### Basics of Echocardiography

```Basics of
Echocardiography
MD,AFSA
Ultrasound principles
Penetration depth and resolution
Factors affecting ultrasound transmission:
cycle length: (wavelength λ [mm])
frequency: (frequency f [Hz])
Speed: (propagation velocity c [m/s]) in the respective medium
The relationship of these parameters is described by the wave equation:
c=λ×f
λ=c/f
longer wavelengths penetrate further than shorter wavelengths
Image resolution cannot be greater than one wavelength
the higher the ultrasound frequency, the better the image resolution
Types of resolution
• Axial resolution
• Lateral resolution
• Elevational resolution
Modes
1-A mode
2-B mode
3-M mode
4-2D
Echogenicity
Doppler principles
Christian Doppler
The difference between the emitted frequency
and the received frequency is called:
Doppler shift (fd )
• Blood flow V = fd × c/2 × f0 × cos α
• For practical application in Doppler
echocardiography: the emitted frequency (f0)
is known and the velocity of sound (c/2) is
constant at 1540 m/s. Therefore, the velocity
causing the Doppler shift can be calculated by:
V = fd × cos α
PRF (or scale)
Nyquist limit
• Nyquist Limit = Pulse Repetition Frequency / 2
1-PW
2-CW
3-CFM
Angle of beam
Pressure or pressure
•∆P = P2-P1 =
2
4(V2
–
2
V1 )
Transducers
Transducers
Manipulation of TEE probe
.
The ASE/SCA 20 Views for a Comprehensive TEE
Exam
Left Ventricle
function
• FS = EDD-ESD
EDD
• FAC = EDA-ESA
EDA
• EF = EDV-ESV
EDV
Left ventricle function
Simpson mode
M-mode
2D Eye balling
TEI index
Regional wall motion
ME 4 chamber view
Trans gastric view
Right ventricle
Size
Contractility
Rt Atrium
LT atrium
LV filling pressure
Mitral valve leaflets
Mitral valve
Stenosis
2-planimetry
3-pressure half time
Regurgitation
1-PISA
2-vena contracta
3-jet area
4-Regurgitant
fraction
5-Indirect indices
Aortic valve
Stenosis
2-planimetry
Regurgitation
1-PISA
2-jet area
3- vena contracta
4-Indirect indices
Tricuspid valve
Stenosis
Regurgitation
Pulmonary valve
Stenosis
Regurgitation
Pulmonary pressure
Pulmonary veins
Shunts
Ascending aorta and LVOT
Descending aorta
IVC and hepatic veins
3D echo (live and offline)
• TDI
• Speckle Tracking: non-Doppler, angleindependent quantification of myocardial deformation, by
tracking the displacement of the speckles during the cardiac
cycle, strain and the strain rate can be measured offline.
Recommended books
1-Practical approach to transesophageal
echocardiography(Perrino)
2-Core topics in echocardiography (Rob Fenneck)
3-Atlas of multiplane transesophageal echocardiography
(Martin Dunitz)
4-transesophageal echocardiography in anesthesia and
intensive care (BMJ)
5-Pocket atlas of echocardiography (Thieme)
5-Essential echocardiography (Humana press)
Questions??
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