Echocardiography Flashcards Preview

RACP Cardio AT > Echocardiography > Flashcards

Flashcards in Echocardiography Deck (71)
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1
Q

In Echo, how do wavelength and frequency affect resolution?

A

High frequency, shorter wavelength increase resolution

2
Q

How does frequency affect tissue penetration?

A

Higher frequency decreases penetration

3
Q

What is scattering and why does it happen?

A

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

4
Q

What is attenuation?

A

Absorption of US energy by conversion to heat

5
Q

Depth of penetration is limited to what amount of wavelengths?

A

200 wavelengths

6
Q

Depth of penetration for:

  1. 1 MHz transducer
  2. 2.5 MHz transducer
  3. 5 MHz transducer
A
  1. 30cm
  2. 12cm
  3. 6cm
7
Q

Physics of M Mode

A

Single crystal rapidly alternating between transmission and receiver modes.

8
Q

Safety of ultrasound?

A

No known adverse effects

However theoretical thermal damage and cavitation (creation of small gas filled bodies by the US beam)

9
Q

What is image quality of 2D echocardiography affected by?

A

Axial resolution, lateral resolution and elevational resolution

10
Q

Define axial resolution

A

Resolution along the length of the US beam

11
Q

What affects axial resolution?

A

Frequency
Bandwidth
Pulse Length

12
Q

Define lateral resolution?

A

resolution perpendicular to the beam

13
Q

What affects lateral resolution?

A
Frequency
Beam Width
Bandwidth
Aperture
Side Lobes
14
Q

Define elevational resolution?

A

Resolution across the thickness of the tomographic slice

15
Q

What is the Nyquist Frequency?

A

Half the Pulse repetition frequency

16
Q

What happens when velocity exceeds the Nyquist Limit?

A

Aliasing

17
Q

What are the factors that affect colour doppler?

A

Gains
Colour Maps
Frame Rate
Nyquist Limit

18
Q

What is use of pulse wave doppler

A

to assess low velocity flows

19
Q

what is the use of continuous wave Doppler

A

to assess high velocity flows

20
Q

What walls of the LV does the A4C view?

A

Anterolateral and inferoseptal

21
Q

What walls of the LV does the A2C view?

A

Anterior and Inferior

22
Q

What walls of the LV does the A3C view?

A

Anteroseptal and Inferolateral

23
Q

What are the echo features of primary TR?

A

Flail gap 15mm or more

24
Q

What are the echo features of functional or secondary TR?

A

Tenting Area >3cm

25
Q

What is the normal aortic valve area?

A

3-4cm2

26
Q

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

A

> 4m/sec

27
Q

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

A

<3m/sec

28
Q

What indexed aortic valve area represents severe stenosis?

A

<0.6cm2/m2

29
Q

What are the echo features of mild aortic stenosis?

A

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

30
Q

What are the echo features of moderate aortic stenosis?

A

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

31
Q

What are the echo features of severe aortic stenosis?

A

Valve area <1.0cm2
Transvalvular Velociy >4
Mean Gradient 40mmhg

32
Q

What are the features of severe aortic regurgitation on echocardiography?

A

Four of the following

  • Vena contracta >6mm
  • Flail Valve
  • Central Jet Width >65% of LVOT
  • Holodiastolic flow reversal in descending aorta
  • Large flow convergence
  • Enlarged LV with normal ED
  • Pressure half time <200ms

OR 2-3 criteria with one or more of the following:

  • Regurg fraction >50%
  • Regurg Volume 60ml
  • EROA >30mm2
33
Q

What are the four echocardiographic measurements to assess LV systolic function?

A

Longitudinal shortening
Anterior mitral leaflet motion
Thickening of wall segments
Change in cavity area

34
Q

Velocity of blood formula?

A

Velocity = wavelength * frequency

35
Q

Wavelength formula?

A

Wavelength = 1.54 * frequency (MHz)

36
Q

What is the general resolution of echo images?

A

1-2 wavelengths

37
Q

What is the formula for acoustic impedance?

A

Acoustic impedance = density of the object * propagation velocity

38
Q

What is the size that induces scattering?

A

Less than 1 wavelength

39
Q

What are the physics characteristics of a sound wave?

A
Frequency 
Period 
Wavelength 
Propagation Speed 
Amplitude 
Intensity
40
Q

What are the qualitative measures to assess valve regurgitation?

A

Valve morphology
Colour flow regurgitant jet
CW signal of regurgitant jet
Other - AR holodiastolic flow reversal, MR large flow convergence zone

41
Q

What are the semi quantitative measures to assess regurgitant murmurs?

A

Vena contracta width
Upstream vein flow
Inflow
Other - AR pressure half time, TR Pisa radius, MR TVI mitral/TVI aortic

42
Q

What are the quantitative measures to assess regurgitant valvulopathy?

A

Effective regurgitant orifice area
Regurgitant volume
Cardiac chamber and vessel enlargement

43
Q

What are the qualitative echocardiogram features of severe AR?

A

Valve morphology - flail, coapt defect
Colour flow regurgitant jet - large central jet
CW signal of regurgitant jet - dense
Other - AR holodiastolic flow reversal in descending aorta >20cm/s

44
Q

What are the qualitative features of severe MR and TR?

A

Valve morphology - coapt defect, flail leaflet, papillary muscle rupture
Colour flow regurgitant jet - large central or adhering eccentric jet reaching posterior LA wall
CW signal of regurgitant jet - dense, triangular
Other - large flow convergence zone (MR)

45
Q

What are the semi quantitative measures that support severe AR?

A

Vena contracta width - >6mm

Pressure half time <200ms

46
Q

What are the semi quantitative measures that support severe MR?

A

Vena contracta width - 7mm or more
Systolic pulmonary vein flow reversal
E wave dominant >1.5m/s
TVI mitral/aortic >1.4

47
Q

What are the semi quantitative measures that support severe TR on echo?

A

Vena contracta width 7mm or more
Hepatic vein systolic flow reversal
Inflow E wave dominant >1
PISA radius >9mm

48
Q

What are the quantitative measures that support severe AR on echo?

A

Effective regurgitant orifice area - >30mm2
Regurgitant volume - >60ml
LV enlargement

49
Q

What are the quantitative measures that support severe TR on echo?

A

Effective regurgitant orifice area - >40mm2
Regurgitant volume - >45ml
RV RA IVC enlargement

50
Q

What are the quantitative measures that support severe primary MR on echo?

A

Effective regurgitant orifice area >40
Regurgitant volume >60
LV LA enlargement

51
Q

What are the quantitative measures that support severe secondary MR on echo?

A

Effective regurgitant orifice area - >20mm2

Regurgitant volume >30ml

52
Q

What is the placement of the cursor for M mode assessment of LV Size and EF?

A

Plax
Base of heart
Perpendicular
(Up one intercostal space if not perpendicular)

53
Q

What is the ERO associated with severe AR?

A

> 0.3

54
Q

What is the regurgitant volume associated with severe AR?

A

> 60mls

55
Q

Formula for mitral valve area with pressure half time.

A

Valve area = 220/pressure half time

Valve area = 760/deceleration time

56
Q

Surface area of sphere

Surface area of half sphere (Pisa method)

A

4 Pi r squared

2 Pi r squared

57
Q

What is the formula using Pisa to estimate mitral valve area in Ms?

A

MVA = 2 Pi r squared * Vr/Vmax * angle/180

58
Q

Stroke volume equation

A

SV = 0.785 * D squared * VTI

59
Q

MVA by the continuity equation.

A

MVA = (0.785 * D LVOT squared * LVOT VTI) / MV VTI

60
Q

Regurgitation volume formula

A

RV = EROA * MR VTI

61
Q

EROA formula from PISA

A

6.28 * r squared * nyquist limit / peak MR velocity

62
Q

How does the eccentricity index assist in determining RV pressure vs volume overload?

A

Eccentricity index >1 only in end diastole indicates volume overload only

Index >1 in end systole and end diastole indicates pressure overload

63
Q

What is normal RA volume in men and women?

A

34ml/m2 men

28ml/m2 women

64
Q

What is the use of RV TDI S wave peak velocity in Pulmonary hypertension?

A

Prognostic value

65
Q

What is the normal S wave value with TDI of the RV?

A

<11.5cm/s

66
Q

What is the normal duration of the RV IVRT?

A

<110ms

67
Q

Effective orifice area formula from SV and Transvalvular VTI

A

EO = SV/ transvalvular VTI

68
Q

Formula for axial resolution?

A

Axial resolution = spatial pulse length / 2

69
Q

Spatial pulse length formula?

A

SPL = wavelength * number of cycles

70
Q

How does the potential trigger for takotsubo (physical vs emotional) influence outcome?

A

Physical trigger is associated with higher mortality

71
Q

In retrospective data, what interventions are associated with improved outcomes for takotsubo cardiomyopathy?

A

ACE/ARB
Antiplatelets

No effect from b blocker on retrospective reviews