ARDMS Exam 69 Questions with Verified Answers,100% CORRECT

ARDMS Exam 69 Questions with Verified Answers Tendonitis of the thumb - CORRECT ANSWER de Quervain's disease - Gripping of transducer What is trigger finger? - CORRECT ANSWER inflammation of tendon sheath in the ...

ARDMS Exam 69 Questions with Verified Answers Tendonitis of the thumb - CORRECT ANSWER de Quervain's disease - Gripping of transducer What is trigger finger? - CORRECT ANSWER inflammation of tendon sheath in the finger due to repeated gripping of the transducer What does the FDA do for ultrasound? - CORRECT ANSWER Regulates instruments according to application, output intensities, and TI/MI What does the AIUM recommend for ultrasound? - CORRECT ANSWER Prudent use of US in clinical environment by minimizing exposure time and output power What US mode has the highest intensity? - CORRECT ANSWER PW doppler - PW > CW doppler What is Temporal average? - CORRECT ANSWER Average intensity during both the transmitting and receiving times (PRP) What is pulse average? - CORRECT ANSWER Average intensity over the entire duration of the pulse (PD) Why is biological effects lower in unfocused transducers compared to focused transducers? - CORRECT ANSWER Unfocused has a larger beam area --> less focused energy What is the maximum exposure seen with no biological effects in 1) unfocused and 2) focused - CORRECT ANSWER 1) Unfocused - 100 mW/cm2 2) Focused - 1W/cm2 What is stable cavitation? - CORRECT ANSWER microbubbles already present in the media expand and contract via pressure from the wave What is transient cavitation and at what intensity - CORRECT ANSWER Bubbles expand and collapse violently - Pulses with intensity greater than 3300W/cm2 (10MPa) can induce it How does frequency relate to MI and TI? - CORRECT ANSWER MI: Lowers MI TI: Raises TI What is duty factor? - CORRECT ANSWER Fraction of time that pulse US is on PD/PRP What is fractional bandwidth? - CORRECT ANSWER Bandwidth/operation frequency What is a half value layer? - CORRECT ANSWER thickness of tissue required to reduce intensity by 1/2 - Known as depth of penetration/half boundary layer, or penetration depth how are harmonic frequencies produced? - CORRECT ANSWER Non-linear interaction as the beam goes through tissue - Not produced on reflections How does harmonic frequency affect our resolution 3 - CORRECT ANSWER - Improves spatial by decreasing AR - Improves contrast resolution - Improves lateral resolution by having a narrower beam (reduces side lobes) How to calculate half value layer? - CORRECT ANSWER 6/frequency or 3/attenuation coefficient How is apodization achieved? - CORRECT ANSWER Nonuniform excitation/driving of elements in an array - Reduces grating lobes What is the aperture? - CORRECT ANSWER Size of transducer elements What does dynamic aperture do overall? - CORRECT ANSWER Minimizes change in the width of the sound beam What is the thickness of the piezeoelectric element related to? - CORRECT ANSWER Thickness is equal to half of the wavelength How does the damping/backing layer help US? 2 - CORRECT ANSWER - Improves axial resolution - Increases bandwidth What is the thickness of the matching layer? - CORRECT ANSWER 1/4 wavelength thick What does NFL depend on? - CORRECT ANSWER - Diameter of element - Frequency FL = D^2 x f / 6 = D^2/(4wavelength) 3 ways to increase contrast resolution - CORRECT ANSWER - Increase compression (DR) - Increase frequency - Decrease beam width What is penetration depth limited by? 2 - CORRECT ANSWER - Propagation speed of medium - Attenuation What is directly related to FOV? - CORRECT ANSWER PRF What is coded excitation? - CORRECT ANSWER Uses a series of pulses and gaps rather than a single driving pulse Where does coded excitation occur? - CORRECT ANSWER In the pulser How does coded excitation help? - CORRECT ANSWER Improves contrast/spatial/axial resolution What two features is code excitation responsible for? - CORRECT ANSWER - Multifocal - Harmonics How does harmonics improve contrast? - CORRECT ANSWER Decreases noise - SNR What are channels - CORRECT ANSWER - Individual signal paths for transmission and reception of the sound beam - equal to number of elements What does the master synchronizer do? - CORRECT ANSWER maintains and organizes the proper timing and interaction of the system's components What does the pulser determine? - CORRECT ANSWER - PRF - PRP - Pulse amplitude How to adjust amplification of the receiver? - CORRECT ANSWER Overall gain setting What is the knee of the TGC curve? - CORRECT ANSWER Deepest region attenuation compensation can occur How does rejection of the receiver improve the image? - CORRECT ANSWER Decreases acoustic noise What is B color and what is its benefit - CORRECT ANSWER Presentation of different echo intensities in various colors - Improves contrast resolution What is a voxel? - CORRECT ANSWER 3D pixel What is another name for PACS? - CORRECT ANSWER DIN/IMACS What does the ACR do? - CORRECT ANSWER Develops standards for encoding patient file information and interpretation What does DICOM do? - CORRECT ANSWER Standardizes protocols for communicating image systems What does NEMA do? - CORRECT ANSWER Develops standards for encoding patient file information and intepretation What is a speckle? - CORRECT ANSWER Echoes from the distribution of scatterers in ta tissue How much resistance does arterioles account for? - CORRECT ANSWER 1/2 of total resistance in the systemic system What is the Bernoulli effect? - CORRECT ANSWER Describes pressure and velocity through a cylinder/vessel What is duplex imaging? - CORRECT ANSWER simultaneous anatomic imaging and doppler What technique does CDI use to obtain doppler shift frequencies? - CORRECT ANSWER autocorrelation How many pulses used for color information in CDI? - CORRECT ANSWER 3-32 How many doppler samples per scan line in CDI? - CORRECT ANSWER 100-400 3 ways to get rid of flash artifacts - CORRECT ANSWER 1. Increase PRF 2. Decrease color gain 3. Increase filtering of low flow velocities What is operation testing? - CORRECT ANSWER Evaluates the US system as a diagnostic tool - Includes entire ultrasound instrument What components does acoustic output testing involve? - CORRECT ANSWER Only the pulser and transducer What is an AIUM 100 test object? - CORRECT ANSWER A device without tissue properties that can measure system performance What can't the AIUM 100 test object evaluate? 3 - CORRECT ANSWER 1. Gray scale 2. Compression 3. Penetration What does a beam profiler do? - CORRECT ANSWER Plots 3D reflection amplitudes received by the transducer How does stiffness affect the speed of sound? - CORRECT ANSWER Increased stiffness = increased c What does acoustic impedance depend on? - CORRECT ANSWER Density and speed of sound Construction probes 3 - CORRECT ANSWER - linear - convex - annular Operation probes 3 - CORRECT ANSWER - sequenced - phased - vector How does color threshold decrease noise? - CORRECT ANSWER Suppresses low echoes What causes noise in doppler? - CORRECT ANSWER - clutter due to high amplitude of doppler frequency What is a packet? - CORRECT ANSWER Multiple sample gates position in CDI How to get rid of mirror effect in doppler? 2 - CORRECT ANSWER - Turn down doppler gain - Changing angle What causes noise/clutter? - CORRECT ANSWER High amplitudes What is the delay portion of the TGC curve? - CORRECT ANSWER Where compensation begins to occur What causes diastolic flow reversal? - CORRECT ANSWER High R distally