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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_5795_Библиотеки_им_академика_М_И_Перельмана.pdf
208
M. Köstenberger et al.
• Describe systemic and pulmonary venous return, hepatic veins, continuity of
IVC and interatrial septum (IAS).
• Assess atrioventricular junction: atrioventricular valves and interventricular septum (IVS).
• Ventriculoarterial junction: origin and course of great vessels.
11.4 Normal 2D Echocardiogram Findings
11.4.1 Parasternal Views
11.4.1.1 Parasternal Long Axis View (Fig.11.2)
Obtained by applying transducer to second till fourth intercostal space, orienting
plane along major axis of heart—from left hip to right shoulder—right ventricle
(RV) and outow tract of LV can be identied.
In infants thymus seen between thoracic wall and heart-improves visualisation
and enlarges sonographic window.
Next structures: IVS and left atrium (LA); inow portion of LV with mitral valve,
outow portion with aortic valve and ascending aorta (Ao)—visualised in
same plane.
11.4.1.2 Parasternal Short Axis Views (Figs.11.3 and11.4)
Obtained by rotating transducer 90° clockwise from long axis view. Several shortaxis planes can be generated by tilting transducer from apical region inferiorly to
base of heart superiorly. Doing this, cross section of LV and part of RV seen at different anatomic levels: cardiac apex, papillary muscles, mitral valve, heart base with
origin of great vessels.
Leftward angulation of transducer: RV outow tract and main pulmonary artery
(PA) with its bifurcation visualised.
At base of heart: origin of coronary arteries.
Fig. 11.2 Long axis view. Part of right ventricle
(RV) seen behind chest wall. Inow part of left
ventricle (LV) with mitral valve (MV) as well as
outow tract of LV with aortic valve (AV)
depicted; LA left atrium
11 Basics ofPaediatric Echocardiography
209
a
Fig. 11.3 Parasternal short axis view at base of the heart. Aorta (Ao) visualised in cross section,
pulmonary artery (PA) with its bifurcation seen left to Ao. Basic grey scale echocardiography (a)
and colour Doppler ow image (b)—PA encoded in blue, Ao in part included as dark blue, the red
colour encodes atrial ow
Fig. 11.4 Parasternal short axis view—at level of
mitral valve. Left ventricle (LV) depicted in cross
section, with leaets of mitral valve appearing as
sh mouth (→) in diastole; RV right ventricle
b
11.4.1.3 Apical Views
Apical four-chamber view (Fig.11.5).
Standard apical four-chamber view: transducer applied to cardiac apex, plane
oriented perpendicular to atrial and ventricular septa.
All four cardiac chambers, mitral and tricuspid valve, IAS and IVS imaged with
anterior angulation of transducer LV outow tract and ascending aorta visualised
(“ve-chamber view”).
11.4.2 Subcostal Views
11.4.2.1 Sagittal Subcostal View
Transducer placed in subcostal region in sagittal plane: descending aorta visualised
left to IVC.
210
Fig. 11.5 All four chambers of the heart—apical
4-chamber view. Interventricular and interatrial
septum (→) seen. LV left ventricle, RV right
ventricle, LA left atrium, RA right atrium
M. Köstenberger et al.
11.4.2.2 Subcostal Four-Chamber View (Fig.11.6)
Transducer applied to subcostal region, plane tilted superiorly: all four cardiac
chambers imaged similar to apical four-chamber view; especially in newborns and
infants, interatrial septum visualised, especially well also drainage of pulmonary
veins (PV) can be demonstrated.
11.4.3 Suprasternal View (Fig.11.7)
Transducer placed in suprasternal notch with overextended neck: entire aortic arch
with arising supra-aortic vessels visualised. Right PA imaged in cross section
beneath aortic arch.
• This view particularly helpful for differentiating between left or right aortic arch
and assessing supra-aortic great vessels.
11.5 Other Techniques
11.5.1 M (Motion)-Mode Echocardiography
M-mode—rst US application in cardiac imaging; based on 1D view of heart.
Amplitude and motion recorded in real time.
Today M-mode generated from 2DUS, imaging plane used to position M-mode
beam (Fig.11.8).
Applications of M-mode in paediatric echocardiography:
• Measurement of cardiac chambers, vessels and cardiac septa.
• LV systolic function (shortening and ejection fraction).
• Study of valve motion and interventricular septum.
11 Basics ofPaediatric Echocardiography
Fig. 11.6 Interatrial septum (IAS)—subcostal
view. IAS (→) imaged especially well, RA right
atrium, LA left atrium
Fig. 11.7 Aortic arch—suprasternal view. Entire
aortic arch with origin of supra-aortal vessels (→)
imaged, right pulmonary artery (RPA) seen in
cross section beneath aortic arch
211
Fig. 11.8 M-mode for left ventricular
function assessment: Parasternal long axis
view—M-mode based measurement of left
ventricular function. Abbreviations: LV left
ventricle, RV right ventricle, LA right atrium;
systolic (→) and diastolic fraction (green
lines) of ventricular motion
212
PP V124
2
-=
M. Köstenberger et al.
11.5.2 Doppler Sonography inEchocardiography
11.5.2.1 CDS with2DUS
Demonstrates several aspects of blood ow in heart and great vessels.
Assesses direction of intra- and extracardiac shunts, valvular stenoses and
regurgitations.
11.5.2.2 PW- andCW-Doppler
Used in combination with 2DUS and CDS to measure direction and velocity of
blood ow in cardiac chambers, great vessels or across intra- and extracardiac shunts.
• Advantage of PW-Doppler: ability to sample blood ow in small specic area.
• Limitation of PW-Doppler: maximum detectable velocity limited by frequency
(Nyquist border). Therefore CW-Doppler used for quantication of severe stenosis and high-ow velocities; also often angle measurements not reliable or
impossible—thus intrinsic measurement errors. Therefore, try to do ow measurements whenever possible at section where ow direction is nearly parallel to
US beam direction and thus measurements achievable at low Doppler angle
(<20°) not needing angle correction.
11.5.2.3 Calculation ofPressure (P) Gradients (P1 Minus P2)
Obtained by measuring peak velocity (V) using modied Bernoulli equation:
Severity of stenosis can be estimated, and pressure in PV can be calculated from
ow velocity of tricuspid regurgitation/peak pressure gradient RV-RA+10mmHg
= peak pressure in RV or through VSD.
11.5.3 Assessment ofLV andRV Function
Often used for assessing heart function, usually incorporated into device with cardiac quantication software—equations:
• Assessment of LV systolic function (Fig.11.8):
– Shortening fraction (SF): M-mode index of percent change in LV diameter
that occurs with systole (SF = LV internal diameter in diastole—LV internal
diameter in systole/LV diameter in diastole).
– Ejection fraction (EF): 2D-echocardiography—calculated from percent
change in LV cavity area that occurs with systole (EF = end-diastolic LV volume—end-systolic LV volume/end-diastolic LV volume).
• Assessment of RV systolic function (M-mode TAPSE):
– Tricuspid annular plane systolic excursion (TAPSE): M-mode index of dis-
placement of RV base between systole and diastole. Measures longitudinal
systolic RV function; currently the most objective estimation of RV function
in adults and children (Fig.11.9).
11 Basics ofPaediatric Echocardiography
Fig. 11.9 TAPSE apical 4-chamber view: White broken line indicates M-mode cursor placement
at tricuspid lateral annulus—representative M-mode image of tricuspid annular plane systolic
excursion (TAPSE). The absolute longitudinal displacement (in cm) indicated by green line, with
upper (white line) and lower level (yellow line) indicating systolic and diastolic excursion, respectively. RA right atrium, LV left ventricle
213
11.6 Special Echocardiographic Techniques
11.6.1 Transoesophageal Echocardiography (TEE)
TEE—semi-invasive procedure (transducer introduced into oesophagus).
Major indications of TEE in children.
• Intraoperative or perioperative echocardiography.
• Exact evaluation of morphology of atrial and ventricular septal defects, of cardiac valves and in cases of suspected infective endocarditis or intracardiac
thrombosis.
• Guidance of interventional procedures during cardiac catheterisation.
• Limited transthoracic echocardiographic window.
11.6.2 Three-/Four-Dimensional (3D/4D) Echocardiography
During last decade computer-based 3D-reconstruction techniques and real-time
3DUS imaging (“4DUS”) have become an additional tool used to calculate ventricular volumes and to assess function (see Fig. 3.20).
3D/4DUS may play a role in exact tomographic evaluation of complex congeni-
tal anomalies and allows more detailed planning of cardiac surgery in some cases.
214
M. Köstenberger et al.
Also useful for assessing valves or postoperative situations (e.g. umbrella occluding
device after interventional closure of a septal defect).
11.6.3 Tissue Doppler Imaging (TDI)
New technique using Doppler principles to measure myocardial motion: Most
important applications: measurement of LV and RV systolic and diastolic function.
11.6.4 Contrast-Enhanced US (ce-US/CEUS)
Agitated saline or polygelatine—injected intravenously in order to produce contrast
echoes. “Echovist”®, a rst generation US-contrast agent unable to pass lung capillaries, is no longer available and therefore now, for example, “Gelofusine” (a plasmaexpander giving some echoes, Braun pharmaceutics/Germany) may be used.
• Clinical application: detection of intracardiac right-to-left shunts, pulmonary
arteriovenous malformations, etc.
Other CM currently has no importance in paediatric echocardiography.
11.7 Normal Values
Vary with age, weight, gender, etc.; age adapted chards should be used. Various
websites such as “parameter(z)” offer a practical tool for checking all kind of relevant measurements and values for different ages, etc. See Tables 11.1, 11.2 and 11.3.
Table 11.1 Normal values for functional parameters
Table 11.2 Normal values of peak
Doppler ow rates
Ascending aorta 1.2–1.8 m/s
Descending
aorta
Pulmonary
artery
Tricuspid valve E-wave: 0.6 m/s, A-wave: 0.4 m/s
Mitral valve E-wave: 0.9 m/s, A-wave 0.5 m/s
Vena cava 0.7 m/s
From Snider AR, Serwer GA, Ritter SB (1997)
Echocardiography in pediatric heart disease. Mosby, St.
Louis: Year Book, Inc
Shortening fraction (SF) (%) 28–44
Ejection fraction (EF) (%) 58.5–75
0.9–1.1 m/s
0.7–1.1 m/s
11 Basics ofPaediatric Echocardiography
215
Table 11.3 Normal values for TAPSE: interactive online table - see respective
publication (Köstenberger, 2009), accessible via website Parameter(z) http://param-
eterz.blogspot.com/2008/09/z-scores-of-cardiac-structures.html.
Note: Most normal values, especially of dimensions of cardiac chambers, vary
with age and body surface area.
1
11.8 Pathologic Findings
11.8.1 Congenital Heart Defects withLeft-to-Right Shunt
11.8.1.1 Atrial Septal Defect (ASD)
The interatrial septum (IAS) is assessed best from subcostal and apical four- chamber
views. Depending on location of defect US plane has to be angulated superiorly or
inferiorly from standard four-chamber view.
IAS is thin, particularly at fossa ovalis—may be difcult to distinguish true
defects from artefacts. True defects usually show echogenic margins (“T artefact”).
CDS and PW-Doppler demonstrate interatrial left-to-right shunt; haemodynamic
relevance of ASD assessed by demonstrating RV volume overloads with dilatation
of RA and PA.
TEE helpful in doubtful cases.
Common Types of ASD (Fig.11.10):
Ostium secundum ASD (ASD II):
• Most common type of ASD (~70%).
• Defect in midportion of IAS, sometimes multiple defects (multifenestrated IAS).
• Occasionally associated with atrial septal aneurysm.
Fig. 11.10 Atrium septum defect of secundum type (ASD II)—apical four-chamber view. CDS
demonstrates interatrial left-to-right shunt by red colour signals crossing interatrial septum.
Enlarged right atrium (RA) and right ventricle (RV) with straight course of interventricular septum
indicating volume overload. LA left atrium
1
Regression equations for calculation of z scores of cardiac structures in a large cohort of healthy
infants, children and adolescents: an echocardiographic study. Pettersen MD, Du W, Skeens ME,
Humes RA (2008) J Am Soc Echocardiogr 21:922–934
216
M. Köstenberger et al.
Patent foramen ovale (PFO):
• In neonates and infants small, ap-like opening with left-to-right shunt in mid-
portion of IAS (overlap of septum primum with septum secundum).
• In ~30% of adults visible (demonstration of right-to-left shunt during valsalva
manoeuvre with contrast-enhanced echocardiography using an agent that quickly
vanishes or does not pass lung capillary bed—see above).
Sinus venosus ASD (superior vena cava defect):
• Defect in most superior and posterior part of IAS.
• Usually no septal tissue between defect and posterior atrial wall.
• In most cases, anomalous drainage of one (or more) right PV into RA or superior
vena cava (SVC), sometimes SVC overrides defect.
11.8.1.2 Atrioventricular Septal Defects (AVSD)
AVSD characterised by common atrioventricular (AV) valve with one common or two
separate orices. Characteristically leaets of common AV-valve insert at same level in
ventricles (normally insertion of tricuspid valve more apical than of mitral valve).
If AV-valve attached to crest of interventricular septum (IVS), shunting only
between RA and LA possible (partial AVSD or ostium primum ASD). AV-valve
regurgitation of different degrees at commissures between leaets (“clefts”) of common AV-valve always present.
Size of interatrial and interventricular communications and ventricles as well as
morphology of common AV-valve best evaluated in subcostal and apical fourchamber views and in parasternal short axis view.
Degree of AV-valve regurgitation and shunting assessed by CDS and CW-Doppler.
Partial AVSD (Ostium Primum ASD):
• Defect only in lowest part of IAS near AV-valve in subcostal and apical four-
chamber view.
• Left-to-right shunt only at atrial level.
• Variable degree of mitral valve regurgitation.
Complete AVSD (Fig.11.11):
• Ostium primum ASD and inlet VSD in the apical and subcostal four-
chamber views.
• Interatrial, interventricular and LV-RA shunt.
• Common AV-valve with mitral and tricuspidal valve regurgitation.
11.8.1.3 Ventricular Septal Defects (VSD)
VSD—most common congenital heart defect. Interventricular septum (IVS) divided
into small upper membranous septum and larger muscular septum. Muscular septum consists of inlet, trabecular and outlet-(infundibular) portion.
11 Basics ofPaediatric Echocardiography
Fig. 11.11 Atrioven tricular (AV) septal
defect—apical four-chamber view. Defects at
ventricular and atrial level (→), common
AV-valve. LV left ventricle, LA left atrium, RA
right atrium, RV right ventricle
Fig. 11.12 Perimem branous ventricular septal
defect (VSD)—parasternal long axis view. CDS
demonstrates left-to-right shunt beneath aortic
valve through VSD (→). LV left ventricle, LA left
atrium, Ao aorta, RV right ventricle
217
Most VSD located in membranous part, often adjacent muscular septum involved
(“perimembranous” VSD).
Muscular and subarterial (infundibular) VSD (below great arteries) less common.
Because IVS visible not in single plane entirely, different views necessary to
provide detailed information about localisation and size of defect and its relation to
adjacent structures.
CDS improves detection of small or multiple VSDs, shows direction of shunt
across defect.
CW-Doppler allows indirect estimation of RV systolic pressure using Bernoulli
equation (systolic blood pressure minus peak pressure gradient between LV and RV
= systolic RV pressure) when blood pressure measured simultaneously; the larger
the defect, the lower the gradient between ventricles. Haemodynamic relevance of
left-to-right shunt demonstrated by degree of enlargement of LA, LV and RV and
dilatation of PA due to increased pulmonary blood ow and pulmonary venous return.
Perimembranous VSD (Fig.11.12):
• Parasternal long and short axis views, in modied four-chamber view: defect
beneath aortic valve.
• Sometimes associated with ventricular septal pseudoaneurysm.