ARDMS SPI Study Guide Questions and Answers 2023

ARDMS SPI Study Guide Questions and Answers 2023 One reason why focused beams with low intensities are less likely to cause bioeffects is that a focused beam is less efficient in heating a large mass of tissue to a critical temperature. True Typically, the sonographer can adjust the compression function of a receiver. True Mean frequency is calculated from weighted sum of frequencies in the power spectrum. True Refraction always occurs at the interface between two media when the propagation speeds of the media are unequal? False - 1. oblique incidence 2. unequal propagation speed The shorter the pulse length the better the picture quality. True The synchronous signal processing in angiodynorgraphy uses a Doppler carrier frequency that is the same as the imaging center operating frequency. True The period of the wave is inversely proportional to the wavelength. False - Reciprocal Changes in the pre processing controls will not affect the numbers stored in the scan converter. False Videotape recorders operating at 30 frames per second cannot be used with mechanical real-time units because the frame rate is too slow False - depends on imaging rate The pulsed- Doppler system yields better depth resolution than the continuous wave system. True Cardiac color flow imaging also works well in the vascular system because the design can handle the high attenuation rates in cardiac imaging. False The sonographer can make an image of uniform brightness by adjusting both output power and receiver gain. False - This is the function of the Time Gain Compensation (TGC) No refraction can occur at an interface if the media impedances are equal False - Refraction= prop speed in medium Reflection and transmission=Z The frame rate of real-time scanners depends on the number of lines used to form one image True Mean frequency corresponds to the fastest moving RBCs within the sample volume at the time of measurement. False Levels of output power and intensity for color flow imaging are generally higher than those for gray-scale imaging. True Linear phased array scanners need no form of mechanical focusing since focusing is performed in electronically. False - slice thickness requires mechanical focusing Filtering widens bandwidth. False Quality assurance evaluations of ultrasound systems should be performed weekly. False - routinely The near zone length should be kept as short as possible False Transit time broadening is a limitation of the FFT processing. True Color Doppler systems are not subject to aliasing. False The pulsed-echo system, the Q factor should be made as large as possible False Length of time that the sound persist Low Q = low SPL= good LARD To transfer sound through a medium, the affected molecules move from one end of the medium to the other. False - microns only The beam diameter is constant in the near zone False - waist The pulse-echo system should have a high Q factor. False. Q factor = length of time sound persists. Optimal low Q factor = short pulse length. Transducers with high bandwidth and low Q factor are desirable. It is not possible to steer an annular phased array electronically. True The period of an ultrasound wave is related to the frequency and is the same regardless whether the wave is pulse or continuous. True Non specular reflectors have physical dimension that are greater than the wavelength. False - they are smaller The color coding of red arteries and blue veins and slow high-resolution frame rates make the identity of arteries and veins in the abdomen direct and easy False abdomen= broad FOV pulse check Focused ultrasound are considered less likely to create bioeffects because they will strike fewer gas bubbles that could potentially cavitate. True A videotape recorder records at a rate of 30 frames/s and therefore cannot be used to record images from a mechanical scanner operating at lower frame rates. False Quality assurance measurements are not required with electronic scanners with digital scan converters False Color flow imaging is unique because it does not have a major problem with high frequency aliasing. False - Color flow imaging is a PW Doppler technique which is also subject to aliasing Interface is the surface forming the boundary between two media having different acoustic impedances. True Asynchronous signal processing in color flow imaging requires the same frequency for both Doppler and gray-scale imaging. False The Doppler angle is not considered in the calculation of velocity in color Doppler imaging False Power spectrum displays a plot of magnitude of individual frequency components versus frequency that converts the complex Doppler signal from time domain into the frequency domain. True Because Doppler signal processing requires more energy, synchronous signal processing always produces Doppler power levels that are higher than those for gray scale imaging. False - synchronous = common transmitter The appearance of negative velocities in a pulsed Doppler display always indicates that red blood cells are moving away from the transducer. False aliasing may occur Side lobe, grating lobe and refraction artifacts all reduce lateral resolution. True