Which gain will increase the risk of bioeffects? a. transmit b. receive c. gain d. overall gain - answera. 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 - answere. digital scan converter Spectral broadening suggest: a. laminar flow b. turbulent flow c. flow away from the transducer d. flow towards the transducer - answerb. turbulent flow With pulse wave Doppler axial resolution: - answerdegrades What color is usually use in color flow Doppler variance map to indicate turbulent flow? - answergreen Doppler high pass filter eliminates: - answerhigh amplitude signals; low velocity flow The Doppler wall filter is considered a: - answerhigh pass filter The Nyquist Limit is equal to: a. propagation speed x frequency b. propagation speed/ wavelength c. PRF/2 d. 4xV^2 - answerc. 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 - answerb. ring down An increase in red blood cell velocity will_____ the Doppler Shift: a. increase b. decrease c. not change d. cannot be predicted - answera. 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 - answere. absence of sampling rate The range for ultrasound begins: a. 20 Hz b. 20,000 Hz c. 2 MHz d. 15 MHz - answerb. 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 - answerd. 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 - answerc. 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 - answerNumber 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