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Mark C. Preul - One of the best experts on this subject based on the ideXlab platform.
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fiducial versus nonfiducial neuronavigation Registration assessment and considerations of accuracy
Neurosurgery, 2008Co-Authors: Wolfgang Pfisterer, Denise Allison Drumm, Kris A Smith, Stephen M. Papadopoulos, Mark C. PreulAbstract:OBJECTIVE: For frameless stereotaxy, users can choose between anatomic landmarks (ALs) or surface fiducial markers (FMs) for their match points during Registration to define an alignment of the head in the physical and radiographic image space. In this study, we sought to determine the concordance among a point-merged FM Registration, a point-merged AL Registration, and a combined point-merged anatomic/surface-merged (SM) Registration, i.e., to determine the accuracy of Registration techniques with and without FMs by examining the extent of agreement between the system-generated predicted value and physical measured values. METHODS: We examined 30 volunteers treated with gamma knife surgery. The frameless stereotactic image-guidance system called the StealthStation (Medtronic Surgical Navigation Technologies, Louisville, CO) was used. Nine FMs were placed on the patient's head and four were placed on a Leksell frame rod-box, which acted as a rigid set to determine the difference in error. For each Registration form, we recorded the generated measurement (GM) and the physical measurement (PM) to each of the four checkpoint FMs. Bland and Altman plot difference analyses were used to compare measurement techniques. Correlations and descriptive analyses were completed. RESULTS: The mean of values for GMs were 1.14 mm for FM, 2.3 mm for AL, and 0.96 mm for SM Registrations. The mean errors of the checkpoints were 3.49 mm for FM, 3.96 mm for AL, and 3.33 mm for SM Registrations. The correlation between GMs and PMs indicated a linear relationship for all three methods. AL Registration demonstrated the greatest mean difference, followed by FM Registration; SM Registration had the smallest difference between GMs and PMs. Differences in the anatomic Registration methods, including SM Registration, compared with FM Registration were within a mean +/- 1.96 (standard deviation) according to the Bland and Altman analysis. CONCLUSION: For our sample of 30 patients, all three Registration methods provided comparable distances to the target tissue for surgical procedures. Users may safely choose anatomic Registration as a less costly and more time-efficient Registration method for frameless stereotaxy.
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fiducial versus nonfiducial neuronavigation Registration assessment and considerations of accuracy
Neurosurgery, 2008Co-Authors: Wolfgang Pfisterer, Denise Allison Drumm, Kris A Smith, Stephen M. Papadopoulos, Mark C. PreulAbstract:OBJECTIVE: For frameless stereotaxy, users can choose between anatomic landmarks (ALs) or surface fiducial markers (FMs) for their match points during Registration to define an alignment of the head in the physical and radiographic image space. In this study, we sought to determine the concordance among a point-merged FM Registration, a point-merged AL Registration, and a combined point-merged anatomic/surface-merged (SM) Registration, i.e., to determine the accuracy of Registration techniques with and without FMs by examining the extent of agreement between the system-generated predicted value and physical measured values. METHODS: We examined 30 volunteers treated with gamma knife surgery. The frameless stereotactic image-guidance system called the StealthStation (Medtronic Surgical Navigation Technologies, Louisville, CO) was used. Nine FMs were placed on the patient's head and four were placed on a Leksell frame rod-box, which acted as a rigid set to determine the difference in error. For each Registration form, we recorded the generated measurement (GM) and the physical measurement (PM) to each of the four checkpoint FMs. Bland and Altman plot difference analyses were used to compare measurement techniques. Correlations and descriptive analyses were completed. RESULTS: The mean of values for GMs were 1.14 mm for FM, 2.3 mm for AL, and 0.96 mm for SM Registrations. The mean errors of the checkpoints were 3.49 mm for FM, 3.96 mm for AL, and 3.33 mm for SM Registrations. The correlation between GMs and PMs indicated a linear relationship for all three methods. AL Registration demonstrated the greatest mean difference, followed by FM Registration; SM Registration had the smallest difference between GMs and PMs. Differences in the anatomic Registration methods, including SM Registration, compared with FM Registration were within a mean +/- 1.96 (standard deviation) according to the Bland and Altman analysis. CONCLUSION: For our sample of 30 patients, all three Registration methods provided comparable distances to the target tissue for surgical procedures. Users may safely choose anatomic Registration as a less costly and more time-efficient Registration method for frameless stereotaxy.
Wolfgang Pfisterer - One of the best experts on this subject based on the ideXlab platform.
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fiducial versus nonfiducial neuronavigation Registration assessment and considerations of accuracy
Neurosurgery, 2008Co-Authors: Wolfgang Pfisterer, Denise Allison Drumm, Kris A Smith, Stephen M. Papadopoulos, Mark C. PreulAbstract:OBJECTIVE: For frameless stereotaxy, users can choose between anatomic landmarks (ALs) or surface fiducial markers (FMs) for their match points during Registration to define an alignment of the head in the physical and radiographic image space. In this study, we sought to determine the concordance among a point-merged FM Registration, a point-merged AL Registration, and a combined point-merged anatomic/surface-merged (SM) Registration, i.e., to determine the accuracy of Registration techniques with and without FMs by examining the extent of agreement between the system-generated predicted value and physical measured values. METHODS: We examined 30 volunteers treated with gamma knife surgery. The frameless stereotactic image-guidance system called the StealthStation (Medtronic Surgical Navigation Technologies, Louisville, CO) was used. Nine FMs were placed on the patient's head and four were placed on a Leksell frame rod-box, which acted as a rigid set to determine the difference in error. For each Registration form, we recorded the generated measurement (GM) and the physical measurement (PM) to each of the four checkpoint FMs. Bland and Altman plot difference analyses were used to compare measurement techniques. Correlations and descriptive analyses were completed. RESULTS: The mean of values for GMs were 1.14 mm for FM, 2.3 mm for AL, and 0.96 mm for SM Registrations. The mean errors of the checkpoints were 3.49 mm for FM, 3.96 mm for AL, and 3.33 mm for SM Registrations. The correlation between GMs and PMs indicated a linear relationship for all three methods. AL Registration demonstrated the greatest mean difference, followed by FM Registration; SM Registration had the smallest difference between GMs and PMs. Differences in the anatomic Registration methods, including SM Registration, compared with FM Registration were within a mean +/- 1.96 (standard deviation) according to the Bland and Altman analysis. CONCLUSION: For our sample of 30 patients, all three Registration methods provided comparable distances to the target tissue for surgical procedures. Users may safely choose anatomic Registration as a less costly and more time-efficient Registration method for frameless stereotaxy.
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fiducial versus nonfiducial neuronavigation Registration assessment and considerations of accuracy
Neurosurgery, 2008Co-Authors: Wolfgang Pfisterer, Denise Allison Drumm, Kris A Smith, Stephen M. Papadopoulos, Mark C. PreulAbstract:OBJECTIVE: For frameless stereotaxy, users can choose between anatomic landmarks (ALs) or surface fiducial markers (FMs) for their match points during Registration to define an alignment of the head in the physical and radiographic image space. In this study, we sought to determine the concordance among a point-merged FM Registration, a point-merged AL Registration, and a combined point-merged anatomic/surface-merged (SM) Registration, i.e., to determine the accuracy of Registration techniques with and without FMs by examining the extent of agreement between the system-generated predicted value and physical measured values. METHODS: We examined 30 volunteers treated with gamma knife surgery. The frameless stereotactic image-guidance system called the StealthStation (Medtronic Surgical Navigation Technologies, Louisville, CO) was used. Nine FMs were placed on the patient's head and four were placed on a Leksell frame rod-box, which acted as a rigid set to determine the difference in error. For each Registration form, we recorded the generated measurement (GM) and the physical measurement (PM) to each of the four checkpoint FMs. Bland and Altman plot difference analyses were used to compare measurement techniques. Correlations and descriptive analyses were completed. RESULTS: The mean of values for GMs were 1.14 mm for FM, 2.3 mm for AL, and 0.96 mm for SM Registrations. The mean errors of the checkpoints were 3.49 mm for FM, 3.96 mm for AL, and 3.33 mm for SM Registrations. The correlation between GMs and PMs indicated a linear relationship for all three methods. AL Registration demonstrated the greatest mean difference, followed by FM Registration; SM Registration had the smallest difference between GMs and PMs. Differences in the anatomic Registration methods, including SM Registration, compared with FM Registration were within a mean +/- 1.96 (standard deviation) according to the Bland and Altman analysis. CONCLUSION: For our sample of 30 patients, all three Registration methods provided comparable distances to the target tissue for surgical procedures. Users may safely choose anatomic Registration as a less costly and more time-efficient Registration method for frameless stereotaxy.
Robert J Maciunas - One of the best experts on this subject based on the ideXlab platform.
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retrospective intermodality Registration techniques for images of the head surface based versus volume based
IEEE Transactions on Medical Imaging, 1999Co-Authors: John B West, Benoit M Dawant, M Y Wang, Calvin R Maurer, Robert M Kessler, J M Fitzpatrick, Robert J MaciunasAbstract:A blinded evaluation of two groups of retrospective image Registration techniques was performed using as a gold standard a prospective marker-based Registration method, and we compared the performance of one group with the other. By grouping the techniques as volume-based or surface-based, we could make some interesting conclusions. In order to ensure blindness, all retrospective Registrations were performed by participants who had no knowledge of the gold-standard results until after their results had been submitted. Image volumes of three modalities (X-ray CT, MRI and PET) were obtained from patients undergoing neurosurgery on whom bone-implanted fiducial markers were mounted. These volumes had all traces of the markers removed and were provided via the Internet to outside collaborators, who then performed retrospective Registrations on the volumes, calculating transformations from CT to MRI and/or from PET to MRI. The accuracy of each Registration was then evaluated. The accuracy is measured at multiple volumes of interest. The volume-based techniques in this study tended to give substantially more accurate and reliable results than the surface-based ones for the CT-to-MRI Registration tasks, and slightly more accurate results for the PET-to-MRI tasks. Analysis of these results revealed that the rotational component of error was more pronounced for the surface-based group. It was also apparent that all of the Registration techniques we examined have the potential to produce satisfactory results much of the time, but that visual inspection is necessary to guard against large errors.
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comparison and evaluation of retrospective intermodality brain image Registration techniques
Journal of Computer Assisted Tomography, 1997Co-Authors: John B West, Benoit M Dawant, M Y Wang, Calvin R Maurer, Robert M Kessler, Robert J Maciunas, J M Fitzpatrick, Christian Barillot, D Lemoine, A CollignonAbstract:PURPOSE: The primary objective of this study is to perform a blinded evaluation of a group of retrospective image Registration techniques using as a gold standard a prospective, marker-based Registration method. To ensure blindedness, all retrospective Registrations were performed by participants who had no knowledge of the gold standard results until after their results had been submitted. A secondary goal of the project is to evaluate the importance of correcting geometrical distortion in MR images by comparing the retrospective Registration error in the rectified images, i.e., those that have had the distortion correction applied, with that of the same images before rectification. METHOD: Image volumes of three modalities (CT, MR, and PET) were obtained from patients undergoing neurosurgery at Vanderbilt University Medical Center on whom bone-implanted fiducial markers were mounted. These volumes had all traces of the markers removed and were provided via the Internet to project collaborators outside Vanderbilt, who then performed retrospective Registrations on the volumes, calculating transformations from CT to MR and/ or from PET to MR. These investigators communicated their transformations again via the Internet to Vanderbilt, where the accuracy of each Registration was evaluated. In this evaluation, the accuracy is measured at multiple volumes of interest (VOIs), i.e., areas in the brain that would commonly be areas of neurological interest. A VOI is defined in the MR image and its centroid c is determined. Then, the prospective Registration is used to obtain the corresponding point c' in CT or PET. To this point, the retrospective Registration is then applied, producing c" in MR. Statistics are gathered on the target Registration error (TRE), which is the distance between the original point c and its corresponding point c". RESULTS: This article presents statistics on the TRE calculated for each Registration technique in this study and provides a brief description of each technique and an estimate of both preparation and execution time needed to perform the Registration. CONCLUSION: Our results indicate that retrospective techniques have the potential to produce satisfactory results much of the time, but that visual inspection is necessary to guard against large errors.
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retrospective intermodality Registration techniques surface based versus volume based
CVRMed-MRCAS '97 Proceedings of the First Joint Conference on Computer Vision Virtual Reality and Robotics in Medicine and Medial Robotics and Compute, 1997Co-Authors: John B West, M Y Wang, Calvin R Maurer, Robert M Kessler, Michael J Fitzpatrick, Robert J MaciunasAbstract:The primary objective of this study is to perform a blinded evaluation of two groups of retrospective image Registration techniques using as a gold standard a prospective, marker-based Registration method, and to compare the performance of one group with the other. In order to ensure blindedness, all retrospective Registrations were performed by participants who had no knowledge of the gold-standard results until after their results had been submitted. Image volumes of three modalities—X-ray Computed Tomography (CT), Magnetic Resonance (MR), and Positron Emission Tomography (PET)—were obtained from patients undergoing neurosurgery at Vanderbilt University Medical Center on whom bone-implanted fiducial markers were mounted. These volumes had all traces of the markers removed and were provided via the Internet to project collaborators outside Vanderbilt, who then performed retrospective Registrations on the volumes, calculating transformations from CT to MR and/or from PET to MR. These investigators communicated their transformations again via the Internet to Vanderbilt, where the accuracy of each Registration was evaluated. In this evaluation, the accuracy is measured at multiple “volumes of interest” (VOIs). Our results indicate that the volume-based techniques in this study tended to give substantially more accurate and reliable results than the surface-based ones for the CT-to-MR Registration tasks and slightly more accurate results for the PET-to-MR tasks. It was also apparent that all of the Registration techniques we examined have the potential to produce satisfactory results much of the time but that visual inspection is necessary to guard against large errors.
Martin J Murphy - One of the best experts on this subject based on the ideXlab platform.
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A neural network based 3D∕3D image Registration quality evaluator for the head-and-neck patient setup in the absence of a ground truth
Medical physics, 2010Co-Authors: Martin J MurphyAbstract:Purpose: To develop a neural network based Registration quality evaluator (RQE) that can identify unsuccessful 3D/3D image Registrations for the head-and-neck patient setup in radiotherapy. Methods: A two-layer feed-forward neural network was used as a RQE to classify 3D/3D rigid Registration solutions as successful or unsuccessful based on the features of the similarity surface near the point-of-solution. The supervised training and test data sets were generated by rigidly registering daily cone-beam CTs to the treatment planning fan-beam CTs of six patients with head-and-neck tumors. Two different similarity metrics (mutual information and mean-squared intensity difference) and two different types of image content (entire image versus bony landmarks) were used. The best solution for each Registration pair was selected from 50 optimizing attempts that differed only by the initial transformation parameters. The distance from each individual solution to the best solution in the normalized parametrical space was compared to a user-defined error threshold to determine whether that solution was successful or not. The supervised training was then used to train the RQE. The performance of the RQE was evaluated using the test data set that consisted of Registration results that were not used in training. Results: The RQE constructed using the mutual information had very good performance when tested using the test data sets, yielding the sensitivity, the specificity, the positive predictive value, and the negative predictive value in the ranges of 0.960–1.000, 0.993–1.000, 0.983–1.000, and 0.909–1.000, respectively. Adding a RQE into a conventional 3D/3D image Registration system incurs only about 10%–20% increase of the overall processing time. Conclusions: The authors’ patient study has demonstrated very good performance of the proposed RQE when used with the mutual information in identifying unsuccessful 3D/3D Registrations for daily patient setup. The classifier had very good generality and required only to be trained once for each implementation. When the RQE is incorporated with an automated 3D/3D image Registration system, it can improve the robustness of the system.
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assessing the intrinsic precision of 3d 3d rigid image Registration results for patient setup in the absence of a ground truth
Medical Physics, 2010Co-Authors: Martin J MurphyAbstract:Purpose: To assess the precision and robustness of patient setup corrections computed from 3D/3D rigid Registration methods using image intensity, when no ground truth validation is possible. Methods: Fifteen pairs of male pelvic CTs were rigidly registered using four different in-house Registration methods. Registration results were compared for different resolutions and image content by varying the image down-sampling ratio and by thresholding out soft tissue to isolate bony landmarks. Intrinsic Registration precision was investigated by comparing the different methods and by reversing the source and the target roles of the two images being registered. Results: The translational reversibility errors for successful Registrations ranged from 0.0 to 1.69 mm. Rotations were less than 1°. Mutual information failed in most Registrations that used only bony landmarks. The magnitude of the reversibility error was strongly correlated with the success/failure of each algorithm to find the global minimum. Conclusions: Rigid image Registrations have an intrinsic uncertainty and robustness that depends on the imaging modality, the Registration algorithm, the image resolution, and the image content. In the absence of an absolute ground truth, the variation in the shifts calculated by several different methods provides a useful estimate of that uncertainty. The difference observed by reversing the source and target images can be used as an indication of robust convergence.
Kris A Smith - One of the best experts on this subject based on the ideXlab platform.
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fiducial versus nonfiducial neuronavigation Registration assessment and considerations of accuracy
Neurosurgery, 2008Co-Authors: Wolfgang Pfisterer, Denise Allison Drumm, Kris A Smith, Stephen M. Papadopoulos, Mark C. PreulAbstract:OBJECTIVE: For frameless stereotaxy, users can choose between anatomic landmarks (ALs) or surface fiducial markers (FMs) for their match points during Registration to define an alignment of the head in the physical and radiographic image space. In this study, we sought to determine the concordance among a point-merged FM Registration, a point-merged AL Registration, and a combined point-merged anatomic/surface-merged (SM) Registration, i.e., to determine the accuracy of Registration techniques with and without FMs by examining the extent of agreement between the system-generated predicted value and physical measured values. METHODS: We examined 30 volunteers treated with gamma knife surgery. The frameless stereotactic image-guidance system called the StealthStation (Medtronic Surgical Navigation Technologies, Louisville, CO) was used. Nine FMs were placed on the patient's head and four were placed on a Leksell frame rod-box, which acted as a rigid set to determine the difference in error. For each Registration form, we recorded the generated measurement (GM) and the physical measurement (PM) to each of the four checkpoint FMs. Bland and Altman plot difference analyses were used to compare measurement techniques. Correlations and descriptive analyses were completed. RESULTS: The mean of values for GMs were 1.14 mm for FM, 2.3 mm for AL, and 0.96 mm for SM Registrations. The mean errors of the checkpoints were 3.49 mm for FM, 3.96 mm for AL, and 3.33 mm for SM Registrations. The correlation between GMs and PMs indicated a linear relationship for all three methods. AL Registration demonstrated the greatest mean difference, followed by FM Registration; SM Registration had the smallest difference between GMs and PMs. Differences in the anatomic Registration methods, including SM Registration, compared with FM Registration were within a mean +/- 1.96 (standard deviation) according to the Bland and Altman analysis. CONCLUSION: For our sample of 30 patients, all three Registration methods provided comparable distances to the target tissue for surgical procedures. Users may safely choose anatomic Registration as a less costly and more time-efficient Registration method for frameless stereotaxy.
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fiducial versus nonfiducial neuronavigation Registration assessment and considerations of accuracy
Neurosurgery, 2008Co-Authors: Wolfgang Pfisterer, Denise Allison Drumm, Kris A Smith, Stephen M. Papadopoulos, Mark C. PreulAbstract:OBJECTIVE: For frameless stereotaxy, users can choose between anatomic landmarks (ALs) or surface fiducial markers (FMs) for their match points during Registration to define an alignment of the head in the physical and radiographic image space. In this study, we sought to determine the concordance among a point-merged FM Registration, a point-merged AL Registration, and a combined point-merged anatomic/surface-merged (SM) Registration, i.e., to determine the accuracy of Registration techniques with and without FMs by examining the extent of agreement between the system-generated predicted value and physical measured values. METHODS: We examined 30 volunteers treated with gamma knife surgery. The frameless stereotactic image-guidance system called the StealthStation (Medtronic Surgical Navigation Technologies, Louisville, CO) was used. Nine FMs were placed on the patient's head and four were placed on a Leksell frame rod-box, which acted as a rigid set to determine the difference in error. For each Registration form, we recorded the generated measurement (GM) and the physical measurement (PM) to each of the four checkpoint FMs. Bland and Altman plot difference analyses were used to compare measurement techniques. Correlations and descriptive analyses were completed. RESULTS: The mean of values for GMs were 1.14 mm for FM, 2.3 mm for AL, and 0.96 mm for SM Registrations. The mean errors of the checkpoints were 3.49 mm for FM, 3.96 mm for AL, and 3.33 mm for SM Registrations. The correlation between GMs and PMs indicated a linear relationship for all three methods. AL Registration demonstrated the greatest mean difference, followed by FM Registration; SM Registration had the smallest difference between GMs and PMs. Differences in the anatomic Registration methods, including SM Registration, compared with FM Registration were within a mean +/- 1.96 (standard deviation) according to the Bland and Altman analysis. CONCLUSION: For our sample of 30 patients, all three Registration methods provided comparable distances to the target tissue for surgical procedures. Users may safely choose anatomic Registration as a less costly and more time-efficient Registration method for frameless stereotaxy.
