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A-545
2001
Virtual TEE. A Virtual Reality Transesophageal Echocardiography (TEE) Simulator To Facilitate Understanding of TEE Scan Planes
Gregg S. Hartman, M.D.; Christopher W. Wiley, M.D.; Mark Mullin
Anesthesiology, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire, United States
Introduction:TEE has become an integral component of modern cardiovascular anesthesia as demonstrated by the development of the SCA/ASE perioperative TEE Certification Examination and the Guidelines for performing a comprehensive intraoperative multiplane TEE examination(1). Performance of a complete TEE examination requires an understanding of the 3 dimensional(3-D) orientation of the heart, the TEE probe and scan plane angle. Aids for these relationships have included anatomy and TEE texts, 3-D heart models, and recently computer programs like TEECHER®. A common limitation is the "predetermined" nature of the illustrations demonstrating standard views, but not how to obtain them. Current computer simulation technology permits the creation and manipulation of complex 3-D objects on affordable computers and has permitted the development of "virtual-echocardiography". We present a PC based TEE simulator which permits 360 degree viewing of the heart, TEE probe, multiplane scan array and, most importantly, the resultant TEE scan displayed in conventional "upsidedown" format while manipulating the probe using onscreen controls.

Methods: Utilizing the V3 core devloped by Vibrant3D, Inc., running on a standard PC platform in the Windows environment, an anatomically correct 3-D heart model, a TEE probe and scan plane were integrated with representative control knobs to create both a display of the TEE scan plane through the heart and the resulting TEE image. The interface permits full manipulation of the probe relative to the heart(depth of insertion, retroflexion/anteflexion, rotation, left/right deflection, transducer angle advancement), as well as control over the viewers vantagepoint. Scan-plane "cuts" of the heart can be viewed either from a cephalad-posterior view, as if from the "top of the table" (standard for most anesthesiolgists)or from an anterior - posterior approach, (i.e., facing the patient) (standard for most cardiologists).

Results: Figure 1 illustrates the virtual TEE images. Screen-left displays the heart, TEE probe images & scan planes and their spatial relationships. The probe controls are centrally located and screen-right displays the resultant scanned image.Discussion: Because TEE is invasive, trainees rarely have the luxury of unlimited time for practice and exploration. Futhermore, since the heart and probe are not visible, the effect of probe controls on the position of the scan plane relative to the heart must be deduced from the TEE image itself. This is difficult and non-intuitive for most. By solving both of these problems, our simulator should both accelarate and enhance skill acquisition by trainees. Studies are underway to test this hypothesis.

1)Anes Analg 1999;89:870-84

Anesthesiology 2001; 95:A545
Figure 1