SPI Midterm| 100 questions| with complete solutions

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 happens to the intensity? CORRECT ANSWERS: It increases by a factor of 9 Which of the following crystals will produce the highest pulsed-wave frequency pulse? CORRECT ANSWERS: 2 mm thickness What is the half-intensity depth for a 10-MHz transducer in soft tissue? CORRECT ANSWERS: 0.6cm Which of the following best describes a liquid crystal display (LCD)? CORRECT ANSWERS: The image is produced by light shining on liquid crystals sandwiched between two polarized filters. What is the main limitation of pulsed wave Doppler? CORRECT ANSWERS: Aliasing An increase in the amplitude of the transmit voltage will result in ________? CORRECT ANSWERS: an increase in the acoustic power Which part of the transducer contributes most to the decreased sensitivity of a pulsed wave transducer? CORRECT ANSWERS: Backing material Which type of blood flow profile results in the least frictional forces? CORRECT ANSWERS: Plug flow What is an advantage of harmonic imaging? CORRECT ANSWERS: Elimination of grating lobes Why does Poiseuille's law not accurately describe what happens in the body? CORRECT ANSWERS: The heart creates pulsatility in the arteries Which of the following parameters is affected by a change in the transducer frequency? CORRECT ANSWERS: Wavelength