Cardiac Imaging & Motion
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| Editor's Note: | ||||||||
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The anatomy chapter is broken up into two different subsections. The first section contains the basic principles of cardiac imaging, nomenclature, probe manipulation and 20 standard views that are obtainable in most patients. This section is recommended to the novice or beginning echocardiographer. The second subsection contains the standard and non-standard views. Non-standard views are not always obtainable in all patients but can provide a valuable view when the anatomy is difficult to discern or if a particular angle is needed for further interrogation. This section provides a more comprehensive look at the anatomical planes and views that are possible with a transesophageal echocardiography probe. This section is recommended for the advanced student or expert echocardiographer. |
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| To go to the advanced section of the anatomy chapter click here. | ||||||||
| Objectives | ||||||||
| The objectives are covered by the basic anatomical principles and the 20 standard views. At the completion of this chapter, the student will be able to: | ||||||||
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| Introduction | ||||||||
| The heart is a three dimensional structure that is displayed on a two dimensional angiographic image. Echocardiography cuts a tomographic plane in space, through which, the heart moves. Since the heart may have slightly different orientation from patient to patient, standard views have been developed that allow comparison from intra-study and inter-study images. | ||||||||
The anatomic view of the heart depends upon the acoustic window, the
probe position, and the longitudinal (electronic) angle of the ultrasound
beam. Acoustic windows can be either transthoracic, transesophageal,
epiaortic or epicardial. The ASE-SCA has developed
standard nomenclature and views for transesophageal and transthoracic acoustic
windows . The transesophageal section presents the standard views followed by the nonstandard views. The standard views should be obtainable in most patients. Non-standard views offers some advantages, but are not obtainable in most patients. |
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| Cardiac Imaging | ||||||||
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An angiographic image of the heart is a three dimensional cut that is displayed on a two dimensional display. Anatomical structures will appear to be displayed in the same plane when, clearly, they are not in the same plane. The three dimensional image crosses many planes but is displayed in a two dimensional background. A 2D echocardiographic image is truly a two dimensional cut of a three dimensional structure that is displayed on a two dimension display. The 2D echocardiographic machine cannot image across many planes. The 2D echocardiographic machine must sweep thru the three dimensional structure to reveal the anatomy of the three dimensional structure. |
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| Cardiac Motion | ||||||||
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The heart moves during contraction and relaxation. During
the contraction-relaxation process the three dimensional heart is moving through the two dimension cut of the 2D echocardiographic sector scan. The
types of cardiac motion are: |
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| Translation is the movement of the heart in the chest. A swinging back-and-forth motion in the thoracic cavity is an example of translation. Rotation is a circular motion of the heart around the long axis of the heart. Torsion is the wringing motion of the heart where the base is stationary but from apex to base the heart contracts further, much like wringing a wet cloth. All of these motions will cause the heart to pass through the ultrasound's sector scan. Therefore, when interpreting views of the heart, slightly different angles can cause small variations in the structures seen in the scan. Some structures will be seen to pass through the view which can result in some interesting artifacts or possible misinterpretation of the scan. | ||||||||
| Cardiac Axis | ||||||||
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