International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV. Part B5. Istanbul 2004
assistant who is using a laptop. Mostly the second approach is
used because the surgeon can keep his concentration to the
surgical intervention. Mainly the visualisation helps the surgeon
in the orientation during surgery. It also simplifies the
discussion between the radiologist and the surgeon during the
sonographic evaluation of the liver after mobilization.
2.8 Distribution of the results
For the easy exchange of the planning results between the
German Cancer Research Center (DKFZ) and the University-
Clinic in Heidelberg a web-based system was established called
LiverLine (Thorn, 2004c). This system provides the possibility
of a secure distribution of the visualisation and volumetric
estimation with the help of an virtual private network
(Guichard, 2000; Yuan, 2001).
This system was established because there where the following
drawbacks of the old workflow:
— the results of the operation planning were transferred
by means of carrying a laptop (validation by the
radiologist, presentation of the 3D-visualisation for
the surgeon in the steps) Therefore, the DKFZ
coworker had to arrange an appointment, copy the
data on a laptop and drive to the hospital.
— inconsistent distributed data storage by copying the
data from the central computer to a laptop.
— the current state of the planning process was not
traceable by the clinical partners during the planning
phase.
— no documentation of the operation planning has taken
place above.
These problems are solved by the web-based information
system LiverLine as shown in the new workflow. All data of
the liver operation planning is available by means of a web
server and a database. The information from the operation
planning is stored in the LiverLine database and can be
accessed with a web browser. All partners involved have online
access to the data of the operation planning so that they are not
any longer temporal and spatially bound. At any time, the
current status of the operation planning, as well as the original
medical images and derived data (segmentations and 3D-
visualisations) can be queried at any time from within the
German Cancer Research Center and the clinic.
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Optimized workflow with the help of the LiverLine
For the representation of the 3D-visualisation over the Internet
the Virtual Reality Modelling Language (VRML) is used. The
VRML model can be rotated and zoomed so the surgeon can
view the liver from all sides.
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The safety requirements of medical information systems have
highest priority. Therefore it must be guaranteed for the
LiverLine that no unauthorized access to confidential patient
data is possible. The most important features of such a internet
solution are:
— Web server: authentication and access control
— Virtual Private Network (VPN) between the German
Cancer Research Center and the hospital
— SSL (Secure Socket Layer) encryption for the security
of the data communication
3. RESULTS AND DISCUSSION
The described planning procedure is completely integrated into
the clinical workflow. For living donor liver transplantation it is
a standardized method for donor selection and is performed for
each donor in the Heidelberg University Clinic. It turned out
that about 30% of planned potential donors were dismissed
because of anatomical reasons. Also volumetric findings lead to
disaffirmations of donors.
The presentation of the planning results topped the
communication between all integrated medical disciplines.
Especially the radiologists were easily able to point up their
findings in the primary CT-images with the help of the three-
dimensional visualisations. Additionally during the surgical
intervention the sonographic findings were traced with the help
of the planning results.
With the help of the LiverLine the planning workflow was
optimized. The clinicians are now able to analyze the findings
of the computer-based planning without any longer temporal
and spatially bounds. This leads to a transparent workflow that
arises the acceptance of the planning procedure in the clinic.
The next step will be the expansation of the planning service to
other clinics which can easily be adapted with the LiverLine.
Our experiences in computer-based operation planning of the
last six years, show a high acceptance and need of three-
dimensional reconstructions in the clinic. But there won't be
any time of the physicians for the most time consuming work -
the segmentation procedure. For that reason we prefer to
centralize this image processing step to be done in a
competence center as a service provided to the clinicians in the
future. With this work we illustrated how such a service can be
provided.
4. REFERENCES
Broelsch CE, Emond JC, Whitington PF, Thistlethwaite JR,
Baker AL, Lichtor JL., 1990, Application of reduced-size liver
transplants as split grafts, auxiliary orthotopic grafts, and living
related segmental transplants. Ann Surg. ;212:368-375.
Discussion 375-377.
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