamic range
Which lines on a phantom check for Axial Resolution? - ANSWER ✔️ A = axial Resolution B = Lateral Resolution C = Depth calibration D = dead zone (ring down) E = Horizontal caliper check, depth calibration, registration, digital calipers, liquid velocity
The medium in a phantom is set to the equivalent of what speed?
- ANSWER ✔️ The speed of soft tissue 1.54 mm/us
What cannot be checked when scanning the phantom from the top only? - ANSWER ✔️ Lateral resolution
SATP=SPTP
SATA=SATP
SPTP=SPPA - ANSWER ✔️ SATA = SATP and inversely SPTP=SPTA
Sound below 20 Hz is called ______________ - ANSWER ✔️ infrasound
Sound above 20,000 Hz is called______________ - ANSWER ✔️ ultrasound - aka 20kHz , or 2Mhz
Sound between 20hz and 20kHz is called - ANSWER ✔️ Audible sound
Perpendicular angle of incidence - ANSWER ✔️ Normal incidence.
Acoustic impedance formula - ANSWER ✔️ acoustic impedance (rayls) = density(kg/m) × propagation speed(m/s)
Curie point - ANSWER ✔️ the temperature above which a material loses its magnetic properties.
The frequency of CW ultrasound is equal to - ANSWER ✔️ the frequency of the electric voltage that drives the piezoelectric crystal
Damping material reduces the _______ of the transducer and _______ of the diagnostic system. - ANSWER ✔️ Pulse Duration and Spatial pulse length
damping material - ANSWER ✔️ The part of transducer assembly that reduces the number of cycles produced in a pulse and absorbs vibrations. (Same as Backing material)
Axial resolution equation= - ANSWER ✔️ Axial Resolution = 1/ SPL
Reducing the number of cycles (damping) - ANSWER ✔️ improves axial resolution (increases frequency) increases bandwidth, which decreases q-factor Decreases duty factor
How thick is the matching layer? - ANSWER ✔️ 1/4 wavelength thick
SPTA is the most relevant intensity with respect to - ANSWER ✔️ Tissue heating. Bioeffects. Don't fry baby's brain! S.top P.laying, T.hat's not A.lara!
Which intensity is the highest? lowest? - ANSWER ✔️ SPTP=highest, SATA=lowest
Is ultrasound an electromagnetic wave? - ANSWER ✔️ No. X-rays, light, infrared, ultraviolet are electromagnetic.
Hertz (Hz) - ANSWER ✔️ cycles or waves per second, a measurement of frequency
What angle of interrogation produces no (likely) doppler shift - ANSWER ✔️ 90 degrees. (the cosine for 90 is zero)
What is a Transducer - ANSWER ✔️ A device that converts energy from one form to another
What is the wavelength of 3MHz in normal tissue? - ANSWER ✔️ 3MHZ= 0.51 mm 2MHZ = 0.77mm 1MHZ = 1.54mm
wavelength formula - ANSWER ✔️ velocity/frequency
Spatial Pulse Length (SPL) = - ANSWER ✔️ Wavelength x number of cycles in a pulse
Power is proportional to - ANSWER ✔️ amplitude²
intensity = - ANSWER ✔️ power/area
Bandwidth and pulse length relationship is - ANSWER ✔️ Opposite! If pulse length decreases, bandwidth increases and vice versa!
If bandwidth increases, Q factor - ANSWER ✔️ decreases. (And pulse length is decreased- see previous card)
The vertical axis - ANSWER ✔️ y-axis
The speed of red blood cells traveling through a blood vessel is 750 cm/sec. You are asked to measure the speed in miles per hour. What information would be sufficient for you to complete your task? - ANSWER ✔️ How many seconds per hour and the number of miles in a centimeter.
How many nanoseconds are in 7 seconds? - ANSWER ✔️ 7,000,000, Nano means billionth.
Which term is the reciprocal of mega? - ANSWER ✔️ Micro. (Mega means million. The reciprocal of million is millionth. Micro means millionth)
What term is used to describe the effects of an ultrasound wave on living tissues? - ANSWER ✔️ Biological effects
How can the volume of an irregularity shaped object be measured most accurately? - ANSWER ✔️ Immerse it in water
As sound travels through a medium, what term describes the effects of the medium on the sound wave? - ANSWER ✔️ Acoustic propagation properties
Which of the following is TRUE of all waves:
- they travel through a medium
- all carry energy from one site to another
- their amplitudes do not change
- they travel in a straight line - ANSWER ✔️ All carry energy from one site to another
Which of the following types of waves do NOT require a medium in order to propagate? (More than one may apply)
- light
- heat
- sound
- television - ANSWER ✔️ Light, heat & television (sound cannot travel through a vacuum).
Which of the following describes the characteristics of a sound wave:
- longitudinal, non-mechanical
- mechanical, transverse
