Physics Lcc Ultrasound Ch.19-21

Front 1

Portions of an image that are brighter than surrounding tissues, or tissues that appear brighter than normal

Back 1

HYPERECHOIC

Front 2

W/O echoes, echo free

Back 2

ANECHOIC

Front 3

Describes structures with equal echo brightness

Back 3

ISOECHOIC

Front 4

A portion of tissue or a structure that has similar echo characteristics throughout

Back 4

HOMOGENOUS

Front 5

Displaying a variety of different echo characteristic w/in the tissue

Back 5

HETEROGENOUS

Front 6

Multiple echoes appearing on the display as a result of US "ping-ponging" b/w 2 refletors. Looks like a ladder or a venetian blind

Back 6

REVERBERATIONS

Front 7

Appears as a solid line direted downward, merged reverberation

Back 7

COMET TAIL OR RING DOWN

Front 8

There are occasions when the US beam is unable to pass through a structure b/c the structure has a higher than usual attenuation

Back 8

SHADOWING

Front 9

Refraction at the edge of a circular structure can also create an artifact.

Back 9

SHADOWING BY REFRACTION OR EDGE SHADOW

Front 10

Pccurs when the medium through which the sound travels has a lower attenuation rate than soft tissue.

Back 10

Enhancement (hyperechoic)

Front 11

Sound may bounce off a strong reflecto,called a mirror, in its path and be redirected

Back 11

MIRROR IMAGE

Front 12

Second copy of a reflector (extra reflections on the scan)

Back 12

MIRROR IMAGE

Front 13

Speed errors appear as a step-off,split or cut

Back 13

PROPAGATION SPEED ERRORS

Front 14

Sound changes direction striking a boundary

Back 14

REFRACTION ARTIFACT

Front 15

Refractin artifact degrades lateral resolution

Back 15

Refractin artifact degrades lateral resolution

Front 16

Mechanical or single crystal transducers create?

Back 16

SIDE LOBES

Front 17

Arrays create?

Back 17

GRATING LOBES

Front 18

Grating lobes artifact can be reduced or cured by dividing each element into even smaller miniature pieces

Back 18

SUBDICING

Front 19

Lobe artifact degrades lateral resolution

Back 19

Lobe artifact degrades lateral resolution

Front 20

Slice thickness artifact occurs when beam has a greater width than the reflector.

Back 20

ELEVATIONAL RESOLUTION

Front 21

Grainy aapearance not directly from reflections from tissues in the shallow part of the image

Back 21

SPECKLE

Front 22

Caused when very deep reflections arrive at transducer after the next pulse was created

Back 22

RANGE AMBIGUITY ARTIFACT

Front 23

System thinks reflection ame from 2nd pulse

Back 23

RANGE AMBIGUITY ARTIFACT

Front 24

Cured by lowering the PRF because the PRF is too high

Back 24

RANGE AMBIGUITY ARTIFACT

Front 25

Low velocity motion from pulsating vessel walls can also produce small Doppler shifts that 'bleed' into surrounding anatomy

Back 25

Doppler artifacts-GHOSTING

Front 26

The wall filter determines wheter low velocity flows are displayed

Back 26

The wall filter determines wheter low velocity flows are displayed

Front 27

Found in Doppler only

Back 27

CROSS TALK

Front 28

Special form of 'mirror image' where the Dppler spectrum appears above and below the baseline

Back 28

CROSS TALK

Front 29

The routine periodic evaluation of the US system to guarantee optimal image quality

Back 29

QUALITY ASSURANCE

Front 30

Propagation speed of soft tissue

Back 30

1,540 m/s

Front 31

Does not have attenuation properties of soft tissue, cannot evaluate gray scale

Back 31

AIUM 100 MM TEST OBJECT

Front 32

Used to assess the accuracy of pulsed, continuous wave and color flow systems.

Back 32

DOPPLER PHANTOM

Front 33

Vibrating string and moving belt phantoms may be used to evaluate doppler systems

Back 33

DOPPLER PHANTOM

Front 34

The depth at which the intensity is the highest and the beam is the narrowest. From the top of the AIUM test object scan pin set labled C

Back 34

FOCAL ZONE

Front 35

A small needle with a piezoelectric crystal at its end. The needle is placed in the ultrasound beam. It attaches to an oscilloscope and displays acoustics signals received by the crystal.

Back 35

HYDROPHONE

Front 36

A transducer which turns acoustic energy into heat.

Back 36

CALORIMETER

Front 37

living

Back 37

IN VIVO

Front 38

nonliving

Back 38

IN VITRO (means in glass)

Front 39

The science of identifying and measuring those characteristics of an US field which are especially relevant to is potential for producing biological effects

Back 39

DOSIMETRY

Front 40

Regulates system and transducer outputs

Back 40

FDA

Front 41

Bioeffects intensity limit

Back 41

SPTA

Front 42

100 mW/cm2 unfocused

Back 42

BIOEFFECTS INTENSITY LIMIT

Front 43

Difficult to study in vivo (in living tissue) due to_____

Back 43

absorption, scattering, reflection

Front 44

Highest output intensities are used with

Back 44

PULSED DOPPLER

Front 45

Lowest output intensities are with

Back 45

GRAY SCALE IMAGING

Front 46

Temperature elevation via absorption resulting from interaction of biologic tissue and US

Back 46

THERMAL MECHANISM

Front 47

Any exam that causes an elevation in temp. of less than __ may be used w/o reservation.

Back 47

2 degrees C

Front 48

Any exam that causes a temp elevation to greater than ___ is considered potenitally harmful to a fetus

Back 48

41 degree C

Front 49

The ____ is a number proposed in the most recent AIUM guidelines that relates to tissue heating.

Back 49

THERMAL INDEX

Front 50

Fetal soft tissues adjacent to bone are of great concern b/c elevation in temp is potenitally harmful.

Back 50

Fetal soft tissues adjacent to bone are of great concern b/c elevation in temp is potenitally harmful.

Front 51

____are less likely to cause temperature elevation in tissues

Back 51

FOCUSED BEAMS

Front 52

If no info is provided on whether a sound beam is focused or unfocused, choose the ____ intensity limit (for unfocused beams, 1oo mW/cm2) as it is safe under all conditions of focusing

Back 52

LOWER

Front 53

This takes the form of shrinking and expanding of the bubble.

Back 53

GASEOUS NUCLEI

Front 54

Mechanical index is higher (more likely to produce cavitation) with

Back 54

1) PEAK RAREFACTION PRESSURE
2) LOWER FQ

Front 55

Microbubbles get __ during rarefactions.

Back 55

BIGGER

Front 56

This expansion shears bubble apart and creates ____

Back 56

CAVITATION

Front 57

_____ is more likely to ocur in lung than other tissues

Back 57

CAVITATION

Front 58

Bubbles tend to oscillate when exposed to acoustic waves of small amplitude. Bubbles do not burst.

Back 58

STABLE CAVITATION

Front 59

Bubbles expand during rarefactions and the bubbles BURST. dEPENDS ON THE PRESSURE OF ULTRASOUND PULSES (MPa)

Back 59

TRANSIENT CAVITATION

Front 60

Hghly localized violent effects

Back 60

TRANSIENT CAVITATION