In recent years, an increasing number of liver tumor indications were treated by minimally invasive laparoscopic
resection. Besides the restricted view, a major issue in laparoscopic liver resection is the enhanced visualization
of (hidden) vessels, which supply the tumorous liver segment and thus need to be divided prior to the resection.
To navigate the surgeon to these vessels, pre-operative abdominal imaging data can hardly be used due to intraoperative
organ deformations mainly caused by appliance of carbon dioxide pneumoperitoneum and respiratory
motion. While regular respiratory motion can be gated and synchronized intra-operatively, motion caused by
pneumoperitoneum is individual for every patient and difficult to estimate.
Therefore, we propose to use an optically tracked mobile C-arm providing cone-beam CT imaging capability intraoperatively.
The C-arm is able to visualize soft tissue by means of its new flat panel detector and is calibrated
offline to relate its current position and orientation to the coordinate system of a reconstructed volume. Also
the laparoscope is optically tracked and calibrated offline, so both laparoscope and C-arm are registered in the
same tracking coordinate system.
Intra-operatively, after patient positioning, port placement, and carbon dioxide insufflation, the liver vessels are
contrasted and scanned during patient exhalation. Immediately, a three-dimensional volume is reconstructed.
Without any further need for patient registration, the volume can be directly augmented on the live laparoscope
video, visualizing the contrasted vessels. This augmentation provides the surgeon with advanced visual aid for
the localization of veins, arteries, and bile ducts to be divided or sealed.