ARDMS SPI Exam 2022/2023 with complete solutions

Which gain will increase the risk of bioeffects? a. transmit b. receive c. gain d. overall gain - ANSWER a. transmit Which of the following is considered the memory of an ultrasound instrument? a. pulser b. transducer c. receiver d. beam former e. digital scan converter f. display monitor - ANSWER e. digital scan converter Spectral broadening suggest: a. laminar flow b. turbulent flow c. flow away from the transducer d. flow towards the transducer - ANSWER b. turbulent flow With pulse wave Doppler axial resolution: - ANSWER degrades What color is usually use in color flow Doppler variance map to indicate turbulent flow? - ANSWER green Doppler high pass filter eliminates: - ANSWER high amplitude signals; low velocity flow The Doppler wall filter is considered a: - ANSWER high pass filter The Nyquist Limit is equal to: a. propagation speed x frequency b. propagation speed/ wavelength c. PRF/2 d. 4xV^2 - ANSWER c. PRF/2 Multiple echoes, equally spaced originating from a gas bubble is called: a. comet tail b. ring down c. slice thickness artifact d. multipath - ANSWER b. ring down An increase in red blood cell velocity will_____ the Doppler Shift: a. increase b. decrease c. not change d. cannot be predicted - ANSWER a. increase The primary advantage of CW Doppler is: a. range resolution b. range discrimination c. range ambiguity d. range gating e. absence of sampling rate - ANSWER e. absence of sampling rate The range for ultrasound begins: a. 20 Hz b. 20,000 Hz c. 2 MHz d. 15 MHz - ANSWER b. 20,000 Hz (useful frequency range for clinical imaging is 2MHz-10MHz) Which instrument control affects the amplitude (dB) of the outgoing signal: a. gain b. receiver gain c. TGC d. transmit gain e. overall gain - ANSWER d. transmit gain; amplitude can be affected by the sonographer Which of the following is used to convert Doppler shift information into color: a. high PRF b. fast Fourier transform c. autocorrelation d. time interval histogram - ANSWER c. autocorrelation b is incorrect because fast Fourier transform is the method used to process conventional Doppler shift information but is too slow a method for color Doppler Pulse repetition frequency - ANSWER Number of pulses that an ultrasound system transmits into the body each second. Hz. Typically 4-15 KHz. PRF and depth of a view are inversely related: When system is imaging deeper, the pulse repetition frequency is lower. Also the number of pulses created each second The best way to increase the near field length of an ultrasound beam is to: - ANSWER increase transducer diameter The range of frequencies produced by a damped PZT element is called: a. fundamental frequencies b. Q Factor c. near field d. bandwith - ANSWER d. bandwidth The percentage of time that the ultrasound instrument is emitting ultrasound is called: a. PRF b. pulse duration c. pulse repetition period d. duty factor - ANSWER d. duty factor; the maximum value is 1, the minimum is 0 The unit of duty factor is: a. Hz b. mm c. ms d. unitless - ANSWER d. unitless Quality Factor= Fundamental frequency/ bandwidth - ANSWER This allows doses of different types of radiation to be compared for their biological effects. Clinical imaging transducers are: - ANSWER wide bandwidth; low q factor Power/area= - ANSWER Intensity Increasing wavelength will ___________ frequency. a. increase b. decrease c. not change d. cannot be predicted. - ANSWER b. decrease All of the following directly affect frame rate except: a. depth of penetration b. field of view c. number of focuses d. line density e. beam width - ANSWER e. beam width A reflection will occur at the boundary of two media if the acoustic impedences of the two media are: a. equal b. different c. unchanged d. cannot be predicted - ANSWER b. different A mechanical transducer utilizes: a. transmit focus b. receive focus c. fixed focus d. dynamic aperture focusing - ANSWER c. fixed focus; sonographer cannot determine the location of # of foci. mechanical transducer uses cross sectional imaging, rotating wheel, wobbler, oscillating mirror The transducer frequency is primarily determined by the transducer element: a. diameter b. thickness c. propagation speed d. type - ANSWER b. thickness A strongly focused transducer implies a: a. short focal length; decreased beam divergence b. medium focal length; increased beam divergence c. long focal length; no beam divergenc d. short focal length; increased beam divergence - ANSWER d. short focal length; increased beam divergence B-mode displays reflector: a. amplitude and distance b. amplitude and velocity c. power and direction d. depth and speed - ANSWER a. amplitude and distance An increase in the number of pixels on the display will improve: - ANSWER detail resolution Propagation speed is determined by: a. frequency b. harmonics c. bandwidth d. bulk modulus - ANSWER d. bulk modulus Increasing transmit gain increases everything except: - ANSWER frequency The correct depth placement of reflectors depends primarily upon: a. frequency b. period c. power d. propagation speed - ANSWER d. propagation speed Which of the following will increase the color flow jet area displayed? a. increase color gain b. increase velocity scale c. increase frequency - ANSWER a. increase color gain Increasing propagation speed: - ANSWER air, soft tissue, bone The most common type of transducer used in echo is: - ANSWER sector phased array Decibels are the units for all of the following except: a. amplitude b. transmit gain c. gain d. attenuation e. TGC f. dynamic range e. intensity - ANSWER e. intensity= mW/cm2 What are the four acoustic variables: - ANSWER 1. temperature, density, particle motion, pressure Frequency is - ANSWER Cycles per second (Hz) not affected by sonographer increase frequency; decrease depth Pulse duration - ANSWER period (ms) x # of cycles in a pulse Wavelength - ANSWER the length of one cycle wavelength= propagation speed/ frequency 1.54/3MHz= .5mm An increase in packet size will _______ the frame rate - ANSWER Decrease The range for audible sound is: - ANSWER 20 Hz- 20kHz The wavelength of a 1MHz transducer is: - ANSWER 1.54/1= 1.54mm The average speed of sound in soft tissue is: - ANSWER 1540m/s; 1.54km/s; 1.54mm/us An increase in overall gain will result in all of the following except: a. increase in image brightness b. increase in output power c. increase in amplification of the returning signal d. decrease risk in bioeffects - ANSWER b. increase in power Reject eliminates: - ANSWER low amplitude signals There have been no proven biological effects for unfocused transducers for intensities below: - ANSWER 100mW/cm2 SPTA The primary cause of attenuation of ultrasound in soft tissue is caused by: - ANSWER absorption Resolution artifact - ANSWER When two structures parallel to the ultrasound beam are displayed as one reflector. Damping does not decrease: - ANSWER bandwidth Spectral Broadening - ANSWER The widening of the doppler shift spectrum. Meaning the increase of the range of doppler shift frequencies present, owing to a broader range of flow speeds encountered by the sound beam. Refraction - ANSWER Change in direction of a wave when it changs speed as in travels from one material to another. The change in the direction of sound as it crosses a boundary. autocorrelation - ANSWER used to convert Doppler shift information into color. PRF - ANSWER Pulse Repetition Frequency. The rate at which pulses are transmitted, given in hertz or pulses per second; reciprocal of pulse-repetition time. Period - ANSWER the time per cycle 1-10usec Period Calculation - ANSWER 1/frequency 1/5MHz= .2 How do you decrease period? - ANSWER Increase frequency Impedance - ANSWER the opposition of sound propagation The unit for impedance? - ANSWER Rayls