Basic Echo As I understand it… Dr Claudia Wong
Types of Ultrasound M-mode 2D echocardiography Doppler
M-mode M is for motion A single beam in an ultrasound scan can be used to produce an M-mode picture, where movement of a structure such as a heart valve can be depicted in a wave-like manner. Because of its high sampling frequency (up to 1000 pulses per second), this is useful in assessing rates and motion
M-mode
2D Echocardiography The principle of ultrasound reflection off cardiac structures to produce images of the heart
2D Echocardiography
Doppler Describes the change in frequency due to relative motion between Wave source (Echo probe) Receiver (Echo probe) Reflector (RBCs)
Principles we should know Doppler principle Bernoulli principle Hydraulic principle Continuity principle
Doppler
Doppler Θ < 20, such that cos Θ ~ 1
Bernoulli Principle
Hydraulic Principle
Continuity Principle Whatever flows in must flow out
Doppler Using these principles, we can determine Pressure Flow Velocity Volume
Particular Doppler Terms We Should Know Colour wave doppler VTI (velocity time integral) TDI (tissue doppler imaging) Pulsed wave doppler Continuous wave doppler
Colour wave doppler
Particular Doppler Terms We Should Know Colour wave doppler VTI (velocity time integral) TDI (tissue doppler imaging) Pulsed wave doppler Continuous wave doppler
Velocity Time Integral (VTI or TVI) TVI (cm) = area under velocity curve & is equal to the sum of velocities (cm/s) during ejection time
Particular Doppler Terms We Should Know Colour wave doppler VTI (velocity time integral) TDI (tissue doppler imaging) Pulsed wave doppler Continuous wave doppler
Tissue Doppler Imaging (TDI) Tissue tracking or displacement is the integral of tissue velocity over a given time. It represents the distance a region of interest moves relative to its original location.
Particular Doppler Terms We Should Know Colour wave doppler VTI (velocity time integral) TDI (tissue doppler imaging) Pulsed wave doppler Continuous wave doppler
Tissue Doppler
Transthoracic Echo 4 standard views Parasternal long axis Parasternal short axis Apical Subcostal
Parasternal long axis
Parasternal short axis
Apical
Subcostal
Clinical Applications RVSP Mitral stenosis Aortic stenosis Stroke volume Mitral regurgitation Diastolic dysfunction
R Ventricular Systolic Pressure RVSP from tricuspid jet = tricuspid gradient ∆ P = 4 (V2 – V1)2 + RAP RAP RAP IVC Collapse 0-5 >1.7 >50% 6-10 <1.7 11-15 <50% 16-20 Nil
Mitral Stenosis Direct measurement of MVA Using M-mode + 3D echo Peak mitral diastolic velocity Continuous wave doppler Mean pressure gradient and TVI MVA Pressure half-time method MVA = 220/PHT Continuity equation + PISA method
Mitral stenosis
Mitral stenosis Severity Severity MVA (cm2) Mean Gradient (mmHg) PASP (mmHg) Mild >1.5 <5 <30 Moderate 1.0-1.5 5-10 30-50 Severe <1.0 >10 >50
Aortic stenosis Velocity Pressure gradient Area Using Doppler + VTI for peak velocity Pressure gradient Using Bernoulli principle P = 4V2 Area Using Continuity principle AVA = (LVOTA x LVOT TVI)/AV TVI LVOT / AVA velocity ratio Based on Continuity principle
Aortic stenosis
Aortic stenosis Severity peak aortic valve velocity >4.5 m/s mean pressure gradient >50 mmHg AVA < 0.75 cm2 LVOT/AV TVI <0.25
Stroke volume Using the hydraulic principle
Mitral regurgitation Uses continuity principle – whatever flows in must flow out Q1=Q2 CSA1 x V1= CSA2 x V2
Mitral regurgitation We compare LVOT SV vs. MV SV
Mitral regurgitation Severity Severity Volume (mL) Mild 30 Moderate 30-44 Moderate - Severe 45-59 Severe 60
Diastolic dysfunction 4 stages Normal Delayed Pseudonormal Restrictive
Diastolic dysfunction Looks at several factors MIF = Mitral inflow E = early diastolic mitral inflow velocity A = late diastolic mitral inflow velocity e’ = early diastolic mitral annulus velocity DTI = Doppler tissue imaging
Diastolic dysfunction Mitral inflow
Diastolic dysfunction
Diastolic dysfunction
Diastolic dysfunction Normal Delayed Pseudo-normal Restrictive E/A 1-2 <0.75 >2 DTI 150-240 >240 <150 E/e’ ≤8 range ≥15