@article {doi:10.1002/ccd.27962, title = {Toward predictive modeling of catheter-based pulmonary valve replacement into native right ventricular outflow tracts}, journal = {Catheterization and Cardiovascular Interventions}, year = {2018}, month = {11/2018}, abstract = {

Abstract Background Pulmonary insufficiency is a consequence of transannular patch repair in Tetralogy of Fallot (ToF) leading to late morbidity and mortality. Transcatheter native outflow tract pulmonary valve replacement has become a reality. However, predicting a secure, atraumatic implantation of a catheter-based device remains a significant challenge due to the complex and dynamic nature of the right ventricular outflow tract (RVOT). We sought to quantify the differences in compression and volume for actual implants, and those predicted by pre-implant modeling. Methods We used custom software to interactively place virtual transcatheter pulmonary valves (TPVs) into RVOT models created from pre-implant and post Harmony valve implant CT scans of 5 ovine surgical models of TOF to quantify and visualize device volume and compression. Results Virtual device placement visually mimicked actual device placement and allowed for quantification of device volume and radius. On average, simulated proximal and distal device volumes and compression did not vary statistically throughout the cardiac cycle (P = 0.11) but assessment was limited by small sample size. In comparison to actual implants, there was no significant pairwise difference in the proximal third of the device (P \> 0.80), but the simulated distal device volume was significantly underestimated relative to actual device implant volume (P = 0.06). Conclusions This study demonstrates that pre-implant modeling which assumes a rigid vessel wall may not accurately predict the degree of distal RVOT expansion following actual device placement. We suggest the potential for virtual modeling of TPVR to be a useful adjunct to procedural planning, but further development is needed.

}, keywords = {Magnetic Resonance Imaging, percutaneous pulmonary valve implantation, prosthetic heart valve, tetralogy of Fallot}, doi = {10.1002/ccd.27962}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/ccd.27962}, author = {MatthewA Jolley and Andras Lasso and HannahH Nam and Dinh, Patrick V. and Adam B. Scanlan and Alexander V. Nguyen and Anna Ilina and Morray, Brian and Glatz, Andrew C. and FrancisX McGowan and Whitehead, Kevin and Dori, Yoav and Robert C. Gorman and Robert C. Gorman and Gabor Fichtinger and Gillespie, Matthew J.} } @article {raey, title = {Open-source image registration for MRI-TRUS fusion-guided prostate interventions}, journal = {International Journal of Computer Assisted Radiology and Surgery}, volume = {10}, number = {6}, year = {2015}, pages = {925-934}, keywords = {Image registration, Image-guided interventions, Magnetic Resonance Imaging, prostate cancer, Targeted biopsy, Ultrasound}, issn = {1861-6410}, doi = {10.1007/s11548-015-1180-7}, url = {http://dx.doi.org/10.1007/s11548-015-1180-7}, author = {Andriy Fedorov and Siavash Khallaghi and Sanchez, C. Antonio and Andras Lasso and Fels, Sidney and Kemal Tuncali and Sugar, Emily Neubauer and Tina Kapur and Zhang, Chenxi and William Wells and Paul Nguyen and Purang Abolmaesumi and Clare M Tempany} } @article {Tokuda2008, title = {Software strategy for robotic transperineal prostate therapy in closed-bore MRI}, journal = {Medical image computing and computer-assisted intervention (MICCAI)}, volume = {11}, number = {Pt 2}, year = {2008}, pages = {701{\textendash}709}, publisher = {Department of Radiology, Brigham, Women{\textquoteright}s Hospital, Harvard Medical School, 75 Francis St , Boston, MA 02115, USA tokuda@bwh harvard edu}, abstract = {

A software strategy to provide intuitive navigation for MRI-guided robotic transperineal prostate therapy is presented In the system, the robot control unit, the MRI scanner, and open-source navigation software are connected to one another via Ethernet to exchange commands, coordinates, and images Six states of the system called "workphases" are defined based on the clinical scenario to synchronize behaviors of all components The wizard-style user interface allows easy following of the clinical workflow On top of this framework, the software provides features for intuitive needle guidance: interactive target planning; 3D image visualization with current needle position; treatment monitoring through real-time MRI These features are supported by calibration of robot, image coordinates by the fiducial-based registration The performance test shows that the registration error of the system was 2 6 mm in the prostate area, and it displayed real-time 2D image 1 7 s after the completion of image acquisition

}, keywords = {Brachytherapy, Computer-Assisted, Humans, Image Interpretation, Interventional, Magnetic Resonance Imaging, Male, methods, Needles, pathology/radiotherapy, Prostatic Neoplasms, Radiotherapy, Robotics, Software, Software Design}, author = {Junichi Tokuda and Gregory Fischer and Csaba Csoma and Simon DiMaio and David Gobbi and Gabor Fichtinger and Clare M Tempany and Nobuhiko Hata} } @article {Krieger2007a, title = {Design and preliminary accuracy studies of an MRI-guided transrectal prostate intervention system}, journal = {Medical image computing and computer-assisted intervention (MICCAI)}, volume = {10}, number = {Pt 2}, year = {2007}, pages = {59{\textendash}67}, publisher = {Department of Mechanical Engineering, Johns Hopkins University, Baltimore, USA}, abstract = {

This paper reports a novel system for magnetic resonance imaging (MRI) guided transrectal prostate interventions, such as needle biopsy, fiducial marker placement, and therapy delivery The system utilizes a hybrid tracking method, comprised of passive fiducial tracking for initial registration, subsequent incremental motion measurement along the degrees of freedom using fiber-optical encoders, mechanical scales Targeting accuracy of the system is evaluated in prostate phantom experiments Achieved targeting accuracy, procedure times were found to compare favorably with existing systems using passive, active tracking methods Moreover, the portable design of the system using only standard MRI image sequences, minimal custom scanner interfacing allows the system to be easily used on different MRI scanners

}, keywords = {Algorithms, Artificial Intelligence, Automated, Biopsy, Computer-Assisted, Equipment Design, Equipment Failure Analysis, Humans, Image Enhancement, Image Interpretation, Imaging, instrumentation/methods, Interventional, Magnetic Resonance Imaging, Male, methods, Needle, pathology/surgery, Pattern Recognition, Pilot Projects, Prostatectomy, Prostatic Neoplasms, Rectum, Reproducibility of Results, Robotics, Sensitivity, Specificity, Three-Dimensional, User-Computer Interface}, author = {Axel Krieger and Csaba Csoma and Iulian Iordachita and Peter Guion and Anurag K. Singh and Gabor Fichtinger and Whitcomb, Louis L.} } @article {DiMaio2007, title = {Dynamic MRI scan plane control for passive tracking of instruments and devices}, journal = {Medical image computing and computer-assisted intervention (MICCAI)}, volume = {10}, number = {Pt 2}, year = {2007}, pages = {50{\textendash}58}, publisher = {Brigham, Women{\textquoteright}s Hospital, Harvard Medical School, Boston, MA, USA}, abstract = {

This paper describes a novel image-based method for tracking robotic mechanisms, interventional devices during Magnetic Resonance Image (MRI)-guided procedures It takes advantage of the multi-planar imaging capabilities of MRI to optimally image a set of localizing fiducials for passive motion tracking in the image coordinate frame The imaging system is servoed to adaptively position the scan plane based on automatic detection, localization of fiducial artifacts directly from the acquired image stream This closed-loop control system has been implemented using an open-source software framework, currently operates with GE MRI scanners Accuracy, performance were evaluated in experiments, the results of which are presented here

}, keywords = {Algorithms, Anatomy, Artificial Intelligence, Automated, Computer-Assisted, Cross-Sectional, Humans, Image Enhancement, Image Interpretation, Imaging, instrumentation/methods, Magnetic Resonance Imaging, methods, Pattern Recognition, Phantoms, Reproducibility of Results, Robotics, Sensitivity, Specificity, Surgery, Three-Dimensional, User-Computer Interface}, author = {Simon DiMaio and Eigil Samset and Gregory Fischer and Iulian Iordachita and Gabor Fichtinger and Ferenc Jolesz and Clare M Tempany} } @article {Fischer2007, title = {MRI image overlay: application to arthrography needle insertion}, journal = {Journal of Computer Aided Surgery}, volume = {12}, number = {1}, year = {2007}, month = {Jan}, pages = {2{\textendash}14}, publisher = {Engineering Research Center, Johns Hopkins University, Baltimore, Maryland, USA gfisch@jhu edu}, abstract = {

Magnetic Resonance Imaging (MRI) offers great potential for planning, guiding, monitoring, controlling interventions MR arthrography (MRAr) is the imaging gold standard for assessing small ligament, fibrocartilage injury in joints In contemporary practice, MRAr consists of two consecutive sessions: (1) an interventional session where a needle is driven to the joint space, MR contrast is injected under fluoroscopy or CT guidance;, (2) a diagnostic MRI imaging session to visualize the distribution of contrast inside the joint space, evaluate the condition of the joint Our approach to MRAr is to eliminate the separate radiologically guided needle insertion, contrast injection procedure by performing those tasks on conventional high-field closed MRI scanners We propose a 2D augmented reality image overlay device to guide needle insertion procedures This approach makes diagnostic high-field magnets available for interventions without a complex, expensive engineering entourage In preclinical trials, needle insertions have been performed in the joints of porcine, human cadavers using MR image overlay guidance; in all cases, insertions successfully reached the joint space on the first attempt

}, keywords = {Arthrography, Cartilage, Contrast Media, diagnosis, Humans, injuries, instrumentation, Joint Diseases, Ligaments, Magnetic Resonance Imaging, Needles}, doi = {10 1080/10929080601169930}, url = {http://dx doi org/10 1080/10929080601169930}, author = {Gregory Fischer and Anton Degeut and Csaba Csoma and Russell H. Taylor and Laura Fayad and John A Carrino and James Zinreich and Gabor Fichtinger} } @article {Singh2007a, title = {Patient selection determines the prostate cancer yield of dynamic contrast-enhanced magnetic resonance imaging-guided transrectal biopsies in a closed 3-Tesla scanner}, journal = {British Journal of Urology international}, volume = {101}, number = {2}, year = {2007}, month = {Jan}, pages = {181{\textendash}185}, publisher = {Radiation Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892-1642, USA Anurag Singh@RoswellPark org}, abstract = {

OBJECTIVE: To evaluate the cancer yield of transrectal prostate biopsies in a 3-T magnetic resonance imaging (MRI) scanner in patients with elevated prostate specific antigen (PSA) levels, recent negative transrectal ultrasonography (TRUS)-guided prostate biopsies PATIENTS AND METHODS: Between July 2004, November 2005, patients with at least one previous negative prostate biopsy within the previous 12 months had MRI-guided biopsy of the prostate in a 3-T MRI scanner Patients with previous positive biopsies for cancer were excluded Target selection was based on T2-weighted imaging, dynamic contrast-enhanced (DCE) imaging studies RESULTS: Thirteen patients were eligible; their median (range) age was 61 (47-74) years, PSA value 4 90 (1 3-12 3) ng/mL Most patients had one previous negative biopsy (range 1-4) Four patients had a family history of prostate cancer There were 37 distinct targets based on T2-weighted imaging Fifteen of 16 distinct DCE abnormalities were co-localized with a target based on T2-weighted imaging Despite this correlation, only one of 13 patients had a directed biopsy positive for cancer Including systematic biopsies, two of 13 patients had a biopsy positive for prostate cancer One patient had prostate intraepithelial neoplasia, one had atypical glands in the specimen CONCLUSION: The prostate-cancer yield of transrectal biopsies in a 3-T MRI scanner, among patients with recent negative TRUS-guided prostate biopsies, is similar to repeat systematic TRUS-guided biopsy DCE correlates with T2-imaging but does not appear to improve prostate cancer yield in this population

}, keywords = {Aged, Biopsy, blood, Cohort Studies, Contrast Media, diagnosis, Digital Rectal Examination, Humans, Interventional, Magnetic Resonance Imaging, Male, methods, Middle Aged, Needle, pathology, Patient Selection, Predictive Value of Tests, Prostate, Prostate-Specific Antigen, Prostatic Neoplasms, Sensitivity, Specificity, standards, Ultrasonography}, doi = {10 1111/j 1464-410X 2007 07219 x}, url = {http://dx doi org/10 1111/j 1464-410X 2007 07219 x}, author = {Anurag K. Singh and Axel Krieger and Jean-Baptiste Lattouf and Peter Guion and R.L. Grubb III and Paul Albert and Greg Metzger and Karen Ullman and Sharon Smith and Gabor Fichtinger and Iclal Ocak and Peter Choyke and Cynthia Menard and Jonathan Coleman} } @article {DiMaio2007a, title = {Robot-assisted needle placement in open MRI: system architecture, integration and validation}, journal = {Journal of Computer Aided Surgery}, volume = {12}, number = {1}, year = {2007}, month = {Jan}, pages = {15{\textendash}24}, publisher = {Brigham, Women{\textquoteright}s Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA simond@bwh harvard edu}, abstract = {

In prostate cancer treatment, there is a move toward targeted interventions for biopsy, therapy, which has precipitated the need for precise image-guided methods for needle placement This paper describes an integrated system for planning, performing percutaneous procedures with robotic assistance under MRI guidance A graphical planning interface allows the physician to specify the set of desired needle trajectories, based on anatomical structures, lesions observed in the patient{\textquoteright}s registered pre-operative, pre-procedural MR images, immediately prior to the intervention in an open-bore MRI scanner All image-space coordinates are automatically computed, and are used to position a needle guide by means of an MRI-compatible robotic manipulator, thus avoiding the limitations of the traditional fixed needle template Automatic alignment of real-time intra-operative images aids visualization of the needle as it is manually inserted through the guide Results from in-scanner phantom experiments are provided

}, keywords = {Biopsy, diagnosis, Humans, instrumentation/methods, Magnetic Resonance Imaging, Male, Needle, Neuronavigation, Prostatic Neoplasms, Robotics}, doi = {10 1080/10929080601168254}, url = {http://dx doi org/10 1080/10929080601168254}, author = {Simon DiMaio and Steve Pieper and Kiyoyuki Chinzei and Nobuhiko Hata and Steven Haker and Daniel Kacher and Gabor Fichtinger and Clare M Tempany and Ron Kikinis} } @article {Fischer2007b, title = {Robotic assistant for transperineal prostate interventions in 3T closed MRI}, journal = {Medical image computing and computer-assisted intervention (MICCAI)}, volume = {10}, number = {Pt 1}, year = {2007}, pages = {425{\textendash}433}, publisher = {Center for Computer Integrated Surgery, Johns Hopkins University, USA gfischer@jhu edu}, abstract = {

Numerous studies have demonstrated the efficacy of image-guided needle-based therapy, biopsy in the management of prostate cancer The accuracy of traditional prostate interventions performed using transrectal ultrasound (TRUS) is limited by image fidelity, needle template guides, needle deflection, tissue deformation Magnetic Resonance Imaging (MRI) is an ideal modality for guiding, monitoring such interventions due to its excellent visualization of the prostate, its sub-structure, surrounding tissues We have designed a comprehensive robotic assistant system that allows prostate biopsy, brachytherapy procedures to be performed entirely inside a 3T closed MRI scanner We present a detailed design of the robotic manipulator, an evaluation of its usability, MR compatibility

}, keywords = {anatomy /\&/ histology/surgery, Computer-Assisted, Equipment Design, Equipment Failure Analysis, Image Interpretation, instrumentation/methods, Interventional, Magnetic Resonance Imaging, Perineum, Prostatectomy, Robotics, Surgery}, author = {Gregory Fischer and Simon DiMaio and Iulian Iordachita and Gabor Fichtinger} } @article {Singh2007b, title = {Simultaneous integrated boost of biopsy proven and MRI defined dominant intra-prostatic lesions to 95 Gray with IMRT: early results of a phase I NCI study}, journal = {Radiation Oncology}, volume = {2}, year = {2007}, pages = {36}, publisher = {Department of Radiation Medicine, Roswell Park Cancer Institute, Buffalo, USA singhanu@yahoo com}, abstract = {

BACKGROUND: To assess the feasibility, early toxicity of selective, IMRT-based dose escalation (simultaneous integrated boost) to biopsy proven dominant intra-prostatic lesions visible on MRI METHODS: Patients with localized prostate cancer, an abnormality within the prostate on endorectal coil MRI were eligible All patients underwent a MRI-guided transrectal biopsy at the location of the MRI abnormality Gold fiducial markers were also placed Several days later patients underwent another MRI scan for fusion with the treatment planning CT scan This fused MRI scan was used to delineate the region of the biopsy proven intra-prostatic lesion A 3 mm expansion was performed on the intra-prostatic lesions, defined as a separate volume within the prostate The lesion + 3 mm, the remainder of the prostate + 7 mm received 94 5/75 6 Gray (Gy) respectively in 42 fractions Daily seed position was verified to be within 3 mm RESULTS: Three patients were treated Follow-up was 18, 6, and 3 months respectively Two patients had a single intra-prostatic lesion One patient had 2 intra-prostatic lesions All four intra-prostatic lesions, with margin, were successfully targeted, treated to 94 5 Gy Two patients experienced acute RTOG grade 2 genitourinary (GU) toxicity One had grade 1 gastrointestinal (GI) toxicity All symptoms completely resolved by 3 months One patient had no acute toxicity CONCLUSION: These early results demonstrate the feasibility of using IMRT for simultaneous integrated boost to biopsy proven dominant intra-prostatic lesions visible on MRI The treatment was well tolerated

}, keywords = {adverse effects/methods, Biopsy, epidemiology, epidemiology/radiotherapy, Follow-Up Studies, Humans, Intensity-Modulated, Magnetic Resonance Imaging, Male, National Cancer Institute (U S ), Patient Selection, Prostatic Neoplasms, Questionnaires, Radiotherapy, Radiotherapy Dosage, United States}, doi = {10 1186/1748-717X-2-36}, url = {http://dx doi org/10 1186/1748-717X-2-36}, author = {Anurag K. Singh and Peter Guion and Nancy Sears-Crouse and Karen Ullman and Sharon Smith and Paul Albert and Gabor Fichtinger and Peter Choyke and Sheng Xu and Jochen Kruecker and Bradford Wood and Axel Krieger and Holly Ning} } @article {Blumenfeld2007, title = {Transperineal prostate biopsy under magnetic resonance image guidance: a needle placement accuracy study}, journal = {Journal of magnetic resonance imaging}, volume = {26}, number = {3}, year = {2007}, month = {Sep}, pages = {688{\textendash}694}, publisher = {Department of Radiology, Brigham, Women{\textquoteright}s Hospital, Harvard Medical School, Boston, Massachusetts, USA}, abstract = {

PURPOSE: To quantify needle placement accuracy of magnetic resonance image (MRI)-guided core needle biopsy of the prostate MATERIALS AND METHODS: A total of 10 biopsies were performed with 18-gauge (G) core biopsy needle via a percutaneous transperineal approach Needle placement error was assessed by comparing the coordinates of preplanned targets with the needle tip measured from the intraprocedural coherent gradient echo images The source of these errors was subsequently investigated by measuring displacement caused by needle deflection, needle susceptibility artifact shift in controlled phantom studies Needle placement error due to misalignment of the needle template guide was also evaluated RESULTS: The mean, standard deviation (SD) of errors in targeted biopsies was 6 5 +/- 3 5 mm Phantom experiments showed significant placement error due to needle deflection with a needle with an asymmetrically beveled tip (3 2-8 7 mm depending on tissue type) but significantly smaller error with a symmetrical bevel (0 6-1 1 mm) Needle susceptibility artifacts observed a shift of 1 6 +/- 0 4 mm from the true needle axis Misalignment of the needle template guide contributed an error of 1 5 +/- 0 3 mm CONCLUSION: Needle placement error was clinically significant in MRI-guided biopsy for diagnosis of prostate cancer Needle placement error due to needle deflection was the most significant cause of error, especially for needles with an asymmetrical bevel

}, keywords = {Aged, Artifacts, Biopsy, Contrast Media, diagnosis/pathology, Humans, Imaging, Magnetic Resonance Imaging, Magnetic Resonance Spectroscopy, Male, methods, Middle Aged, Needle, Needles, Phantoms, pharmacology, Prostatectomy, Prostatic Neoplasms, Reproducibility of Results, Retrospective Studies}, doi = {10 1002/jmri 21067}, url = {http://dx doi org/10 1002/jmri 21067}, author = {Philip Blumenfeld and Nobuhiko Hata and Simon DiMaio and Kelly Zou and Steven Haker and Gabor Fichtinger and Clare M Tempany} } @article {Fischer2007a, title = {Validation system of MR image overlay and other needle insertion techniques}, journal = {Studies in health technology and informatics}, volume = {125}, year = {2007}, pages = {130{\textendash}135}, publisher = {Engineering Research Center, Johns Hopkins University, Baltimore, MD, USA}, abstract = {

In order to develop accurate, effective augmented reality (AR) systems used in MR, CT guided needle placement procedures, a comparative validation environment is necessary Clinical equipment is prohibitively expensive, often inadequate for precise measurement Therefore, we have developed a laboratory validation system for measuring operator performance using different assistance techniques Electromagnetically tracked needles are registered with the preoperative plan to measure placement accuracy, the insertion path The validation system provides an independent measure of accuracy that can be applied to varying methods of assistance ranging from augmented reality guidance methods to tracked navigation systems, autonomous robots In preliminary studies, this validation system is used to evaluate the performance of the image overlay, bi-plane laser guide, and traditional freehand techniques

}, keywords = {Computer Simulation, Magnetic Resonance Imaging, Needles, Reproducibility of Results, Tomography, United States, X-Ray Computed}, author = {Gregory Fischer and Eva Dyer and Csaba Csoma and Anton Degeut and Gabor Fichtinger} } @article {Fischer2006, title = {MRI image overlay: applications to arthrography needle insertion}, journal = {Studies in health technology and informatics}, volume = {119}, year = {2006}, pages = {150{\textendash}155}, abstract = {

Magnetic Resonance Imaging (MRI) has unmatched potential for planning, guiding, monitoring, controlling interventions MR arthrography (MRA) is the imaging gold standard to assess small ligament, fibrocartilage injury in joints In contemporary practice, MRA consists of two consecutive sessions: 1) an interventional session where a needle is driven to the joint space, gadolinium contrast is injected under fluoroscopy or CT guidance 2) A diagnostic MRI imaging session to visualize the distribution of contrast inside the joint space, evaluate the condition of the joint Our approach to MRA is to eliminate the separate radiologically guided needle insertion, contrast injection procedure by performing those tasks on conventional high-field closed MRI scanners We propose a 2D augmented reality image overlay device to guide needle insertion procedures This approach makes diagnostic high-field magnets available for interventions without a complex, expensive engineering entourage

}, keywords = {Arthrography, Humans, Magnetic Resonance Imaging, Needles, United States, User-Computer Interface}, author = {Gregory Fischer and Anton Degeut and Daniel Schlattman and Russell H. Taylor and Laura Fayad and James Zinreich and Gabor Fichtinger} } @article {DiMaio2006, title = {Needle artifact localization in 3T MR images}, journal = {Studies in health technology and informatics}, volume = {119}, year = {2006}, pages = {120{\textendash}125}, publisher = {Brigham, Women{\textquoteright}s Hospital, Harvard Medical School, Boston 02115, USA simond@bwh harvard edu}, abstract = {

This work explores an image-based approach for localizing needles during MRI-guided interventions, for the purpose of tracking, navigation Susceptibility artifacts for several needles of varying thickness were imaged, in phantoms, using a 3 tesla MRI system, under a variety of conditions The relationship between the true needle positions, the locations of artifacts within the images, determined both by manual, automatic segmentation methods, have been quantified, are presented here

}, keywords = {Artifacts, Magnetic Resonance Imaging, Needles, United States}, author = {Simon DiMaio and Daniel Kacher and Randy Ellis and Gabor Fichtinger and Nobuhiko Hata and Gary Zientara and Lawrence Panych and Ron Kikinis and Ferenc Jolesz} } @article {Chowning2006, title = {A preliminary analysis and model of prostate injection distributions}, journal = {The Prostate}, volume = {66}, number = {4}, year = {2006}, month = {Mar}, pages = {344{\textendash}357}, publisher = {Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA schowning@mri jhu edu}, abstract = {

PURPOSE: Understanding the internal dynamics of prostate injections, particularly injection pattern distribution is a key step to developing new therapies for prostate disease that may be best served with a direct injection approach Due to excellent properties involving liquid contrast agents, MRI can be used for targeting, monitoring of injections into organs, tissues MATERIALS AND METHODS: Eleven intraprostatic injections were performed in vivo with canines using a custom transrectal guiding, imaging system for use in a standard 1 5 T MR scanner In addition, 25 injections were performed on excised cadaveric human prostates, using a MedRad Spectris injector system MRI was used to guide the injections, monitor intraparenchymal injection distribution RESULTS: T1, T2-weighted MR images were correlated with histology to produce three-dimensional data sets that can be used to analyze trends in injection patterns This analysis was used to develop strategies for injection prediction such as gadolinium pre-injections, diffusion-weighted imaging guidance In addition, a rough model of prostate injections is described, and a preliminary injection guide is developed that takes into account the individual clinician{\textquoteright}s goals for therapy CONCLUSIONS: MR visualization of injected therapeutic agents allows for prediction, monitoring of drug distributions, possibly improving efficacy, reducing side effects Injection analysis, modeling may be used to assist in optimizing clinical treatments that require or would benefit from focal parenchymal injections into the prostate

}, keywords = {Animals, Antineoplastic Agents, Dogs, drug therapy, Forecasting, Magnetic Resonance Imaging, Male, Models, pharmacokinetics/pharmacology, Prostate, Prostatic Neoplasms, Rectum, Theoretical}, doi = {10 1002/pros 20298}, url = {http://dx doi org/10 1002/pros 20298}, author = {Scott Chowning and Robert Susil and Axel Krieger and Gabor Fichtinger and Whitcomb, Louis L. and Ergin Atalar} } @article {DiMaio2006b, title = {Robot-assisted needle placement in open-MRI: system architecture, integration and validation}, journal = {Studies in health technology and informatics}, volume = {119}, year = {2006}, pages = {126{\textendash}131}, publisher = {Brigham, Women{\textquoteright}s Hospital, Harvard Medical School, USA simond@bwh harvard edu}, abstract = {

This work describes an integrated system for planning, performing percutaneous procedures-such as prostate biopsy-with robotic assistance under MRI-guidance The physician interacts with a planning interface in order to specify the set of desired needle trajectories, based on anatomical structures, lesions observed in the patient{\textquoteright}s MR images All image-space coordinates are automatically computed, and used to position a needle guide by means of an MRI-compatible robotic manipulator, thus avoiding the limitations of the traditional fixed needle template Direct control of real-time imaging aids visualization of the needle as it is manually inserted through the guide Results from in-scanner phantom experiments are provided

}, keywords = {Biopsy, Computer Systems, diagnosis, Humans, instrumentation, Magnetic Resonance Imaging, Male, Needle, Prostatic Neoplasms, Robotics}, author = {Simon DiMaio and Steve Pieper and Kiyoyuki Chinzei and Nobuhiko Hata and Emese Balogh and Gabor Fichtinger and Clare M Tempany and Ron Kikinis} } @article {Susil2006, title = {Transrectal prostate biopsy and fiducial marker placement in a standard 1 5T magnetic resonance imaging scanner}, journal = {The Journal of Urology}, volume = {175}, number = {1}, year = {2006}, month = {Jan}, pages = {113{\textendash}120}, publisher = {Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA}, abstract = {

PURPOSE: We investigated the accuracy, feasibility of a system that provides transrectal needle access to the prostate concurrent with 1 5 Tesla MRI which previously has not been possible MATERIALS AND METHODS: In 5 patients with previously diagnosed prostate cancer, MRI guided intraprostatic placement of gold fiducial markers (4 procedures),/or prostate biopsy (3 procedures) was performed using local anesthesia RESULTS: Mean procedure duration was 76 minutes, all patients tolerated the intervention well Procedure related adverse events included self-limited hematuria, hematochezia following 3 of 8 procedures (all resolved in less than 1 week) Mean needle placement accuracy was 1 9 mm for the fiducial marker placement studies, 1 8 mm for the biopsy procedures Mean fiducial marker placement accuracy was 4 8 mm, the mean fiducial marker placement accuracy transverse to the needle direction was 2 6 mm All patients who underwent the procedure were able to complete their course of radiotherapy without delay or complication CONCLUSIONS: While studies of clinical usefulness are warranted, transrectal 1 5 T MRI guided prostate biopsy, fiducial marker placement is feasible using this system, providing new opportunities for image guided diagnostic, therapeutic prostate interventions

}, keywords = {Biopsy, Equipment Design, Feasibility Studies, Humans, instrumentation, instrumentation/methods, Magnetic Resonance Imaging, Male, Needle, pathology, Prostate, Prostatic Neoplasms}, doi = {10 1016/S0022-5347(05)00065-0}, url = {http://dx doi org/10 1016/S0022-5347(05)00065-0}, author = {Robert Susil and Cynthia Menard and Axel Krieger and Jonathan Coleman and Kevin Camphausen and Peter Choyke and Gabor Fichtinger and Whitcomb, Louis L. and Norman Coleman and Ergin Atalar} } @article {Krieger2005a, title = {Design of a novel MRI compatible manipulator for image guided prostate interventions}, journal = {IEEE Transactions on Biomedical Engineering}, volume = {52}, number = {2}, year = {2005}, month = {Feb}, pages = {306{\textendash}313}, abstract = {

This paper reports a novel remotely actuated manipulator for access to prostate tissue under magnetic resonance imaging guidance (APT-MRI) device, designed for use in a standard high-field MRI scanner The device provides three-dimensional MRI guided needle placement with millimeter accuracy under physician control Procedures enabled by this device include MRI guided needle biopsy, fiducial marker placements, and therapy delivery Its compact size allows for use in both standard cylindrical, open configuration MRI scanners Preliminary in vivo canine experiments, first clinical trials are reported

}, keywords = {Animals, Biopsy, Computer-Assisted, Dogs, Equipment Design, Equipment Failure Analysis, Feasibility Studies, Imaging, instrumentation/methods, Magnetic Resonance Imaging, Male, Micromanipulation, Needle, pathology/surgery, Prostate, Reproducibility of Results, Robotics, Sensitivity, Specificity, Surgery, Three-Dimensional}, doi = {10 1109/TBME 2004 840497}, url = {http://dx doi org/10 1109/TBME 2004 840497}, author = {Axel Krieger and Robert Susil and Cynthia Menard and Jonathan Coleman and Gabor Fichtinger and Ergin Atalar and Whitcomb, Louis L.} } @article {Susil2003, title = {System for MR image-guided prostate interventions: canine study}, journal = {Radiology}, volume = {228}, number = {3}, year = {2003}, month = {Sep}, pages = {886{\textendash}894}, abstract = {

The purpose of this study was to demonstrate the use of a transrectal system that enables precise magnetic resonance (MR) image guidance, monitoring of prostate interventions The system used a closed-bore 1 5-T MR imaging unit, enables one to take advantage of the higher signal-to-noise ratio achieved with traditional magnet designs, which is crucial for accurate targeting, monitoring of prostate interventions In the first of the four canine studies, reliable needle placement, with all needles placed within 2 mm of the desired target site, was achieved In two other studies, MR imaging was used to monitor distribution of injected contrast agent solution (gadopentetate dimeglumine mixed with trypan blue dye) in, around the prostate, thereby confirming that solution had been delivered to the desired tissue, also detecting faulty injections In the final study, accurate placement, MR imaging of brachytherapy seeds in the prostate were demonstrated The described system provides a flexible platform for a variety of minimally invasive MR image-guided therapeutic, diagnostic prostate interventions

}, keywords = {administration /\&/ dosage, administration /\&/ dosage/diagnostic use, Animals, Brachytherapy, Contrast Media, Dogs, Gadolinium DTPA, Injections, Intralesional, Magnetic Resonance Imaging, Male, methods, Prostate, Prostatic Neoplasms, Radiography, Radiotherapy, Trypan Blue}, doi = {10 1148/radiol 2283020911}, url = {http://dx doi org/10 1148/radiol 2283020911}, author = {Robert Susil and Axel Krieger and Andrew Derbyshire and Attila Tanacs and Whitcomb, Louis L. and Gabor Fichtinger and Ergin Atalar} } @article {Lee2002, title = {Numerical algorithms for spatial registration of line fiducials from cross-sectional images}, journal = {Journal of Medical Physics}, volume = {29}, number = {8}, year = {2002}, month = {Aug}, pages = {1881{\textendash}1891}, abstract = {

We present several numerical algorithms for six-degree-of-freedom rigid-body registration of line fiducial objects to their marks in cross-sectional planar images, such as those obtained in CT, MRI, given the correspondence between the marks, line fiducials The area of immediate application is frame-based stereotactic procedures, such as radiosurgery, functional neurosurgery The algorithms are also suitable to problems where the fiducial pattern moves inside the imager, as is the case in robot-assisted image-guided surgical applications We demonstrate the numerical methods on clinical CT images, computer-generated data, compare their performance in terms of robustness to missing data, robustness to noise, and speed The methods show two unique strengths: (1) They provide reliable registration of incomplete fiducial patterns when up to two-thirds of the total fiducials are missing from the image;, (2) they are applicable to an arbitrary combination of line fiducials without algorithmic modification The average speed of the fastest algorithm is 0 3236 s for six fiducial lines in real CT data in a Matlab implementation

}, keywords = {Algorithms, Anatomy, anatomy /\&/ histology/radiography, Cross-Sectional, Head, Humans, Image Enhancement, Imaging, Magnetic Resonance Imaging, methods, Quality Control, Reproducibility of Results, Sensitivity, Specificity, Stereotaxic Techniques, Stochastic Processes, Subtraction Technique, Three-Dimensional, Tomography, X-Ray Computed}, author = {Sangyoon Lee and Gabor Fichtinger and Gregory Chirikjian} }