@conference {Ahmidi2010a, title = {Surgical Task and Skill Classification from Eye Tracking and Tool Motion in Minimally Invasive Surgery}, booktitle = {Medical Image Computing and Computer-Assisted Intervention (MICCAI) 2010}, year = {2010}, pages = {295-302}, publisher = {Springer}, organization = {Springer}, address = {Beijing, China}, isbn = {978-3-642-15710-3}, doi = {http://dx.doi.org/10.1007/978-3-642-15711-0_37}, author = {Narges Ahmidi and Gregory D. Hager and Lisa Ishii and Gabor Fichtinger and Gary L. Gallia and Masaru Ishii} } @conference {Foroughi2009, title = {Multi-modality fusion of CT and 3D ultrasound and tracked strain images for breast irradiation planning}, booktitle = {SPIE Medical Imaging 2009: Ultrasonic Imaging and Signal Processing}, volume = {7265}, number = {72651B}, year = {2009}, author = {Pezhman Foroughi and Csaba Csoma and Hassan Rivaz and Gabor Fichtinger and Richard Zellars and Gregory D. Hager and Emad Boctor} } @article {Krupa2009b, title = {Real-time Motion Stabilization with B-Mode Ultrasound Using Image Speckle Information and Visual Servoing}, journal = {International Journal of Robotics Research}, volume = {28}, year = {2009}, month = {10/2009}, pages = {1334-1354}, chapter = {1334}, doi = {10.1177/0278364909104066}, author = {Alexandre Krupa and Gabor Fichtinger and Gregory D. Hager} } @conference {Krupa2009, title = {Rigid motion compensation with a robotized 2D ultrasound probe using speckle information and visual servoing}, booktitle = {ICRA}, year = {2009}, author = {Alexandre Krupa and Gabor Fichtinger and Gregory D. Hager} } @article {Rivaz2008b, title = {Ablation monitoring with elastography: 2D in-vivo and 3D ex-vivo studies}, journal = {Medical image computing and computer-assisted intervention (MICCAI)}, volume = {11}, number = {Pt 2}, year = {2008}, pages = {458{\textendash}466}, publisher = {ERC for Computer Integrated Surgery, Johns Hopkins University, USA rivaz@jhu edu}, abstract = {

The clinical feasibility of 2D elastography methods is hindered by the requirement that the operator avoid out-of-plane motion of the ultrasound image during palpation, and also by the lack of volumetric elastography measurements In this paper, we develop, evaluate a 3D elastography method operating on volumetric data acquired from a 3D probe Our method is based on minimizing a cost function using dynamic programming (DP) The cost function incorporates similarity of echo amplitudes, displacement continuity We present, to the best of our knowledge, the first in-vivo patient studies of monitoring liver ablation with freehand DP elastography The thermal lesion was not discernable in the B-mode image but it was clearly visible in the strain image as well as in validation CT We also present 3D strain images from thermal lesions in ex-vivo ablation Good agreement was observed between strain images, CT, gross pathology

}, keywords = {Carcinoma, Catheter Ablation, Computer-Assisted, Elasticity Imaging Techniques, Feasibility Studies, Hepatectomy, Hepatocellular, Humans, Image Interpretation, Imaging, Liver Neoplasms, methods, Surgery, surgery/ultrasonography, Three-Dimensional, Treatment Outcome}, author = {Hassan Rivaz and Ioana Fleming and Lia Assumpcao and Gabor Fichtinger and Ulrike Hamper and Michael Choti and Gregory D. Hager and Emad Boctor} } @article {Kazanzides2008a, title = {Surgical and Interventional Robotics - Core Concepts, Technology and Design [Tutorial]}, journal = {IEEE Robotics \& Automation Magazine}, volume = {15}, number = {2}, year = {2008}, month = {June}, pages = {122{\textendash}130}, doi = {10 1109/MRA 2008 926390}, author = {Peter Kazanzides and Gabor Fichtinger and Gregory D. Hager and Allison Okamura and Whitcomb, Louis L. and Russell H. Taylor} } @article {Fichtinger2008, title = {Surgical and interventional robotics: Part II}, journal = {IEEE Robotics \& Automation Magazine}, volume = {15}, number = {3}, year = {2008}, month = {September}, pages = {94{\textendash}102}, doi = {10 1109/MRA 2008 927971}, author = {Gabor Fichtinger and Peter Kazanzides and Allison Okamura and Gregory D. Hager and Whitcomb, Louis L. and Russell H. Taylor} } @article {Hager2008, title = {Surgical and interventional robotics: part III [Tutorial]}, journal = {IEEE Robotics \& Automation Magazine}, volume = {15}, number = {4}, year = {2008}, month = {Dec}, pages = {84{\textendash}93}, doi = {10 1109/MRA 2008 930401}, author = {Gregory D. Hager and Allison Okamura and Peter Kazanzides and Whitcomb, Louis L. and Gabor Fichtinger and Russell H. Taylor} } @article {Rivaz2008a, title = {Ultrasound elastography: a dynamic programming approach}, journal = {IEEE transactions on medical imaging}, volume = {27}, number = {10}, year = {2008}, month = {Oct}, pages = {1373{\textendash}1377}, publisher = {Engineering Research Center for Computer Integrated Surgery, Johns Hopkins University, 3400 N Charles Street, Baltimore, MD 21218, USA}, abstract = {

This paper introduces a 2-D strain imaging technique based on minimizing a cost function using dynamic programming (DP) The cost function incorporates similarity of echo amplitudes, displacement continuity Since tissue deformations are smooth, the incorporation of the smoothness into the cost function results in reduced decorrelation noise As a result, the method generates high-quality strain images of freehand palpation elastography with up to 10\% compression, showing that the method is more robust to signal decorrelation (caused by scatterer motion in high axial compression, nonaxial motions of the probe) in comparison to the standard correlation techniques The method operates in less than 1 s, is thus also potentially suitable for real time elastography

}, keywords = {Algorithms, Computer-Assisted, Elasticity Imaging Techniques, Humans, Image Enhancement, Image Interpretation, Imaging, instrumentation/methods, methods, Numerical Analysis, Phantoms, Sensitivity, Specificity}, doi = {10 1109/TMI 2008 917243}, url = {http://dx doi org/10 1109/TMI 2008 917243}, author = {Hassan Rivaz and Emad Boctor and Pezhman Foroughi and Richard Zellars and Gabor Fichtinger and Gregory D. Hager} } @conference {Rivaz2007, title = {Beam Steering Approach for Speckle Characterization and Out-of-Plane Motion Estimation in Real Tissue}, booktitle = {Procedings IEEE Ultrasonics Symposium}, year = {2007}, month = {10/2007}, pages = {781{\textendash}784}, doi = {10 1109/ULTSYM 2007 200}, author = {Hassan Rivaz and Richard Zellars and Gregory D. Hager and Gabor Fichtinger and Emad Boctor} } @conference {Krupa2007c, title = {Full Motion Tracking in Ultrasound Using Image Speckle Information and Visual Servoing}, booktitle = {Procedings IEEE International Conference on Robotics and Automation}, year = {2007}, month = {10{\textendash}14 April}, pages = {2458{\textendash}2464}, doi = {10 1109/ROBOT 2007 363688}, author = {Alexandre Krupa and Gabor Fichtinger and Gregory D. Hager} } @conference {Fichtinger2007, title = {New approaches to calibration and segmentation in interventional ultrasound}, booktitle = {Procedings 4th IEEE International Symposium on Biomedical Imaging: From Nano to Macro ISBI 2007}, year = {2007}, month = {12{\textendash}15 April}, pages = {1060{\textendash}1063}, doi = {10 1109/ISBI 2007 357038}, author = {Gabor Fichtinger and Emad Boctor and Gregory D. Hager} } @article {Krupa2007a, title = {Real-time 6 DOF Tissue Tracking with B-Mode Ultrasound Using Speckle and Visual Servoing}, journal = {Medical Image Computing and Computer-Assisted Intervention (MICCAI) Proceedings in Lecture Notes in Computer Science}, volume = {4792}, year = {2007}, pages = {1-8}, author = {Alexandre Krupa and Gabor Fichtinger and Gregory D. Hager} } @article {Krupa2007, title = {Real-time tissue tracking with B-mode ultrasound using speckle and visual servoing}, journal = {Tenth International Conference on Medical Image Computing and Computer-Assisted Intervention (MICCAI)}, volume = {10}, number = {Pt 2}, year = {2007}, pages = {1{\textendash}8}, publisher = {IRISA - INRIA Rennes, France alexandre krupa@irisa fr}, abstract = {

We present a method for real-time tracking of moving soft tissue with B-mode ultrasound (US) The method makes use of the speckle information contained in the US images to estimate the in-plane, out-of-plane motion of a fixed target relative to the ultrasound scan plane The motion information is then used as closed-loop feedback to a robot which corrects for the target motion The concept is demonstrated for translation motions in an experimental setup consisting of an ultrasound speckle phantom, a robot for simulating tissue motion, and a robot that performs motion stabilization from US images This concept shows promise for US-guided procedures that require real-time motion tracking, compensation

}, keywords = {Algorithms, Artificial Intelligence, Computer Systems, Computer-Assisted, Equipment Design, Equipment Failure Analysis, Image Enhancement, Image Interpretation, Imaging, instrumentation/methods, Interventional, methods, Pilot Projects, Reproducibility of Results, Robotics, Sensitivity, Specificity, Surgery, Three-Dimensional, Ultrasonography, User-Computer Interface}, author = {Alexandre Krupa and Gabor Fichtinger and Gregory D. Hager} } @conference {Rivaz2007d, title = {Speckle Characterization And Out-Of-Plane Motion Estimation In Tissue}, booktitle = {Sixth International Conference on the Ultrasonic Measurement and Imaging of Tissue Elasticity}, year = {2007}, author = {Hassan Rivaz and Gregory D. Hager and Richard Zellars and Gabor Fichtinger and Emad Boctor} } @conference {Rivaz2007b, title = {Toward Real-Time 2d Ultrasound Elastography Using Global Optimization Of A Regularized Displacement Field}, booktitle = {Sixth International Conference on the Ultrasonic Measurement and Imaging of Tissue Elasticity}, year = {2007}, author = {Hassan Rivaz and Pezhman Foroughi and Emad Boctor and Richard Zellars and Gabor Fichtinger and Gregory D. Hager} } @conference {Rivaz2007c, title = {Ultrasound Elastography: a Dynamic Programming Approach}, booktitle = {Workshop to the 10th MICCAI Conference}, year = {2007}, author = {Hassan Rivaz and Pezhman Foroughi and Emad Boctor and Richard Zellars and Gabor Fichtinger and Gregory D. Hager} } @article {Boctor2006a, title = {Bootstrapped ultrasound calibration}, journal = {Studies in health technology and informatics}, volume = {119}, year = {2006}, pages = {61{\textendash}66}, publisher = {Engineering Research Center, Johns Hopkins University, USA}, abstract = {

This paper introduces an enhanced (bootstrapped) method for tracked ultrasound probe calibration Prior to calibration, a position sensor is used to track an ultrasound probe in 3D space, while the US image is used to determine calibration target locations within the image From this information, an estimate of the transformation matrix of the scan plane with respect to the position sensor is computed While all prior calibration methods terminate at this phase, we use this initial calibration estimate to bootstrap an additional optimization of the transformation matrix on independent data to yield the minimum reconstruction error on calibration targets The bootstrapped workflow makes use of a closed-form calibration solver, associated sensitivity analysis, allowing for rapid, robust convergence to an optimal calibration matrix Bootstrapping demonstrates superior reconstruction accuracy

}, keywords = {Calibration, Imaging, standards, Three-Dimensional, Ultrasonography, United States}, author = {Emad Boctor and Iulian Iordachita and Michael Choti and Gregory D. Hager and Gabor Fichtinger} } @article {Boctor2006b, title = {Ultrasound monitoring of tissue ablation via deformation model and shape priors}, journal = {Medical image computing and computer-assisted intervention (MICCAI)}, volume = {9}, number = {Pt 2}, year = {2006}, pages = {405{\textendash}412}, abstract = {

A rapid approach to monitor ablative therapy through optimizing shape, elasticity parameters is introduced Our motivating clinical application is targeting, intraoperative monitoring of hepatic tumor thermal ablation, but the method translates to the generic problem of encapsulated stiff masses (solid organs, tumors, ablated lesions, etc ) in ultrasound imaging The approach involves the integration of the following components: a biomechanical computational model of the tissue, a correlation approach to estimate/track tissue deformation, and an optimization method to solve the inverse problem, recover the shape parameters in the volume of interest Successful convergence, reliability studies were conducted on simulated data Then ex-vivo studies were performed on 18 ex-vivo bovine liver samples previously ablated under ultrasound monitoring in controlled laboratory environment While B-mode ultrasound does not clearly identify the development of necrotic lesions, the proposed technique can potentially segment the ablation zone The same framework can also yield both partial, full elasticity reconstruction

}, keywords = {Algorithms, Animals, Automated, Biological, Cattle, Computer-Assisted, Elasticity, Hepatectomy, Image Enhancement, Image Interpretation, Imaging, Interventional, Liver, Mechanical, methods, Models, Pattern Recognition, physiology/surgery/ultrasonography, Reproducibility of Results, Sensitivity, Specificity, Statistical, Stress, Subtraction Technique, Surgery, Three-Dimensional, Ultrasonography}, author = {Emad Boctor and Michelle de Oliveira and Michael Choti and Roger Ghanem and Russell H. Taylor and Gregory D. Hager and Gabor Fichtinger} } @conference {Boctor2006, title = {Ultrasound self-calibration}, booktitle = {Medical Imaging 2006: Visualization, Image-Guided Procedures, and Display}, volume = {6141}, number = {1}, year = {2006}, pages = {61412N}, publisher = {SPIE}, organization = {SPIE}, doi = {10 1117/12 659594}, url = {http://link aip org/link/?PSI/6141/61412N/1}, author = {Emad Boctor and Iulian Iordachita and Gabor Fichtinger and Gregory D. Hager} } @conference {Kon2005, title = {CIS-UltraCal: an open-source ultrasound calibration toolkit}, booktitle = {Medical Imaging 2005: Ultrasonic Imaging and Signal Processing}, volume = {5750}, number = {1}, year = {2005}, pages = {516-523}, publisher = {SPIE}, organization = {SPIE}, doi = {10 1117/12 596929}, url = {http://link aip org/link/?PSI/5750/516/1}, author = {Ryan Kon and Joshua Leven and Kishore Kothapalli and Emad Boctor and Gabor Fichtinger and Gregory D. Hager and Russell H. Taylor} } @article {Boctor2005, title = {Real-time quality control of tracked ultrasound}, journal = {Medical image computing and computer-assisted intervention (MICCAI)}, volume = {8}, number = {Pt 1}, year = {2005}, pages = {621{\textendash}630}, abstract = {

The overwhelming majority of intra-operative hazard situations in tracked ultrasound (US) systems are attributed to failure of registration between tracking, imaging coordinate frames We introduce a novel methodology for eal-time in-vivo quality control of tracked US systems, in order to capture registration failures during the clinical procedure In effect, we dynamically recalibrate the tracked US system for rotation, scale factor, and in-plane position offset up to a scale factor We detect any unexpected change in these parameters through capturing discrepancies in the resulting calibration matrix, thereby assuring quality (accuracy, consistency) of the tracked system No phantom is used for the recalibration We perform the task of quality control in the background, transparently to the clinical user while the subject is being scanned We present the concept, mathematical formulation, and experimental evaluation in-vitro This new method can play an important role in guaranteeing accurate, consistent, and reliable performance of tracked ultrasound

}, keywords = {Algorithms, Computer Systems, Computer-Assisted, Health Care, Humans, Image Enhancement, Image Interpretation, Interventional, methods, Quality Assurance, Quality Control, Reproducibility of Results, Sensitivity, Specificity, Surgery, Ultrasonography, User-Computer Interface}, author = {Emad Boctor and Iulian Iordachita and Gabor Fichtinger and Gregory D. Hager} } @conference {Boctor2005b, title = {Ultrasound Self-Calibration and Real-Time Quality Control for Interventions}, booktitle = {IEEE International Ultrasonics Symposium}, year = {2005}, author = {Emad Boctor and Iulian Iordachita and Gabor Fichtinger and Gregory D. Hager} } @article {Viswanathan2004, title = {Immediate Ultrasound Calibration from Three Poses and Minimal Image Processing}, journal = {Proceedings in Lecture Notes in Computer Science Medical Image Computing and Computer-Assisted Intervention (MICCAI)}, volume = {3217}, year = {2004}, pages = {446-454}, author = {Anand Viswanathan and Emad Boctor and Russell H. Taylor and Gregory D. Hager and Gabor Fichtinger} } @conference {Boctor2004, title = {A novel closed form solution for ultrasound calibration}, booktitle = {Procedings IEEE International Symposium on Biomedical Imaging: Nano to Macro}, year = {2004}, month = {15{\textendash}18 April}, pages = {527{\textendash}530}, doi = {10 1109/ISBI 2004 1398591}, author = {Emad Boctor and Anand Viswanathan and Michael Choti and Russell H. Taylor and Gabor Fichtinger and Gregory D. Hager} }