right parasternal imaging: an underutilized echocardiographic technique

CARDIAC SONOGRAPHERS' COMMUNICATIONS

Right Parasternal Imaging: An Underutilized Echocardiographic Technique

Christopher P. Marcella, RCVT, and Lauren E. Johnson, MA, RCVT, Portland, Oregon, and Spokane, Washington

If the echocardiographer uses only standard imaging planes, he or she may fail to obtain vital information about the aorta, atrial septum, superior and inferior vena cavae, and the coronary arteries. The evaluation of caval-to-systemic venous atrial connections (Senning or Mustard) in transposition of the great arteries or systemic vena caval or right atrial-to-pulmonary anastomosis (Fontan) in tricuspid atresia and single ventricle may not be adequately seen when only the standard left parasternal, apical, subcostal, and suprasternal imaging planes are used. Therefore, the use of the right parasternal imaging plane may help to provide crucial information regarding these areas when the standard views are unable to delineate them adequately. The right parasternal window is an additional echocardiographic window that should become part of a complete echocardiographic examination. ( J AM Soc EcHOCARDIOGR

1993;6:453-66.)

An echocardiographer must frequently alter the standard echocardiographic examination to perform a complete study. We have found that one such "nonstandard" technique, right parasternal (RPS) imaging, yields useful and, at times, crucial information. For example, in some patients the aortic arch view cannot be visualized with the standard suprasternal notch window. We have found that the entire ascending aorta, part or all of the transverse aorta, and the descending aorta can often be readily visualized via a right parasternal approach. Furthermore, a view in which the transducer transects the atrial septum relatively perpendicular to the fossa ovalis can be obtained. In addition, the superior and inferior vena cavae and their connection to the right atrium, occasionally the tricuspid valve, the aortic valve, and the coronary arteries can be visualized by this approach. In congenital and acquired heart disease this

From the Echocardiographic and Hemodynamic Laboratory Division of Adult and Pediatric Cardiology, Department of Medicine and Pediatrics, School of Medicine, Oregon Health Sciences University, Portland, and the Non-Invasive Cardiovascular Technology Program, Spokane Community College.

Reprint requests: Christopher P. Marcella, RCVT, Echo Lab L462, Oregon Health Sciences University, 3181 SW Sam Jackson Park Road, Portland, OR 97201.

Copyright© 1993 by the American Society ofEchocardiography.

0894-7317/93 $1.00 + .10 27/l/43705

echocardiographic window can yield relevant information in lieu of or in addition to those images obtained from the left sternal border. The purpose of the present communication is to demonstrate the effectiveness of RPS imaging as a useful adjunct to standard tomographic planes and to demonstrate the benefit of establishing it as part of a complete echocardiographic examination.

GENERAL PRINCIPLES

Patient Position and Transducer Orientation

The patient must assume a right-lateral decubitus position that may vary from supine to more than 90 degrees. An angle of approximately 45 degrees is most commonly used. The transducer index marker is directed either toward the patient's head or to the patient's left. This transducer orientation allows the anatomy that is nearest to the marker to be displayed on the right of the echocardiographic video monitor. The following descriptions of echocardiographic images and all associated examples will use this convention. "Right parasternal imaging" as we define it represents an image plane obtained from the right of the sternum. The actual window may range from the xiphoid process to the subclavicular region. The right axilla is the lateral limit.

Generally, the sequence of RPS views that we try

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454 Marcella and Johnson Journal of the American Society of Echocardiography

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Figure 1 The RPS long-axis ascending aorta view. ASAO, Ascending aorta; LA, left atrium; A V, aortic valve.

Table 1 Percentage of adequate right parasternal views obtained by age

Age (years)

0-5 6-15 <o16 Total

Views (n = 10) (n = 8) (n = 26) (n = 44)

LAXASAO 90 87 33 55 ASAOIDSAO 60 50 35 43 RCA/LAX ASAO 90 50 12 41 RCA/ SAX ASAO 90 75 19 45 SAX SVC/ ASAO 90 75 27 50 SAX lAS 80 87 35 55 SVC/lVC-lAS 100 75 23 50 SAX LV 80 50 23 41

LAX, Long-axis; SAX, short-axis; SVC, superior vena cava; IVC, inferior vena cava; lAS, interatrial septum; ASAO, ascending aorta; DSAO, descending aorta; RCA, right coronary artery; LV, left ventricle.

to obtain starts with a long-axis view of the ascending aorta. Next, the aortic arch view, along with an attempt to identify the right coronary artery (RCA) from this plane, is performed, followed by the longaxis view of the atrial septum as well as the superior and inferior vena cavae. After these RPS views from the long-axis plane, the transducer is rotated approximately 90 degrees to obtain the short-axis views. The RPS short-axis examination generally starts with a short-axis view at the base of the heart. First, the atrial septum, aortic valve, and RCA views are attempted, followed by the short-axis view of the

superior vena cava (SVC) and aorta. The short-axis view of the left and right ventricles completes the examination.

In this communication we will show that the RPS window is useful in many patients. Although not every patient will have an adequate RPS window, we were able to demonstrate that out of 44 consecutive patients imaged from the RPS border, approximately 50% have adequate images (Table 1). The table shows the percentage of adequate views that we obtained in each view in three different age groups. The age groups were: newborn to 5 years, 6 to 15 years, and greater than 16 years. We have arbitrarily named the different views to aid in the ease of discussion. As shown, the highest percentage of adequate views could be obtained in the newborn to 5 year age group, followed by the 6 to 15 year group and then the 16 years and older groups. This table is meant to show the number of adequate views we were able to obtain in various patients and not for establishing validity of these views in the diagnosis or the evaluation of specific disease states.

TECHNIQUE AND EXAMPLES

Nonnal Anatomy

Aorta. The aortic anatomy visualized by the RPS window includes the valve, ascending aorta, transverse aorta, and descending aorta. The view is obtained to the right of the sternum in the region of

Journal of the American Society of Echocardiography Volume 6 Number 4 Marcella and Johnson 455

Figure 2 RPS ascending/descending aorta view. A, View of the ascending and descending aorta in the long-axis plane. B, The entire aortic arch in a different patient. RA, Right atrium; LA, left atrium; ASAO, ascending aorta; RPA, right pulmonary artery; DSAO, descending aorta.

the second to fourth intercostal space. These views are usually the easiest to obtain. After imaging the ascending aorta from the standard left parasternal region, slide the transducer to the right of the sternum while maintaining the long-axis view of the aorta (Figure 1). Via the long-axis view, the transverse aortic arch and the respective arch vessels are also visualized by slightly tilting the ultrasonic beam superiorly. Also, from the long-axis view the entire aortic arch can often be visualized by slight clockwise rotation with medial angulation of the ultrasound beam (Figure 2, A and B). In comparison with the standard cephalad-caudal suprasternal aortic arch

view, the RPS arch view is seen from a more rightto-left angle. Thus, the ascending aorta is visualized at the top of the screen, with the transverse aorta being visualized to the right and the descending aorta being found at the bottom of the screen. The shortaxis RPS view of the aorta and its valve is obtained by rotating the transducer clockwise approximately 90 degrees from the long-axis view.

Coronary arteries. The coronary arteries can be readily visualized via the RPS approach. The right coronary artery is viewed from the long-axis image of the ascending aorta angled to visualize the aortic arch view (Figure 3, A). Once the arch view is ob-


July-August 1993

Figure 3 The RPS right coronary artery view. A, From the long-axis of the ascending aorta. B, From the short-axis of the aortic valve. C, From the short-axis plane, showing approximately 5 em of the artery. RCA, Right coronary artery; RA, right atrium; LA, left atrium; ASAO, ascending aorta; AV, aortic valve; MPA, main pulmonary artery.

tained, a slight rotation in either direction or a rightward tilt of the ultrasound beam should reveal the RCA. It is usually seen arising from the right sinus of V alsalva as an anterior and rightward-curving structure. This vessel is best visualized via a shortaxis view. After the RPS short-axis view of the aortic valve and tricuspid valve leaflets is obtained, superior angulation of the ultrasound beam will yield the tricuspid valve ring. Within this ring the characteristic linear echo of the RCA is imaged. The RCA is usually visualized initially extending anteriorly then rightward from the right sinus ofValsalva within the atrioventricular groove (Figure 3, B). This artery can be followed out quite a distance from its origin with a small lateral or rightward tilt or by sliding of the transducer rightward with appropriate clockwise or counter-clockwise rotation (Figure 3, C).

The left coronary artery views are generally limited to the left main, proximal-to-midanterior descending, and proximal portions of the left circumflex coronary artery. These views are obtained in the shortaxis plane of the aortic valve with minimal clockwise rotation or superior or inferior tilting of the ultrasonic beam.

Interatrial septum. The interatrial septum (lAS) can be clearly visualized in many patients from the right sternal border, and can be viewed in both longand short-axis planes. The RPS short-axis view of the atrial septum is similar to that of the left parasternal short-axis view in that the same cardiac base anatomy is seen (except that the atrial septum is visualized from an angle where the ultrasound beam interrogates the anatomic plane of the lAS perpendicular to the fossa ovalis). The view is obtained by imaging

Journal of the American Society of Echocardiography Volume 6 Number 4 Marcella and Johnson 45 7

Figure 4 A, RPS short-axis view of the atrial septum. B, RPS long-axis view of atrial septum (SVC/IVC-IAS) obtained by rotation of approximately 90 degrees counter-clockwise from the short axis with optimization of the interatrial septum. RA, Right atrium; lAS, interatrial septum;AO, aorta;MPA, main pulmonary artery; IVC, inferior vena cava; SVC, superior vena cava.

the base of the heart in short-axis to the right of the sternum. Medial angulation and/ or appropriate rotation may be needed to optimize the image of the lAS. Occasionally movement of the transducer quite laterally or inferiorly is necessary to visualize the lAS well (Figure 4, A).

The long-axis of the atrial septum images the septal surface orthogonal to the short-axis plane. This view is obtained by rotating the transducer 90 degrees counter-clockwise from the RPS short-axis view of the lAS (Figure 4, B). The aorta and/or the superior

and inferior vena cavae may be seen in this plane with medial or lateral tilt of the ultrasound beam, respectively.

Superior and inferior vena cavae and the right atrium. The superior and inferior vena cavae and their connection to the right atrium can be seen in many patients from the RPS image plane. The superior and inferior vena cavae view is obtained by placing the transducer in the region of the second or third intercostal space with the index marker toward the patient's head. Slight lateral angulation and ap-


July-August 1993

Figure 5 The SVC/IVC-IAS view. Both the SVC and IVC are imaged simultaneously along with the long axis of the atrial septum with optimization of the SVC and IV C. RA) Right atrium; L4.S) interatrial septum; LA) left atrium; SVC) superior vena cava; IVC) inferior vena cava.

Figure 6 RPS short-axis view of the SVC and ascending aorta. This view is obtained in an orthogonal plane to the SVC/IVC-IAS view.AO) Aorta; SVC) superior vena cava; RPA) right pulmonary artery.


Figure 7 A stenotic bicuspid aortic valve from the RPS long·axis view of the ascending/descending aorta. ASAO, Ascending aorta; AV, aortic valve; DSAO, descending aorta.

propriate counter-clockwise or clockwise rotation may be necessary to image both the SVC and the inferior vena cava (IVC) as well as their connection to the right atrium (Figure 5). Generally, approximately a length of 4 to 5 em of the superior vena cava and 2 to 3 em of the inferior vena cava can be imaged entering the right atrium from this view. If a greater length of either vena cavae is desired, sliding the transducer superiorly or inferiorly will allow better visualization of the SVC or IVC, respectively. Note that in this view the atrial septum is also visualized. Thus, both the SVC/IVC and the long-axis of the atrial septum can be imaged simultaneously; therefore, we arbitrarily named this the SVC/IVCIAS view for ease of discussion.

A short-axis view of the SVC and the aorta can be obtained by rotating the transducer approximately 90 degrees clockwise from the SVC/IVC-IAS view followed by a superior tilt of the ultrasound beam (Figure 6). The SVC and aorta are seen in cross section. The aorta is to the left of the SVC and, therefore, displayed nearest the index marker on the right of the echocardiographic video monitor. The tricuspid valve can occasionally be visualized via this approach by tilting the ultrasound plane medially

from the SVC/IVC-IAS view. Finally, portions of the right ventricular outflow tract, pulmonic valve, pulmonary artery, and left atrium can be imaged. We believe, however, that RPS imaging of these structures usually adds no additional information when compared with standard left parasternal views.

TECHNIQUE AND EXAMPLES

Pathology

Aortic stenosis. As shown previously, the ascending aorta and the aortic valve are seen well from the RPS approach. This approach is also of benefit if color flow irnaging of the ascending aorta is desired. The long-axis view of the ascending aorta is excellent for imaging valvular and supravalvular stenosing regions (Figure 7). The angle used permits excellent continuous wave Doppler interrogation of these regions in many patients. 1 This view is always attempted in our laboratory when aortic stenosis is suspected. In many patients the continuous wave signal of aortic insufficiency can be observed as a negative signal from this approach. Furthermore, the RPS short-axis view


July-August 1993

Figure 8 RPS ascending/descending aorta view. A, Marfan syndrome demonstrating dilation of the ascending aorta. B, Aneurysmal dilation of the ascending and descending aorta with a measured ascending aorta of 77 mm and descending aorta of 55 mm. RA) Right atrium; LA) left atrium, ASAO) ascending aorta; DSAO) descending aorta, RPA) right pulmonary artery.


Figure 9 Interatrial septal defects from the RPS approach in the short-axis plane. A, Atrial septal aneurysm bowing toward the right atrium. B, Secundum atrial septal defect. RA, Right atrium; LA, left atrium; IASA, interatrial septal aneurysm; A V, aortic valve; LAA, left atrial appendage; ASD, atrial septal defect.

of the aortic valve may also aid in the evaluation of aortic valve disease.

Marfan syndrome and aortic aneurysm. The Marfan syndrome can be accompanied by minimal to severe aneurysmal dilation of the aorta with or without dissection.2

•3 In many patients the RPS aor

tic long-axis view images the entire ascending aorta extremely well. In our laboratory, this is a routine view that is attempted on all patients with the Marfan syndrome (Figure 8, A). We also use this view to measure the ascending aorta as standard protocol.

The RPS aortic arch view is well suited to image the . upper thoracic descending aorta in some patients.

This view can be helpful in patients with pectus excavatum in whom the cardiac structures are shifted to the right. Also, when the aorta becomes aneurysmally dilated it is usually visualized well via the RPS approach (Figure 8, B). This view may also be beneficial in those patients in whom a standard suprasternal arch view is desired but not obtainable (i.e., patients with neck trauma or tracheostomy).

Atrial septal defect. The right parasternal short-


July-August 1993

Figure 10 Atrial septal defects visualized from the RPS SCV /IVC-IAS view. A, Secundum atrial septal defect. B, Sinus venosus atrial septal defect. C, A second patient with sinus venosus atrial septal defect. RA, Right atrium; LA, left atrium; IVC, inferior vena cava; SVC, superior vena cava; ASD, atrial septal defect; ASAO, ascending aorta; DSAO, descending aorta.

axis view has been shown to be useful in evaluating the atrial septum by two-dimensional and Doppler echocardiography when a secundum atrial septal defect is suspected. 4-

6 The atrial septum is visualized from a right-to-left orientation allowing for excellent interrogation of interatrial septal aneurysms (Figure 9, A) and secundum atrial septal defects (Figure 9, B). This short-axis view has been previously described by Tei et al. 5 and Minagoe et al. 6 These authors used the RPS window to evaluate Doppler- , derived shunt flow across secundum atrial septal defects.

From the long-axis plane, defects of the secundum and sinus venosus type can be seen as well (Figure 10). Muhler et al. 7 have demonstrated the effectiveness of the subcostal long-axis vena cava superiorinferior plane in diagnosing sinus venosus defects. To our knowledge, the RPS long-axis SVC/IVC-

lAS view has not been reported regarding the evaluation of secundum or sinus venosus atrial septal defects. Care must be taken in interrogating the long axis of the atrial septum and the SVC, because we have observed that the window may be extremely high on the patient's chest and very small as well. We have also observed that the long axis of the SVC/IVC-IAS is of benefit when using color flow Doppler in sinus venosus defects. In these defects the ultrasound beam is relatively parallel to the flow of blood when viewed from the RPS approach, thus making it easier to discriminate the flow of the SVC from the flow across the septal defect. We believe that this RPS view may be better in the evaluation of sinus venosus defects because of the close proximity of the transducer to the SVC and interatrial septum and perhaps warrants further investigation.

Coronary artery aneurysm. Several studies have


Figure 11 Coronary artery imaging via the RPS short-axis approach in Kawasaki's disease. Proximal right and left coronary artery aneurysms. RA, Right atrium; RCA, right coronary artery; MPA, main pulmonary artery; AV, aortic valve; IM, left main coronary artery.

Figure 12 A superior vena caval pathway visualized from the SVC/IVC-IAS view in a patient with transposition of the great arteries and atrial switch procedure. Superior vena cava is connected to the left-sided and more posterior atrium via systemic venous baffle. PVA, Pulmonary venous atrium; SV A , systemic venous atrium; BAF, baffle; SVC, superior vena cava.


July-Augusr 1993

Figure 13 RPS view of a systemic venous conduit/right atrial to main pulmonary artery pathway in a patient with a Fontan procedure. IVC, Inferior vena cava; LA, left atrium; PA, pulmonary artery; DSA.O, descending aorta; CONDUIT, caval pathway through right atrium to pulmonary artery.

shown echocardiography to be beneficial in the evaluation of coronary artery aneurysms. s- Io These studies evaluated the coronary arteries from left parasternal, apical, and subcostal approaches. We have been able to evaluate the RCA in many of our patients by use of the RPS approach (Figure 11). By positioning the patient in the right-lateral decubitus position for RPS imaging, the RCA is more accessible in many patients from the long- and short-axis planes. The RCA can be followed distally from its origin by lateral sliding of the transducer in the long- and short-axis planes as previously described. The images obtained from the RPS approach may help to evaluate the mid and distal RCA more thoroughly than by viewing it only from standard planes.

Transposition of the great arteries. In patients in whom an atrial switch procedure for transposition of the great arteries is done, RPS imaging can be very useful. The inferior baffle limb and its connection to the systemic venous atrium is often visualized quite well in an apical or subcostal view. These views allow adequate two-dimensional visualization and Doppler interrogation of this portion of the baffie. Chin et al. 11 have shown the subcostal four-chamber and short-axis (transverse) views to be useful in the evaluation of the superior vena caval pathway in the Senning operation in infants and young children.

Our experience has been that the superior baffle limb of the systemic venous pathway is not usually

adequately delineated from these views in older children and adults. Occasionally, the proximal SVCsuperior limb can be seen from the suprasternal notch or slight modifications of this view, allowing for interrogation of this portion with ultrasound. As previously described, when the RPS approach is used, the SVC can be seen coursing downward toward the right atrium in the SVC/IVC-IAS view. In patients in whom an atrial switch procedure was performed, RPS imaging often identifies the SVC connection to the left-sided and more posterior atria via a superior vena caval-to-systemic venous atrial baffie instead of its normal connection to the right atrium (Figure 12) . This view is obtained in the manner previously described for the SVC/IVC-IAS but may require appropriate counter-clockwise or clockwise rotation or superior and medial tilt of the ultrasound beam to optimize image quality.

Fontan. With patients in whom a Fontan procedure is done, visualization of the anastomosis of the right atrium or IVC/ SVC to the pulmonary arteries is useful. From the RPS approach a baffie-conduit through the right atrium directing inferior vena caval and hepatic venous flow to the pulmonary artery can be seen (Figure 13). This right atrial baffie-pathway is seen connecting to the pulmonary artery above the pulmonic valve. This view can be obtained in some patients from the SVC/IVC-IAS view with a medial coronal tilt of the ultrasound beam. Appropriate


Figure 14 Miscellaneous right parasternal views. A, RPS image of a patient with right pneumonectomy. Right and left ventricles and left atrium are visible as well as aortic and mitral valves. B, RPS short-axis view of the left and right ventricles with an anterior and posterior pericardia! effusion. C, RPS long-axis view of the superior vena cava (SVC/IVC) compressed by a malignant lymphosarcomatous mass. RA, Right atrium; R V, right ventricle; LV, left ventricle; A V, aortic valve; MV, mitral valve; SVC, superior vena cava; TUMOR, malignant lymphosarcoma; PE, pericardia! effusion.

clockwise or counter-clockwise rotation may be necessary to optimize the image. This view is reasonably suited for color flow and pulsed Doppler interrogation of this region. Direct right atrial appendageto-pulmonary artery or SVC-to-right pulmonary artery anastomosis may be occasionally imaged by the RPS approach. Various short- and long-axis views with appropriate rotation may be needed to 1lee the particular connection.

Shunts. Many shunts placed to increase pulmonary blood flow can be seen via the RPS approach. Blalock-Taussig shunts placed on the right are usually visualized easily with the use of color flow Doppler. Long- and short-axis views of the ascending aorta

and right pulmonary artery region will usually yield adequate results. W aterston and Glenn shunts can also be seen from this approach, but in our experience are not seen with any frequency.

MISCELLANEOUS

Occasionally, all cardiac chambers can be viewed from the right side. In a patient in whom a partial right pneumonectomy was performed, a view was obtained by imaging the heart from the right axillary region (Figure 14, A). With the transducer index marker toward the patient's head, the cardiac apex is

466 Marcella and Johnson

to the left of ·the echocardiographic video monitor and the right ventricle is in the near field. In addition, a short-axis view of the ventricles can occasionally be obtained from the RPS approach (Figure 14, B). This view can be obtained via the short-axis view of the aortic valve or atrial septum with an inferior and medial tilt of the ultrasound beam. From the RPS long axis of the SVC, superior vena caval compression from a malignant lymphosarcomatous mass was seen in a patient; the mass had not been seen by subcostal imaging (Figure 14, C).

CONCLUSION

The right parasternal window can yield relevant information in conjunction with or in lieu of information gathered from standard imaging planes. This includes views of the aortic valve, ascending aorta, transverse aorta, descending aorta, and the coronary arteries. In addition, the atrial septum can be viewed from a more perpendicular right-to-left and a superior-to-inferior angle. The superior and inferior vena cavae, vena caval-to-pulmonary baffles or conduits, vena caval-to-systemic venous atria, and systemicto-pulmonary arterial shunts can be evaluated by this approach. Though the right parasternal border images cannot be visualized adequately in all patients, we strongly believe that this imaging region should be used more frequently in the evaluation of patients with congenital as well as acquired heart disease.

As echocardiographers we constantly try to improve the diagnostic information yielded from each echocardiogram. Certainly the right parasternal window can increase this yield with patients in whom the necessary information cannot be obtained from standard echocardiographic images.

The authors greatly appreciate the critical review of this communication by Mary Jo Rice, MD, G. Michael Silberbach, MD, Randal L. Imus, RCVT, and Robert B. Brazee, RCVT, and would like to thank Robert W. McDonald, RCVT, RDCS, for the subject idea and thoughtful critique. We also thank Dennis K. Carney,

journal of the American Society of Echocardiography july-August 1993

RCVT, director of the Non-Invasive Cardiovascular Technology program at Spokane Community College, for his sincere commitment to producing outstanding, competent, and skilled cardiac sonographers.

REFERENCES

l. Kisslo J, Adams D, Mark D. The Doppler examination. In: Basic Doppler echocardiography. New York: Churchill Livingstone, 1986:63-89.

2. Feigenbaum H. Diseases of the aorta. In: Echocardiography. 4th ed. Philadelphia: Lea & Febiger, 1986:606-20.

3. Nakamura K, Suzuki S, Satomi G, eta!. Two dimensional echocardiographic and RI angiographic features of aneurysms of the ascending aorta in patients with anuloaortic ectasia. Journal of Cardiography (Tokyo) 1981;11:239-52.

4. Minagoe S, Tei C, Kisanuki A, et a!. Noninvasive pulsed Doppler echocardiographic detection of the direction of shunt flow in patients with atrial septal defect: usefulness of the right parasternal approach. Circulation 1985;71:745-53.

5. Tei C, Tanaka H, Kashima T, Yoshimura H, Minagoe S, Kanehisa T. Real-time cross-sectional echocardiography of the interatrial septum by right atrium-interatrial septum-left atrium direction of ultrasound beam. Circulation 1979; 60:539-47.

6. Minagoe S, Yoshimura H, Sakurai S, eta!. Detection of ostium secundum atrial septal defect by 2-D echocardiographyusefulness of right parasternal approach ( ASA direction) [ Abstract). Jpn Circ J 1981;45:930.

7. Muhler EG, Englehardt W, Bemuth G. Detection of sinus venosus atrial septal defect by two-dimensional echocardiography. Eur Heart J 1992;13:453-6.

8. Capannari T, Daniels S, Meyer R, Schwartz D, Kaplan S. Sensitivity, specificity and predictive value of two-dimensional echocardiography in detecting coronary artery aneurysms in patients with Kawasaki disease. J Am Coli Cardia! 1986;7:355-60.

9. Arjunan K, Daniels S, Meyer R, Schwartz D, Barron H, Kaplan S. Coronary artery caliber in normal children and patients with Kawasaki disease but without aneurysms: an echocardiographic and angiographic study. JAm Coli Cardia! 1986;8: 1119-24.

10. Yoshida H, Maeda T, Funabashi T, et a!. Subcostal twodimensional echocardiographic imaging of peripheral right coronary artery in Kawasaki disease. Circulation 1982; 65:956-61.

11. Chin A, Sanders S, Williams R, Lang P, Norwood W, Castaneda A. Two-dimensional echocardiographic assessment of caval and pulmonary venous pathways after the Senning operation. Am J Cardiol1983;52:118-26.

right parasternal imaging: an underutilized echocardiographic technique

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