[Transesophageal, anatomic and Doppler echocardiography. Technic, indications, interpretation].
Cardiac ultrasonography completed by the Doppler technique has demonstrated his ability to visualize almost all of the anatomical pathology including description and semi-quantification of pathological blood flows within the heart. However, the physical properties of the ultrasound beam frequently limit the imaging process and Doppler flow studies. Absorption of ultrasound by the chest wall is a major determinant of quality and hence interpretation, together with the depth of the examined zone of interest. It's a common finding that echo-Doppler images are better in children than in obese adults. Moreover, strong echo-reflectors, such as calcification or prosthetic heart valves, create large acoustic shadowing effects behind which obtaining an ultrasound signal is difficult if not impossible. For this reason transesophageal echocardiography represents a new essential window into the heart. By positioning a transducer mounted on a fibroscopy sheath into the esophagus in close contact with the left atrium, images of unequaled quality are obtained. An image-resolution of the order of 1-2 mm explains the diagnostic quality in infectious aortic and mitral valve diseases for assessing small vegetations, annular abscesses, and regurgitant lesions by adding color-coded Doppler. The investigation of prosthetic valves dysfunction is completely renewed for detecting disinsertion and thromboses. Heart screening for systemic emboli includes mandatory how the visualization of left (and also right) auricles and the interatrial septum associated with contrast study. Lesions of the descending aorta (aneurysms, thromboses and especially dissections) are perfectly documented in combination with color-Doppler indicating true and false channels as well as re-entry sites. Lastly, other applications are being developed including global and segmental myocardial contractility at rest or even at stress, although this last application is still at the experimental stage. Transesophageal echocardiography therefore appears to constitute a real revolution as an added possibility to the cardiological use of ultrasound: the indication for this "window" being decided for the preferential cases described above only after having performed a standard echo examination. Very often, the indication will be raised by the echocardiographer who, after performing a conventional echo may consider that better or supplementary information could be obtained via the esophageal route. This technique performed by trained operators, is relatively simple, minimally traumatic and can be performed on an outpatient basis provided certain precautions, imposed by the preparation and the consequences of premedication received by the patient, are respected.
Scheublé
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Centre Cardiologique du Nord, Saint-Denis.
Castillo-Fenoy
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D001013:Aorta, Thoracic / Q000033:anatomy & histology*; D015150:Echocardiography, Doppler / Q000295:instrumentation / Q000379:methods; D004617:Embolism / Q000175:diagnosis*; D004697:Endocarditis, Bacterial / Q000175:diagnosis; D004947:Esophagus; D006321:Heart / Q000033:anatomy & histology*; D006331:Heart Diseases / Q000175:diagnosis*; D006349:Heart Valve Diseases / Q000175:diagnosis; D006801:Humans
Echocardiographie, anatomique et Doppler, transoesophagienne. Technique, indications, interprétation.