Plax

Pericardium

Fig. 4. M-mode through the mitral valve. From this measurement, the morphology of the mitral valve can be visualized. Note the typical M configuration of the mitral valve during early diastolic filling (E), and atrial filling (A). The anterior mitral leaflet (AML) and the posterior mitral leaflet (PML) are noted, as is the pericardium.

Pericardium

Fig. 4. M-mode through the mitral valve. From this measurement, the morphology of the mitral valve can be visualized. Note the typical M configuration of the mitral valve during early diastolic filling (E), and atrial filling (A). The anterior mitral leaflet (AML) and the posterior mitral leaflet (PML) are noted, as is the pericardium.

(see Chapter 1). Doppler is primarily used to assess blood flow velocity. Spectral Doppler (Fig. 5) shows waveforms that represent blood velocity, with time on the x-axis and velocity on the y-axis. See Chapter 1 for an explanation of the differences between pulsed- and continuous-wave Doppler.

Color Flow Doppler Echocardiography

Color flow Doppler depicts blood velocity data superimposed on the 2D image (Fig. 6; please see companion DVD for corresponding video). Nonturbulent flow that is below the Nyquist limit (see Chapter 1) and directed toward the transducer appears in red and nonturbulent

Right Ventricle Inflow Tract
Fig. 5. Pulsed Doppler through the left ventricular outflow tract. The waveform demonstrates the velocity of blood (y-axis), with time on the x-axis. The electrocardiogram allows correlation with the cardiac cycle.
Cardiac Blood Flow Cycle

! Right ventricular inflow

Fig. 6. Example of color flow Doppler demonstrating tricuspid regurgitation (a normal finding in this patient). Color flow Doppler is a form of pulsed-wave Doppler in which blood velocities are color encoded and superimposed on top of the two-dimensional image. The scale on the upper right hand side of the image shows the velocity associated with each color gradation as described in the text. (Please see companion DVD for corresponding video.)

flow below the Nyquist limit directed away from the transducer appears in blue. Perpendicular flow is not well visualized by Doppler images. Turbulent flow, and flow in which the velocities are faster than the Nyquist limit, is seen as a multi-color mosaic signal.

The Views

This patient's study, like most studies, is comprised of a standard set of views recommended by the American Society of Echocardiography. Multiple different viewing angles are needed to fully visualize all the cardiac bo Oo

Subcostal Short Axis View

Fig. 7. Illustration showing transducer placement for each of the major echocardiography views: (A) parasternal location for parasternal long and short-axis; (B) apical location for apical four-, two-chamber and long-axis views; (C) subcostal location for subcostal views; (D) suprasternal location for suprasternal notch view.

Fig. 7. Illustration showing transducer placement for each of the major echocardiography views: (A) parasternal location for parasternal long and short-axis; (B) apical location for apical four-, two-chamber and long-axis views; (C) subcostal location for subcostal views; (D) suprasternal location for suprasternal notch view.

Table 1 Echocardiographic Views

View

Patient/transducer position

Structures imaged

Doppler

Left parasternal: long-axis view

Left parasternal: RV inflow

Left parasternal: short-axis view

Apical: four and five chamber

Apical: two and three chamber

Subcostal

Supine/third to fourth interspace

Same but tilt inferomedially, slight clockwise rotation

Same but rotate perpendicular, tilt up and down to image from base to apex

Left lateral decub/point of maximal impulse. Anterior rotation produces five-chamber view.

Same but with perpendicular rotation.

Supine with hips and knees flexed/subxiphoid, at or slightly right of midline

Overview of cardiac structures, chamber dimensions, and ventricular function. Most standard measurements, including LA, aortic root, LV diastolic and systolic dimensions. RV size and function measurements variable in this (and all) views.

Long-axis view of RV, RA; good view for TV and regurgitant velocity.

Cross-section of LV to assess global and regional LV function from apex to base as transducer is tilted. Papillary muscles, MV in cross-section—good for planimetry of MV in mitral stenosis. At base, AV seen in cross-section; RVOT seen across top of image, PV to right of AV.

All four chambers; ventricular septum, lateral wall of LV. Atrial septum, MV and TV with regurgitant jets and inflow velocity profiles. Inferior pulmonary veins seen as they enter LA. In five chamber view, aortic valve and root also seen, good view to assess for aortic regurgitation or stenosis.

LV anterior and inferior walls, LA, MV and regurgitant jet. Three-chamber view brings aortic valve and root into view, and shifts to inferolateral and anteroseptal segments of LV.

Often best view in patients with hyperinflated lungs; long-axis similar to parasternal window but may provide better visualizaion of apex, RA and IVC, interatrial septum. Good view to look for PFO/ASD. Short-axis similar to parasternal. Abdominal aorta can be seen in this window.

Color flow Doppler looking for mitral regurgitation and aortic insufficiency.

Color flow Doppler looking for tricuspid regurgitation; spectral Doppler (CW) demonstrating tricuspid regurgitant velocity.

Color flow Doppler through the aortic valve for assessment of aortic insufficiency.

Color flow Doppler looking for mitral regurgitation, aortic insufficiency, and tricuspid regurgitation; spectral Doppler (PW) of mitral inflow, outflow tract, and in suspected aortic stenosis, CW Doppler of aortic valve. CW Doppler for assessment of tricuspid regurgitant velocity.

Color flow Doppler for mitral regurgitation (two- and three-chamber views), and aortic insufficiency (three-chamber view).

Color flow Doppler of intra-atrial septum looking for evidence of atrial septal defect.

(Continued)

Table 1 (Continued)

View

Patient/transducer position

Structures imaged

Doppler

Suprasternal

Supine with pillow under shoulders, head to left/suprasternal notch.

Ascending aorta, aortic arch, proximal brachiocephalic vessels, descending thoracic aorta, and right and main PAs (sometimes the left PA). Good position to measure transaortic velocity/gradient in aortic stenosis, assess for diastolic flow reversal in aortic regurgitation. Depending on image quality, may detect aortic aneurysm or dissection, postductal coarctation or patent ductus arteriosus; superior vena cava flow velocity profile.

PW or CW Doppler can be used to interrogate possible coarctation of the aorta.

CW, continuous wave; LA, left atrium; LV, left ventricle; MV, mitral valve; PA, pulmonary artery; PW, pulsed wave; RA, right atrium; RVOT, right ventricular outflow tract; TV, tricuspid valve.

structures, because each echo view provides only a 2D image of the 3D heart. There are four major transducer positions: the parasternal, apical, subcostal, and suprasternal notch positions (Fig. 7). From each transducer position, rotating and tilting the probe will produce several different tomographic images.

By convention, the echo images shown here and at most centers are presented in a triangular window, with the top of the triangle generally at the top of the screen (Fig. 1). Some labs, by convention, invert the triangle. The location of the transducer, relative to the image, is always at the top of the triangle; the structures closest to the top are therefore those closest to the transducer (and closest to the patient's skin). An electrocardiogram tracing is recorded simultaneously with the echo images, so that the phase of the cardiac cycle can be correlated to the mechanical activity of the heart; this is usually located at the bottom of the screen.

The proper positioning of the patient and the probe is described for each view. Transducer heads are marked with a notch, groove, or dot known as the "index;" this index is perpendicular to the imaging plane.

Keep in mind that the views and positions described next are those most frequently used in the majority of patients. However, certain anatomical variations or pathological conditions may require nonstandard views; deviating from the usual transducer positions may be necessary to obtain optimal images in these cases.

echocardiography views

Table 1 describes each echocardiography view, the patient and transducer position, and structures imaged in each view.

The Parasternal Position

For the parasternal views, the patient lies in the left lateral decubitus position with the left arm supporting the head. The transducer is generally placed just left of the sternum, in the second, third, or fourth intercostal space (Fig. 7). From here, both short- and long-axis views of the heart can be obtained.

Parasternal Long-Axis View (Fig. 1)

The index is pointed toward the patient's right shoulder, producing a longitudinal section through the LV. Remember that the image is displayed as if the transducer tip were at the top of the triangle; therefore, the structures at the top of the triangle are the most anterior (i.e., closest to the surface of the chest). The right ventricle (RV) lies anterior to the LV, so the chamber at the top of the triangle is the RV. (If there is a pericardial fluid collection or a prominent epicardial fat pad anterior to the RV, this will be seen above the RV in the parasternal long-axis view.) Below the RV is the LV; the anterior interventricular septum is uppermost, and the posterior LV wall is below, with the LV apex to the left. The ascending aorta is on the

Systole

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