Illustrative visualization of 3D planning models for augmented reality in liver surgery.
OBJECTIVE
Augmented reality (AR) obtains increasing acceptance in the operating room. However, a meaningful augmentation of the surgical view with a 3D visualization of planning data which allows reliable comparisons of distances and spatial relations is still an open request.


METHODS
We introduce methods for intraoperative visualization of 3D planning models which extend illustrative rendering and AR techniques. We aim to reduce visual complexity of 3D planning models and accentuate spatial relations between relevant objects. The main contribution of our work is an advanced silhouette algorithm for 3D planning models (distance-encoding silhouettes) combined with procedural textures (distance-encoding surfaces). In addition, we present a method for illustrative visualization of resection surfaces.


RESULTS
The developed algorithms have been embedded into a clinical prototype that has been evaluated in the operating room. To verify the expressiveness of our illustration methods, we performed a user study under controlled conditions. The study revealed a clear advantage in distance assessment with the proposed illustrative approach in comparison to classical rendering techniques.


CONCLUSIONS
The presented illustration methods are beneficial for distance assessment in surgical AR. To increase the safety of interventions with the proposed approach, the reduction of inaccuracies in tracking and registration is a subject of our current research.
Hansen
Christian
C
Fraunhofer MEVIS, Insitute for Medical Image Computing, Bremen, Germany. Christian.Hansen@mevis.fraunhofer.de
Wieferich
Jan
J
Ritter
Felix
F
Rieder
Christian
C
Peitgen
Heinz-Otto
HO
D006801:Humans; D021621:Imaging, Three-Dimensional; D007432:Intraoperative Period; D008107:Liver Diseases / Q000601:surgery*; D012984:Software; D013028:Space Perception; D025321:Surgery, Computer-Assisted / Q000379:methods* / Q000592:standards