Perioperative 3D transoesophageal echocardiography. Part 1: fundamental principles

Figures

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  Fig 1. Transoesophageal echocardiography transducers. (A) A comparison between a 64-crystal linear array in a 2D TOE probe and (B) 2500 crystals in a matrix array 3D TOE probe. Images courtesy of Michael Corrin. (C) Microscopy image displaying the piezoelectric crystals in a matrix array compared with a human hair (with permission).7 (D) A schematic representation of the matrix array transducer shows the arrangement of thousands of piezoelectric elements in the azimuthal and elevation directions (with permission).12 Electronic activation of individual piezoelectric elements allows the acquisition of a volumetric dataset.

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  Fig 2. Multiplane imaging. The 3D matrix array probe permits simultaneous multiplane 2D imaging. (A) Illustration of the heart showing triplane imaging with the three 2D planes at 0°, 60° and 120°. (B) The corresponding three 2D images from the mid-oesophageal 0°, 60° and 120° appear simultaneously in a single display. Courtesy of Toronto General Hospital Department of Anaesthesia, Perioperative Interactive Education website (https://pie.med.utoronto.ca). (C) Biplane imaging (xPlane) with independent plane control shows two 2D images on a single display. One plane is fixed (the base view, left image) while the secondary plane (right image) can be adjusted (by moving the blue triangular marker in the left image to the right or left) so that it can show multiple orthogonal slices of the ventricle. Although in this example the secondary plane is orthogonal, its angle can be tilted between 0° and 180° in relation to the base plane.

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  Fig 3. Three-dimensional imaging acquisition modes. A 3D structure is displayed with an illustration of the 3D volume in relation to the heart for (A–C). (A) A live mode acquisition of aortic valve. (B) Zoom mode acquisition of the mitral valve. (C) Full volume acquisition of the left ventricle. (D) Colour flow Doppler imposed over the mitral and tricuspid valves, depicting in blue the blood inflow. Courtesy of Toronto General Hospital Department of Anaesthesia, Perioperative Interactive Education website (https://pie.med.utoronto.ca).

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  Fig 4. Three-dimensional dataset acquisition workflow.