3D-sonography as 2-dimensional M-mode-sonography in foetal echocardiography

Aim: Establishing a technique employing 3D-ultrasound for the echocardiographic examination of foetuses. Method: M-mode sonography has reached considerable importance in the detection of arrhythmia as well as pathological changes of the heart valves and contraction disorders of the foetal heart. The variability of the position of the foetus leads to problems typically arising with this method. The ventro-anterior position along the long axis of the foetal heart, being the optimal position for prenatal echocardiography, allows no examination in M-mode because the plane of the valve lies vertically in relation to the direction of the ultrasound. A special appliance of 3D-sonography solves the problem by providing a 2-dimensional examination technique of the heart in M-mode independent of the position of the foetal heart. The method allows simultaneous measurement of the movement of different parts of the myocardium in several different planes. By fixing the position of the applicator tin B-mode) and choosing the 3D-sequence in the,,free-hand-mode" one gets a 2-dimensional time-tissue-block which contains all movements in the chosen axis. These,,time planes" can be deliberately selected for the examination of different planes in the fixed B-mode image which shows their variations along the time axis. Results: Our study describes the application and evaluation of this examination during pregnancy between the 28th and 40th week. Reliable images of the AV-valves or the aortic valve could be produced in 73% of examinations.