Download ARDMS SPI Study Guide Question And Answers 2025. and more Exams Diagnostics in PDF only on Docsity!
ARDMS SPI Study Guide Question And Answers 2025.
In soft tissue, if the frequency of a wave is increased the Propagation Speed (PS) will... Correct Answer: Remain the Same because stiffness and density affect Propagation Speed. What is the audible range? Correct Answer: 20-20,000Hz
20,000Hz=Ultrasound Frequency is measured in Correct Answer: Hertz (Hz) is Cycles per Second Not affected by sonographer Increase Frequency; Decrease Depth A period is the length of time it takes for Correct Answer: one complete wavelength to pass a fixed point PRP is determined by Correct Answer: Transmit time and receive time. Period is measured in Correct Answer: Time (μs) When the sonographer changes the imaging depth what parameters are changed? Correct Answer: PRP, PRF, Duty Factor
What is duty factor? Correct Answer: The percentage or fraction of time that the system is transmitting a pulse (Time Sound is ON or ON-Time). Propagation Speed in SOFT TISSUE Correct Answer: 1.54 mm/μs (1540 m/sec) Unit of measurement for Pulse Duration, Duty Factor, PRP, and Period Correct Answer: Time, (μs) Pulse duration is determined by Correct Answer: Sound Source Only Pulse Duration is controlled by Correct Answer: the ultrasound system and transducer Pulse Duration Formula Correct Answer: pulse duration (μs) = # cycles in pulse/frequency(MHz) PD= Number of cycles in Pulse/ Frequency(Hz) Spatial Pulse Length (SPL) (measurement) Correct Answer: The distance that a pulse occupies in space from the start to the end of a pulse. (mm) Typical values for spatial pulse length in soft tissue. Correct Answer: 0.1 to 1.0 mm Spatial pulse length is determined by Correct Answer: sound source and medium
↓ Density ↑ Speed An increase in pulse repetition frequency would lead to: Correct Answer: Increasing pulse repetition frequency, increases duty factor. ↑ PRF ↑ Duty Factor Which of the following would have the highest propagation speed? Correct Answer: Bone has the highest propagation speed, at 2000-4000 m/s. What has the lowest propagation speed? Correct Answer: air technically has the lowest propagation speed at 300 m/s Which has the Slowest Propagation Speed? Water Soft Tissue Bone Lung tissue Correct Answer: Lung Tissue As imaging depth increases, the pulse repetition frequency (PRF) must: Correct Answer: Decrease As imaging depth increase, pulse repeition freqency (PRF) decreases. ↑ Imaging Depth ↓ PRF
What describes the amount of refraction that occurs at an interface? Correct Answer: Snell's law Refraction: the redirection of the transmitted sound beam Snell's law describes the angle of transmission at an interface based on the angle of incidence and the propagation speeds of the two media. Pressure is typically expressed in: Correct Answer: Pascals (Pa) The typical range of frequency for diagnostic ultrasound imaging is Correct Answer: 1-20 Mhz is the typical range of frequency for diagnostic ultrasound imaging. The attentuation coefficient in soft tissue is equal to: Correct Answer: Attentuation Coeffcient = 1/2 (one half of the frequency in soft tissue) The attentuation coeffcient (in dB/cm) is the rate at which sound is attentuated per unit depth. Micro is denoted as: Correct Answer: Micro is denoted as millionth (μ) What is described as the distance over which one cycle occurs? Correct Answer: Wavelength is distance over which one cycle occurs, or the distance from the beginning of one cycle to the end of the same cycle. Remember, it asks for distance over which one cycle occurs.
1.5 mm/μs / 5 MHz = 0.3 mm An ultrasound transducer converts Correct Answer: Electrical energy into Mechanical energy and vice versa Lowest attenuation to highest Correct Answer: bone, muscle, fat, air If frequency doubles, what happens to the wavelength? Correct Answer: Wavelength is decreased by 1/ Frequency and Wavelength are: Correct Answer: Inversely related What happens to intensity if the amplitude of a signal is halved? Correct Answer: Amplitude halved will result in intensity quartered amplitude = intensity Ultrasound pulses contain a range of frequencies called Correct Answer: bandwidth How is time related to frequency Correct Answer: inversely What describes the percentage of time that sound is on? Correct Answer: Duty factor is the percentage of time the sound is being transmitted A 3 dB gain would indicate an increase in intensity by: Correct Answer: Two Times
3 dB results in doubling of intensity (or power) The intensity of the ultraosund beam is usually greater at the focal zone because of Correct Answer: the smaller beam diameter Attenuation denotes Correct Answer: Progressive weakening of the sound beam as it travels Which of the following has the lowest intensity Correct Answer: SATA is the lowest of the intensities What is the definition of the beam uniformity ratio? Correct Answer: Beam Uniformity Ratio = Spatial peak / Spatial average Continuous wave Doppler has a duty factor of Correct Answer: 100% CW Doppler is always transmitting sound making it's duty factor 100% The spatial pulse length is defined as: Correct Answer: the product of the wavelength and the number of cycles in a pulse? SPL = wavelength x cycles What term and philosophy relates the amount of exposure time for the sonographer and patient during a diagnostic ultrasound examination? Correct Answer: ALARA
- As Low As Reasonably Achievable
Air > Bone & Lung > Soft Tissue > Water What type of wave is sound? Correct Answer: Mechanical and Longitudinal wave The speed of sound in soft tissue: Correct Answer: 1540 m/s The unit for wavelength: Correct Answer: Distance (mm) Enhancement is caused by: Correct Answer: weakly attenuating structures Lowest attenuating to highest attenuation Correct Answer: Fat-Muscle-Bone-Air List propagation speed from lowest to highest Correct Answer: Air-Fat-Muscle- Bone Which of these media has the lowest attenuation and the greatest speed? bone tendon lung fat air Correct Answer: Bone Air > Bone & Lung > Soft Tissue > Water
Bone is more stiff than air (remember ↑ stiffness, ↑ speed) What describes the physics of refraction mathematically? Correct Answer: Snell's Law What is a reflection arising from a rough boundary? Correct Answer: Non-specular Specular reflection is from a smooth reflector (like mirrors). They return in one direction. Whereas, non-specular is diffuse or scatter, reflection from a rough boundary. When time-of-flight is measured, we can determine the? Correct Answer: Reflector Depth A sound pulse travels from the transducer to location A, reflects off of it, and returns to the transducer in 130 μs. How deep is location A? Correct Answer: Location A is 10 cm from the transducer Total travel distance would be 20 cm Which of the following would be considered the narrowest part of a sound beam? Correct Answer: The focus is the narrowest part of the beam
What would cause an increase in frame rate? Correct Answer: Decreasing the imaging depthwould increase the frame rate When you decrease the imaging depth it can work faster (increase frame rate) because it doesn't have to go as deep. The diameter of the beam in the Fresnel zone/near zone does what? Correct Answer: Decreases Which resolution is best in the clinical imaging? Correct Answer: Axial resolution is best in imaging will increase the near zone length? Correct Answer: A large crystal diameter with high frequency would increase the near zone length What will decrease beam divergence in the far field? Correct Answer: A large crystal diameter and high frequency would decrease the beam divergence in the far field Imaging transducers have Correct Answer: Imaging transducers have low quality factors and wide bandwidiths. What is the speed of a wave with a wavelength of 3 m and a frequency of .1 Hz? Correct Answer: 0.3 m/s wave speed= frequency x wavelength
Wavelength and Frequency are Correct Answer: inversely proportional to each other How do you calculate the speed of a wave given the wavelength and frequency? Correct Answer: Frequency (Hz) x wavelength (distance)= Wave Speed What is the speed of a wave with a frequency of 2 Hz and a wavelength of 87 m? Correct Answer: 174 m/s 2Hz x 87m= 174m/s speed of a wave: frequency x wavelength The of a wave is the number of wavelengths that pass a fixed point in a second. Correct Answer: frequency Frequency is the number of wavelengths that pass a fixed point in a second A sound wave is traveling in the body and propagates from muscle to air. What percentage of the sound wave is most likely reflected at the muscle-air boundary? Correct Answer: 75% Which of the following lists is in decreasing order? Correct Answer: Mega, kilo, deca, milli, nano The conversion of sound energy to heat Correct Answer: Absorption
Compression Correct Answer: An area in the sound wave of high pressure and density Continuous Wave Correct Answer: Sound that is continuously transmitted Damping Correct Answer: The process of reducing the number of cycles of each pulse in order to improve axial resolution Decibels Correct Answer: A unit that establishes a relationship or comparison between two values of power, intensity, or amplitude Density Correct Answer: Mass per unit volume Directly Related Correct Answer: Relationship that implies that if one variable decreases, the other also decreases or if one variable increases, the other also increases; also referred to as Directly Proportional Distance Correct Answer: How far apart objects are AKA vibration or displacement Duty Factor Correct Answer: The percentage of time that sound is actually being produced Elasticity Correct Answer: The ability of a material to bounce back after being disturbed
Frequency (Hz) Correct Answer: The number of cycles per second Half-Intensity Depth Correct Answer: the depth at which sound has lost half of its intensity Half Intensity Depth is also called Correct Answer: Half-Value Layer Thickness Hertz (Hz) Correct Answer: A unit of frequency Hydrophone Correct Answer: a device used to measure the output intensity of the transducer Impedence Correct Answer: the resistance to the propagation of sound through a medium. Inertia Correct Answer: Newton's principle that states that an object at rest stays at rest and an object in motion stays in motion, unless acted on by an outside force. Intensity Correct Answer: the power of a wave divided by the area over which it is spread; the energy per unit area Intensity Reflection Coefficient (IRC) Correct Answer: The percentage of sound reflected at an interface. The percentage of the sounds intensity that is reflected when sound hits a boundary or tissue
What happens to axial resolution with Pulse Wave Doppler Correct Answer: Axial Resolution Degrades when using Pulse Wave Doppler What color is usually used in Color Flow Doppler variance map to indicate turbulent flow? Correct Answer: Green A Doppler (high pass filter) eliminates? Correct Answer: high amplitude signals, low velocity flow The Doppler wall filter is considered a: Correct Answer: High Pass Filter The Nyquist Limit is equal to: Correct Answer: PRF/ Pulse Repetition Frequency divided by two Multiple echoes, equally spaced originating from a gas bubble is called Correct Answer: Ring Down An increase in red blood cell velocity will Doppler Shift: Correct Answer: Increase increase in rbc velocity increases Doppler shift The primary advantage of CW Doppler is: Correct Answer: Absence of Sampling Rate
The range for ultrasound begins: Correct Answer: at 20,000Hz or 20KHz (Useful Frequency Range for Clinical Imaging is 2MHz-10MHz) Which instrument control affects the amplitude (db) of the outgoing signal? Correct Answer: Transmit Gain; Amplitude can be affected by the sonographer What is used to convert Doppler shift information into color? Correct Answer: Autocorrelation What is used to process conventional Doppler shift information but is too slow of a method for Color Doppler? Correct Answer: Fast Fourier transform Pulse Repetition Frequency Correct Answer: The number of pulses that an ultrasound system transmits into the body each second. Unit: Hz. Typically 4-15 KHz. PRF and Depth of View are inversely related. When the system is imaging deeper, the pulse repetition frequency is lower, as well as, the number of pulses created each second. What is the best way to increase the near field length of an ultrasound beam? Correct Answer: Increase Transducer Diameter
