Sem 2 Exam Ques

Question 1

What is homogeneity defined as?

Answer 1

Uniform tissue texture

Homogeneity refers to the consistency in the texture of tissue in imaging.

Question 2

What does anechoic mean?

Answer 2

No echogenicity

Anechoic describes areas in ultrasound that do not produce echoes.

Question 3

What occurs with a higher transmit frequency in ultrasound imaging?

Answer 3

Finer speckled pattern

Higher frequencies can enhance the resolution of the image.

Question 4

What is the effect of a boundary between two mediums with similar acoustic impedances?

Answer 4

Very little reflection

This occurs when the impedances are close, such as 4 Mrayls and 4.1 Mrayls.

Question 5

Is PW Doppler considered a scanned modality?

Answer 5

No

PW Doppler operates differently from scanned modalities.

Question 6

If duty factor increases, what also increases?

Answer 6

Pulse repetition period

A higher duty factor indicates more time spent transmitting.

Question 7

What generally limits the maximum power in non-skin modalities?

Answer 7

Risk of thermal bio effects

This is a crucial safety concern in ultrasound applications.

Question 8

What are the non-scanned modalities of ultrasound?

Answer 8

• CW
• PW
• A mode
• M mode

These modalities do not scan in a traditional sense.

Question 9

What is the sampling rate in ultrasound?

Answer 9

The frequency at which signals are detected or assessed

It is crucial for accurate signal processing.

Question 10

What is frame time?

Answer 10

The time required to transmit and receive the required number of beams

This affects how quickly an image can be generated.

Question 11

What is an acoustic beam?

Answer 11

A single transmit event in a specific direction and the associated echoes

This is fundamental in ultrasound imaging.

Question 12

What is frame rate?

Answer 12

The reciprocal of the frame time

Higher frame rates lead to smoother images.

Question 13

What does a display line represent?

Answer 13

Data displayed on the screen that corresponds to a single direction within the patient

This is important for visualizing specific structures.

Question 14

What is pulsed wave in ultrasound?

Answer 14

Any modality which turns the transmitter on and off periodically

This helps reduce range ambiguity.

Question 15

How is an image defined in ultrasound?

Answer 15

The received data for a specific time, formatted as a picture

This represents the visual output of the ultrasound system.

Question 16

What is a received beam?

Answer 16

The returning echoes registered over time from a single transmit event

This is essential for reconstructing the image.

Question 17

What is the formula for axial resolution?

Answer 17

Axial resolution equals SPL divided by two

SPL stands for spatial pulse length.

Question 18

What is the relationship between PRF and PRP?

Answer 18

PRF = 1/PRP

This indicates the frequency of pulse repetition.

Question 19

What is the formula for PRP?

Answer 19

PRP = 1/PRF = 13 microsec/cm x imaging depth/line

This formula aids in calculating the timing of ultrasound pulses.

Question 20

What does PD stand for in ultrasound?

Answer 20

PD = P x # of cycles

P represents the pulse duration.

Question 21

What is the formula for SPL?

Answer 21

SPL = wavelength x # of cycles

This relates to the physical characteristics of the ultrasound wave.

Question 22

To achieve better axial resolution related to SPL, you want a _______.

Answer 22

Shorter wavelength and fewer cycles in the pulse

This improves the clarity of images.

Question 23

What factors increase the frame rate?

Answer 23

• Decreased depth
• Decreased width
• Write zoom

These adjustments help enhance image refresh rates.

Question 24

What type of imaging is plane wave imaging?

Answer 24

A non-scanned modality

This technique differs from traditional scanning methods.

Question 25

Formula for frame time

Answer 25

FT = 13microsec/cm x cm/lines x lines/frame

Question 26

What frequency does a PO transducer normally operate in cardiac imaging?

Answer 26

1.9 MHz ## Footnote This frequency is typically used for optimal imaging in cardiac ultrasound.

Question 27

What was the main limitation of a mechanical transducer?

Answer 27

No ability to vary the focus ## Footnote This limitation affects the versatility and quality of imaging.

Question 28

What do annular rays allow for in ultrasound imaging?

Answer 28

Variable focus in both lateral and elevation planes ## Footnote This capability enhances image resolution and clarity.

Question 29

What is sequencing in ultrasound imaging?

Answer 29

A method where each transmitted beam is sent individually, with the following beam sent after the prior returns ## Footnote This technique ensures better management of signal processing.

Question 30

What does dicing allow in the context of ultrasound probes?

Answer 30

Creation of an array that can be cut into a series of independent but still connected elements ## Footnote This allows for more flexible and versatile probe designs.

Question 31

How does a cardiac ultrasound probe create a sector scan?

Answer 31

By phasing ## Footnote Phasing enables the probe to focus on different depths and angles.

Question 32

True or False: Trapezoid scanning was created to produce a smaller field of view.

Answer 32

False ## Footnote Trapezoid scanning is designed to enhance the field of view rather than reduce it.

Question 33

What is an advantage of averaging?

Answer 33

Speckle reduction ## Footnote Speckle reduction is important in imaging techniques to enhance the clarity of the images.

Question 34

If averaging is used and the SNR is improved by a factor of three, how many samples are most likely used in the average?

Answer 34

Nine or 10 ## Footnote This indicates the relationship between SNR improvement and the number of samples in averaging.

Question 35

What concept are averaging techniques based on?

Answer 35

Constructive impartial, constructive interference ## Footnote Constructive interference enhances the signal while reducing noise.

Question 36

What is an example of a line averaging technique?

Answer 36

Color Doppler ## Footnote Color Doppler is utilized in medical imaging to assess blood flow and velocity.

Question 37

What buffering technique is used to maintain frame rate by replacing the oldest frame with the newest frame?

Answer 37

FIFO ## Footnote FIFO stands for First In, First Out, a method for managing data in a queue.

Question 38

What is not an advantage of compound imaging?

Answer 38

Improved temporal resolution ## Footnote Temporal resolution refers to the precision of the timing of the image capture.

Question 39

What does fricassee fusion compounding involve?

Answer 39

Transmitting with a broadband signal and simultaneously processing multiple images at different frequencies ## Footnote The resulting image is a combination of the processed images.

Question 40

If there are four foci, how does the frame rate change?

Answer 40

The frame rate does not decrease by a factor of four ## Footnote This implies that the system can manage multiple focuses without a proportional decrease in performance.

Question 41

What does the term 'synthetic aperture' refer to?

Answer 41

The effective aperture created by adding signals from individual elements ## Footnote This technique enhances image resolution by utilizing signals from multiple elements in an array.

Question 42

What is the two-way beam a product of?

Answer 42

The transmit and receive beams ## Footnote This concept is crucial in understanding how ultrasound imaging works.

Question 43

Do most AI systems currently exhibit self-awareness in cardiac applications?

Answer 43

No ## Footnote AI in cardiac applications primarily focuses on image processing rather than self-awareness.

Question 44

What has become extremely valuable for assessing structural interventions in imaging?

Answer 44

3-D imaging ## Footnote 3-D imaging provides detailed spatial information crucial for planning and assessing interventions.

Question 45

Can AI currently be used for image interpretation?

Answer 45

No ## Footnote AI is still developing in this area and is not yet capable of fully interpreting images.

Question 46

What effect does a multifocal sequence have on temporal resolution?

Answer 46

Degrades temporal resolution ## Footnote This indicates that temporal resolution suffers when multiple focal points are used.

Question 47

What does retrospective transmit focus improve?

Answer 47

Lateral resolution ## Footnote This technique enhances the clarity of images in the lateral dimension.

Question 48

Does multiline transmit decrease the frame rate?

Answer 48

No ## Footnote This suggests that multiline transmit can be used without sacrificing frame rate performance.