Cardiac Imaging & Motion

Non-Standard &  Standard Views Chapter Go to ASE-SCA Standard Views
 
Editor's Note:
 

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.

 
To go to the SCA Views Only 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: 
 
  • Identify the Cardiac Planes
  • Describe the Anatomy-Image Correlation
  • List the ASE-SCA Nomenclature (2D)
  • Describe Probe Manipulation and Insertion
  • Recognize the 20 Standard Views
  • Recognize the Anatomy in each of the 20 Standard Views.
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 offer some advantages, but may not be obtainable in all patients.
 
Cardiac Imaging
 

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 through the three dimensional structure to reveal the anatomy of the three dimensional structure.

 
Cardiac Motion
 

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:

  • Translation
  • Rotation
  • Torsion
  Image Translation Image Rotation Image Torsion
 
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
 
The heart is not anatomically located in the thorax that allows it to be easily described by classical anterior-posterior or caudad-crainial planes. The heart is about 30 degrees off the caudad-crainial axis. Therefore, the heart is described by its own internal axis. The axis from the base of the heart to the apex of the heart is called the long axis of the heart (LAX). If all four chambers are visualized then the view is called the 4 chamber view (4CV). Perpendicular to the 4 chamber view is the long axis view of the heart where 2 chambers are visualized, called the 2 chamber view (2CV). Perpendicular to the 2 chamber view and the 4 chamber view is the short axis view (SAX) of the heart. In the short axis view the classical view of the "doughnut" of the left ventricle is visualized.
Cardiac Axis Animation
 

Cardiac Axis Left Ventricular Long Axis (LVLAX)
Cardiac Planes LV Long Axis
LV Long Axis - 4 Chamber View
LV Short Axis