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Flashcards in Echocardiography Deck (71)
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1

In Echo, how do wavelength and frequency affect resolution?

High frequency, shorter wavelength increase resolution

2

How does frequency affect tissue penetration?

Higher frequency decreases penetration

3

What is scattering and why does it happen?

Reflection of US beam in multiple directions due to structures less than 1 wavelength in lateral dimension

4

What is attenuation?

Absorption of US energy by conversion to heat

5

Depth of penetration is limited to what amount of wavelengths?

200 wavelengths

6

Depth of penetration for:
1. 1 MHz transducer
2. 2.5 MHz transducer
3. 5 MHz transducer

1. 30cm
2. 12cm
3. 6cm

7

Physics of M Mode

Single crystal rapidly alternating between transmission and receiver modes.

8

Safety of ultrasound?

No known adverse effects
However theoretical thermal damage and cavitation (creation of small gas filled bodies by the US beam)

9

What is image quality of 2D echocardiography affected by?

Axial resolution, lateral resolution and elevational resolution

10

Define axial resolution

Resolution along the length of the US beam

11

What affects axial resolution?

Frequency
Bandwidth
Pulse Length

12

Define lateral resolution?

resolution perpendicular to the beam

13

What affects lateral resolution?

Frequency
Beam Width
Bandwidth
Aperture
Side Lobes

14

Define elevational resolution?

Resolution across the thickness of the tomographic slice

15

What is the Nyquist Frequency?

Half the Pulse repetition frequency

16

What happens when velocity exceeds the Nyquist Limit?

Aliasing

17

What are the factors that affect colour doppler?

Gains
Colour Maps
Frame Rate
Nyquist Limit

18

What is use of pulse wave doppler

to assess low velocity flows

19

what is the use of continuous wave Doppler

to assess high velocity flows

20

What walls of the LV does the A4C view?

Anterolateral and inferoseptal

21

What walls of the LV does the A2C view?

Anterior and Inferior

22

What walls of the LV does the A3C view?

Anteroseptal and Inferolateral

23

What are the echo features of primary TR?

Flail gap 15mm or more

24

What are the echo features of functional or secondary TR?

Tenting Area >3cm

25

What is the normal aortic valve area?

3-4cm2

26

What is the peak velocity across the aortic valve which suggests severe stenosis?

>4m/sec

27

What is the peak velocity across the aortic valve which suggests mild stenosis?

<3m/sec

28

What indexed aortic valve area represents severe stenosis?

<0.6cm2/m2

29

What are the echo features of mild aortic stenosis?

Valve area >1.5cm2
Transvalvular Velociy 2.0-2.9
Mean Gradient <20mmhg

30

What are the echo features of moderate aortic stenosis?

Valve area 1.0 - 1.5cm2
Transvalvular Velociy 3.0-3.9
Mean Gradient 20-39mmhg