SPI

What is the main disadvantage of continuous wave (Pedof) transducers? CORRECT ANSWERS: Depth ambiguity What function of the receiver is responsible for the rectification and smoothing? CORRECT ANSWERS: Demodulation What is the purpose of a transmit/receive (T/R) switch? CORRECT ANSWERS: It ensures that the pulser voltages go to the transducer, and the received voltages from the transducer go to the signal processor. If the amplitude of a wave is increased by a factor of 3, what happe...

Which of the following is used to eliminate the low-frequency signals that appear as noise as a result of wall/valve motion? A. High-pass filter B. Bass-thump filter C. Low-pass filter D. High-frequency filter CORRECT ANSWERS: A. High-pass filter AKA wall filter AKA wall-thump filter According to Poiseuille, the most significant contributor to flow is: A. Length of vessel B. Viscosity C. Radius D. Pressure CORRECT ANSWERS: C. Radius *Poiseuille's Law Volume flow rate = π(pres...

Electronic pulses from the pulser are applied to the CORRECT ANSWERS: Transducer Which of the following is performed by the receiver CORRECT ANSWERS: Amplification, compensation, compression, demodulation The dynamic range of ultrasound system is defined as CORRECT ANSWERS: The ratio of the maximum to the minimum intensity that can be displayed How is Q (quality factor) of a transducer determined CORRECT ANSWERS: Frequency divided by bandwidth The most commonly used man-made crys...

Absorption CORRECT ANSWERS: The conversion of sound energy to heat Acoustic speckle CORRECT ANSWERS: The interference pattern caused by scatters and produces the granular appearance of tissue on a sonographic image Amplitude CORRECT ANSWERS: The maximum or minimum deviation of an acoustic variable from the average value of that variable; the strength of the reflector Attenuation CORRECT ANSWERS: A decrease in the amplitude, power, and intensity of the sound beam as sound travels thr...

1. The term Anechoic in relation to a sonographic image means? A. structure that appears lighter than the surrounding structures B. The absence of echos C. A structure that appears the same as surrounding structures D. A structure that reflects 100% of the sound wave CORRECT ANSWERS: B. The absence of echos Question 1 Explanation: An (without) echoic (producing echoes) 2. If you have two near identical systems with different diameter piezoelectric crystals in the transducer which syst...

When sound hits a boundary between two media of the same propagation speed at oblique incidence: CORRECT ANSWERS: no refraction will occur. Refraction requires the oblique incidence of sound across a boundary between two media with different propagation speeds. As transducer frequency increases: CORRECT ANSWERS: axial and lateral resolution will increase Blood flow volume changes in the body are mainly controlled by what two factors? CORRECT ANSWERS: cardiac function and peripheral r...

frequency and period CORRECT ANSWERS: inverse stiffness and propagation speed CORRECT ANSWERS: direct density and propagation speed CORRECT ANSWERS: inverse frequency and wavelength CORRECT ANSWERS: inverse power and amplitude CORRECT ANSWERS: direct proportional to amplitude squared CORRECT ANSWERS: intensity and power CORRECT ANSWERS: direct intensity and area CORRECT ANSWERS: inverse intensity and amplitude CORRECT ANSWERS: direct proportional to amplitude...

The doppler effect is observed as a change in ________ and has units of _________. CORRECT ANSWERS: Frequence, per second In clinical imaging, which reflectors produce most relevant Doppler shifts? CORRECT ANSWERS: Red blood cells If red blood cells are traveling TOWARD a trasducer, the F emitted by the transducer is _______ the frequency reflected from the red blood cells. CORRECT ANSWERS: Less than What is the range of Doppler shifts commonly measure in clinical exams? CORRECT ANS...

All of the following are AIUM recommendations regarding the use of ultrasound, except: A. Always adhere to the ALARA principle when scanning B. Limit the examination time to the shortest time necessary to complete a diagnostic exam C. In order to limit ultrasound intensity, always use PW Doppler instead of M-mode to evaluate the fetal heart D. Limit ultrasound exposure to patients that require an examination for a specific reason CORRECT ANSWERS: C. In order to limit ultrasound intensity, ...

What is described as the ability of an object to resist compression and relates to the hardness of a medium? CORRECT ANSWERS: stiffness An increase in PRF would lead to CORRECT ANSWERS: an increase in DF what has the higher propagation speed? air, bone, soft tissue or water CORRECT ANSWERS: bone what has a lower propagation speed? water, soft tissue, bone or lung tissue CORRECT ANSWERS: lung tissue as imaging depth increases, the PRF must CORRECT ANSWERS: decrease what law de...