Chapter 19: SPI Study Guide Part 3

The zooming noise from the engine seems to increase in frequency or pitch as the motorcycle approaches and decrease in frequency as the motorcycle departs. The change in frequency is due to the Doppler shift. Doppler shift is also called

• Doppler frequency

• Velocity

• Transducer frequency

• Cosine

The Doppler shift is a low frequency that "rides" on top of the much higher transducer frequency. The process of extracting the low Doppler frequency from the transducers carrier frequency is

• demodulation

• Speed

• Velocity

• Doppler shifts

True or False

Transducer frequencies of 2 MHz to 10 MHz are used to perform clinical Doppler exams

• True

• False

When blood cells move toward the transducer, the reflected frequency is higher than the transmitted frequency. The Doppler shift is

• Positive

• Negative

When blood cells move away from the transducer, the reflected frequency is lower than the transmitted frequency, the Doppler shift is

• Positive

• Negative

True or False

Doppler shifts are created when transmitted sound waves strike moving red blood cells

• True

• False

True or False

Doppler frequencies indicates velocity and speed

• True

• False

Answer explanation

Only velocity

This is purely a magnitude indicates the distance that a red blood cell moves in 1 second.

• Speed

• Velocity

• Demodulation

• Frequency

This is defined by a magnitude and a direction.

• Speed

• Velocity

• Demodulation

• Frequency

True or False

Doppler shift is directly related to the velocity of the blood cells.

• True

• False