ECHO

Question 1

What frequency is US in Echo?

Answer 1

> 20,000Hz (1-5MHz in adults, can go up to 10MHz)

Question 2

What is the velocity (speed) of sound through soft tissue?

Answer 2

1,540m/s

Question 3

What happens to the wavelength at higher frequencies?

Answer 3

It is shorter
Speed depends on density and soundwaves move faster through higher density mediums

Question 4

What is the formula for wavelength?

Answer 4

The speed of sound is the product of frequency times the wavelength (c= f x λ)
So, λ = c / f

Question 5

What symbol is wavelength represented by and what is its SI unit?

Answer 5

Lambda λ
Measured in meters

Question 6

If the frequency of an US = 3MHz, what is its wavelength?

Answer 6

λ = 1540 /3000000 = 5.13m

Question 7

What happens if wavelength is shorter?

Answer 7

More detailed visualisation, increased resolution, and anything below this λ and f cannot be seen

Question 8

What is amplitude in terms of soundwaves of US?

Answer 8

The strength of the soundwave, measured in dB
Larger amplitude = higher pressure difference = louder sound

Question 9

What are the echo windows?

Answer 9

Parasternal
Apical
Subcostal
Suprasternal notch

Question 10

What are the views of each window?

Answer 10

Parasternal = long axis (PLAX) and short axis (PSAX)
Apical = 2 chamber, 4 chamber, 5 chamber

Question 11

What are the levels of PSAX?

Answer 11

Aortic level (base)
Mitral level (mid)
Papillary level (apex)

Question 12

What structures is PLAX looking at?

Answer 12

RVOT, LV, LA, AoV, MV, LVOT

Question 13

What US/Doppler modes are used in PLAX?

Answer 13

2D = structural analysis of cavities, walls, and valves
M-Mode = dimensions and thickness
Colour Doppler = regurgitation/stenosis in AoV/MV
Pulsed-Wave = velocity of flow through valves

Question 14

What structures is PSAX looking at?

Answer 14

Aortic level = AoV and leaflets, RA, LA, pulmonary valve, tricuspid valve
Mitral level = MV and leaflets, LV
Papillary level = LV cavity and walls, papillary muscles

Question 15

What US/Doppler modes are used in PSAX?

Answer 15

2D = structural analysis, valve morphology
M-Mode = in papillary level to assess LV
Colour Doppler = regurgitation/stenosis
Pulsed-Wave Doppler = blood flow velocity
Continuous-Wave Doppler = extent of stenosis/regurgitation

Question 16

What structures is Apical 2 looking at?

Answer 16

Focuses on left side of the heart - LV, LA, MV

Question 17

What US/Doppler modes are used in Apical 2?

Answer 17

2D = LVOT and valve function
Colour Flow = mitral stenosis/regurgitation

Question 18

What structures is Apical 4 looking at?

Answer 18

Full visualisation of all chambers and atrioventricular valves (RA, LA, RV, LV, MV, TV)

Question 19

What US/Doppler modes are used in Apical 4?

Answer 19

2D = chamber evaluation
Colour Flow = stenosis/regurgitation
Pulsed-Wave = mitral inflow and diastolic function
Continuous-Wave = extent of any stenosis/regurgitation

Question 20

What structures is Apical 5 looking at?

Answer 20

Adds LVOT and AoV to Apical 4 Chamber view (RA, LA, RV, LV, MV, TV, LVOT, AoV)

Question 21

What structures is Apical 3 looking at?

Answer 21

Focuses on LA, LV, LVOT, AoV, MV
Long-axis of the heart, longitudinal view

Question 22

What are the levels of the Subcostal window?

Answer 22

Subcostal 4 Chamber
Inferior Vena Cava (IVC) View
Subcostal Short-Axis View

Question 23

What are the Subcostal views looking at?

Answer 23

4 Chamber = same as Apical 4 but obtained through the abdomen - good for pericardial effusion
IVC = IVC and its junction with the RA
Short-Axis = cross-section of the ventricles same as PSAX

Question 24

What US/Doppler modes are used in Subcostal views?

Answer 24

2D = structural views
Colour Flow = abnormal flow/pericardial fluid, flow direction through IVC, collapsibility of IVC
Pulsed-Wave = velocity through valves and IVC
Continuous Wave = tricuspid regurgitation

Question 25

What are the Suprasternal views?

Answer 25

Aortic Arch Longitudinal View and Aortic Arch Cross-Sectional View

Question 26

What are Suprasternal views looking at?

Answer 26

Ascending aorta, aortic arch, descending aorta, brachiocephalic vessels

Question 27

Which windows are best to evaluate aortic stenosis/regurgitation?

Answer 27

Apical 5 for Doppler alignment
PLAX for valve anatomy and regurgitant jets
Suprasternal for aortic gradients

Question 28

What windows are best for mitral stenosis/regurgitation?

Answer 28

Apical 4 Chamber for flow velocities and regurgitant jets
PLAX for for MV anatomy and leaflet structure

Question 29

Which windows are best for RVOT and LVOT evaluation?

Answer 29

PSAX for anatomy/structure abnormalities
Apical 4 for LV/RV function

Question 30

Which windows best obtain ventricular wall thickness?

Answer 30

PLAX with 2D and M-Mode
Apical 4 for chamber size