[3-D echocardiography reconstruction of the thoracic aorta]

Since the beginning of the nineties the combination of echocardiography equipment with a computer algorithm for 3-D reconstruction is commercially available. The initial experiences with this unit (TomTec-system, Munich, Germany) in clinical and intraoperative settings are reported. The described unit consisted of a specially constructed transesophageal echo probe, in which the transducer (5 MHz) is mounted on a sliding carriage allowing free up and down movement in axial directions. The transducer obtains digitally dynamic 3-D information by automated pull-back of the transducer in 0.67 mm slices, gated to ECG and respiration. The information is stored on a hard disk and in the computer RAM. The acquisition time--depending on different trigger intervals--ranges from 5 to 10 minutes, usually not longer than for conventional TEE. The images are stored in special 4-D (that is 3-D in motion) data sets, allowing the calculation of any desired plane in real-time at a triggered ECG phase or dynamically. Thus this technique gives the capability of retrospective reconstruction of any view into the aorta in contrast to the omniplane TEE examination, the so-called anyplane echocardiography. In the clinical management of patients with thoracic aortic diseases transesophageal echocardiography (TEE) has become the central diagnostic tool as well as for the follow-up. This is caused by its high sensitivity and specificity comparable with that obtained by MRI. Nevertheless in a small percentage of cases there remains a questionable situation concerning the morphology of the distal ascending aorta and the aortic arch illuminated by the use of 3-D reconstruction.