Krem Ch5

Question 1

Autocorrelation

Answer 1

A rapid technique, used in most color Doppler instruments, to obtain mean Doppler-shift frequency.

Question 2

Baseline shift

Answer 2

Movement of the zero Doppler shift frequency or zero flow speeds line up or down on a spectral display.

Question 3

Bernoulli effect

Answer 3

Pressure reduction in a region of high-flow speed

Question 4

Bidirectional

Answer 4

Indicating Doppler instrument capable of distinguishing between positive and negative Doppler shift (approaching and receding flow).

Question 5

Clutter

Answer 5

Noise in the Doppler signal that generally is caused by high amplitude, Doppler-shifted echoes from the heart or vessel walls.

Question 6

Color-Doppler display

Answer 6

The presentation of two dimensional, real time Doppler shift information in color superimposed on a real-time grayscale, anatomic, cross-sectional image. Flow directions toward and away from transducer are presented as different colors on the display.

Question 7

Compliance

Answer 7

Distensibility; non-rigid stretchability a vessels.

Question 8

Continues-wave Doppler

Answer 8

A Doppler device or procedure that uses continuous wave ultrasound.

Question 9

Cosine

Answer 9

The cosine angle A in figure C – 1 is the length of side B divided by the length of side see. Abbreviated COS.

Question 10

Disturbed flow

Answer 10

Flow that cannot be described by straight, parallel streamlines.

Question 11

Doppler angle

Answer 11

The angle between the sound beam and the flow direction.

Question 12

Doppler effect

Answer 12

A change in frequency caused by reflector motion.

Question 13

Doppler equation

Answer 13

The mathematical description of the relationship between Doppler shift, frequency, Doppler angle, propagation speed, and reflector speed.

Question 14

Doppler-power display

Answer 14

Color Doppler display in which colors are assigned according to the strength (amplitude, power, intensity, energy) of the Doppler shifted echoes.

Question 15

Doppler shift

Answer 15

Reflected frequency minus incident frequency; the change in frequency caused by motion.

Question 16

Doppler spectrum

Answer 16

The rate of frequencies present and Doppler shift it echoes.

Question 17

Duplex instrument

Answer 17

And ultrasound instrument that combines grayscale sonography with pulsed Doppler and, possibly, continuous wave Doppler.

Question 18

Eddies

Answer 18

Regions of circular flow patterns present in turbulence.

Question 19

Ensemble length

Answer 19

Number of pulses used to generate one color – Doppler image scan line.

Question 20

Fast Fourier transform

Answer 20

Digital computer inflammation of the Fourier transform.

Question 21

Filter

Answer 21

And electric circuit that passes frequency within a defined range.

Question 22

Flow

Answer 22

To move in a stream; volume flow rate.

Question 23

Fluid

Answer 23

A material that flows and conforms to the shape of its container; a gas or liquid.

Question 24

Frequency spectrum

Answer 24

The range of Doppler shift frequency’s present in the returning echoes.

Question 25

Gate

Answer 25

A device that allows only a goes from a selected depth to pass.

Question 26

Hue

Answer 26

The color precede based on the frequency of light.

Question 27

Inertia

Answer 27

Resistance to acceleration.

Question 28

Laminar flow

Answer 28

Flow in which fluid layers slide over each other in a smooth, orderly manner, with no mixing between layers.

Question 29

Luminance

Answer 29

Brightness of a presented Hue and saturation.

Question 30

Parabolic flow

Answer 30

Laminar flow with a profile in the shape of a parabola.

Question 31

Phase quadrature

Answer 31

Two signals differing by one fourth of a cycle.

Question 32

Plug flow

Answer 32

Flow with all fluid portions traveling with the same flow speed and direction.

Question 33

Poise

Answer 33

Unit of viscosity.

Question 34

Poiseuille equation

Answer 34

The mathematical description of the dependence of Volume flow rate on pressure, vessel length and radius and fluid viscosity.

Question 35

Priority

Answer 35

The gray – scale echo strength below which color – Doppler information is shown preferentially on a display.

Question 36

Pulsatile flow

Answer 36

Flow that accelerates and decelerates with each cardiac cycle.

Question 37

Pulsed Doppler

Answer 37

A Doppler device or procedure that uses pulsed – wave ultrasound.

Question 38

Range gating

Answer 38

Selection of the depth from which echoes are excepted based on echo arrival time.

Question 39

Resistance

Answer 39

Pressure difference divided by volume flow rate for steady flow.

Question 40

Sample volume

Answer 40

The anatomic region from which pulsed Doppler echoes are accepted.

Question 41

Saturation

Answer 41

The amount of hue present in a mix with white.

Question 42

Spectral analysis

Answer 42

Separation of frequencies in a Doppler signal for display as a doubler spectrum; the application of the Fourier transform to determine the frequency components present in a Doppler signal.

Question 43

Spectral broadening

Answer 43

Why didn't of the Doppler shift spectrum; that is, the increase in the range of Doppler shift frequency's present that occurs because of a broad and range of flow velocities encountered by the sound being. This occurs for disturbed and turbulent flow.

Question 44

Spectral-Doppler display

Answer 44

The presentation of Doppler information in a quantitive form of Doppler shift versus time. Visual display of a Doppler spectrum.

Question 45

Spectral analyzer

Answer 45

A device that derives a frequency spectrum from a complex signal.

Question 46

Stenosis

Answer 46

Narrowing of a vessel lumen.

Question 47

Streamline

Answer 47

A line representing the path of motion of a particle of fluid.

Question 48

Turbulence

Answer 48

Random, chaotic, multidirectional flow of a fluid with mixing between layers; flow that is not laminar.

Question 49

Variance

Answer 49

Square of standard deviation; one of the outputs of the auto correction process; a measure of spectral broadening.

Question 50

Viscosity

Answer 50

Resistance of a fluid to flow.

Question 51

Volumetric flow rate

Answer 51

Fiamm of fluid passing a point per unit of time.

Question 52

Wall filter

Answer 52

And electric filter that passes frequencies above a set level and eliminates strong, low-frequency Doppler shift from pulsating heart or vessel walls or tissue motion.

Question 53

Window

Answer 53

An anechoic region appearing the need echo frequencies presented on a Doppler spectral display.