@article{feuerste2007tmi,
  author = {Marco Feuerstein and Thomas Mussack and Sandro M. Heining and Nassir
	Navab},
  title = {Intraoperative Laparoscope Augmentation for Port Placement and Resection
	Planning in Minimally Invasive Liver Resection},
  journal = {{IEEE} Trans. Med. Imag.},
  year = {2008},
  volume = {27},
  pages = {355--369},
  number = {3},
  month = {March},
  abstract = {In recent years, an increasing number of liver tumor indications were
	treated by minimally invasive laparoscopic resection. Besides the
	restricted view, two major intraoperative issues in laparoscopic
	liver resection are the optimal planning of ports as well as the
	enhanced visualization of (hidden) vessels, which supply the tumorous
	liver segment and thus need to be divided (e.g., clipped) prior to
	the resection. We propose an intuitive and precise method to plan
	the placement of ports. Preoperatively, self-adhesive fiducials are
	affixed to the patient's skin and a computed tomography (CT) data
	set is acquired while contrasting the liver vessels. Immediately
	prior to the intervention, the laparoscope is moved around these
	fiducials, which are automatically reconstructed to register the
	patient to its preoperative imaging data set. This enables the simulation
	of a camera flight through the patient's interior along the laparoscope's
	or instruments' axes to easily validate potential ports. Intraoperatively,
	surgeons need to update their surgical planning based on actual patient
	data after organ deformations mainly caused by application of carbon
	dioxide pneumoperitoneum. Therefore, preoperative imaging data can
	hardly be used. Instead, we propose to use an optically tracked mobile
	C-arm providing cone-beam CT imaging capability intraoperatively.
	After patient positioning, port placement, and carbon dioxide insufflation,
	the liver vessels are contrasted and a 3-D volume is reconstructed
	during patient exhalation. Without any further need for patient registration,
	the reconstructed volume can be directly augmented on the live laparoscope
	video, since prior calibration enables both the volume and the laparoscope
	to be positioned and oriented in the tracking coordinate frame. The
	augmentation provides the surgeon with advanced visual aid for the
	localization of veins, arteries, and bile ducts to be divided or
	sealed.},
  doi = {10.1109/TMI.2007.907327}
}