@conference {Dehghan2016, title = {CT AND MRI FUSION FOR POSTIMPLANT PROSTATE BRACHYTHERAPY EVALUATION}, booktitle = {IEEE Int. Symp on Biomedical Imaging}, year = {2016}, month = {04/2016}, pages = {625-628}, abstract = {

Postoperative evaluation of prostate brachytherapy is typically
performed using CT, which does not have sufficient
soft tissue contrast for accurate anatomy delineation. MR-CT
fusion enables more accurate localization of both anatomy
and implanted radioactive seeds, and hence, improves the
accuracy of postoperative dosimetry. We propose a method
for automatic registration of MR and CT images without a
need for manual initialization. Our registration method employs
a point-to-volume registration scheme during which
localized seeds in the CT images, produced by commercial
treatment planning systems as part of the standard of care,
are rigidly registered to preprocessed MRI images. We tested
our algorithm on ten patient data sets and achieved an overall
registration error of 1.6 {\textpm} 0.8mm with a running time of less
than 20s. With high registration accuracy and computational
speed, and no need for manual intervention, our method has
the potential to be employed in clinical applications.

}, keywords = {Brachytherapy, Prostate}, author = {Ehsan Dehghan and Yi Le and Junghoon Lee and Danny Y Song and Gabor Fichtinger and Jerry L. Prince} } @conference {Avni2010, title = {Design of a predictive targeting error simulator for MRI-guided prostate biopsy}, booktitle = {Medical Imaging 2010: Visualization, Image-Guided Procedures, and Modeling}, year = {2010}, month = {2010}, pages = {76251A-1 - 76251A-8}, publisher = {SPIE}, organization = {SPIE}, address = {San Diego, California, USA}, abstract = {

Multi-parametric MRI is a new imaging modality superior in quality to Ultrasound (US) which is currently used in standard prostate biopsy procedures. Surface-based registration of the pre-operative and intra-operative prostate volumes is a simple alternative to side-step the challenges involved with deformable registration. However, segmentation errors inevitably introduced during prostate contouring spoil the registration and biopsy targeting accuracies. For the crucial purpose of validating this procedure, we introduce a fully interactive and customizable simulator which determines the resulting targeting errors of simulated registrations between prostate volumes given user-provided parameters for organ deformation, segmentation, and targeting. We present the workflow executed by the simulator in detail and discuss the parameters involved. We also present a segmentation error introduction algorithm, based on polar curves and natural cubic spline interpolation, which introduces statistically realistic contouring errors. One simulation, including all I/O and preparation for rendering, takes approximately 1 minute and 40 seconds to complete on a system with 3 GB of RAM and four Intel Core 2 Quad CPUs each with a speed of 2.40 GHz. Preliminary results of our simulation suggest the maximum tolerable segmentation error given the presence of a 5.0 mm wide small tumor is between 4-5 mm. We intend to validate these results via clinical trials as part of our ongoing work.

}, keywords = {Biopsy, cancer, error, modeling, MRI, Prostate, segmentation, validation}, isbn = {0277-786X}, doi = {http://dx.doi.org/10.1117/12.844476}, author = {Shachar Avni and Siddharth Vikal 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 {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 {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 {Shen2004a, title = {Optimized prostate biopsy via a statistical atlas of cancer spatial distribution}, journal = {Medical image analysis}, volume = {8}, number = {2}, year = {2004}, month = {Jun}, pages = {139{\textendash}150}, abstract = {

A methodology is presented for constructing a statistical atlas of spatial distribution of prostate cancer from a large patient cohort, and it is used for optimizing needle biopsy An adaptive-focus deformable model is used for the spatial normalization, registration of 100 prostate histological samples, which were provided by the Center for Prostate Disease Research of the US Department of Defense, resulting in a statistical atlas of spatial distribution of prostate cancer Based on this atlas, a statistical predictive model was developed to optimize the needle biopsy sites, by maximizing the probability of detecting cancer Experimental results using cross-validation show that the proposed method can detect cancer with a 99\% success rate using seven needles, in these samples

}, keywords = {Algorithms, Biological, Biopsy, Cohort Studies, Computer Simulation, Computer-Assisted, Forecasting, Humans, Image Processing, Imaging, Male, Models, Needle, pathology, Probability, Prostate, Prostatic Neoplasms, Reproducibility of Results, Statistical, statistics /\&/ numerical data, Three-Dimensional}, doi = {10 1016/j media 2003 11 002}, url = {http://dx doi org/10 1016/j media 2003 11 002}, author = {Dinggang Shen and Zhiqiang Lao and Jianchao Zeng and Wei Zhang and Isabel Sesterhenn and Leon Sun and Judd Moul and Edward Herskovits and Gabor Fichtinger and Christos Davatzikos} } @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} }