The Experts below are selected from a list of 66246 Experts worldwide ranked by ideXlab platform
J. Mühling - One of the best experts on this subject based on the ideXlab platform.
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Image-to-Patient Registration by natural anatomical surfaces of the head
Open Medicine, 2007Co-Authors: Rüdiger Marmulla, J. Mühling, Georg EggersAbstract:The use of Registration markers in computer-assisted surgery is combined with high logistic costs and efforts.
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Laser surface Registration for lateral skull base surgery.
Minimally invasive neurosurgery : MIN, 2005Co-Authors: R. Marmulla, Georg Eggers, J. MühlingAbstract:Objective Logistics in the run-up to computer-assisted lateral skull base intervention can be reduced by markerless Registration methods. So far, only the facial skin surface but not the skin surface that was near to the lateral skull base was used for markerless Patient Registration. The present study was designed to evaluate whether the auricles may serve as an accurate spatial reference for markerless Patient Registration in image-guided lateral skull base surgery. Study design In a prospective clinical study, the precision of markerless Patient Registration was checked by using periauricular evaluation markers and additional distant oral evaluation markers that served as targets for the infrared pointer of a navigation system. Ten Patients with cranial tumors, bony malformations, or foreign bodies who were planned for image-guided surgery were selected. Markerless Patient Registration was performed by laser-scanning with the SSN++ navigation system. Results Based on the auricle, a high accuracy (mean target detection error tde = 0.9 mm +/- s = 0.3 mm) was achieved in markerless Patient Registration as long as the auricle was not deformed during CT imaging or during laser scanning. However, the conventional CT acquisition with a head support caused temporary auricular deformations in half of the Patients, which made a precise laser-scan Registration impossible. Conclusions Automated laser Registration of the auricle reduces the logistical input in connection with computer-assisted lateral skull base surgery, ensuring the accuracy that has been achieved up to now with marker-based methods. Constantly good results can be achieved if the head support of the computer tomograph has an appropriate opening at the level of the auricles in order to avoid auricular deformations during CT acquisition.
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High-resolution laser surface scanning for Patient Registration in cranial computer-assisted surgery.
Minimally invasive neurosurgery : MIN, 2004Co-Authors: R. Marmulla, J. Mühling, S. HassfeldAbstract:Objective: Markerless Patient Registration is a new procedure that may reduce logistical efforts and possibly also the radiation load on the Patients prior to a computer-assisted intervention. Congruent surfaces, such as bone surfaces or skin surfaces, represented in a data set and in the surgical site, can be overlapped using surface-matching. Previous studies describing this kind of markerless Registration, however, show inaccuracies of up to 10 mm during computer-assisted navigation. Furthermore, these systems use less than 1000 surface points of the soft tissue surface in order to establish a correlation between the Patient and the data set. Previous papers did not answer the question whether it is this scanning resolution that induces these inaccuracies in Registration or rather intraoperative skin deformations. Study Design: In the present study therefore a new navigation system (SSN++) was used which is able to register up to 180,000 surface points of the surgical site. SSN++ is an infrared navigation system enlarged by a Minolta VI 900 3D volume digitizer. Three different kinds of laser scan-resolution were used for data correlation. An additional congruence analysis was performed in order to assess the geometry of the matched skin surfaces. 22 Patients suffering from different cranial diseases (tumors, bony malformations, foreign bodies) were prepared for a computer-assisted intervention. Intraoral titanium-markers, rigidly fixed on the Patients by a maxillary splint, were placed as targets while the CT data sets were made. These targets were - after markerless laser scan Registration of the Patients - supposed to serve for validating the new high-resolution navigation system SSN++. Results: The accuracy of markerless laser scan Registration depends on the intraoperative laser scan's resolution. A high accuracy of the data correlation can be achieved if the number ofthe laser scan cloud points is about the same as the number of voxels of the corresponding surface on the CT data set. A reduction of the laser scan cloud points to less than 10% compared to the number of voxels of the CT surface, however, leads to a significant loss of accuracy after markerless Patient Registration. Conclusion: The markerless laser scan Registration of the surgical site may achieve the same accuracy as a Patient Registration made by rigidly fixed titanium screws (mean accuracy: 1.2 mm) as long as a high-resolution laser scan is being used.
Keith D. Paulsen - One of the best experts on this subject based on the ideXlab platform.
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Medical Imaging: Image-Guided Procedures - Automatic intraoperative fiducial-less Patient Registration using cortical surface
Medical Imaging 2017: Image-Guided Procedures Robotic Interventions and Modeling, 2017Co-Authors: Xiaoyao Fan, David W. Roberts, Jonathan D. Olson, Keith D. PaulsenAbstract:In image-guided neurosurgery, Patient Registration is typically performed in the operating room (OR) at the beginning of the procedure to establish the Patient-to-image transformation. The accuracy and efficiency of Patient Registration are crucial as they are associated with surgical outcome, workflow, and healthcare costs. In this paper, we present an automatic fiducial-less Patient Registration (FLR) by directly registering cortical surface acquired from intraoperative stereovision (iSV) with preoperative MR (pMR) images without incorporating any prior information, and illustrate the method using one Patient example. T1-weighted MR images were acquired prior to surgery and the brain was segmented. After dural opening, an image pair of the exposed cortical surface was acquired using an intraoperative stereovision (iSV) system, and a three-dimensional (3D) texture-encoded profile of the cortical surface was reconstructed. The 3D surface was registered with pMR using a multi-start binary Registration method to determine the location and orientation of the iSV patch with respect to the segmented brain. A final transformation was calculated to establish the Patient-to-MR relationship. The total computational time was ~30 min, and can be significantly improved through code optimization, parallel computing, and/or graphical processing unit (GPU) acceleration. The results show that the iSV texture map aligned well with pMR using the FLR transformation, while misalignment was evident with fiducial-based Registration (FBR). The difference between FLR and FBR was calculated at the center of craniotomy and the resulting distance was 4.34 mm. The results presented in this paper suggest potential for clinical application in the future.
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CSI@MICCAI - Patient Registration via Topologically Encoded Depth Projection Images in Spine Surgery
Lecture Notes in Computer Science, 2016Co-Authors: Xiaoyao Fan, David W. Roberts, Keith D. Paulsen, Sohail K Mirza, Jonathan D. Olson, Linton T. Evans, S. Scott LollisAbstract:Accurate and efficient Patient Registration is essential for surgical image-guidance. Here, we present a Registration pipeline to establish spatial correspondence between tracked intraoperative stereovision (iSV) and preoperative computed tomography (pCT) for spine surgery. First, depth projection images encoding the common vertebral dorsal surface “height” were generated from pCT and iSV. For pCT, vertebral pose was adjusted when necessary based on anatomic landmarks. For iSV, multiple reconstructed surfaces were combined to generate a unified projection image with accounting of overlapped regions to maximize the sampling of the surgical scene. Rigid Registration between the resulting projection images produced an initial alignment for refined Registration using an improved iterative closest point algorithm. The technique was applied to four explanted porcine spines in a total of eight poses. Registration accuracy was assessed using bone-implanted mini screws. The average fiducial Registration error and target Registration error (TRE) for ground-truth probe Registration was \(0.50\,{\pm }\,0.08\) and \(0.63\,{\pm }\,0.08\), respectively. The accuracy for iSV Registration was \(1.77\,{\pm }\,0.31\,\text {mm}\) in TRE and was \(2.01\,{\pm }\,0.44\,\text {mm}\) for surface reconstruction. The entire Registration completed within 2 min. These results suggest potential for application of the method in human Patients.
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Medical Imaging: Image-Guided Procedures - Automatic geometric rectification for Patient Registration in image-guided spinal surgery
Medical Imaging 2016: Image-Guided Procedures Robotic Interventions and Modeling, 2016Co-Authors: Yunliang Cai, David W. Roberts, Keith D. Paulsen, Sohail K Mirza, Xiaoyao Fan, Jonathan D. Olson, Linton T. Evans, S. Scott LollisAbstract:Accurate and efficient Patient Registration is crucial for the success of image-guidance in open spinal surgery. Recently, we have established the feasibility of using intraoperative stereovision (iSV) to perform Patient Registration with respect to preoperative CT (pCT) in human subjects undergoing spinal surgery. Although a desired accuracy was achieved, the method required manual segmentation and placement of feature points on reconstructed iSV and pCT surfaces. In this study, we present an improved Registration pipeline to eliminate these manual operations. Specifically, automatic geometric rectification was performed on spines extracted from pCT and iSV into pose-invariant shapes using a nonlinear principal component analysis (NLPCA). Rectified spines were obtained by projecting the reconstructed 3D surfaces into an anatomically determined orientation. Two-dimensional projection images were then created with image intensity values encoding feature "height" in the dorsal-ventral direction. Registration between the 2D depth maps yielded an initial point-wise correspondence between the 3D surfaces. A refined Registration was achieved using an iterative closest point (ICP) algorithm. The technique was successfully applied to two explanted and one live porcine spines. The computational cost of the Registration pipeline was less than 1 min, with an average target Registration error (TRE) less than 2.2 mm in the laminae area. These results suggest the potential for the pose-invariant, rectification-based Registration technique for clinical application in human subjects in the future.
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Intraoperative fiducial-less Patient Registration using volumetric 3D ultrasound: a prospective series of 32 neurosurgical cases
Journal of neurosurgery, 2015Co-Authors: Xiaoyao Fan, David W. Roberts, Alex Hartov, Keith D. PaulsenAbstract:OBJECT Fiducial-based Registration (FBR) is used widely for Patient Registration in image-guided neurosurgery. The authors of this study have developed an automatic fiducial-less Registration (FLR) technique to find the Patient-to-image transformation by directly registering 3D ultrasound (3DUS) with MR images without incorporating prior information. The purpose of the study was to evaluate the performance of the FLR technique when used prospectively in the operating room and to compare it with conventional FBR. METHODS In 32 surgical Patients who underwent conventional FBR, preoperative T1-weighted MR images (pMR) with attached fiducial markers were acquired prior to surgery. After craniotomy but before dural opening, a set of 3DUS images of the brain volume was acquired. A 2-step Registration process was executed immediately after image acquisition: 1) the cortical surfaces from pMR and 3DUS were segmented, and a multistart sum-of-squared-intensity-difference Registration was executed to find an initial...
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Patient Registration using intraoperative stereovision in image guided open spinal surgery
IEEE Transactions on Biomedical Engineering, 2015Co-Authors: Songbai Ji, David W. Roberts, Keith D. Paulsen, Sohail K Mirza, Scott S LollisAbstract:Despite its widespread availability and success in open cranial neurosurgery, image-guidance technology remains more limited in use in open spinal procedures, in large part, because of Patient Registration challenges. In this study, we evaluated the feasibility of using intraoperative stereovision (iSV) for accurate, efficient, and robust Patient Registration in an open spinal fusion surgery. Geometrical surfaces of exposed vertebrae were first reconstructed from iSV. A classical multistart Registration was then executed between point clouds generated from iSV and preoperative computed tomography images of the spine. With two pairs of feature points manually identified to facilitate the Registration, an average Registration accuracy of 1.43 mm in terms of surface-to-surface distance error was achieved in eight Patient cases using a single iSV image pair sampling 2–3 vertebral segments. The iSV Registration error was consistently smaller than the conventional landmark approach for every case (average of 2.02 mm with the same error metric). The large capture ranges (average of 23.8 mm in translation and 46.0° in rotation) found in the iSV Patient Registration suggest the technique may offer sufficient robustness for practical application in the operating room. Although some manual effort was still necessary, the manually-derived inputs for iSV Registration only needed to be approximate as opposed to be precise and accurate for the manual efforts required in landmark Registration. The total computational cost of the iSV Registration was 1.5 min on average, significantly less than the typical ∼30 min required for the landmark approach. These findings support the clinical feasibility of iSV to offer accurate, efficient, and robust Patient Registration in open spinal surgery, and therefore, its potential to further increase the adoption of image guidance in this surgical specialty.
David W. Roberts - One of the best experts on this subject based on the ideXlab platform.
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Medical Imaging: Image-Guided Procedures - Automatic intraoperative fiducial-less Patient Registration using cortical surface
Medical Imaging 2017: Image-Guided Procedures Robotic Interventions and Modeling, 2017Co-Authors: Xiaoyao Fan, David W. Roberts, Jonathan D. Olson, Keith D. PaulsenAbstract:In image-guided neurosurgery, Patient Registration is typically performed in the operating room (OR) at the beginning of the procedure to establish the Patient-to-image transformation. The accuracy and efficiency of Patient Registration are crucial as they are associated with surgical outcome, workflow, and healthcare costs. In this paper, we present an automatic fiducial-less Patient Registration (FLR) by directly registering cortical surface acquired from intraoperative stereovision (iSV) with preoperative MR (pMR) images without incorporating any prior information, and illustrate the method using one Patient example. T1-weighted MR images were acquired prior to surgery and the brain was segmented. After dural opening, an image pair of the exposed cortical surface was acquired using an intraoperative stereovision (iSV) system, and a three-dimensional (3D) texture-encoded profile of the cortical surface was reconstructed. The 3D surface was registered with pMR using a multi-start binary Registration method to determine the location and orientation of the iSV patch with respect to the segmented brain. A final transformation was calculated to establish the Patient-to-MR relationship. The total computational time was ~30 min, and can be significantly improved through code optimization, parallel computing, and/or graphical processing unit (GPU) acceleration. The results show that the iSV texture map aligned well with pMR using the FLR transformation, while misalignment was evident with fiducial-based Registration (FBR). The difference between FLR and FBR was calculated at the center of craniotomy and the resulting distance was 4.34 mm. The results presented in this paper suggest potential for clinical application in the future.
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CSI@MICCAI - Patient Registration via Topologically Encoded Depth Projection Images in Spine Surgery
Lecture Notes in Computer Science, 2016Co-Authors: Xiaoyao Fan, David W. Roberts, Keith D. Paulsen, Sohail K Mirza, Jonathan D. Olson, Linton T. Evans, S. Scott LollisAbstract:Accurate and efficient Patient Registration is essential for surgical image-guidance. Here, we present a Registration pipeline to establish spatial correspondence between tracked intraoperative stereovision (iSV) and preoperative computed tomography (pCT) for spine surgery. First, depth projection images encoding the common vertebral dorsal surface “height” were generated from pCT and iSV. For pCT, vertebral pose was adjusted when necessary based on anatomic landmarks. For iSV, multiple reconstructed surfaces were combined to generate a unified projection image with accounting of overlapped regions to maximize the sampling of the surgical scene. Rigid Registration between the resulting projection images produced an initial alignment for refined Registration using an improved iterative closest point algorithm. The technique was applied to four explanted porcine spines in a total of eight poses. Registration accuracy was assessed using bone-implanted mini screws. The average fiducial Registration error and target Registration error (TRE) for ground-truth probe Registration was \(0.50\,{\pm }\,0.08\) and \(0.63\,{\pm }\,0.08\), respectively. The accuracy for iSV Registration was \(1.77\,{\pm }\,0.31\,\text {mm}\) in TRE and was \(2.01\,{\pm }\,0.44\,\text {mm}\) for surface reconstruction. The entire Registration completed within 2 min. These results suggest potential for application of the method in human Patients.
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Medical Imaging: Image-Guided Procedures - Automatic geometric rectification for Patient Registration in image-guided spinal surgery
Medical Imaging 2016: Image-Guided Procedures Robotic Interventions and Modeling, 2016Co-Authors: Yunliang Cai, David W. Roberts, Keith D. Paulsen, Sohail K Mirza, Xiaoyao Fan, Jonathan D. Olson, Linton T. Evans, S. Scott LollisAbstract:Accurate and efficient Patient Registration is crucial for the success of image-guidance in open spinal surgery. Recently, we have established the feasibility of using intraoperative stereovision (iSV) to perform Patient Registration with respect to preoperative CT (pCT) in human subjects undergoing spinal surgery. Although a desired accuracy was achieved, the method required manual segmentation and placement of feature points on reconstructed iSV and pCT surfaces. In this study, we present an improved Registration pipeline to eliminate these manual operations. Specifically, automatic geometric rectification was performed on spines extracted from pCT and iSV into pose-invariant shapes using a nonlinear principal component analysis (NLPCA). Rectified spines were obtained by projecting the reconstructed 3D surfaces into an anatomically determined orientation. Two-dimensional projection images were then created with image intensity values encoding feature "height" in the dorsal-ventral direction. Registration between the 2D depth maps yielded an initial point-wise correspondence between the 3D surfaces. A refined Registration was achieved using an iterative closest point (ICP) algorithm. The technique was successfully applied to two explanted and one live porcine spines. The computational cost of the Registration pipeline was less than 1 min, with an average target Registration error (TRE) less than 2.2 mm in the laminae area. These results suggest the potential for the pose-invariant, rectification-based Registration technique for clinical application in human subjects in the future.
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Intraoperative fiducial-less Patient Registration using volumetric 3D ultrasound: a prospective series of 32 neurosurgical cases
Journal of neurosurgery, 2015Co-Authors: Xiaoyao Fan, David W. Roberts, Alex Hartov, Keith D. PaulsenAbstract:OBJECT Fiducial-based Registration (FBR) is used widely for Patient Registration in image-guided neurosurgery. The authors of this study have developed an automatic fiducial-less Registration (FLR) technique to find the Patient-to-image transformation by directly registering 3D ultrasound (3DUS) with MR images without incorporating prior information. The purpose of the study was to evaluate the performance of the FLR technique when used prospectively in the operating room and to compare it with conventional FBR. METHODS In 32 surgical Patients who underwent conventional FBR, preoperative T1-weighted MR images (pMR) with attached fiducial markers were acquired prior to surgery. After craniotomy but before dural opening, a set of 3DUS images of the brain volume was acquired. A 2-step Registration process was executed immediately after image acquisition: 1) the cortical surfaces from pMR and 3DUS were segmented, and a multistart sum-of-squared-intensity-difference Registration was executed to find an initial...
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Patient Registration using intraoperative stereovision in image guided open spinal surgery
IEEE Transactions on Biomedical Engineering, 2015Co-Authors: Songbai Ji, David W. Roberts, Keith D. Paulsen, Sohail K Mirza, Scott S LollisAbstract:Despite its widespread availability and success in open cranial neurosurgery, image-guidance technology remains more limited in use in open spinal procedures, in large part, because of Patient Registration challenges. In this study, we evaluated the feasibility of using intraoperative stereovision (iSV) for accurate, efficient, and robust Patient Registration in an open spinal fusion surgery. Geometrical surfaces of exposed vertebrae were first reconstructed from iSV. A classical multistart Registration was then executed between point clouds generated from iSV and preoperative computed tomography images of the spine. With two pairs of feature points manually identified to facilitate the Registration, an average Registration accuracy of 1.43 mm in terms of surface-to-surface distance error was achieved in eight Patient cases using a single iSV image pair sampling 2–3 vertebral segments. The iSV Registration error was consistently smaller than the conventional landmark approach for every case (average of 2.02 mm with the same error metric). The large capture ranges (average of 23.8 mm in translation and 46.0° in rotation) found in the iSV Patient Registration suggest the technique may offer sufficient robustness for practical application in the operating room. Although some manual effort was still necessary, the manually-derived inputs for iSV Registration only needed to be approximate as opposed to be precise and accurate for the manual efforts required in landmark Registration. The total computational cost of the iSV Registration was 1.5 min on average, significantly less than the typical ∼30 min required for the landmark approach. These findings support the clinical feasibility of iSV to offer accurate, efficient, and robust Patient Registration in open spinal surgery, and therefore, its potential to further increase the adoption of image guidance in this surgical specialty.
R. Marmulla - One of the best experts on this subject based on the ideXlab platform.
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Image-to-Patient Registration techniques in head surgery.
International journal of oral and maxillofacial surgery, 2006Co-Authors: Georg Eggers, Joachim Mühling, R. MarmullaAbstract:Frame-based stereotaxy was developed in neurosurgery at the beginning of the last century, evolving from atlas-based stereotaxy to stereotaxy based on the individual Patient's image data. This established method is still in use in neurosurgery and radiotherapy. There have since been two main developments based on this concept: frameless stereotaxy and markerless Registration. Frameless stereotactic systems ('navigation systems') replaced the cumbersome stereotactic frame by mechanically and later also optically or magnetically tracked instruments. Stereotaxy based on the individual Patient's image data introduced the problem of Patient-to-image data Registration. The development of navigation systems based on frameless stereotaxy has dramatically increased its use in surgical disciplines other than neurosurgery, but image-guided surgery based on fiducial marker Registration needs dedicated imaging for Registration purposes, in addition to the diagnostic imaging that might have been performed. Markerless Registration techniques can overcome the resulting additional cost and effort, and result in more widespread use of image-guided surgery techniques. In this review paper, the developments that led to today's navigation systems are outlined, and the applications and possibilities of these methods in the field of maxillofacial surgery are presented.
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Laser surface Registration for lateral skull base surgery.
Minimally invasive neurosurgery : MIN, 2005Co-Authors: R. Marmulla, Georg Eggers, J. MühlingAbstract:Objective Logistics in the run-up to computer-assisted lateral skull base intervention can be reduced by markerless Registration methods. So far, only the facial skin surface but not the skin surface that was near to the lateral skull base was used for markerless Patient Registration. The present study was designed to evaluate whether the auricles may serve as an accurate spatial reference for markerless Patient Registration in image-guided lateral skull base surgery. Study design In a prospective clinical study, the precision of markerless Patient Registration was checked by using periauricular evaluation markers and additional distant oral evaluation markers that served as targets for the infrared pointer of a navigation system. Ten Patients with cranial tumors, bony malformations, or foreign bodies who were planned for image-guided surgery were selected. Markerless Patient Registration was performed by laser-scanning with the SSN++ navigation system. Results Based on the auricle, a high accuracy (mean target detection error tde = 0.9 mm +/- s = 0.3 mm) was achieved in markerless Patient Registration as long as the auricle was not deformed during CT imaging or during laser scanning. However, the conventional CT acquisition with a head support caused temporary auricular deformations in half of the Patients, which made a precise laser-scan Registration impossible. Conclusions Automated laser Registration of the auricle reduces the logistical input in connection with computer-assisted lateral skull base surgery, ensuring the accuracy that has been achieved up to now with marker-based methods. Constantly good results can be achieved if the head support of the computer tomograph has an appropriate opening at the level of the auricles in order to avoid auricular deformations during CT acquisition.
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High-resolution laser surface scanning for Patient Registration in cranial computer-assisted surgery.
Minimally invasive neurosurgery : MIN, 2004Co-Authors: R. Marmulla, J. Mühling, S. HassfeldAbstract:Objective: Markerless Patient Registration is a new procedure that may reduce logistical efforts and possibly also the radiation load on the Patients prior to a computer-assisted intervention. Congruent surfaces, such as bone surfaces or skin surfaces, represented in a data set and in the surgical site, can be overlapped using surface-matching. Previous studies describing this kind of markerless Registration, however, show inaccuracies of up to 10 mm during computer-assisted navigation. Furthermore, these systems use less than 1000 surface points of the soft tissue surface in order to establish a correlation between the Patient and the data set. Previous papers did not answer the question whether it is this scanning resolution that induces these inaccuracies in Registration or rather intraoperative skin deformations. Study Design: In the present study therefore a new navigation system (SSN++) was used which is able to register up to 180,000 surface points of the surgical site. SSN++ is an infrared navigation system enlarged by a Minolta VI 900 3D volume digitizer. Three different kinds of laser scan-resolution were used for data correlation. An additional congruence analysis was performed in order to assess the geometry of the matched skin surfaces. 22 Patients suffering from different cranial diseases (tumors, bony malformations, foreign bodies) were prepared for a computer-assisted intervention. Intraoral titanium-markers, rigidly fixed on the Patients by a maxillary splint, were placed as targets while the CT data sets were made. These targets were - after markerless laser scan Registration of the Patients - supposed to serve for validating the new high-resolution navigation system SSN++. Results: The accuracy of markerless laser scan Registration depends on the intraoperative laser scan's resolution. A high accuracy of the data correlation can be achieved if the number ofthe laser scan cloud points is about the same as the number of voxels of the corresponding surface on the CT data set. A reduction of the laser scan cloud points to less than 10% compared to the number of voxels of the CT surface, however, leads to a significant loss of accuracy after markerless Patient Registration. Conclusion: The markerless laser scan Registration of the surgical site may achieve the same accuracy as a Patient Registration made by rigidly fixed titanium screws (mean accuracy: 1.2 mm) as long as a high-resolution laser scan is being used.
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Automated laser Registration in image-guided surgery: evaluation of the correlation between laser scan resolution and navigation accuracy.
International journal of oral and maxillofacial surgery, 2004Co-Authors: R. Marmulla, Joachim Mühling, Tim Lüth, S. HassfeldAbstract:Markerless Patient Registration based on the facial skin surface makes logistics prior to image-guided surgery much easier, as it is not necessary to place and measure Registration markers. A laser scan Registration of the surgical site takes the place of conventional marker-based Registration. In a clinical study, the stability and accuracy of markerless Patient Registration was evaluated in 12 Patients. Intraoral titanium markers served as targets for the infrared-pointer of the navigation system in order to check the accuracy of the markerless Registration process. The correlation between laser scan resolution and navigation accuracy was checked using seven different laser scan resolutions (a cloud of 300,000 laser scan points down to 3750 laser scan points of the surgical site). The markerless Patient Registration was successful as long as high laser scan resolution was used (30,000 laser scan points and more): the titanium markers were detected with a mean deviation of 1.1 +/- 0.2 mm. Low resolution laser scans (6000 laser scan points of the surgical site and less) revealed inaccuracies up to 6 mm.
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CARS - Next generation's navigation systems
International Congress Series, 2003Co-Authors: R. Marmulla, Tim Lüth, S. Hassfeld, Joachim MühlingAbstract:Abstract The data set correlation between the surgical site and the corresponding image data set in the operating room (OR) is the most time-consuming process for the surgeon. The next generation's navigation systems ought to perform an automatic and highly accurate Patient Registration in the OR. Two systems that meet these criteria, the Surgical Segment Navigator SSN and the SSN++, are described. The SSN was developed in 1997 and is used for computer-assisted bone segment navigation. The SSN++, which has further been developed since 1999, utilizes laser scans of the surgical site. Both systems perform Patient Registration by just one click on a command button.
Georg Eggers - One of the best experts on this subject based on the ideXlab platform.
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Image-to-Patient Registration by natural anatomical surfaces of the head
Open Medicine, 2007Co-Authors: Rüdiger Marmulla, J. Mühling, Georg EggersAbstract:The use of Registration markers in computer-assisted surgery is combined with high logistic costs and efforts.
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Image-to-Patient Registration techniques in head surgery.
International journal of oral and maxillofacial surgery, 2006Co-Authors: Georg Eggers, Joachim Mühling, R. MarmullaAbstract:Frame-based stereotaxy was developed in neurosurgery at the beginning of the last century, evolving from atlas-based stereotaxy to stereotaxy based on the individual Patient's image data. This established method is still in use in neurosurgery and radiotherapy. There have since been two main developments based on this concept: frameless stereotaxy and markerless Registration. Frameless stereotactic systems ('navigation systems') replaced the cumbersome stereotactic frame by mechanically and later also optically or magnetically tracked instruments. Stereotaxy based on the individual Patient's image data introduced the problem of Patient-to-image data Registration. The development of navigation systems based on frameless stereotaxy has dramatically increased its use in surgical disciplines other than neurosurgery, but image-guided surgery based on fiducial marker Registration needs dedicated imaging for Registration purposes, in addition to the diagnostic imaging that might have been performed. Markerless Registration techniques can overcome the resulting additional cost and effort, and result in more widespread use of image-guided surgery techniques. In this review paper, the developments that led to today's navigation systems are outlined, and the applications and possibilities of these methods in the field of maxillofacial surgery are presented.
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Laser surface Registration for lateral skull base surgery.
Minimally invasive neurosurgery : MIN, 2005Co-Authors: R. Marmulla, Georg Eggers, J. MühlingAbstract:Objective Logistics in the run-up to computer-assisted lateral skull base intervention can be reduced by markerless Registration methods. So far, only the facial skin surface but not the skin surface that was near to the lateral skull base was used for markerless Patient Registration. The present study was designed to evaluate whether the auricles may serve as an accurate spatial reference for markerless Patient Registration in image-guided lateral skull base surgery. Study design In a prospective clinical study, the precision of markerless Patient Registration was checked by using periauricular evaluation markers and additional distant oral evaluation markers that served as targets for the infrared pointer of a navigation system. Ten Patients with cranial tumors, bony malformations, or foreign bodies who were planned for image-guided surgery were selected. Markerless Patient Registration was performed by laser-scanning with the SSN++ navigation system. Results Based on the auricle, a high accuracy (mean target detection error tde = 0.9 mm +/- s = 0.3 mm) was achieved in markerless Patient Registration as long as the auricle was not deformed during CT imaging or during laser scanning. However, the conventional CT acquisition with a head support caused temporary auricular deformations in half of the Patients, which made a precise laser-scan Registration impossible. Conclusions Automated laser Registration of the auricle reduces the logistical input in connection with computer-assisted lateral skull base surgery, ensuring the accuracy that has been achieved up to now with marker-based methods. Constantly good results can be achieved if the head support of the computer tomograph has an appropriate opening at the level of the auricles in order to avoid auricular deformations during CT acquisition.
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CARS - Image-to-Patient-Registration by the natural anatomical surfaces of the auricle, mandible, and maxilla
International Congress Series, 2004Co-Authors: Rüdiger Marmulla, Joachim Mühling, Tim Lüth, Georg Eggers, Stefan HassfeldAbstract:Abstract A new developed navigation system, named SSN++, was evaluated for automated and markerless Patient Registration. The purpose of this system is to reduce radiation load and logistical input prior to computer-assisted surgery, as it is not necessary to place and measure reference markers. The method of image-to-Patient-Registration is based on natural anatomical surfaces such as the surfaces of the auricle, the mandible, and the maxilla.