ARDMS SPI Exam.docx

Which gain will increase the risk of bioeffects? a. transmit b. receive c. gain d. overall gain - 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 - e. digital scan converter Spectral broadening suggest: a. laminar flow b. turbulent flow c. flow away from the transducer d. flow towards the transducer - b. turbulent flow With pulse wave Doppler axial resolution: - degrades What color is usually use in color flow Doppler variance map to indicate turbulent flow? - green Doppler high pass filter eliminates: - high amplitude signals; low velocity flow The Doppler wall filter is considered a: - high pass filter The Nyquist Limit is equal to: a. propagation speed x frequency b. propagation speed/ wavelength c. PRF/2 d. 4xV^2 - 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 - 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 - 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 - e. absence of sampling rate The range for ultrasound begins: a. 20 Hz b. 20,000 Hz c. 2 MHz d. 15 MHz - 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 - 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 - 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 - 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: - 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 - 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 - 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 - d. unitless Quality Factor= Fundamental frequency/ bandwidth - This allows doses of different types of radiation to be compared for their biological effects. Clinical imaging transducers are: - wide bandwidth; low q factor