TeleInViVo: Telemedicine on the Desktop and on the Road

Fraunhofer CRGG has developed TeleInViVo, a medical visualization software programm that permits two geographically seperated radiologists to view patient data simultaneously and to consult with each other in real time. It is an extension of the Interactive Visualizer of volumes (InViVo), Fraunhofer IGD´s family of highly portable software that has helped bring computer-based visualization power to the desktop. In 1996, the Battelle Pacific Northwest Laboratories deployed for DARPA the first version of TeleInViVO to Bosnia. They did so as part of the MustPAC (Medical Ultrasound, Three-dimensional and Protable with Advanced Communications) 3D Ultrasound Diagnostic System. We also tested TeleInViVo over the transatlantic ATM link between CRGG Providence and IGD Darmstadt as part of the trade project.

Architecture

TeleInViVo extends InViVo´s software architecture by using distributed, shared state system. When changes to the local state are made, the scope of these changes is analyzed. Messages communicating state changes are sent over the network. Analogous changes are then made in the state of remote system. If the TeleInViVo cvannot be kept synchronized by these incremental updates, the entire state transfers from one participant to the other, reestablishing consistent view.

Scanning 3D ultrasound data

Fraunhofer CRGG has been studying ways to use TeleInViVo in new domains and aplications scenarios. One such area, which prioves increasingly important for this kind of technology, is in 3D ultrasonography. Becaue of ist noninvasive nature, relatively low cost, and portability, ultrasound is quickly becoming the modality of choice when considering difficult-to-serve or expensive-to-serve areas. The MustPAC system was located at the field hospital in Tuzla. A similar workstation was located at Madigan Army Medical Center in the state of Washington (near seattle), where radiology specialist consulted in real time with their medical counterparts on location in Bosnia. They used TCP/IP over shared military communication channels to make the connection. The Madigan site was configured with a six degree-of-freedom immersion Probe input device. Attached to the probe`s "stylus" is a mock-up of an ultrasound transducer. This supports remote diagnosis be letting the remote expert arbitrarily scan the data rather than the patient, using the immersion Probe as though it were an ultrasound sensor. The concept of scanning hte data rather than the patient is a relatively new paradigm an d significantly aids in remote collaboration.

Collaborative diagnosis

As Figure D shows, TeleInViVo supports shared viewing tools to help facilitate discussion among the collaborators. These tolls include a telepointer, which had become standard in collaborative applications. Additionally, domain-specific pointing methods are supported by extending proven viewing tools like InViVo´s realtime magnifying glass. TeleInViVo allows one user to operate the magnifying glass on the local screen and have a duplicate glass moving synchronously on the remote end. This lets the user call attetion to spüecific details in the data by transmitting part of the user´s "way of looking at the data." Because the data being visualized is 3D, common visualization tasks involve frequent changesa in the angle from which useres view the data. TeleInViVo lets users interactivelya change the view of both the local and remote machine, while keeping the view consistent. In this manner, both usres can movethe data around and telepoint on the top of the 3D views. Visualization settings not controlled by direct manipulation are also shared between the users. TeleInViVo´s menus manipulate a shared set of settings ion this case. By controlling the view on the remote end as well as the current filtering settings, TeleInViVop can be used to teach or assist with a diagnosis session. For example, a specialist could assist a physician from a remote site by selecting an appropriate view and isolating critical details in the data.

For more information on TeleInViVo, contact John Coleman, Fraunhofer CRCG, jcoleman@crcg.edu or Georgios Sakas, Fraunhofer IGD Darmstadtm gsakas@igd.fhg. de. For the MustPAC system, contact Rik Littlefield, Battelle Pacific Northwest Laboratories, rj_littlefield@pnl.gov.