SPI Exam Review (Key Terms) questions and answers

13 microsecond rule CORRECT ANSWERS: the rule that states that it takes 13 microseconds for sound to travel 1 cm in soft tissue absorption CORRECT ANSWERS: the conversion of sound energy to heat acoustic cavitation CORRECT ANSWERS: the production of bubbles in a liquid medium acoustic speckle CORRECT ANSWERS: the interference pattern caused by scatterers that produces the granular appearance of tissue on a sonographic image AUIM test object CORRECT ANSWERS: an outdated test object that used an acrylic tank that was filled with fluid; the fluid in this test object attempted to simulate the speed of sound in soft tissue ALARA CORRECT ANSWERS: As Low As Reasonably Achievable; the principle that states one should always use the lowest power and shortest scanning time possible to reduce potential exposure to the patient aliasing CORRECT ANSWERS: the wraparound of the spectral or color Doppler display that occurs when the frequency shift exceeds the Nyquist limit; only occurs with pulsed-wave Doppler A-mode CORRECT ANSWERS: amplitude mode; the height of the spike on the image is related to the strength (amplitude) of the echo generated by the reflector amplification CORRECT ANSWERS: the part of the receiver that increases or decreases the received echoes equally, regardless of depth amplitude CORRECT ANSWERS: the maximum or minimum deviation of an acoustic variable from the average value of that variable; the strength of the reflector analog-to-digital (A-to-D) converter CORRECT ANSWERS: the part of the digital scan converter that converts the analog signals from the receiver to binary for processing by the computer anechoic CORRECT ANSWERS: without echoes, or black angle correct CORRECT ANSWERS: the tool used to inform the machine what the flow angle is so that velocities can be accurately calculated aperture CORRECT ANSWERS: the diameter of the piezoelectric element(s) producing the beam