ECHO Flashcards
What frequency is US in Echo?
> 20,000Hz (1-5MHz in adults, can go up to 10MHz)
What is the velocity (speed) of sound through soft tissue?
1,540m/s
What happens to the wavelength at higher frequencies?
It is shorter
Speed depends on density and soundwaves move faster through higher density mediums
What is the formula for wavelength?
The speed of sound is the product of frequency times the wavelength (c= f x λ)
So, λ = c / f
What symbol is wavelength represented by and what is its SI unit?
Lambda λ
Measured in meters
If the frequency of an US = 3MHz, what is its wavelength?
λ = 1540 /3000000 = 5.13m
What happens if wavelength is shorter?
More detailed visualisation, increased resolution, and anything below this λ and f cannot be seen
What is amplitude in terms of soundwaves of US?
The strength of the soundwave, measured in dB
Larger amplitude = higher pressure difference = louder sound
What are the echo windows?
Parasternal
Apical
Subcostal
Suprasternal notch
What are the views of each window?
Parasternal = long axis (PLAX) and short axis (PSAX)
Apical = 2 chamber, 4 chamber, 5 chamber
What are the levels of PSAX?
Aortic level (base)
Mitral level (mid)
Papillary level (apex)
What structures is PLAX looking at?
RVOT, LV, LA, AoV, MV, LVOT
What US/Doppler modes are used in PLAX?
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
What structures is PSAX looking at?
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
What US/Doppler modes are used in PSAX?
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
What structures is Apical 2 looking at?
Focuses on left side of the heart - LV, LA, MV
What US/Doppler modes are used in Apical 2?
2D = LVOT and valve function
Colour Flow = mitral stenosis/regurgitation
What structures is Apical 4 looking at?
Full visualisation of all chambers and atrioventricular valves (RA, LA, RV, LV, MV, TV)
What US/Doppler modes are used in Apical 4?
2D = chamber evaluation
Colour Flow = stenosis/regurgitation
Pulsed-Wave = mitral inflow and diastolic function
Continuous-Wave = extent of any stenosis/regurgitation
What structures is Apical 5 looking at?
Adds LVOT and AoV to Apical 4 Chamber view (RA, LA, RV, LV, MV, TV, LVOT, AoV)
What structures is Apical 3 looking at?
Focuses on LA, LV, LVOT, AoV, MV
Long-axis of the heart, longitudinal view
What are the levels of the Subcostal window?
Subcostal 4 Chamber
Inferior Vena Cava (IVC) View
Subcostal Short-Axis View
What are the Subcostal views looking at?
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
What US/Doppler modes are used in Subcostal views?
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
What are the Suprasternal views?
Aortic Arch Longitudinal View and Aortic Arch Cross-Sectional View
What are Suprasternal views looking at?
Ascending aorta, aortic arch, descending aorta, brachiocephalic vessels
Which windows are best to evaluate aortic stenosis/regurgitation?
Apical 5 for Doppler alignment
PLAX for valve anatomy and regurgitant jets
Suprasternal for aortic gradients
What windows are best for mitral stenosis/regurgitation?
Apical 4 Chamber for flow velocities and regurgitant jets
PLAX for for MV anatomy and leaflet structure
Which windows are best for RVOT and LVOT evaluation?
PSAX for anatomy/structure abnormalities
Apical 4 for LV/RV function
Which windows best obtain ventricular wall thickness?
PLAX with 2D and M-Mode
Apical 4 for chamber size
