Pediatric Echo Training

Protocol and Nomenclature in Transthoracic Echocardiography

Bernard E. Bulwer, MD, MSc and Jose Rivero, MD

Contents

Equipment Basics

Standard Transducer Positions

Transducer Scan Plane and Index Mark

Two-Dimensional Echocardiographic Imaging Planes

Transducer Maneuvers

Examination Protocol

Parasternal Views

PLAX View

RV Inflow

RV Outflow

PSAX View

Apical Four-Chamber View Apical Five-Chamber View Apical Two-Chamber View Apical Three-Chamber View Subcostal Views Suprasternal Views Examination Report Summary equipment basics

The transducer probe is the component that houses the piezoelectric crystals (see Chapter 1) and emits and receives the sound waves (Fig. 1).

The central processing unit receives raw data from the transducer, instrument controls, and the keyboard. It integrates and translates received data into visual images and calculations (on the display monitor). some newer models are bundled with sophisticated software that permit postprocessing of acquired images and newer research tools.

Transducer and Doppler controls adjust the amplitude, frequency, and duration of the ultrasound waves emitted from the transducer probe. The details of instrument settings, e.g., power output, receiver gain, filters, sample volumes, velocity scale, sweep speed, and dynamic range, are outside the scope of this chapter, but are essential for optimal image acquisition and reporting. some equipment models routinely display these on acquired images.

The ultrasound display allows visualization of images, calculations, and reports. Storage devices may be analog or digital. Digital images require much

From: Contemporary Cardiology: Essential Echocardiography: A Practical Handbook With DVD Edited by: S. D. Solomon © Humana Press, Totowa, NJ

Fig. 1. Adult transthoracic echocardiography transducers generally range between 2 and 7 mmHz, with lower frequency transducers— 2.5 and 3 mmHz—being the most commonly used. Higher frequency transducers are routinely used in pediatric echocardiography and transesophageal echocardiography. They provide increased resolution, but decreased penetration. The dedicated Doppler transducer (bottom right) is a nonimaging probe. These are standard components on modern echocardiography machines.

Pediatric Echocardiography Imageswww.asecho.org)."/>
Fig. 2. Panorama of echocardiography services at a university teaching hospital. Guidelines on echocardiography laboratory standards and training are available at the American Society of Echocardiography website (www.asecho.org).
Echocardiography Images
Fig. 3. (A) Standard transducer positions. (B) Cross-sectional cardiac topography.

memory. Hard disks, CDs, DVDs, central digital storage, and imaging work stations are parts of a modern digital echocardiography service (Fig. 2).

standard transducer positions

The standard echocardiographic images are acquired by transducer maneuvers within four standard anatomical positions—left parasternal (or simply parasternal), left apical, subcostal, and suprasternal (Fig. 3).

Individual patient and clinical characteristics often require the use of additional or non-standard windows, e.g., in congenital heart disease and post-chest surgery patients.

transducer scan plane and index mark

The ultrasound scan plane fans out from the piezoelectric electrodes housed in the transducer tip as shown (Fig. 4, left).

Anatomy Model For Echocardiography
Fig. 4. Transducer scan plane and index mark.

Note the position of the index mark—a constant guide to transducer positions during the examination (Fig. 4, right). This model and others are designed with a palpable ridge.

By convention, the index mark indicates the part of the image plane that appears on the right side of the image display.

two-dimensional echocardiography imaging planes

Three orthogonal planes that transect the long and short axes of the heart are the reference standards during the two-dimensional (2D) echocardiography examination.

Two parameters—transducer position (Fig. 3) and imaging plane (Fig. 5)—are used to define images in 2D echocardiography.

transducer maneuvers

Three major transducer movements are described— tilting, angling, and rotating are shown in Figs. 6-8.

The aim of these movements is to acquire the best possible image of the area of interest.

Transducer movements are fluid and a skilled sono-grapher maneuvers the transducer to capture the desired images (Fig. 9).

examination protocol

Following equipment and patient preparation, the examination begins at the left parasternal window, followed by apical, subcostal, and suprasternal views (Fig. 3).

At each window, a standard images and measurements are obtained as outlined in Table 1. The still frames in the protocol described below are from normal individuals.

Depending on the indication, the examination can be extended according to the clinical indication (Chapter 4). Additional imaging and analyses are conducted and discussed in the chapters that follow.

Following image acquisition, the formal echocardiography report follows. This is usually performed by attending cardiologists.

parasternal views

From the left parasternal position, the parasternal long-axis (PLAX) views, the right ventricle (RV) inflow and outflow views, and parasternal short-axis (PSAX) views are obtained.

Unless stated otherwise, parasternal views refer to the left parasternal position.

plax view

With the index mark at approx the 10 o'clock position (Fig. 10) indicating a scan plane as shown in Figs. 11

Short Paresternal Long Axis
Fig. 5. Imaging planes: 2D transthoracic echocardiography.
Echocardiogram Transducer Positioning

Fig. 6. Transducer movements: TILT.

Pediatrian Medical Exam Positions

Fig. 7. Transducer movements: ANGLE.

Fig. 6. Transducer movements: TILT.

Fig. 7. Transducer movements: ANGLE.

Short Paresternal Long Axis
Fig. 8. Transducer movements: ROTATION.
Fig. 9. Examination model (sonographer) in the left lateral position with attached electrocardiogram leads and transducer in the left parasternal position. Transducer gel is routinely used. It eliminates the air pocket—a poor conductor of ultrasound— between the transducer and the chest wall.

Table 1

2D Transthoracic Echocardiogram Examination Protocol"

1. Parasternal long axis—depth 20-24 cm

2. Parasternal long axis—depth 15-16 cm a. M-mode MV/AV, aortic root/LA, LV

b. Measure aortic root (end systole; 2D or M-mode)

c. Suspected aortic stenosis measure LVOT 1 cm below aortic leaflets (end systole; 2D)

d. Measure LA (end of diastole; 2D or M-mode)

e. Measure IVS in diastole/LV internal diameter/ posterior wall thickness (2D or M-mode)

f. Measure LV internal diameter in systole (2-D or M-mode)

h. Color Doppler on MV/AV for regurgitation

3. RV inflow—depth 20 cm, then 15-16 cm a. Zoom on TV

b. Color Doppler TV for TR

c. CW TR for max velocity

4. Parasternal short axis a. 2D AV level; zoom on AV, color for AI width b. Color Doppler TV for TR, CW TR for velocity c. Color Doppler PV for PI (PW and CW)

d. 2D image of PA bifurcation, PW from RVOT to bifurcation (look for PDA)

e. 2D MV level (color Doppler optional)

f. 2D papillary level g. 2D apical level

5. Apical four chamber —depth 20-24 cm

6. Apical four chamber—depth 15-16 cm a. Decrease depth to visualize apex b. Color Doppler MV for MR

c. PW pulmonary veins d. PW mitral inflow (tips of leaflets in LV) for velocity, E:a ratio e. CW MV

f. PW tissue Doppler at level of mitral annulus (lateral and septal), scale 20:20

g. Visualize RV, color TV

h. CW if TR present

7. Apical five chamber a. Visualize AV

b. Color Doppler AV for AI

c. PW along septum from apex for valve d. Aortic stenosis PW 1 cm below AV; freeze and trace TV1

e. Aortic stenosis CW through AV; freeze and trace for TV2

f. Afib trace five beats in a row

8. Apical two chamber a. Color Doppler for MR

(Continued)

Tissue Doppler Images

Table 1 (Continued)

9. Apical three chamber a. Color Doppler MV/AV regurgitation

10. Subcostal four chamber a. Color Doppler atrial septum for ASD

b. Color Doppler RV for TR

c. Visualize IVC; color Doppler, measure IVC, and PW hepatic vein

11. Suprasternal notch—depth 24 cm, decrease if necessary a. Color Doppler and PW descending aorta

"Additional views, measurements, and modalities are performed based on the clinical context, the information requested, and findings encountered during the examination.

2D, two dimensional; MV, mitral valve; AV, atrioventricular; LVOT, left ventricular outflow tract; LA, left atrium; IVS, interventricular septum; LV, left ventricle; TV, tricuspid valve; TR, tricuspid regurgitation; CW, continuous wave; AI, aortic insufficiency; PV, pulmonary vein; PI, pulmonic insufficiency; PW, pulsed wave; PA, pulmonary artery; RVOT, right ventricular outflow tract; PDA, patent ductus arteriosus; MR, mitral regurgitation; ASD, atrial septal defect.

Fig. 10. Patient and transducer positioning: parasternal long-axis views (PLAX).

Fig. 11. Parasternal long-axis (PLAX) (depth 20-24 cm). (See companion DVD.)

and 12, and at a depth of 20-24 cm to visualize extra-cardiac structures, e.g., descending thoracic aorta or possible pleural effusion, cine images are optimized (adjust gain, depth, and sector width) and then acquired. Depth is then decreased to 15-16 cm for closer views of cardiac structures (area of interest).

At each position during the examination, the desired standard views (areas of interest) are optimized and acquired. When a particular frame or measurement is desired, the freeze function is used, measurements are taken and/or annotated accordingly.

M-mode sweep through the aortic valve, mitral valve (MV), and just distal to the tips of the mitral leaflets and standard measurements are obtained.

Color flow Doppler is applied to the region(s) of interest and images are acquired (Figs. 13-16).

Parasternal Long Axis Deep Depth
Fig. 12. Parasternal long-axis (depth 15-16 cm, PLAX). (See companion DVD.)

rv inflow

With the transducer in the standard PLAX position the transducer is slightly angled inferomedially (Fig. 17) until the RV inflow view (Figs. 18-20) comes into view. Images are then optimized and acquired at depths of approx 20 and 15-16 cm.

The tricuspid valve is evaluated (by zoom or decrease depth), color Doppler is applied (Fig. 21A) and followed by continuous-wave (CW) Doppler interrogation of flow across the tricuspid valve (Fig. 21B).

rv outflow

The sonographer may opt to image the RV outflow by angling supero-laterally with the transducer scan plane transecting the pulmonary artery (PA) as shown in (Fig. 21C) followed by Doppler evaluation (Fig. 21D).

This view provides good visualization of the pulmonary valves and the bifurcation of the main PA trunk into the right and left PAs (right pulmonary artery, left pulmonary artery; "trunk and trousers" view).

psax view

With the transducer in the initial left PLAX position and with the aortic valve in focus, the transducer is then

Diastole

Interventricular septum

^Anterior leaflet (mitral valve) *

Postero-medial papillary muscle

Posterior wall (left ventricle)

. Right ventricular free wall 'Jjjf , Membranous septum RV / Right coronary cusp

Ascending aorta

Non-coronary cusp

. Right ventricular free wall 'Jjjf , Membranous septum RV / Right coronary cusp

Ascending aorta

Posterior wall (left ventricle)

Aortic Root Ncc Rcc Lcc

descending thoracic aorta

Pericardium

Coronary sinus

Pericardium

Coronary sinus descending thoracic aorta

Parasternal long-axis view (PLAX)

Fig. 13. Annotated parasternal long-axis view (PLAX) (depth 15-16 cm). Ao, aortic root; LA, left atrium; LV, left ventricle; RA, right atrium; RV, right ventricle.

Parasternal Long Coronary Cusps

Fig. 14. Parasternal long-axis (PLAX) measurements. Ao, aortic root; LA, left atrium; IVS, interventricular septum; LV, left ventricle; ncc, noncoronary aortic cusp; PW, posterior wall; RA, right atrium; rcc, right coronary aortic cusp; RV, right ventricle. M-Mode sweeps through the aortic valve, mitral valve, and upper left ventricular levels (A-C) reveals structures as shown. (A) Note the systolic anterior movement of the aortic root during systole. Atrial volumes and hence measured 2D left atrial dimensions are maximal during systole. Aortic valve leaflets may appear faint on M-mode in young patients with normal aortic valve leaflets (cusps). Note the thin diastolic closure line and the normal box-like opening and closing profile of the normal aortic cusps (sketch). (C) Shows M-mode recording done just distal to the tips of the mitral leaflets. This is the standard M-mode image from which to measure left ventricular dimensions. At end-diastole, the ventricular septal diameter (septal thickness, IVSd), the maximal left ventricular internal diameter (LVIDd), the left ventricular posterior wall diameter (thickness, LVPWd) are measured. At end-systole, the left ventricular internal diameter (LVIDs) is measured. The upper limit of normal for maximal wall thickness is 1.1 and 5.5 cm for maximal LVIDd in the "average" adult. (D) Color flow Doppler is applied to the region of interest to identify regurgitant or stenotic jets across the aortic and mitral valves. Flow across a ventricular septal defect in the membranous septum (Fig. 13) is best visualized in the PLAX view. An end-systolic frame is shown in A. (See companion DVD.)

Fig. 14. Parasternal long-axis (PLAX) measurements. Ao, aortic root; LA, left atrium; IVS, interventricular septum; LV, left ventricle; ncc, noncoronary aortic cusp; PW, posterior wall; RA, right atrium; rcc, right coronary aortic cusp; RV, right ventricle. M-Mode sweeps through the aortic valve, mitral valve, and upper left ventricular levels (A-C) reveals structures as shown. (A) Note the systolic anterior movement of the aortic root during systole. Atrial volumes and hence measured 2D left atrial dimensions are maximal during systole. Aortic valve leaflets may appear faint on M-mode in young patients with normal aortic valve leaflets (cusps). Note the thin diastolic closure line and the normal box-like opening and closing profile of the normal aortic cusps (sketch). (C) Shows M-mode recording done just distal to the tips of the mitral leaflets. This is the standard M-mode image from which to measure left ventricular dimensions. At end-diastole, the ventricular septal diameter (septal thickness, IVSd), the maximal left ventricular internal diameter (LVIDd), the left ventricular posterior wall diameter (thickness, LVPWd) are measured. At end-systole, the left ventricular internal diameter (LVIDs) is measured. The upper limit of normal for maximal wall thickness is 1.1 and 5.5 cm for maximal LVIDd in the "average" adult. (D) Color flow Doppler is applied to the region of interest to identify regurgitant or stenotic jets across the aortic and mitral valves. Flow across a ventricular septal defect in the membranous septum (Fig. 13) is best visualized in the PLAX view. An end-systolic frame is shown in A. (See companion DVD.)

rotated clockwise to approximately the 12 o'clock position (Fig. 22) or until the short-axis view of aortic valve ("inverted Mercedes Benz sign") is visualized (Figs. 23 and 24).

The aortic valve is then zoomed (decrease depth) and interrogated by color Doppler (Fig. 25A,B) to evaluate possible aortic insufficiency (Fig. 26).

The region of interest then moves to the tricuspid valve. Color Doppler is applied across the valve followed by CW Doppler assessment (Fig. 25C,D). Peak tricuspid regurgitation velocity measured 2.5 m/s.

Next is the evaluation of the pulmonary valve for pulmonary regurgitation using color flow Doppler, pulsed-wave (PW) Doppler and CW Doppler.

Imaging of the PA bifurcation, and PW interrogation from the right ventricular outflow tract to the bifurcation can be performed when looking for a patent ductus arteriosus.

Slight transducer movements (or angling) toward the cardiac apex permits the acquisition of a series of PSAX at the level of the MV, the papillary muscles, and the apex (Figs. 27-30).

Mode Mitral Stenosis

Fig. 15. M-Mode: mitral valve leaflets. Normal ranges for these dimensions are shown in the EF slope reflects the speed of anterior mitral leaflet (AML) closure. This pattern is significantly altered in mitral stenosis, becoming box-like. Posterior mitral leaflet (PML) movement essentially mirrors that of the anterior leaflet.

Fig. 15. M-Mode: mitral valve leaflets. Normal ranges for these dimensions are shown in the EF slope reflects the speed of anterior mitral leaflet (AML) closure. This pattern is significantly altered in mitral stenosis, becoming box-like. Posterior mitral leaflet (PML) movement essentially mirrors that of the anterior leaflet.

Subcostal Pediatric Echo
Fig. 17. Patient and transducer positioning: right ventricular inflow view.

End-systole

Left atrium diameter

Adult icho NTHI V Contrait 1

Your Heart and Nutrition

Your Heart and Nutrition

Prevention is better than a cure. Learn how to cherish your heart by taking the necessary means to keep it pumping healthily and steadily through your life.

Get My Free Ebook


Responses

  • makda
    How to get cross trained in pediatric echocardiography?
    3 years ago
  • aira
    How to hold transducer to get pediatric echo images?
    7 months ago

Post a comment