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principles of transthoracic echocardiography—practical aspects 5 Fig. 1.2 Examples of inconveniently holding the transducer. In (a) the fourth and fifth finger are between the transducer and the skin like writing with a pencil. No stable contact to the skin results in non-stabilization of the transducer. In (b) the holding is like encompassing a horizontal bar. Thus, rotation of the transducer is not performed by the hand—it has to be done by the shoulder and/or cubital joint. In (c) the thumb is too extended and the pulp of the thumb is not at the notch causing a blind feeling when moving or rotating the transducer. In addition, the mistake in Fig. 1.2a is also seen. In (d) no finger has contact to the skin. Thus, every trembling of the hand is bridged to the transducer and consequently to the images on the monitor. It is also not possible to get a basis for a defined flipping, tilting and rotation, because the starting position is not stable. position of the transducer in the parasternal long-axis view of the heart ( Fig. 1.1c, d). The loss of the feeling for the notch and extended or tensed fingers in the starting position will induce discomfort and restrict the degrees of freedom for the movement of the transducer. Thus, wrong transducer holdings ( Fig. 1.2a–d) will lead to disorientation and difficulties in fine-tuning for adjusting correct standardized views. An often observed mistake is not to fix the fourth and fifth finger on the skin of the patient, leading to an unstable transducer position. With tilting over the small edge using the transducer holding of this starting position in the long-axis view, the mitral valve, for example, can be moved from the right to the left and vice versa without losing the longaxis view. A clockwise rotation of the transducer from the starting position is easy ( Fig. 1.3a), because there is free space to turn the thumb clockwise by bending backwards the fourth and fifth fingers ( Fig. 1.3b, c). A 90° rotation is easily possible and thus, you will get the feeling of rotating exactly 90° clockwise at the left parasternal window to visualize a correct short-axis view ( Fig. 1.3d). After acquisition of the necessary parasternal short-axis views the transducer is rotated counterclockwise back to the correct long-axis view. The correct position of the apical window and the correct apical long-axis view can be achieved by sliding down from the parasternal window to the apex without losing the sectional plane of the long-axis view ( Fig. 1.4). At the end of this movement the right hand can support itself against the thorax with the complete auricular finger ( Figs 1.5a,b). Fingers placed between the transducer and the thorax in this position will disturb or inhibit the correct documentation of apical standard views by positioning the transducer too perpendicular to the body surface inducing a right twisted position of the heart within the scan sector and/or foreshortening views. Without tilting and flipping the correct apical long-axis view, a clockwise rotation of exactly 60° can be performed ( Fig. 1.5c) to visualize a correct 2-chamber view ( Fig. 1.5d). Combining a defined transducer holding always with the longaxis view and getting the stable feeling for this combination are the prerequisites for target-controlled scanning and the accurate assessment of cardiac structures. It is obvious that minimal manipulations of the transducer position can be easily performed and stably fixed using the correct scanning technique. Thus, a correct scanning technique is the prerequisite for images with at least best possible image quality. The aim of a sufficient transthoracic, and also transoesophageal, echocardiographic investigation should be an almost reproducible standardized documentation, which enables an accurate diagnostic analysis for correct decision-making. A standardization of the documentation enables a comparison between current and previous findings to detect changes, improvements or deterioration of the cardiac state in follow-ups. Furthermore, the more standardization is present, the more
6 chapter 1 conventional echocardiography—basic principles Fig. 1.3 Starting with the correct holding of the transducer for displaying the parasternal long-axis view (a) the transducer is exactly rotated 90° clockwise (b), after this movement the pulp of the thumb is at the broad side of the transducer at the top and the third finger is at the broad side of the transducer at the bottom (b), while the fourth and fifth finger are retracted (c), but they have still contact to the skin. This holding is linked with all parasternal short-axis views (d). Fig. 1.4 Photo composition of the transducer holding for the different long-axis views between the standardized parasternal approach and the standardized apical approach. On the left side the different holdings at the correct parasternal position, at a position between the parasternal and apical position, as well as at the correct apical position are shown. In the centre the photomontage of all transducer holdings is shown documenting the plane of all long-axis views. On the right side the corresponding views are shown.
left ventricular diastolic function