title: Transesophageal real-time three-dimensional echocardiography methods and initial in vitro and human in vivo studies.
abstract: OBJECTIVE
  The purpose of this study was to develop a transesophageal probe that: 1) enables on-line representation of the spatial structures of the heart, and 2) enables navigation of medical instruments.
  
  
  BACKGROUND
  Whereas transthoracic real-time 3-dimensional (3D) echocardiography could recently be implemented, there is still no corresponding transesophageal system. Transesophageal real-time 3D echocardiography would have great potential for numerous clinical applications, such as navigation of catheters.
  
  
  METHODS
  The newly developed real-time 3D system is based on a transesophageal probe in which multiple transducers are arranged in an interlaced pattern on a rotating cylinder. This enables continuous recording of a large echo volume of 70 mm in length and a sector angle of 120 degrees . The presentation of the volume-reconstructed data is made with a time lag of <100 ms. The frame rate is up to 20 Hz. In addition to conventional imaging, the observer can obtain a stereoscopic image of the structures examined with red/blue goggles.
  
  
  RESULTS
  It was shown in vitro on ventricle- and aorta-form agar models and in vivo that the system enables excellent visualization of the 3D structures. Shape, spatial orientation, and the navigation of various catheters (e.g., EPS-catheter, Swan-Ganz-catheter), stents, or atrial septal defect occluders could be recorded on-line and stereoscopically depicted. The size of the echo sector enables a wide field of view without changing the position of the probe.
  
  
  CONCLUSIONS
  Transesophageal real-time 3D echocardiography can be technically realized with the system presented here. The in vitro and in vivo studies show particularly the potential for navigation in the heart and large vessels on the basis of stereoscopic images.
authors.affiliation: Department of Cardiology and Angiology, University Hospital Freiburg, Freiburg, Germany. MHandke@uhbs.ch
authors.forename: Michael
authors.initials: M
authors.lastname: Handke
authors.forename: Gudrun
authors.initials: G
authors.lastname: Heinrichs
authors.forename: Urs
authors.initials: U
authors.lastname: Moser
authors.forename: Felix
authors.initials: F
authors.lastname: Hirt
authors.forename: Felix
authors.initials: F
authors.lastname: Margadant
authors.forename: Felix
authors.initials: F
authors.lastname: Gattiker
authors.forename: Christoph
authors.initials: C
authors.lastname: Bode
authors.forename: Annette
authors.initials: A
authors.lastname: Geibel
mesh_terms: D001011:Aorta / Q000000981:diagnostic imaging; D003199:Computer Systems; D019560:Echocardiography, Three-Dimensional / Q000295:instrumentation / Q000379:methods*; D017548:Echocardiography, Transesophageal / Q000295:instrumentation / Q000379:methods*; D006352:Heart Ventricles; D006801:Humans; D066298:In Vitro Techniques; D008955:Models, Cardiovascular