Harmonic Imaging

Question 1

Where are harmonics generated?

Answer 1

The tissue

Question 2

Harmonic imaging is a form of?

Answer 2

Signal filtering

Question 3

What echoes are accepted in harmonics?

Answer 3

The second harmonic frequency

Question 4

Where is the bandpass filter located?

Answer 4

Centered at the second harmonic frequency

Question 5

In what portion of the beam are harmonics generated?

Answer 5

The highest-intensity portion

Question 6

T or F? The harmonic beam is more narrow

Answer 6

TRUE

Question 7

What type of resolution is improved by harmonics having a more narrow beam?

Answer 7

Lateral resolution

Question 8

What artifact is eliminated with harmonics?

Answer 8

Grating lobes

Question 9

How is axial resolution improved in harmonics?

Answer 9

Pulse-inversion technique (The second pulse is the inverse of the first pulse)

Question 10

What is reduced with harmonics?

Answer 10

FR

Question 11

What resolution is degraded in harmonics?

Answer 11

Temporal resolution due to a lower frame rate

Question 12

What ratio is improved with harmonics?

Answer 12

Signal:Noise due to filtering out more signals

Question 13

When are harmonics beneficial clinically?

Answer 13

1. Obese patients
2. Hollow, cystic structures
3. Deep seated major vessels

Question 14

What is a disadvantage of harmonics?

Answer 14

Reduced penetration depth

Question 15

Function of the bandpass filter

Answer 15

Only allow for specific range of frequencies to pass through the transducer

Question 16

How are grating lobes eliminated in harmonic imaging?

Answer 16

They do not have strong enough echoes to pass through