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Submitted by Dr. Yasser Mokhtar, MD. Dept. of internal
medicine. School of medicine, University of South Dakota.
TEE improves diagnostic information in various cardiovascular diseases compared to conventional echo.
There are two approaches to a
The first is to begin imaging from transgastric position (normally obtained
when the transducer is at 40-45 cm from incisors) and then pull the probe
back to examine various sections of the heart from apex to base and to
view aorta by posterior rotation of transducer.
The second approach is to start at the base of the heart (25-30 cm
from the incisors) and progress towards transgastric views and examination
of aorta during withdrawal.
Biplane TEE imaging
This was described by Fisher et al. in 1991 and
later by Khandheria et al. in 1994. Biplane probe gives additional longitudinal
windows. Transducer position is detected by echocardiographic images on
monitor and probe?s centimeter markings that measure the depth from the
incisor teeth to transducer position within the esophagus
et al., 1991
and Khandheria et al.,
I. Horizontal TEE imaging
horizontal imaging, structures that are anterior anatomically are most
distant from transducer and appear on the bottom of the screen and posterior
structures appear at the top because they are more proximal to the probe.
and retroflexion are the maneuvers most commonly used to optimize anatomic
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A. Basal short axis scans:
is at 25-30 cm from incisor teeth where it is posterior to the left atrium.
With mild anteflexion (tilting the tip superiorly) or slight withdrawal
of the transducer sequential basal short axis scans are obtained. Traditional
orientation is to place anterior structures at the bottom, posterior structures
at the top, left sided structures to viewer?s right on video display.
valve view: Where aortic root, aortic valve cusps and atrial septum
artery view: The left coronary artery is seen more often and more
clearly than the right coronary artery. TEE is used to detect left main
coronary stenosis and anomalous coronary arteries and to assess coronary
blood flow (Pearce
et al., 1989, Yoshida et al., 1990, Salloum et al., 1991, Iliceto et
al., 1991, Smolin et al., 1992 and Rubin et al., 1992).
atrial appendage view: Left atrial appendage is seen as a triangular
extension of the left atrium (pectinate muscles are seen with high-resolution
TEE transducers and should not be confused with thrombi). Also seen
are the left upper pulmonary vein, the transverse sinus of pericardium,
the transverse orifice of SVC, aortic and pulmonary valves, the right
pulmonary veins and the right and left atria separated by the interatrial
artery view: Main pulmonary artery and its bifurcation, proximal
ascending aorta and superior vena cava are seen in this view. Clockwise
rotation of the transducer allows the visualization of the proximal
portion of the left pulmonary artery. The portion distal to its first
bifurcation can be seen. Counterclockwise rotation enables the examiner
to see the very proximal portion of the left pulmonary artery. Its distal
portion can not be viewed as it is obscured by air in the left main
B. Frontal four chamber scans:
position is at the mid esophageal level (30-35 cm from the incisor teeth.
ventricle outflow view: Transducer tip anteflexed. Shows the left
ventricle outflow tract, anterolateral papillary muscle, aortic valve,
left atrium, mitral valve and its support structures.
view: Transducer tip retroflexed. Shows atrial septum with membrane
of fossa ovalis, ventricular septum, septal leaflet of the tricuspid
valve and septal attachment of the anterior mitral leaflet (mitral valve
inserts higher than the tricuspid valve), anterolateral papillary muscle,
coronary sinus, right atrium, right ventricle, right coronary artery
and inferior vena cava.
sinus view: The coronary sinus courses in the atrioventricular groove
and enters the right atrium at the lower margin of the atrial septum.
II. Longitudinal TEE imaging:
In the longitudinal
plane, to optimize the anatomic delineation, axial rotation and lateral
movement of the transducer are the maneuvers most commonly used.
A. Primary longitudinal views:
are in the sagittal plane of the thorax but are oblique to the heart.
Transducer tip is at 25-30 cm from the incisor teeth. Axial rotation of
the transducer from the left to right side yields the following views
in the following sequence:
ventricle and left atrial two chambers view: is ideal for longitudinal
examination of left atrial appendage, left pulmonary veins, anterior
and inferior walls of the left ventricle and the mitral leaflets and
its support apparatus.
ventricle outflow long axis view: allows visualization of the right
ventricle outflow tract, pulmonary valve and main and proximal pulmonary
arteries. It is helpful in assessment of the congenital anomalies of
the right ventricle outflow tract and for detection of proximal pulmonary
aorta and atrial septum view: Aortic dissection localized to the
aortic root is best delineated in this imaging plane.
right atrial and atrial septal view: shows SVC in long axis, ascending
aorta, left atrium, atrial septum, right atrium, right atrial appendage
and IVC. This view is commonly used during contrast echocardiography
for detection of patent foramen ovale. Atrial septal defects are best
delineated in this view. It also facilitates evaluation of atrial masses
arrays can be reoriented from sagittal plane of the thorax to planes that
are in the long or short axes of the heart.
axis view: results from leftward flexion of the transducer tip.
Permits left ventricle outflow tract visualization in the long axis.
axis view: results from rightward flexion of the transducer tip.
Comparable to conventional transthoracic short axis view. Visualizes
aortic valve in short axis.
III. Transgastric views:
is advanced into fundus of stomach (35-40 cm from incisors). Images are
oriented to show anterior structures at top and left sided structures
to right of screen. Both views are similar to transthoracic parasternal
long and short axes views.
axis view: permits evaluation of the anterior and inferior left
ventricle walls, both papillary muscles and the mitral valve.
axis view: By anteflexing the transducer, the examiner can scan
from the apices of the left and right ventricles to the level of the
IV. Examination of the aorta:
TEE can image
the entire aorta from the basal short axis views of the left ventricle.
The transducer is rotated counterclockwise so that the descending aorta
is visualized. The aortic root, the proximal supravalvular-ascending aorta,
the transverse aortic arch and the descending aortic arch are examined.
A 1-2 cm long region of ascending thoracic aorta just above the aortic
root is obscured by the air filled trachea and is a blind spot for monoplane
horizontal imaging but is more easily seen on biplane longitudinal imaging
which enhances visualization of the descending aorta. Transthoracic and
transesophageal imaging should be combined to facilitate complete evaluation
of the entire aorta (Fisher
et al., 1991).
of the right heart cavities with dense ultrasound reflectances during
IV contrast injection was first applied clinically in 1968
et al., 1968).
of the dense intracavitary echoes is the microbubbles within the injectate.
Any agitated liquid injected intravenously causes this effect
et al., 1980).
air microbubbles with the diameter of pulmonary capillaries persist in
the blood for less than one second before dissolving, agitated agents
injected IV can not cross the lungs and enter the left heart chambers.
Thus, the presence of echoic contrast entering the left heart chambers
after IV injection of an agitated liquid indicates the presence of a right
to left shunt (Kerber
et al., 1974 and Valdes et al., 1984).
can be used to delineate right heart anatomy. Identification of intracardiac
shunts, particularly patent foramen ovale in patients with unexplained
cerebral ischemia remains the most frequent indication for contrast echocardiography.
Simple agitated saline solution remains the most commonly used contrast
agent for such studies
et al., 1988).