Mostafa Eladawy MD,AFSA Basics of Echocardiography

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 gradient?

∆P = P 2 -P 1 = 4(V 2 2 – V 1 2 )

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 1-gradient 2-planimetry 3-pressure half time

Regurgitation 1-PISA 2-vena contracta 3-jet area 4-Regurgitant fraction 5-Indirect indices

Aortic valve Stenosis 1-gradient 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

Recent adavances 3D echo (live and offline)

TDI Speckle Tracking: non-Doppler, angle- independent 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??