Interventional MRI: Technical Developments & Clinical Applications
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Tuesday May 10th
Room 511A-C  10:30 - 12:30 Moderators: Claudia Hillenbrand and Harald H. Quick

10:30 194.   Assessment and Completion of RF Ablation for the Treatment of Atrial Fibrillation using Real-Time MRI Guidance  
Sathya Vijayakumar1,2, Eugene G Kholmovski1,2, Ravi Ranjan2,3, Gaston Vergara2,3, Joshua Blauer2,4, Gene Payne1,2, Nelly Volland1,2, Kamal Vij5, Gregory Gardner2,4, Peter Piferi5, Kimberly Johnson2,3, Li Pan6, Klaus Kirchberg6, Rob MacLeod2,4, Christopher J McGann2,3, and Nassir F Marrouche2,3
1UCAIR, Department of Radiology, University of Utah, Salt Lake City, Utah, United States, 2CARMA Center, University of Utah, Salt Lake City, Utah, United States,3Department of Cardiology, University of Utah, Salt Lake City, Utah, United States, 4SCI, University of Utah, Salt Lake City, Utah, United States, 5SurgiVision Inc., Irvine, California, United States, 6Center for Applied Medical Imaging, Siemens Corporate Research, Princeton, NJ

In this work, we study the feasibility of an EP-MRI workflow for RF ablation procedures for the treatment of atrial fibrillation. This approach consists of the assessment of ablation performed in the EP-suite using MRI, and completing the ablation procedure in the MRI-suite if necessary using real time MRI guidance. This work flow may possibly reduce the number of repeat ablation procedures.

10:42 195.   An Integrated System for Catheter Tracking and Visualization in MR-Guided Cardiovascular Interventions 
Li Pan1, Julien Barbot2, Steven M. Shea1, Sunil Patil1, Klaus J. Kirchberg2, Glenn Meredith2, Tongbai Meng1, Eugene G. Kholmovski3,4, Sathya Vijayakumar3,4, Kamal Vij5, Mike Guttman5, Peter G. Piferi5, Kimble L. Jenkins5, and Christine H. Lorenz1
1Center for Applied Medical Imaging, Siemens Corporate Research, Baltimore, MD, United States, 2Center for Applied Medical Imaging, Siemens Corporate Research, Princeton, NJ, United States, 3UCAIR, Department of Radiology, University of Utah, Salt Lake City, UT, United States, 4CARMA Center, University of Utah, Salt Lake City, UT, United States, 5SurgiVision, Inc., Irvine, CA, United States

In this work, we present an integrated system that incorporates active device tracking implemented in an interactive real-time sequence as well as a graphical interface for real-time catheter visualization and navigation. The system supports tracking and visualization of multiple catheters and several options for automatically updating imaging planes. The tracking provided robust catheter location accuracy, and the visualization of the catheters provided the users with an environment similar as with X-ray fluoroscopy guided procedures. The system is especially suitable for MR guided intravascular interventions in which real-time catheter tracking and visualization for navigation is mandatory.

10:54 196.   Prospective High Resolution Respiratory Resolved Whole-Heart MRI for Image-Guided Cardiovascular Interventions 
Christoph Kolbitsch1, Claudia Prieto1, Christian Buerger1, Reza Razavi1, Jouke Smink2, and Tobias Schaeffter1
1Division of Imaging Sciences and Biomedical Engineering, King's College London, London, United Kingdom, 2Philips Healthcare, Best, Netherlands

Image-guided catheterisations are an important clinical tool for cardiovascular diseases. In order to increase the accuracy of the procedure with an additional MRI roadmap, a 3D high resolution scan and additional respiratory information are required. Here we present a method that records all the necessary information during a single whole-heart scan with a prospective respiratory resolved acquisition scheme. Moreover, an affine model to describe the breathing motion can be obtained from the same acquired data. Validation on volunteer data yielded a maximum target registration error of less than 3.4mm.

11:06 197.   Evaluation of a novel MR-RF Ablation Catheter with full clinical Functionality  -permission withheld
Steffen Weiss1, Bernd David1, Kai-Michael Luedeke1, Oliver Lips1, Daniel Wirtz1, Sascha Krueger1, Peter Koken1, Ronald Holthuizen2, Tobias Schaeffter3, Jas Gill3, and Reza Razavi3
1Philips Research Laboratories, Hamburg, Germany, 2Philips Healthcare, Best, Netherlands, 3Division of Imaging Sciences, King's College, London, United Kingdom

Earlier work on an MR-RF ablation catheter has been complemented by adding a sensor to measure the temperature of the ablation electrode as in standard catheters but here connected via highly resistive wires. This provides much increased RF safety and compatibility with clinical RF generators. All wiring in the final prototype either dampens RF resonances by high resistance or avoids RF resonances by segmentation of long cables into short sections using transformers and switches. RF safety of the catheter is demonstrated by RF heating measurements, and all EP functions of the catheter are evaluated by various measurements including MR-guided ablation procedures.

11:18 198.   MRI-Guided Sclerotherapy of Veno-lymphatic Vascular Malformations: Evaluation of Procedure Safety and Long-term Efficacy 
Sherif G Nour1, Daniel P. Hsu2, Jamal J Derakhshan3, and Jonathan S Lewin4
1Radiology, Emory University Hospital, Atlanta, GA, United States, 2Radiology, Case Medical Center, Cleveland, OH, 3Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States, 4Radiology, Johns Hopkins School of Medicine, Baltimore, MA, United States

Veno-lymphatic (slow-flow) vascular malformations typically present in children and young adults with various combinations of pain, localized dysfunction, and disfigurement. They may also bleed or result in fatal coagulopathy. The treatment is often challenging with high recurrence after surgery or traditional x-ray fluoroscopy guided sclerotherapy. This work describes our experience with 46 sclerotherapy procedures performed exclusively within a high-field interventional MRI suite, highlights the necessary technical aspects, demonstrates the safety features related to MRI guidance as compared to traditional x-ray guidance, and reports the long-term efficacy of these procedures as observed on extended follow-up durations of up to 36.1 months.

11:30 199.   Longitudinal high resolution MRI to evaluate a novel statin loaded HDL nanoparticle therapy in experimental atherosclerosis 
Raphael Duivenvoorden1,2, Jun Tang1, David Izquierdo-Garcia3, David P. Cormode1, Eric S.G. Stroes2, Edward A. Fisher4, Zahi A. Fayad1,3, and Willem J.M. Mulder1
1Translational and Molecular Imaging Institute, Mount Sinai School of Medicine, New York, NY, United States, 2Vascular Medicine, Academic Medical Center, Amsterdam, NH, Netherlands, 3Radiology, Mount Sinai School of Medicine, New York, NY, United States, 4Department of Medicine, Division of Cardiology, New York University School of Medicine, New York, NY, United States

We hypothesized that targeted statin delivery to atherosclerotic plaque with a reconstituted high density lipoprotein (rHDL) nanoparticle can inhibit plaque inflammation and development more potently than oral statin therapy or rHDL infusion. We divided 48 apoE-KO mice in 3 equal groups that were either treated with oral simvastatin, rHDL infusion or our rHDL like nanoparticle loaded with simvastatin for 12 weeks. We performed MRI and histology measurements to quantify aortic atherosclerosis. We found that targeted statin delivery to atherosclerotic plaque with rHDL like nanoparticles showed considerably more efficacy in the treatment of atherosclerosis than oral statin therapy or rHDL infusion.

11:42 200.   Quantitative Transcatheter Intraarterial Perfusion MRI to Predict Drug Delivery during Chemoembolization for Hepatocellular Carcinoma 
Dingxin Wang1,2, Brian Jin3, Robert Lewandowski3, Robert Ryu3, Kent Sato3, Ann Ragin3, Laura Kulik4, Mary Mulcahy5,6, Frank Miller3, Riad Salem3,6, Andrew Larson3,6, and Reed Omary3,6
1Siemens Medical Solutions USA, Inc., Minneapolis, Minnesota, United States, 2Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, Minnesota, United States, 3Department of Radiology, Northwestern University, Chicago, Illinois, United States, 4Department of Hepatology, Northwestern University, Chicago, Illinois, United States, 5Department of Medicine, Northwestern University, Chicago, Illinois, United States, 6Robert H. Lurie Comprehensive Cancer Center, Northwestern University, Chicago, Illinois, United States

This study accessed the utility of quantitative Transcatheter Intraarterial Perfusion (TRIP)-MRI for predicting chemotherapy-lipiodol delivery during transcatheter arterial chemoembolization (TACE). The volumes of drug distribution in the tumors and liver as well as the selectivity of chemotherapy emulsion delivery to the tumors obtained from pre-TACE TRIP-MRI highly correlated with corresponding parameters seen on CT scans after TACE. These findings suggest that quantitative TRIP-MRI may have the potential to provide important spatial biodistribution information of subsequent drug delivery during liver-directed transarterial locoregional therapies with same catheter positioning.

11:54 201.   Detection and quantification of Holmium-166 loaded microspheres in patients with liver metastases: initial experience within the framework of a phase I study 
Gerrit Hendrik van de Maat1, Mattijs Elschot2, Peter Roland Seevinck1, Hendrik de Leeuw1, H.W. de Jong2, M.L. Smits2, M.A. van den Bosch2, M.G. Lam2, B.A. Zonnenberg2, A D van het Schip2, J Frank Nijsen2, and Chris J Bakker1
1Image Sciences Institute, University Medical Center, Utrecht, Utrecht, Netherlands, 2Department of Radiology and Nuclear Medicine, University Medical Center, Utrecht, Netherlands

We report the first results of the detection and quantification of Holmium-166 loaded microspheres in patients with liver metastases that were treated within the framework of a clinical phase I study. HoMS concentration maps determined from T2* weighted data acquired using a multi gradient echo sequence show good correspondence with activity maps acquired with Single Photon Emission Computed Tomography (SPECT). The total amount of HoMS in the liver determined from the concentration maps was in good agreement with the total amount that was delivered to the liver. The HoMS were found to mainly accumulate at the tumor site.

12:06 202.   Clinically usable tool for dynamic scan-plane tracking for real-time MRI-guided needle interventions in a high-field-open MRI system 
Uta Wonneberger1, Sascha Krüger2, Daniel Wirtz2, Christoph Leussler2, Steffen Weiss2, Kerstin Jungnickel1, Matthias Ludewig1, Jürgen Bunke3, Jens Ricke1, and Frank Fischbach1
1Klinik für Radiologie und Nuklearmedizin, Otto-von-Guericke-Universität Magdeburg, D-39120 Magdeburg, Germany, 2Imaging Systems and Intervention, Philips Research Europe, D-22335 Hamburg, Germany, 3Healthcare, Philips, D-22335 Hamburg, Germany

An actively tracked needle guidance tool, directly connected to the MR system, with respective MR system software modifications to allow for simple-to-use, fast and accurate scan plane controlling with inherent registration to the MRI coordinate system is presented for the use in clinical routine for needle interventions in freehand-technique with the physician practicing from inside the open MR-system. The hand-held device is equipped with a guide bar to automatically align the needle path with the device and with a thumb switch to perform fast, immediate 90° scan plane rotations around the needle axis without actual rotation of the device while simultaneously toggling between the two viewports of the real-time interactive scanner user interface.

12:18 203.   Pass-through Piston Driver for MR Elastography Assessment of Percutaneous Laser Ablation  -permission withheld
David Arthur Woodrum1, Jun Chen1, Kevin J Glaser1, Krzysztof Gorny1, and Richard L Ehman1
1Radiology, Mayo Clinic, Rochester, Minnesota, United States

A critical part of the tumor ablation is intra-treatment monitoring to determine whether an adequate treatment is achieved. Our hypothesis is MR elastography can be used to measure the changing stiffness of the ablation zone during and after the ablation. The purpose of this study is to demonstrate the feasibility of new acoustic path-thru driver at producing mechanical waves through a laser ablation applicator to the ablation zone. In vivo studies in porcine liver demonstrate that these waves can be produced and measured within the porcine liver. The stiffness at tip of laser applicator demonstrates increasing stiffness during the ablation.