2014
26.
Mewes, A; Adler, S; Rose, G; Hansen, C
Augmented-Reality-Mikroskop – Implementierung einer flexiblen Datenverbindung zwischen CT-Angiographieanlage und Mikroskop Proceedings Article
In: Proceedings of the Annual Meeting of the German Society of Computer- and Robot-Assisted Surgery, pp. 28–31, München, 2014.
@inproceedings{mewes_augmented-reality-mikroskop_2014,
title = {Augmented-Reality-Mikroskop - Implementierung einer flexiblen Datenverbindung zwischen CT-Angiographieanlage und Mikroskop},
author = {A Mewes and S Adler and G Rose and C Hansen},
url = {https://www.var.ovgu.de/pub/Mewes_2014_CURAC.pdf},
year = {2014},
date = {2014-01-01},
booktitle = {Proceedings of the Annual Meeting of the German Society of Computer- and Robot-Assisted Surgery},
pages = {28–31},
address = {München},
abstract = {Während einer neurochirurgischen Intervention muss es dem Operateur möglich sein diagnostische Bilder zu aktuali-
sieren. Bei dem hier verwendeten neurochirurgischen Mikroskop können diagnostische Bilder als virtuelle Modelle und
Schnittbilder eingeblendet werden, um einen Sichtwechsel zwischen Patient und externen Bildschirmen zu vermeiden.
Um eine intraoperative Aktualisierung der Modelle zu ermöglichen, wurde im Rahmen dieser Arbeit das Mikroskop an
eine C-Arm-Angiographieanlage über einen PACS-Server angebunden. Außerdem wird ein effizienter Workflow vorge-
stellt, der u. a. die Modellgenerierung aus den DICOM-Bildern mit Hilfe der Entwicklungsumgebung MeVisLab vor-
sieht. Unter Laborbedingungen durchgeführte Experimente ergaben eine mittlere Dauer der Modellaktualisierung von
maximal 18,5 ± 2,5 min. Die Abweichung der virtuellen Überlagerung von realen Strukturen im Mikroskop liegt im We-
sentlichen im Submillimeterbereich. Das Mikroskopsystem bildet mit diesem Workflow eine solide Forschungsgrundlage
für zukünftige Projekte im Bereich der neurochirurgischen Navigation},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
Während einer neurochirurgischen Intervention muss es dem Operateur möglich sein diagnostische Bilder zu aktuali-
sieren. Bei dem hier verwendeten neurochirurgischen Mikroskop können diagnostische Bilder als virtuelle Modelle und
Schnittbilder eingeblendet werden, um einen Sichtwechsel zwischen Patient und externen Bildschirmen zu vermeiden.
Um eine intraoperative Aktualisierung der Modelle zu ermöglichen, wurde im Rahmen dieser Arbeit das Mikroskop an
eine C-Arm-Angiographieanlage über einen PACS-Server angebunden. Außerdem wird ein effizienter Workflow vorge-
stellt, der u. a. die Modellgenerierung aus den DICOM-Bildern mit Hilfe der Entwicklungsumgebung MeVisLab vor-
sieht. Unter Laborbedingungen durchgeführte Experimente ergaben eine mittlere Dauer der Modellaktualisierung von
maximal 18,5 ± 2,5 min. Die Abweichung der virtuellen Überlagerung von realen Strukturen im Mikroskop liegt im We-
sentlichen im Submillimeterbereich. Das Mikroskopsystem bildet mit diesem Workflow eine solide Forschungsgrundlage
für zukünftige Projekte im Bereich der neurochirurgischen Navigation
sieren. Bei dem hier verwendeten neurochirurgischen Mikroskop können diagnostische Bilder als virtuelle Modelle und
Schnittbilder eingeblendet werden, um einen Sichtwechsel zwischen Patient und externen Bildschirmen zu vermeiden.
Um eine intraoperative Aktualisierung der Modelle zu ermöglichen, wurde im Rahmen dieser Arbeit das Mikroskop an
eine C-Arm-Angiographieanlage über einen PACS-Server angebunden. Außerdem wird ein effizienter Workflow vorge-
stellt, der u. a. die Modellgenerierung aus den DICOM-Bildern mit Hilfe der Entwicklungsumgebung MeVisLab vor-
sieht. Unter Laborbedingungen durchgeführte Experimente ergaben eine mittlere Dauer der Modellaktualisierung von
maximal 18,5 ± 2,5 min. Die Abweichung der virtuellen Überlagerung von realen Strukturen im Mikroskop liegt im We-
sentlichen im Submillimeterbereich. Das Mikroskopsystem bildet mit diesem Workflow eine solide Forschungsgrundlage
für zukünftige Projekte im Bereich der neurochirurgischen Navigation
25.
Wang, L; Hansen, C; Zidowitz, S; Hahn, H
Segmentation and Separation of Venous Vasculatures in Liver CT Images Proceedings Article
In: Proc. SPIE, pp. 90350Q–90350Q–8, San Diego, USA, 2014.
@inproceedings{wang_segmentation_2014,
title = {Segmentation and Separation of Venous Vasculatures in Liver CT Images},
author = {L Wang and C Hansen and S Zidowitz and H Hahn},
url = {https://www.var.ovgu.de/pub/Wang_SPIE2014_Manuscript.pdf},
year = {2014},
date = {2014-01-01},
booktitle = {Proc. SPIE},
volume = {9035},
pages = {90350Q–90350Q–8},
address = {San Diego, USA},
abstract = {Computer-aided analysis of venous vasculatures including hepatic veins and portal veins is important in liver
surgery planning. The analysis normally consists of two important pre-processing tasks: segmenting both vascu-
latures and separating them from each other by assigning different labels. During the acquisition of multi-phase
CT images, both of the venous vessels are enhanced by injected contrast agent and acquired either in a common
phase or in two individual phases. The enhanced signals established by contrast agent are often not stably ac-
quired due to non-optimal acquisition time. Inadequate contrast and the presence of large lesions in oncological
patients, make the segmentation task quite challenging. To overcome these difficulties, we propose a framework
with minimal user interactions to analyze venous vasculatures in multi-phase CT images. Firstly, presented
vasculatures are automatically segmented adopting an efficient multi-scale Hessian-based vesselness filter. The
initially segmented vessel trees are then converted to a graph representation, on which a series of graph filters
are applied in post-processing steps to rule out irrelevant structures. Eventually, we develop a semi-automatic
workflow to refine the segmentation in the areas of inferior vena cava and entrance of portal veins, and to si-
multaneously separate hepatic veins from portal veins. Segmentation quality was evaluated with intensive tests
enclosing 60 CT images from both healthy liver donors and oncological patients. To quantitatively measure the
similarities between segmented and reference vessel trees, we propose three additional metrics: skeleton distance,
branch coverage, and boundary surface distance, which are dedicated to quantifying the misalignment induced
by both branching patterns and radii of two vessel trees.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
Computer-aided analysis of venous vasculatures including hepatic veins and portal veins is important in liver
surgery planning. The analysis normally consists of two important pre-processing tasks: segmenting both vascu-
latures and separating them from each other by assigning different labels. During the acquisition of multi-phase
CT images, both of the venous vessels are enhanced by injected contrast agent and acquired either in a common
phase or in two individual phases. The enhanced signals established by contrast agent are often not stably ac-
quired due to non-optimal acquisition time. Inadequate contrast and the presence of large lesions in oncological
patients, make the segmentation task quite challenging. To overcome these difficulties, we propose a framework
with minimal user interactions to analyze venous vasculatures in multi-phase CT images. Firstly, presented
vasculatures are automatically segmented adopting an efficient multi-scale Hessian-based vesselness filter. The
initially segmented vessel trees are then converted to a graph representation, on which a series of graph filters
are applied in post-processing steps to rule out irrelevant structures. Eventually, we develop a semi-automatic
workflow to refine the segmentation in the areas of inferior vena cava and entrance of portal veins, and to si-
multaneously separate hepatic veins from portal veins. Segmentation quality was evaluated with intensive tests
enclosing 60 CT images from both healthy liver donors and oncological patients. To quantitatively measure the
similarities between segmented and reference vessel trees, we propose three additional metrics: skeleton distance,
branch coverage, and boundary surface distance, which are dedicated to quantifying the misalignment induced
by both branching patterns and radii of two vessel trees.
surgery planning. The analysis normally consists of two important pre-processing tasks: segmenting both vascu-
latures and separating them from each other by assigning different labels. During the acquisition of multi-phase
CT images, both of the venous vessels are enhanced by injected contrast agent and acquired either in a common
phase or in two individual phases. The enhanced signals established by contrast agent are often not stably ac-
quired due to non-optimal acquisition time. Inadequate contrast and the presence of large lesions in oncological
patients, make the segmentation task quite challenging. To overcome these difficulties, we propose a framework
with minimal user interactions to analyze venous vasculatures in multi-phase CT images. Firstly, presented
vasculatures are automatically segmented adopting an efficient multi-scale Hessian-based vesselness filter. The
initially segmented vessel trees are then converted to a graph representation, on which a series of graph filters
are applied in post-processing steps to rule out irrelevant structures. Eventually, we develop a semi-automatic
workflow to refine the segmentation in the areas of inferior vena cava and entrance of portal veins, and to si-
multaneously separate hepatic veins from portal veins. Segmentation quality was evaluated with intensive tests
enclosing 60 CT images from both healthy liver donors and oncological patients. To quantitatively measure the
similarities between segmented and reference vessel trees, we propose three additional metrics: skeleton distance,
branch coverage, and boundary surface distance, which are dedicated to quantifying the misalignment induced
by both branching patterns and radii of two vessel trees.
24.
Hansen, C; Zidowitz, S; Stravrou, G; Oldhafer, K; Hahn, H
Impact of Model-based Risk Analysis for Liver Surgery Planning Journal Article
In: International Journal of Computer Assisted Radiology and Surgery, vol. 9, no. 2, pp. 473–480, 2014, ISSN: 1861-6410.
@article{hansen_impact_2014,
title = {Impact of Model-based Risk Analysis for Liver Surgery Planning},
author = {C Hansen and S Zidowitz and G Stravrou and K Oldhafer and H Hahn},
url = {https://www.var.ovgu.de/pub/Hansen_RiskAnalysis_IJCARS2013.pdf},
doi = {10.1007/s11548-013-0937-0},
issn = {1861-6410},
year = {2014},
date = {2014-01-01},
journal = {International Journal of Computer Assisted Radiology and Surgery},
volume = {9},
number = {2},
pages = {473–480},
abstract = {Purpose A model-based risk analysis for oncologic liver surgery was described in previous work [1].
In this paper, we present an evaluation of this method.
Methods To prove whether and how the risk analysis facilitates the process of liver surgery planning,
an explorative user study with 10 liver experts was conducted. The purpose was to compare and
analyze their decision making.
Results The results of the study show that model-based risk analysis enhances the awareness of
surgical risk in the planning stage. Participants preferred smaller resection volumes and agreed more
on the safety margins width in case the risk analysis was available. In addition, time to complete the
planning task and confidence of participants was not increased when using the risk analysis.
Conclusion This work shows that the applied model-based risk analysis may influence important
planning decisions in liver surgery. It lays a basis for further clinical evaluations and points out
important fields for future research.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Purpose A model-based risk analysis for oncologic liver surgery was described in previous work [1].
In this paper, we present an evaluation of this method.
Methods To prove whether and how the risk analysis facilitates the process of liver surgery planning,
an explorative user study with 10 liver experts was conducted. The purpose was to compare and
analyze their decision making.
Results The results of the study show that model-based risk analysis enhances the awareness of
surgical risk in the planning stage. Participants preferred smaller resection volumes and agreed more
on the safety margins width in case the risk analysis was available. In addition, time to complete the
planning task and confidence of participants was not increased when using the risk analysis.
Conclusion This work shows that the applied model-based risk analysis may influence important
planning decisions in liver surgery. It lays a basis for further clinical evaluations and points out
important fields for future research.
In this paper, we present an evaluation of this method.
Methods To prove whether and how the risk analysis facilitates the process of liver surgery planning,
an explorative user study with 10 liver experts was conducted. The purpose was to compare and
analyze their decision making.
Results The results of the study show that model-based risk analysis enhances the awareness of
surgical risk in the planning stage. Participants preferred smaller resection volumes and agreed more
on the safety margins width in case the risk analysis was available. In addition, time to complete the
planning task and confidence of participants was not increased when using the risk analysis.
Conclusion This work shows that the applied model-based risk analysis may influence important
planning decisions in liver surgery. It lays a basis for further clinical evaluations and points out
important fields for future research.
2013
23.
Wang, L; Hansen, C; Zidowitz, S; Hahn, H
Interactive Segmentation of Vascular Structures in CT Images for Liver Surgery Planning Proceedings Article
In: Proceedings of the Annual Meeting of the German Society of Computer- and Robot-Assisted Surgery (CURAC), pp. 98–102, Univ. Prof. Dr. Mag. Wolfgang Freysinger, Innsbruck , Österreich, 2013.
@inproceedings{wang_interactive_2013,
title = {Interactive Segmentation of Vascular Structures in CT Images for Liver Surgery Planning},
author = {L Wang and C Hansen and S Zidowitz and H Hahn},
url = {https://www.var.ovgu.de/pub/Wang_CURAC2013_Manuscript.pdf},
year = {2013},
date = {2013-01-01},
booktitle = {Proceedings of the Annual Meeting of the German Society of Computer- and Robot-Assisted Surgery (CURAC)},
pages = {98–102},
publisher = {Univ. Prof. Dr. Mag. Wolfgang Freysinger},
address = {Innsbruck , Österreich},
abstract = {Vasculature analysis based on CT images is indispensable in liver surgical planning and diagnosis of liver disease. We
propose a novel framework and efficient workflow with minimal user interactions to analyze liver vasculature in multi-
phase CT images. To ensure segmentation quality and efficiency, a set of semi-automatic algorithms are applied to initially
segment different vascular structures in different phase. A fully automatic vessel separation procedure runs parallel to
separately connected hepatic and portal veins. In addition, an interactive editing method is integrated into the framework
to refine the segmentation of each individual structure. Quantitative evaluations of segmented vessels conducted for 60
test data sets are demonstrated.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
Vasculature analysis based on CT images is indispensable in liver surgical planning and diagnosis of liver disease. We
propose a novel framework and efficient workflow with minimal user interactions to analyze liver vasculature in multi-
phase CT images. To ensure segmentation quality and efficiency, a set of semi-automatic algorithms are applied to initially
segment different vascular structures in different phase. A fully automatic vessel separation procedure runs parallel to
separately connected hepatic and portal veins. In addition, an interactive editing method is integrated into the framework
to refine the segmentation of each individual structure. Quantitative evaluations of segmented vessels conducted for 60
test data sets are demonstrated.
propose a novel framework and efficient workflow with minimal user interactions to analyze liver vasculature in multi-
phase CT images. To ensure segmentation quality and efficiency, a set of semi-automatic algorithms are applied to initially
segment different vascular structures in different phase. A fully automatic vessel separation procedure runs parallel to
separately connected hepatic and portal veins. In addition, an interactive editing method is integrated into the framework
to refine the segmentation of each individual structure. Quantitative evaluations of segmented vessels conducted for 60
test data sets are demonstrated.
22.
Black, D; Issawi, J Al; Rieder, C; Hansen, C; Hahn, H
Auditory Support for Navigated Radiofrequency Ablation Proceedings Article
In: Proceedings of the Annual Meeting of the German Society of Computer- and Robot-Assisted Surgery (CURAC), pp. 30–33, Univ. Prof. Dr. Mag. Wolfgang Freysinger, Innsbruck , Österreich, 2013.
@inproceedings{black_auditory_2013,
title = {Auditory Support for Navigated Radiofrequency Ablation},
author = {D Black and J Al Issawi and C Rieder and C Hansen and H Hahn},
url = {https://www.var.ovgu.de/pub/curac2013_dblack_Auditory_support_for_Navigated_Radiofrequency_Ablation.pdf},
year = {2013},
date = {2013-01-01},
booktitle = {Proceedings of the Annual Meeting of the German Society of Computer- and Robot-Assisted Surgery (CURAC)},
pages = {30–33},
publisher = {Univ. Prof. Dr. Mag. Wolfgang Freysinger},
address = {Innsbruck , Österreich},
abstract = {Radiofrequency ablation is applied to treat a lesion using a needle inserted into the patient, which delivers local radiof-
requency energy. Guided surgical methods allow surgeons to view the placement of the needle in relation to the patient
to aid in guiding the tip of the needle to the target point. Unfortunately, such methods require that surgeons remove at-
tention from the patient in order to receive guidance information from a screen. We introduce a novel method to align
and insert an ablation needle using auditory display, allowing the surgeon to retain attention on the patient. First eval-
uation results show that novice users can successfully guide a needle towards a target point using primarily auditory
display. We hypothesize that successful auditory display will lead to increased attention on the patient and reduce un-
necessary operator head and neck movements.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
Radiofrequency ablation is applied to treat a lesion using a needle inserted into the patient, which delivers local radiof-
requency energy. Guided surgical methods allow surgeons to view the placement of the needle in relation to the patient
to aid in guiding the tip of the needle to the target point. Unfortunately, such methods require that surgeons remove at-
tention from the patient in order to receive guidance information from a screen. We introduce a novel method to align
and insert an ablation needle using auditory display, allowing the surgeon to retain attention on the patient. First eval-
uation results show that novice users can successfully guide a needle towards a target point using primarily auditory
display. We hypothesize that successful auditory display will lead to increased attention on the patient and reduce un-
necessary operator head and neck movements.
requency energy. Guided surgical methods allow surgeons to view the placement of the needle in relation to the patient
to aid in guiding the tip of the needle to the target point. Unfortunately, such methods require that surgeons remove at-
tention from the patient in order to receive guidance information from a screen. We introduce a novel method to align
and insert an ablation needle using auditory display, allowing the surgeon to retain attention on the patient. First eval-
uation results show that novice users can successfully guide a needle towards a target point using primarily auditory
display. We hypothesize that successful auditory display will lead to increased attention on the patient and reduce un-
necessary operator head and neck movements.
21.
Mönch, J; Mühler, K; Hansen, C; Oldhafer, K; Stavrou, G; Hillert, C; Logge, C; Preim, B
The LiverSurgeryTrainer: training of Computer-based Planning in Liver Resection Surgery Journal Article
In: International Journal of Computer Assisted Radiology and Surgery, vol. 8, no. 5, pp. 809–818, 2013.
@article{monch_liversurgerytrainer_2013,
title = {The LiverSurgeryTrainer: training of Computer-based Planning in Liver Resection Surgery},
author = {J Mönch and K Mühler and C Hansen and K Oldhafer and G Stavrou and C Hillert and C Logge and B Preim},
url = {https://link.springer.com/article/10.1007/s11548-013-0812-z},
year = {2013},
date = {2013-01-01},
journal = {International Journal of Computer Assisted Radiology and Surgery},
volume = {8},
number = {5},
pages = {809–818},
abstract = {Purpose The training of liver surgeons depends on local conditions such as the specialization of the clinic, the spectrum of cases, and the instructing surgeons. We present the LiverSurgeryTrainer a software application to support the training of prospective surgeons in preoperative decision making.
Methods The LiverSurgeryTrainer visualizes radiological images, volumetric information, and interactive 3D models of patients’ liver anatomy. In addition, it provides special interaction techniques and tools to perform individual resections on the training data. To assess the correctness of decisions made by the learner, comments and decisions from experienced liver surgeons are provided for each case. To complete the case, additional material concerning the actual surgery (e.g., videos, reports) is presented. The application workflow is derived from a scenario-based design process and is based on an instructional design model.
Results The LiverSurgeryTrainer was evaluated in several steps. A formative usability evaluation identified workflow and user interface flaws that were resolved in further development process. A summative evaluation shows the improvement of the LiverSurgeryTrainer in nearly all analyzed aspects. First results of a learning success evaluation show that learners experience a learning effect.
Conclusion Our training system allows surgeons to train procedures and interaction techniques for computer-based planning of liver interventions. The evaluations showed acceptance and usability.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Purpose The training of liver surgeons depends on local conditions such as the specialization of the clinic, the spectrum of cases, and the instructing surgeons. We present the LiverSurgeryTrainer a software application to support the training of prospective surgeons in preoperative decision making.
Methods The LiverSurgeryTrainer visualizes radiological images, volumetric information, and interactive 3D models of patients’ liver anatomy. In addition, it provides special interaction techniques and tools to perform individual resections on the training data. To assess the correctness of decisions made by the learner, comments and decisions from experienced liver surgeons are provided for each case. To complete the case, additional material concerning the actual surgery (e.g., videos, reports) is presented. The application workflow is derived from a scenario-based design process and is based on an instructional design model.
Results The LiverSurgeryTrainer was evaluated in several steps. A formative usability evaluation identified workflow and user interface flaws that were resolved in further development process. A summative evaluation shows the improvement of the LiverSurgeryTrainer in nearly all analyzed aspects. First results of a learning success evaluation show that learners experience a learning effect.
Conclusion Our training system allows surgeons to train procedures and interaction techniques for computer-based planning of liver interventions. The evaluations showed acceptance and usability.
Methods The LiverSurgeryTrainer visualizes radiological images, volumetric information, and interactive 3D models of patients’ liver anatomy. In addition, it provides special interaction techniques and tools to perform individual resections on the training data. To assess the correctness of decisions made by the learner, comments and decisions from experienced liver surgeons are provided for each case. To complete the case, additional material concerning the actual surgery (e.g., videos, reports) is presented. The application workflow is derived from a scenario-based design process and is based on an instructional design model.
Results The LiverSurgeryTrainer was evaluated in several steps. A formative usability evaluation identified workflow and user interface flaws that were resolved in further development process. A summative evaluation shows the improvement of the LiverSurgeryTrainer in nearly all analyzed aspects. First results of a learning success evaluation show that learners experience a learning effect.
Conclusion Our training system allows surgeons to train procedures and interaction techniques for computer-based planning of liver interventions. The evaluations showed acceptance and usability.
20.
Hansen, C; Black, D; Lange, C; Rieber, F; Lamade, W; Donati, M; Oldhafer, K; Hahn, H
Auditory Support for Resection Guidance in Navigated Liver Surgery Journal Article
In: International Journal of Medical Robotics and Computer Assisted Surgery, vol. 9, no. 1, pp. 36–43, 2013.
@article{hansen_auditory_2013,
title = {Auditory Support for Resection Guidance in Navigated Liver Surgery},
author = {C Hansen and D Black and C Lange and F Rieber and W Lamade and M Donati and K Oldhafer and H Hahn},
url = {https://onlinelibrary.wiley.com/doi/full/10.1002/rcs.1466?casa_token=9UlwLmOWMLsAAAAA%3AitwaNmk2KVOn8dleZ-MmI46wBzVHqAPOM1C4ptkiXxo4DodiHBYOWCbhGwzD9OejBcKdNEsCb2YVxkOM},
year = {2013},
date = {2013-01-01},
journal = {International Journal of Medical Robotics and Computer Assisted Surgery},
volume = {9},
number = {1},
pages = {36–43},
abstract = {Background
An alternative mode of interaction with navigation systems for open liver surgery was requested. Surgeons who use such systems are impeded by having to constantly switch between viewing the navigation system screen and the patient during an operation.
Methods
To this end, an auditory display system for open liver surgery is introduced with support for guiding the tracked instrument towards and remaining on a predefined resection line. To evaluate the method, a clinically orientated user study with 12 surgeons was conducted.
Results
It is shown in qualitative results from the user study that the proposed auditory display is recognized as a useful addition to the current visual mode of interaction. It was revealed in a statistical analysis that participants spent less time looking on the screen (10% vs. 96%). Accuracy for resection guidance was significantly improved when using auditory display as an additional information channel (0.6 vs. 1.4 mm); however, the overall time for the resection task was shorter without auditory display (47 vs. 24 s).
Conclusions
By reducing dependence on the visual modality during resection guidance, the auditory display is well suited to become integrated in navigation systems for liver surgery. Copyright © 2012 John Wiley & Sons, Ltd.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Background
An alternative mode of interaction with navigation systems for open liver surgery was requested. Surgeons who use such systems are impeded by having to constantly switch between viewing the navigation system screen and the patient during an operation.
Methods
To this end, an auditory display system for open liver surgery is introduced with support for guiding the tracked instrument towards and remaining on a predefined resection line. To evaluate the method, a clinically orientated user study with 12 surgeons was conducted.
Results
It is shown in qualitative results from the user study that the proposed auditory display is recognized as a useful addition to the current visual mode of interaction. It was revealed in a statistical analysis that participants spent less time looking on the screen (10% vs. 96%). Accuracy for resection guidance was significantly improved when using auditory display as an additional information channel (0.6 vs. 1.4 mm); however, the overall time for the resection task was shorter without auditory display (47 vs. 24 s).
Conclusions
By reducing dependence on the visual modality during resection guidance, the auditory display is well suited to become integrated in navigation systems for liver surgery. Copyright © 2012 John Wiley & Sons, Ltd.
An alternative mode of interaction with navigation systems for open liver surgery was requested. Surgeons who use such systems are impeded by having to constantly switch between viewing the navigation system screen and the patient during an operation.
Methods
To this end, an auditory display system for open liver surgery is introduced with support for guiding the tracked instrument towards and remaining on a predefined resection line. To evaluate the method, a clinically orientated user study with 12 surgeons was conducted.
Results
It is shown in qualitative results from the user study that the proposed auditory display is recognized as a useful addition to the current visual mode of interaction. It was revealed in a statistical analysis that participants spent less time looking on the screen (10% vs. 96%). Accuracy for resection guidance was significantly improved when using auditory display as an additional information channel (0.6 vs. 1.4 mm); however, the overall time for the resection task was shorter without auditory display (47 vs. 24 s).
Conclusions
By reducing dependence on the visual modality during resection guidance, the auditory display is well suited to become integrated in navigation systems for liver surgery. Copyright © 2012 John Wiley & Sons, Ltd.
19.
Hansen, C; Zidowitz, S.; Ritter, F; Lange, C; Oldhafer, K; Hahn, H K
Risk maps for Liver Surgery Journal Article
In: International Journal of Computer Assisted Radiology and Surgery, vol. 8, no. 3, pp. 419–428, 2013.
@article{hansen_risk_2013,
title = {Risk maps for Liver Surgery},
author = {C Hansen and S. Zidowitz and F Ritter and C Lange and K Oldhafer and H K Hahn},
year = {2013},
date = {2013-01-01},
urldate = {2013-01-01},
journal = {International Journal of Computer Assisted Radiology and Surgery},
volume = {8},
number = {3},
pages = {419–428},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
2012
18.
Hansen, C; Zidowitz, S; Preim, B; Oldhafer, K; Hahn, H
Impact of Model-based Risk Analyses for Liver Surgery Planning Proceedings Article
In: Düsseldorf, 2012.
@inproceedings{hansen_impact_2012,
title = {Impact of Model-based Risk Analyses for Liver Surgery Planning},
author = {C Hansen and S Zidowitz and B Preim and K Oldhafer and H Hahn},
url = {https://link.springer.com/article/10.1007/s11548-013-0937-0},
year = {2012},
date = {2012-01-01},
address = {Düsseldorf},
series = {Proceedings of the Annual Meeting of the German Society of Computer- and Robot-Assisted Surgery},
abstract = {Purpose
A model-based risk analysis for oncologic liver surgery was described in previous work (Preim et al. in Proceedings of international symposium on computer assisted radiology and surgery (CARS), Elsevier, Amsterdam, pp. 353–358, 2002; Hansen et al. Int I Comput Assist Radiol Surg 4(5):469–474, 2009). In this paper, we present an evaluation of this method.
Methods
To prove whether and how the risk analysis facilitates the process of liver surgery planning, an explorative user study with 10 liver experts was conducted. The purpose was to compare and analyze their decision-making.
Results
The results of the study show that model-based risk analysis enhances the awareness of surgical risk in the planning stage. Participants preferred smaller resection volumes and agreed more on the safety margins’ width in case the risk analysis was available. In addition, time to complete the planning task and confidence of participants were not increased when using the risk analysis.
Conclusion
This work shows that the applied model-based risk analysis may influence important planning decisions in liver surgery. It lays a basis for further clinical evaluations and points out important fields for future research.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
Purpose
A model-based risk analysis for oncologic liver surgery was described in previous work (Preim et al. in Proceedings of international symposium on computer assisted radiology and surgery (CARS), Elsevier, Amsterdam, pp. 353–358, 2002; Hansen et al. Int I Comput Assist Radiol Surg 4(5):469–474, 2009). In this paper, we present an evaluation of this method.
Methods
To prove whether and how the risk analysis facilitates the process of liver surgery planning, an explorative user study with 10 liver experts was conducted. The purpose was to compare and analyze their decision-making.
Results
The results of the study show that model-based risk analysis enhances the awareness of surgical risk in the planning stage. Participants preferred smaller resection volumes and agreed more on the safety margins’ width in case the risk analysis was available. In addition, time to complete the planning task and confidence of participants were not increased when using the risk analysis.
Conclusion
This work shows that the applied model-based risk analysis may influence important planning decisions in liver surgery. It lays a basis for further clinical evaluations and points out important fields for future research.
A model-based risk analysis for oncologic liver surgery was described in previous work (Preim et al. in Proceedings of international symposium on computer assisted radiology and surgery (CARS), Elsevier, Amsterdam, pp. 353–358, 2002; Hansen et al. Int I Comput Assist Radiol Surg 4(5):469–474, 2009). In this paper, we present an evaluation of this method.
Methods
To prove whether and how the risk analysis facilitates the process of liver surgery planning, an explorative user study with 10 liver experts was conducted. The purpose was to compare and analyze their decision-making.
Results
The results of the study show that model-based risk analysis enhances the awareness of surgical risk in the planning stage. Participants preferred smaller resection volumes and agreed more on the safety margins’ width in case the risk analysis was available. In addition, time to complete the planning task and confidence of participants were not increased when using the risk analysis.
Conclusion
This work shows that the applied model-based risk analysis may influence important planning decisions in liver surgery. It lays a basis for further clinical evaluations and points out important fields for future research.
17.
Hansen, C; Zidowitz, S.; Ritter, F; Lange, C; Oldhafer, K J; Hahn, H K
Risk Maps for Liver Surgery Proceedings Article
In: pp. 144–145, Pisa, Italien, 2012.
@inproceedings{hansen_risk_2012,
title = {Risk Maps for Liver Surgery},
author = {C Hansen and S. Zidowitz and F Ritter and C Lange and K J Oldhafer and H K Hahn},
year = {2012},
date = {2012-01-01},
urldate = {2012-01-01},
pages = {144–145},
address = {Pisa, Italien},
series = {Proceedings of International Congress for Computer-Assisted Radiology and Surgery (CARS)},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
2010
16.
Demedts, D; Schenk, A; Hansen, C; Peitgen, H
Evaluation of Resection Proposals for Liver Surgery Planning Proceedings Article
In: Proc. of the 9th Annual Meeting of the German Society of Computer- and Robot-Assisted Surgery, pp. 13–16, 2010.
@inproceedings{demedts_evaluation_2010,
title = {Evaluation of Resection Proposals for Liver Surgery Planning},
author = {D Demedts and A Schenk and C Hansen and H Peitgen},
url = {https://ceur-ws.org/Vol-1475/Proceedings_CURAC_2010_Paper_3.pdf},
year = {2010},
date = {2010-01-01},
booktitle = {Proc. of the 9th Annual Meeting of the German Society of Computer- and Robot-Assisted Surgery},
pages = {13–16},
abstract = {Modern software for surgery planning allows for definition of virtual resections within the liver. Thus, surgeons can si-
mulate different resection strategies and assess the associated surgical risk preoperatively. Until now, it was impossible
to measure the quality of different resection plans objectively. The choice for the optimal resection strategy was based
on subjective judgment acquired by other examinations and subsequent risk analyses. We present a fast method for
quality assessment of resection proposals with respect to surgical risk factors such as safety margin, remnant volume,
remnant perfusion, surface curvature, and resection area. Our new method has been integrated into planning software
used in the daily routine. The results from a preliminary user study confirm that the interactive quality feedback is
beneficial for precise liver surgery planning.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
Modern software for surgery planning allows for definition of virtual resections within the liver. Thus, surgeons can si-
mulate different resection strategies and assess the associated surgical risk preoperatively. Until now, it was impossible
to measure the quality of different resection plans objectively. The choice for the optimal resection strategy was based
on subjective judgment acquired by other examinations and subsequent risk analyses. We present a fast method for
quality assessment of resection proposals with respect to surgical risk factors such as safety margin, remnant volume,
remnant perfusion, surface curvature, and resection area. Our new method has been integrated into planning software
used in the daily routine. The results from a preliminary user study confirm that the interactive quality feedback is
beneficial for precise liver surgery planning.
mulate different resection strategies and assess the associated surgical risk preoperatively. Until now, it was impossible
to measure the quality of different resection plans objectively. The choice for the optimal resection strategy was based
on subjective judgment acquired by other examinations and subsequent risk analyses. We present a fast method for
quality assessment of resection proposals with respect to surgical risk factors such as safety margin, remnant volume,
remnant perfusion, surface curvature, and resection area. Our new method has been integrated into planning software
used in the daily routine. The results from a preliminary user study confirm that the interactive quality feedback is
beneficial for precise liver surgery planning.
15.
Hansen, C; Lindow, B; Zidowitz, S; Schenk, A; Peitgen, H
Towards Automatic Generation of Resection Surfaces for Liver Surgery Planning Proceedings Article
In: pp. 119–120, Genf, Schweiz, 2010.
@inproceedings{hansen_towards_2010,
title = {Towards Automatic Generation of Resection Surfaces for Liver Surgery Planning},
author = {C Hansen and B Lindow and S Zidowitz and A Schenk and H Peitgen},
year = {2010},
date = {2010-01-01},
pages = {119–120},
address = {Genf, Schweiz},
series = {Proceedings of International Congress for Computer-Assisted Radiology and Surgery (CARS)},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
14.
Hansen, C; Wieferich, J; Ritter, F; Rieder, C; Peitgen, H
Illustrative Visualization of 3D Planning Models for Augmented Reality in Liver Surgery Journal Article
In: International Journal of Computer Assisted Radiology and Surgery, vol. 5, no. 2, pp. 133–141, 2010.
@article{hansen_illustrative_2010,
title = {Illustrative Visualization of 3D Planning Models for Augmented Reality in Liver Surgery},
author = {C Hansen and J Wieferich and F Ritter and C Rieder and H Peitgen},
url = {https://link.springer.com/article/10.1007/s11548-009-0365-3},
year = {2010},
date = {2010-01-01},
journal = {International Journal of Computer Assisted Radiology and Surgery},
volume = {5},
number = {2},
pages = {133–141},
abstract = {Purpose
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.
Conclusion
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.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Purpose
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.
Conclusion
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.
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.
Conclusion
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.
13.
Hansen, C; Zidowitz, S; Schenk, A; Oldhafer, K; Lang, H; Peitgen, H
Risk Maps for Navigation in Liver Surgery Proceedings Article
In: Proceedings of SPIE Medical Imaging, pp. 762528–1–8, San Diego, USA, 2010.
@inproceedings{hanse_risk_2010,
title = {Risk Maps for Navigation in Liver Surgery},
author = {C Hansen and S Zidowitz and A Schenk and K Oldhafer and H Lang and H Peitgen},
url = {https://www.spiedigitallibrary.org/conference-proceedings-of-spie/7625/762528/Risk-maps-for-navigation-in-liver-surgery/10.1117/12.843493.short},
year = {2010},
date = {2010-01-01},
urldate = {2010-01-01},
booktitle = {Proceedings of SPIE Medical Imaging},
pages = {762528–1–8},
address = {San Diego, USA},
abstract = {The optimal transfer of preoperative planning data and risk evaluations to the operative site is challenging. A common practice is to use preoperative 3D planning models as a printout or as a presentation on a display. One important aspect is that these models were not developed to provide information in complex workspaces like the operating room. Our aim is to reduce the visual complexity of 3D planning models by mapping surgically relevant information onto a risk map. Therefore, we present methods for the identification and classification of critical anatomical structures in the proximity of a preoperatively planned resection surface. Shadow-like distance indicators are introduced to encode the distance from the resection surface to these critical structures on the risk map. In addition, contour lines are used to accentuate shape and spatial depth. The resulting visualization is clear and intuitive, allowing for a fast mental mapping of the current resection surface to the risk map. Preliminary evaluations by liver surgeons indicate that damage to risk structures may be prevented and patient safety may be enhanced using the proposed methods.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
The optimal transfer of preoperative planning data and risk evaluations to the operative site is challenging. A common practice is to use preoperative 3D planning models as a printout or as a presentation on a display. One important aspect is that these models were not developed to provide information in complex workspaces like the operating room. Our aim is to reduce the visual complexity of 3D planning models by mapping surgically relevant information onto a risk map. Therefore, we present methods for the identification and classification of critical anatomical structures in the proximity of a preoperatively planned resection surface. Shadow-like distance indicators are introduced to encode the distance from the resection surface to these critical structures on the risk map. In addition, contour lines are used to accentuate shape and spatial depth. The resulting visualization is clear and intuitive, allowing for a fast mental mapping of the current resection surface to the risk map. Preliminary evaluations by liver surgeons indicate that damage to risk structures may be prevented and patient safety may be enhanced using the proposed methods.
12.
Black, D; Hansen, C; Loviscach, J; Peitgen, H
Auditory Support for Image-Guided Liver Surgery Proceedings Article
In: pp. 197–188, Genf, Schweiz, 2010.
@inproceedings{black_auditory_2010,
title = {Auditory Support for Image-Guided Liver Surgery},
author = {D Black and C Hansen and J Loviscach and H Peitgen},
url = {https://www.researchgate.net/profile/David-Black-14/publication/313655446_Auditory_Support_for_Image-Guided_Liver_Surgery/links/58a1a699a6fdccf5e97089fc/Auditory-Support-for-Image-Guided-Liver-Surgery.pdf},
year = {2010},
date = {2010-01-01},
urldate = {2010-01-01},
pages = {197–188},
address = {Genf, Schweiz},
series = {Proceedings of International Congress for Computer-Assisted Radiology and Surgery (CARS)},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
2009
11.
Ritter, F; Hansen, C; Wilkens, K; Köhn, A; Peitgen, H
User Interfaces for Direct Interaction with 3D Planning Data in the Operation Room Journal Article
In: i-com – Journal of Interactive Media, vol. 8, no. 1, pp. 24–31, 2009.
@article{ritter_user_2009,
title = {User Interfaces for Direct Interaction with 3D Planning Data in the Operation Room},
author = {F Ritter and C Hansen and K Wilkens and A Köhn and H Peitgen},
year = {2009},
date = {2009-01-01},
journal = {i-com - Journal of Interactive Media},
volume = {8},
number = {1},
pages = {24–31},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
10.
Hansen, C; Zidowitz, S; Hindennach, M; Schenk, A; Hahn, H; Peitgen, H
Interactive Determination of Robust Safety Margins for Oncologic Liver Surgery Proceedings Article
In: pp. 469–474, Berlin, 2009.
@inproceedings{hansen_interactive_2009,
title = {Interactive Determination of Robust Safety Margins for Oncologic Liver Surgery},
author = {C Hansen and S Zidowitz and M Hindennach and A Schenk and H Hahn and H Peitgen},
url = {https://link.springer.com/article/10.1007/s11548-009-0359-1},
year = {2009},
date = {2009-01-01},
pages = {469–474},
address = {Berlin},
series = {Proceedings of International Congress for Computer-Assisted Radiology and Surgery (CARS)},
abstract = {Objective
Complex oncologic interventions in the liver require an extensive and careful preoperative analysis. Particularly the achievement of an optimal safety margin around tumors remains a difficult task for surgeons.
Methods
We present new methods for evaluating different safety margins and their effect on the associated interruption of vascular supply or drainage. The characteristic of vascular risk distributions can be evaluated in real-time by exploiting precomputed safety maps that provide a volume curve for each vascular system. By applying fast visualization methods in 3D it is possible to assist the surgeon in the determination of a tumor-free safety margin while preserving sufficient vital hepatic parenchyma. The combination of risk analysis from different vascular systems and their sensitivity is considered.
Results
We provide physicians with a novel computer-aided planning tool that allows for interactive determination of safety margins in real-time. The planning tool integrates smoothly into the preoperative workflow. Preliminary evaluations confirm that the width of safety margins can be determined more precisely, which may affect the proposed resection strategy.
Conclusion
Our new methods provide interactive feedback and support for decision making during the preoperative planning stage and thus might potentially improve the outcome of surgical interventions.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
Objective
Complex oncologic interventions in the liver require an extensive and careful preoperative analysis. Particularly the achievement of an optimal safety margin around tumors remains a difficult task for surgeons.
Methods
We present new methods for evaluating different safety margins and their effect on the associated interruption of vascular supply or drainage. The characteristic of vascular risk distributions can be evaluated in real-time by exploiting precomputed safety maps that provide a volume curve for each vascular system. By applying fast visualization methods in 3D it is possible to assist the surgeon in the determination of a tumor-free safety margin while preserving sufficient vital hepatic parenchyma. The combination of risk analysis from different vascular systems and their sensitivity is considered.
Results
We provide physicians with a novel computer-aided planning tool that allows for interactive determination of safety margins in real-time. The planning tool integrates smoothly into the preoperative workflow. Preliminary evaluations confirm that the width of safety margins can be determined more precisely, which may affect the proposed resection strategy.
Conclusion
Our new methods provide interactive feedback and support for decision making during the preoperative planning stage and thus might potentially improve the outcome of surgical interventions.
Complex oncologic interventions in the liver require an extensive and careful preoperative analysis. Particularly the achievement of an optimal safety margin around tumors remains a difficult task for surgeons.
Methods
We present new methods for evaluating different safety margins and their effect on the associated interruption of vascular supply or drainage. The characteristic of vascular risk distributions can be evaluated in real-time by exploiting precomputed safety maps that provide a volume curve for each vascular system. By applying fast visualization methods in 3D it is possible to assist the surgeon in the determination of a tumor-free safety margin while preserving sufficient vital hepatic parenchyma. The combination of risk analysis from different vascular systems and their sensitivity is considered.
Results
We provide physicians with a novel computer-aided planning tool that allows for interactive determination of safety margins in real-time. The planning tool integrates smoothly into the preoperative workflow. Preliminary evaluations confirm that the width of safety margins can be determined more precisely, which may affect the proposed resection strategy.
Conclusion
Our new methods provide interactive feedback and support for decision making during the preoperative planning stage and thus might potentially improve the outcome of surgical interventions.
2008
9.
Mühler, K; Hansen, C; Neugebauer, M; Preim, B
Automatische Kamerapositionierung für Intraoperative Visualisierungen in der Onkologischen Leberchirurgie Proceedings Article
In: pp. 143–147, Berlin, 2008.
@inproceedings{muhler_automatische_2008,
title = {Automatische Kamerapositionierung für Intraoperative Visualisierungen in der Onkologischen Leberchirurgie},
author = {K Mühler and C Hansen and M Neugebauer and B Preim},
url = {https://link.springer.com/chapter/10.1007/978-3-540-78640-5_29},
year = {2008},
date = {2008-01-01},
pages = {143–147},
address = {Berlin},
series = {Proceedings of Bildverarbeitung für die Medizin},
abstract = {In diesem Beitrag wird ein Verfahren vorgestellt, mit
dessen Hilfe automatisch gute Blickpunkte auf dreidimensionale Pla-
nungsmodelle f¨ur die Leberchirurgie berechnet werden k¨onnen. Das Ver-
fahren passt die Position der virtuellen Kamera w¨ahrend einer Operation
dynamisch an, insbesondere im Falle einer Aktualisierung von onkologi-
schen Planungsdaten durch neue intra-operative Befunde.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
In diesem Beitrag wird ein Verfahren vorgestellt, mit
dessen Hilfe automatisch gute Blickpunkte auf dreidimensionale Pla-
nungsmodelle f¨ur die Leberchirurgie berechnet werden k¨onnen. Das Ver-
fahren passt die Position der virtuellen Kamera w¨ahrend einer Operation
dynamisch an, insbesondere im Falle einer Aktualisierung von onkologi-
schen Planungsdaten durch neue intra-operative Befunde.
dessen Hilfe automatisch gute Blickpunkte auf dreidimensionale Pla-
nungsmodelle f¨ur die Leberchirurgie berechnet werden k¨onnen. Das Ver-
fahren passt die Position der virtuellen Kamera w¨ahrend einer Operation
dynamisch an, insbesondere im Falle einer Aktualisierung von onkologi-
schen Planungsdaten durch neue intra-operative Befunde.
8.
Hansen, C; Köhn, A; Schlichting, S; Weiler, F; Konrad, O; Zidowitz, S; Peitgen, H
Intraoperative Modification of Resection Plans for Liver Surgery Proceedings Article
In: pp. 291–297, Barcelona, Spanien, 2008.
@inproceedings{hansen_intraoperative_2008,
title = {Intraoperative Modification of Resection Plans for Liver Surgery},
author = {C Hansen and A Köhn and S Schlichting and F Weiler and O Konrad and S Zidowitz and H Peitgen},
url = {https://link.springer.com/article/10.1007/s11548-008-0161-5},
year = {2008},
date = {2008-01-01},
pages = {291–297},
address = {Barcelona, Spanien},
series = {Proceedings of International Congress for Computer-Assisted Radiology and Surgery (CARS)},
abstract = {Objective
Recent surgical planning software provides valuable tools for evaluating different resection strategies preoperatively. With such virtual resections, predictions and quantitative analyses may be carried out to assess the resection feasibility with respect to tumors and risk structures. In oncologic liver surgery, additional tumors that were not seen in the preoperative images are often found during the intervention using intraoperative ultrasound (IOUS). Due to such findings, the resection strategy must be updated or completely revised.
Materials and methods
Therefore, we have developed methods for the intraoperative modification of resection plans. The probe of an ultrasound-based navigation system and alternatively the pointing device Wiimote are proposed as intraoperative interaction devices. Fast adaptation of planning information and the communication with both interaction devices is supported by our system, the Intraoperative Planning Assistant (IPA). The IPA has been evaluated in the operation room (OR) during laparoscopic liver interventions on pigs.
Results
Our preliminary results confirm that intraoperative modifications of resection plans are both feasible and beneficial for liver surgery. After the intraoperative modification task, updated remaining liver volume and resection volume were displayed and quantified within 10 s.
Conclusion
For the first time, surgeons are provided with a system for intraoperative modification of resection plans that offers a crucial decision support, is easy to use and integrates smoothly into the clinical workflow. The new system provides major support for decision making in the OR and thus improves the safety of surgical interventions.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
Objective
Recent surgical planning software provides valuable tools for evaluating different resection strategies preoperatively. With such virtual resections, predictions and quantitative analyses may be carried out to assess the resection feasibility with respect to tumors and risk structures. In oncologic liver surgery, additional tumors that were not seen in the preoperative images are often found during the intervention using intraoperative ultrasound (IOUS). Due to such findings, the resection strategy must be updated or completely revised.
Materials and methods
Therefore, we have developed methods for the intraoperative modification of resection plans. The probe of an ultrasound-based navigation system and alternatively the pointing device Wiimote are proposed as intraoperative interaction devices. Fast adaptation of planning information and the communication with both interaction devices is supported by our system, the Intraoperative Planning Assistant (IPA). The IPA has been evaluated in the operation room (OR) during laparoscopic liver interventions on pigs.
Results
Our preliminary results confirm that intraoperative modifications of resection plans are both feasible and beneficial for liver surgery. After the intraoperative modification task, updated remaining liver volume and resection volume were displayed and quantified within 10 s.
Conclusion
For the first time, surgeons are provided with a system for intraoperative modification of resection plans that offers a crucial decision support, is easy to use and integrates smoothly into the clinical workflow. The new system provides major support for decision making in the OR and thus improves the safety of surgical interventions.
Recent surgical planning software provides valuable tools for evaluating different resection strategies preoperatively. With such virtual resections, predictions and quantitative analyses may be carried out to assess the resection feasibility with respect to tumors and risk structures. In oncologic liver surgery, additional tumors that were not seen in the preoperative images are often found during the intervention using intraoperative ultrasound (IOUS). Due to such findings, the resection strategy must be updated or completely revised.
Materials and methods
Therefore, we have developed methods for the intraoperative modification of resection plans. The probe of an ultrasound-based navigation system and alternatively the pointing device Wiimote are proposed as intraoperative interaction devices. Fast adaptation of planning information and the communication with both interaction devices is supported by our system, the Intraoperative Planning Assistant (IPA). The IPA has been evaluated in the operation room (OR) during laparoscopic liver interventions on pigs.
Results
Our preliminary results confirm that intraoperative modifications of resection plans are both feasible and beneficial for liver surgery. After the intraoperative modification task, updated remaining liver volume and resection volume were displayed and quantified within 10 s.
Conclusion
For the first time, surgeons are provided with a system for intraoperative modification of resection plans that offers a crucial decision support, is easy to use and integrates smoothly into the clinical workflow. The new system provides major support for decision making in the OR and thus improves the safety of surgical interventions.
7.
Hansen, C; Schlichting, S; Zidowitz, S; Kleemann, M; Peitgen, H
Intraoperative Adaptation of Planning Data for Oncologic Liver Surgery Proceedings Article
In: pp. 36–45, New York, USA, 2008.
@inproceedings{hansen_intraoperative_2008-1,
title = {Intraoperative Adaptation of Planning Data for Oncologic Liver Surgery},
author = {C Hansen and S Schlichting and S Zidowitz and M Kleemann and H Peitgen},
url = {https://publica.fraunhofer.de/bitstreams/c9f194d5-3de7-4302-a8e2-f6de0c73c02d/download#page=41},
year = {2008},
date = {2008-01-01},
pages = {36–45},
address = {New York, USA},
series = {Proceedings of MICCAI Workshop on Image Guidance and Computer Assistance for Soft-Tissue Interventions},
abstract = {Recent surgical planning software provides valuable tools for
evaluating different resection strategies preoperatively. Risk analyses and
virtual resections may be carried out before surgery in order to assess the
resection feasibility with respect to tumors and risk structures. However,
in oncologic liver surgery, additional tumors that were not seen in the
preoperative images are often found during the intervention using intra-
operative ultrasound. Due to such findings, the resection strategy must
be updated or completely revised. We have developed new methods for
intraoperative adaptation of planning data using an ultrasound-based
navigation system. Fast adaptation of planning data and the communi-
cation with the navigation system is supported by our system, the In-
traoperative Planning Assistant. The system has been evaluated in the
operating room during laparoscopic liver interventions on pigs. For the
first time, surgeons are provided with a tool for intraoperative adapta-
tion of planning data that offers crucial decision support, is easy to use
and integrates smoothly into the clinical workflow.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
Recent surgical planning software provides valuable tools for
evaluating different resection strategies preoperatively. Risk analyses and
virtual resections may be carried out before surgery in order to assess the
resection feasibility with respect to tumors and risk structures. However,
in oncologic liver surgery, additional tumors that were not seen in the
preoperative images are often found during the intervention using intra-
operative ultrasound. Due to such findings, the resection strategy must
be updated or completely revised. We have developed new methods for
intraoperative adaptation of planning data using an ultrasound-based
navigation system. Fast adaptation of planning data and the communi-
cation with the navigation system is supported by our system, the In-
traoperative Planning Assistant. The system has been evaluated in the
operating room during laparoscopic liver interventions on pigs. For the
first time, surgeons are provided with a tool for intraoperative adapta-
tion of planning data that offers crucial decision support, is easy to use
and integrates smoothly into the clinical workflow.
evaluating different resection strategies preoperatively. Risk analyses and
virtual resections may be carried out before surgery in order to assess the
resection feasibility with respect to tumors and risk structures. However,
in oncologic liver surgery, additional tumors that were not seen in the
preoperative images are often found during the intervention using intra-
operative ultrasound. Due to such findings, the resection strategy must
be updated or completely revised. We have developed new methods for
intraoperative adaptation of planning data using an ultrasound-based
navigation system. Fast adaptation of planning data and the communi-
cation with the navigation system is supported by our system, the In-
traoperative Planning Assistant. The system has been evaluated in the
operating room during laparoscopic liver interventions on pigs. For the
first time, surgeons are provided with a tool for intraoperative adapta-
tion of planning data that offers crucial decision support, is easy to use
and integrates smoothly into the clinical workflow.
6.
Hansen, C; Zidowitz, S; Schenk, A; Oldhafer, K; Lang, H; Peitgen, H
Intraoperative Adaptation and Visualization of Preoperative Risk Analyses for Oncologic Liver Surgery Proceedings Article
In: pp. 691809–1–10, San Diego, USA, 2008.
@inproceedings{hansen_intraoperative_2008-2,
title = {Intraoperative Adaptation and Visualization of Preoperative Risk Analyses for Oncologic Liver Surgery},
author = {C Hansen and S Zidowitz and A Schenk and K Oldhafer and H Lang and H Peitgen},
url = {https://www.spiedigitallibrary.org/conference-proceedings-of-spie/6918/691809/Intraoperative-adaptation-and-visualization-of-preoperative-risk-analyses-for-oncologic/10.1117/12.770243.short},
year = {2008},
date = {2008-01-01},
pages = {691809–1–10},
address = {San Diego, USA},
series = {Proceedings of SPIE Medical Imaging},
abstract = {Tumor resections from the liver are complex surgical interventions. With recent planning software, risk analyses based on individual liver anatomy can be carried out preoperatively. However, additional tumors within the liver are frequently detected during oncological interventions using intraoperative ultrasound. These tumors are not visible in preoperative data and their existence may require changes to the resection strategy. We propose a novel method that allows an intraoperative risk analysis adaptation by merging newly detected tumors with a preoperative risk analysis. To determine the exact positions and sizes of these tumors we make use of a navigated ultrasound-system. A fast communication protocol enables our application to exchange crucial data with this navigation system during an intervention. A further motivation for our work is to improve the visual presentation of a moving ultrasound plane within a complex 3D planning model including vascular systems, tumors, and organ surfaces. In case the ultrasound plane is located inside the liver, occlusion of the ultrasound plane by the planning model is an inevitable problem for the applied visualization technique. Our system allows the surgeon to focus on the ultrasound image while perceiving context-relevant planning information. To improve orientation ability and distance perception, we include additional depth cues by applying new illustrative visualization algorithms. Preliminary evaluations confirm that in case of intraoperatively detected tumors a risk analysis adaptation is beneficial for precise liver surgery. Our new GPU-based visualization approach provides the surgeon with a simultaneous visualization of planning models and navigated 2D ultrasound data while minimizing occlusion problems.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
Tumor resections from the liver are complex surgical interventions. With recent planning software, risk analyses based on individual liver anatomy can be carried out preoperatively. However, additional tumors within the liver are frequently detected during oncological interventions using intraoperative ultrasound. These tumors are not visible in preoperative data and their existence may require changes to the resection strategy. We propose a novel method that allows an intraoperative risk analysis adaptation by merging newly detected tumors with a preoperative risk analysis. To determine the exact positions and sizes of these tumors we make use of a navigated ultrasound-system. A fast communication protocol enables our application to exchange crucial data with this navigation system during an intervention. A further motivation for our work is to improve the visual presentation of a moving ultrasound plane within a complex 3D planning model including vascular systems, tumors, and organ surfaces. In case the ultrasound plane is located inside the liver, occlusion of the ultrasound plane by the planning model is an inevitable problem for the applied visualization technique. Our system allows the surgeon to focus on the ultrasound image while perceiving context-relevant planning information. To improve orientation ability and distance perception, we include additional depth cues by applying new illustrative visualization algorithms. Preliminary evaluations confirm that in case of intraoperatively detected tumors a risk analysis adaptation is beneficial for precise liver surgery. Our new GPU-based visualization approach provides the surgeon with a simultaneous visualization of planning models and navigated 2D ultrasound data while minimizing occlusion problems.
5.
Hansen, C; Wieferich, J; Ritter, F; Rieder, C; Peitgen, H
Illustrative Visualization of 3D Planning Models for Augmented Reality in Liver Surgery Proceedings Article
In: pp. 1–4, Leipzig, 2008.
@inproceedings{hansen_illustrative_2008,
title = {Illustrative Visualization of 3D Planning Models for Augmented Reality in Liver Surgery},
author = {C Hansen and J Wieferich and F Ritter and C Rieder and H Peitgen},
url = {https://link.springer.com/article/10.1007/s11548-009-0365-3},
year = {2008},
date = {2008-01-01},
pages = {1–4},
address = {Leipzig},
series = {Proceedings of the Annual Meeting of the German Society of Computer- and Robot-Assisted Surgery},
abstract = {Purpose
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.
Conclusion
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.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
Purpose
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.
Conclusion
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.
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.
Conclusion
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.
2007
4.
Hansen, C; Koehn, A; Ritter, F; Zidowitz, S; Peitgen, H
Simultaneous Visualization of Preoperative Planning Models and Intraoperative Ultrasound for Liver Surgery Proceedings Article
In: pp. 117–120, Prag, Tschechische Republik, 2007.
@inproceedings{hansen_simultaneous_2007,
title = {Simultaneous Visualization of Preoperative Planning Models and Intraoperative Ultrasound for Liver Surgery},
author = {C Hansen and A Koehn and F Ritter and S Zidowitz and H Peitgen},
url = {http://mre-web.mevis.fraunhofer.de/~ritter/awakeideas/files/publications/EG2007.pdf},
year = {2007},
date = {2007-01-01},
pages = {117–120},
address = {Prag, Tschechische Republik},
series = {Proceedings of Eurographics},
abstract = {This paper introduces new techniques for simultaneous visualization of preoperative planning models and in-
traoperative 2D ultrasound for open liver surgery. The driving motivation for our work is to improve the visual
presentation of a moving ultrasound plane within a complex, interweaving three-dimensional model of hepatic
vascular structures. Major drawbacks of existing systems are occlusions of the ultrasound plane by the planning
model and fade-out of crucial context information. Our system allows the surgeon to focus on the ultrasound image
while perceiving context-relevant planning information without discarding important morphological information
and depth cues. The contribution of this paper is a GPU-accelerated rendering pipeline including new illustrative
visualization algorithms for focus & context rendering, distance and intersection accentuation, as well as a hybrid
technique for high quality silhouette and hatching stroke generation.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
This paper introduces new techniques for simultaneous visualization of preoperative planning models and in-
traoperative 2D ultrasound for open liver surgery. The driving motivation for our work is to improve the visual
presentation of a moving ultrasound plane within a complex, interweaving three-dimensional model of hepatic
vascular structures. Major drawbacks of existing systems are occlusions of the ultrasound plane by the planning
model and fade-out of crucial context information. Our system allows the surgeon to focus on the ultrasound image
while perceiving context-relevant planning information without discarding important morphological information
and depth cues. The contribution of this paper is a GPU-accelerated rendering pipeline including new illustrative
visualization algorithms for focus & context rendering, distance and intersection accentuation, as well as a hybrid
technique for high quality silhouette and hatching stroke generation.
traoperative 2D ultrasound for open liver surgery. The driving motivation for our work is to improve the visual
presentation of a moving ultrasound plane within a complex, interweaving three-dimensional model of hepatic
vascular structures. Major drawbacks of existing systems are occlusions of the ultrasound plane by the planning
model and fade-out of crucial context information. Our system allows the surgeon to focus on the ultrasound image
while perceiving context-relevant planning information without discarding important morphological information
and depth cues. The contribution of this paper is a GPU-accelerated rendering pipeline including new illustrative
visualization algorithms for focus & context rendering, distance and intersection accentuation, as well as a hybrid
technique for high quality silhouette and hatching stroke generation.
3.
Hansen, C; Schlichting, S; Markert, M; Hindennach, M; Zidowitz, S; Peitgen, H
Intraoperative Adaptation of Preoperative Risk Analyses for Oncologic Liver Surgery using tracked 2D ultrasound Proceedings Article
In: pp. 155–158, Karlsruhe, 2007.
@inproceedings{hansen_intraoperative_2007,
title = {Intraoperative Adaptation of Preoperative Risk Analyses for Oncologic Liver Surgery using tracked 2D ultrasound},
author = {C Hansen and S Schlichting and M Markert and M Hindennach and S Zidowitz and H Peitgen},
url = {https://www.researchgate.net/profile/Stefan-Schlichting/publication/234038197_Intraoperative_Adaptation_of_Preoperative_Risk_Analyses_for_Oncologic_Liver_Surgery_using_Navigated_2D_Ultrasound/links/02bfe50e74a032f2e6000000/Intraoperative-Adaptation-of-Preoperative-Risk-Analyses-for-Oncologic-Liver-Surgery-using-Navigated-2D-Ultrasound.pdf},
year = {2007},
date = {2007-01-01},
pages = {155–158},
address = {Karlsruhe},
series = {Proceedings of the Annual Meeting of the German Society of Computer- and Robot-Assisted Surgery},
abstract = {Preoperative risk analyses for oncologic liver interventions have only a limited value when new tumour findings are
made during operation. We propose a new method that allows an intraoperative risk analysis adaptation by merging
newly detected tumors with a preoperative risk analysis. To determine the exact positions and sizes of these tumors
we make use of an ultrasound-based navigation system. For the first time, we provide surgeons with an
intraoperational tool for risk analyses adaptation that can easily be integrated into a surgical workflow.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
Preoperative risk analyses for oncologic liver interventions have only a limited value when new tumour findings are
made during operation. We propose a new method that allows an intraoperative risk analysis adaptation by merging
newly detected tumors with a preoperative risk analysis. To determine the exact positions and sizes of these tumors
we make use of an ultrasound-based navigation system. For the first time, we provide surgeons with an
intraoperational tool for risk analyses adaptation that can easily be integrated into a surgical workflow.
made during operation. We propose a new method that allows an intraoperative risk analysis adaptation by merging
newly detected tumors with a preoperative risk analysis. To determine the exact positions and sizes of these tumors
we make use of an ultrasound-based navigation system. For the first time, we provide surgeons with an
intraoperational tool for risk analyses adaptation that can easily be integrated into a surgical workflow.
2006
2.
Ritter, F; Hansen, C; Dicken, V; Konrad, O; Preim, B; Peitgen, H
Real-time Illustration of Vascular Structures Journal Article
In: IEEE Transactions on Visualization and Computer Graphics, vol. 12, no. 5, pp. 877–884, 2006, (Place: Baltimore, Maryland, USA).
@article{ritter_real-time_2006,
title = {Real-time Illustration of Vascular Structures},
author = {F Ritter and C Hansen and V Dicken and O Konrad and B Preim and H Peitgen},
url = {https://ieeexplore.ieee.org/abstract/document/4015442},
year = {2006},
date = {2006-01-01},
journal = {IEEE Transactions on Visualization and Computer Graphics},
volume = {12},
number = {5},
pages = {877–884},
abstract = {We present real-time vascular visualization methods, which extend on illustrative rendering techniques to particularly accentuate spatial depth and to improve the perceptive separation of important vascular properties such as branching level and supply area. The resulting visualization can and has already been used for direct projection on a patient's organ in the operation theater where the varying absorption and reflection characteristics of the surface limit the use of color. The important contributions of our work are a GPU-based hatching algorithm for complex tubular structures that emphasizes shape and depth as well as GPU-accelerated shadow-like depth indicators, which enable reliable comparisons of depth distances in a static monoscopic 3D visualization. In addition, we verify the expressiveness of our illustration methods in a large, quantitative study with 160 subjects},
note = {Place: Baltimore, Maryland, USA},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
We present real-time vascular visualization methods, which extend on illustrative rendering techniques to particularly accentuate spatial depth and to improve the perceptive separation of important vascular properties such as branching level and supply area. The resulting visualization can and has already been used for direct projection on a patient’s organ in the operation theater where the varying absorption and reflection characteristics of the surface limit the use of color. The important contributions of our work are a GPU-based hatching algorithm for complex tubular structures that emphasizes shape and depth as well as GPU-accelerated shadow-like depth indicators, which enable reliable comparisons of depth distances in a static monoscopic 3D visualization. In addition, we verify the expressiveness of our illustration methods in a large, quantitative study with 160 subjects
0000
1.
Saalfeld, P; Mewes, A; Hansen, C; Preim, B
Gaze-Based Annotations: Labels on Demand Journal Article
In: 0000.
@article{saalfeld_gaze-based_201,
title = {Gaze-Based Annotations: Labels on Demand},
author = {P Saalfeld and A Mewes and C Hansen and B Preim},
url = {https://www.var.ovgu.de/pub/Saalfeld_2015_CURAC.pdf},
abstract = {We present an approach that tracks the gaze position of a user to determine a structure of interest in a medical planning model. This structure is automatically and dynamically annotated with an external label. The approach considers aspects from hand-crafted illustrations and interactive applications. In general, labels are simultaneously shown for all structures in interactive applications. However, this leads to visual clutter and is costly regarding computation time. Both aspects could be neglected if annotations are only shown regarding user’s demands, i.e., only one label at a time. We use an eye tracker to obtain the user’s gaze positions and, thus, the structure of interest. We address problems due to imprecise input with smoothing and increasing the selection area around each structure. The prototype was evaluated with an unstructured interview, which confirmed the suitability of our approach, e.g., during interventions where surgeons benefit from sterile interaction.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
We present an approach that tracks the gaze position of a user to determine a structure of interest in a medical planning model. This structure is automatically and dynamically annotated with an external label. The approach considers aspects from hand-crafted illustrations and interactive applications. In general, labels are simultaneously shown for all structures in interactive applications. However, this leads to visual clutter and is costly regarding computation time. Both aspects could be neglected if annotations are only shown regarding user’s demands, i.e., only one label at a time. We use an eye tracker to obtain the user’s gaze positions and, thus, the structure of interest. We address problems due to imprecise input with smoothing and increasing the selection area around each structure. The prototype was evaluated with an unstructured interview, which confirmed the suitability of our approach, e.g., during interventions where surgeons benefit from sterile interaction.