Room 155 EF

13:30 - 15:30

Moderators:

Charles L. Dumoulin, Graham Wright

Steffen Weiss¹, Sascha Krueger¹, Peter Koken¹, Gregg Stenzel², Steve Wedan², Ronald Holthuizen³, Jouke Smink⁴, Anne Krogh Grøndal⁵, Lars Ølgaard Bloch⁵, James Harrison⁶, Mark O'Neill⁶, Reza Razavi⁶, and Tobias Schaeffter^6
1Innovative Technologies, Research Laboratories, Philips Technologie GmbH, Hamburg, Germany, ²Imricor Medical Systems, Burnsville, MN, United States, ³MR Clinical Functionality, Philips Healthcare, Best, Netherlands, ⁴MR Clinical Science, Philips Healthcare, Best, Netherlands, ⁵MR Research Centre, Aarhus University Hospital, Aarhus, Denmark, ⁶Division of Imaging Sciences and Biomedical Engineering, King’s College London, London, United Kingdom

An MR-EP suite was developed that closely integrates all components required for clinical EP procedures. This includes wireless transmission of the ECG from the patient monitor to the EP recorder, automatic transmission of activation time delays from the EP recorder with on-the-fly generation of color-coded time maps based on a cardiac model, and automatic planning of scan orientations based on the position of the active tracking catheter. The suite was evaluated in pre-clinical mapping and ablation sessions in pigs. It enabled time-efficient mapping and ablation including catheter-navigated monitoring of catheter-tissue contact and lesion formation including wall thickening.

Tobias Voigt¹, Peter Koken², James Harrison³, Steffen Weiss², Sascha Krueger², and Tobias Schaeffter^3
1Clinical Research Europe, Philips Research, London, London, United Kingdom, ²Tomographic Imaging Systems, Philips Research, Hamburg, Hamburg, Germany, ³Division of Imaging Sciences, King's College London, London, London, United Kingdom

In this work a fully integrated MR Wall Thickness Imagin (WTI) procedure for cavotricuspid isthmus (CTI) ablation is described. The treatment of cardiac arrhythmias by RF ablation has grown rapidly in recent years. The main goal of atrial ablation procedures is to block unwanted conduction pathways by creating transmural lesions. A major challenge is given by the unknown atrial wall thickness. MR atrial wall thickness imaging (WTI) may provide this information and contribute to increase in ablation success rates. The proposed technique is validated in a phantom study and applied in healthy volunteers and an atrial flutter patient.

Di Xu¹, Daniel A. Herzka², Paul A. DiCamillo³, Wesley D. Gilson⁴, Elliot R. McVeigh¹, Jonathan S. Lewin³, and Clifford R. Weiss^3
1Biomedical Engineering, The Johns Hopkins School of Medicine, Baltimore, MD, United States, ²Biomedical Engineering, Johns Hopkins University, Baltimore, MD, United States, ³Radiology, The Johns Hopkins School of Medicine, Baltimore, MD, United States, ⁴Siemens Corporation, Corporate Technology, Baltimore, MD, United States

Venous and lymphatic malformations (VMs/LMs) are diagnostically visualized using T2-weighted fat-suppressed turbo spin echo. Once identified, lesions typically are treated percutaneously using ultrasound and fluoroscopic guidance. Treatment is limited in lesions that are deep, lie beneath scar, or within bone. Additionally, almost all patients require multiple treatments, accruing significant exposure to ionizing radiation. Real-time MR-guided intervention serves as a safer alternative, with better visualization of critical structures. Conventional sequences are limited: with blurry, distorted edges (HASTE) or with inferior VM/LM delineation because of poor T2-weighting (SSFP). We present real-time imaging for the VMs/LMs visualization during MR-guided sclerotherapy: Contrast-Prepared SSFP.

Prasheel Lillaney¹, Vincent Malba¹, Leland Evans¹, Anthony Bernhardt¹, Mark Wilson¹, Timothy Roberts², Alastair Martin¹, Maythem Saeed¹, Ronald Arenson¹, and Steven W. Hetts^1
1Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California, United States, ²Radiology Department, University of Pennsylvania, Philadelphia, PA, United States

This work presents a method for the fabrication of micro-coils assembled onto the tips of catheters for use in guiding a catheter in an MR field. The approach utilizes the static magnetic field of an MR system to interact with a magnetic moment created by passing an electric current through coils placed at the catheter tip.

Shashank Sathyanarayana Hegde¹, Yi Zhang², and Paul A. Bottomley^1
1Radiology, Johns Hopkins University, Baltimore, Maryland, United States, ²Electrical and Computer Engineering, Johns Hopkins University, Baltimore, Maryland, United States

High-resolution intravascular (IV) MRI is susceptible to degradation from physiological motion, and requires high frame-rates for true endoscopy. Fortunately, IV MRI detectors have intrinsically radial and sparsely-localized sensitivity profiles, and high local signal-to-noise ratios. Here, compressed sensing with sparse reconstruction is combined with motion correction using frame-by-frame projection shifting based on a singularity at the probe’s location, to provide up to four-fold effective speed-up in image acquisition and a significant reduction in motion sensitivity. We present data acquired in phantoms, and human vessel specimens. These strategies can greatly facilitate high-resolution (~100 micron) real-time MRI endoscopy.

Kevan Anderson¹, Nicolas Yak¹, Labonny Biswas¹, Jennifer Barry¹, and Graham Wright^1,2
1Physical Sciences, Sunnybrook Research Institute, Toronto, Ontario, Canada, ²Medical Biophysics, University of Toronto, Toronto, Ontario, Canada

Studies investigating the use of MRI for lesion revascularization have focused on the development of specialized active catheters and guidewires that incorporate receive coils to enable device visualization. There are many engineering challenges associated with this approach and the added complexity will typically limit device performance. In this study we evaluate the ability to actively visualize a commercially available radio-frequency ablation guidewire in an animal model of occlusive arterial disease. The selected technique utilizes an external coupling device that is magnetically coupled to the guidewire and the capacity to visualize the guidewire in vivo is demonstrated.

Andriy Fedorov¹, Kemal Tuncali¹, Tobias Penzkofer^1,2, Junichi Tokuda¹, Sang-Eun Song¹, Nobuhiko Hata¹, and Clare Tempany^1
1Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States, ²Department of Diagnostic and Interventional Radiology, RWTH Aachen University Hospital, Aachen, North Rhine-Westphalia, Germany

Interventional applications of MRI in PCa management include MRI-guided core needle biopsy that can be recommended for some patient populations, and may lead to improved accuracy of cancer detection. In this work we apply deformable registration retrospectively to recover and quantify intra-procedural motion of the pelvis and prostate gland. Our results show significant motion of the gland, which cannot be fully recovered by compensating for pelvis motion. This can lead to significant errors between the planned and true location of the biopsy target. Application of intra-procedural registration is recommended for intra-procedural quantification and recovery of target motion.

Weiguo Li^1,2, Zhuoli Zhang¹, Yang Guo¹, Jodi Nicolai¹, Reed A. Omary¹, and Andrew C. Larson^1
1Radiology, Northwestern University, Chicago, Illinois, United States, ²Research Resource Center, University of Illinois at Chicago, Chicago, Illinois, United States

Visualization and quantification of Yttrium-90 (90Y) microsphere biodistribution using conventional radiologic modalities is challenging. Whereas labeling 90Y microspheres with SPIOs offers the potential to use MRI to visualize in vivo biodistribution, optimization of the amount of SPIO included within these microspheres may be critical. In this study, we have demonstrated the potential to optimize SPIO content for future studies intended to quantify microsphere concentrations in vivo; we found that spheres with 2% SPIO contents will be ideal candidates for in vivo studies.

Waltraud Brigitte Buchenberg¹, Ramona Lorenz¹, Peter Laudy², Wolfgang Mader³, Carsten Bienek⁴, and Bernd Jung^1
1Dept. of Radiology, Medical Physics, University Medical Center, Freiburg, Baden-Württemberg, Germany, ²CardioTek B.V., Maastricht-Airport, Limburg, Netherlands, ³Freiburg Center for Data Analysis and Modeling, Albert-Ludwigs-University, Freiburg, Baden-Württemberg, Germany, ⁴R&D, Schwarzer GmbH, Heilbronn, Baden-Württemberg, Germany

The analyses of the magnetohydrodynamic (MHD) effect occurring in electro-physiologic (EP) examinations carried out in an MR environment is of importance in order to establish tool boxes to remove MHD related effects from intra-cardiac ECG signals. The aim in this work was to establish an experimental setup to simulate the MHD effect in a model system using standard EP-measurement equipment with respect to a characterization of the pure MHD signal.

Matthew Toews¹, Chang-Sheng Mei¹, Renxin Chu¹, W. Scott Hoge¹, Benjamin M. Schwartz¹, Guangyi Wang^1,2, Lawrence P. Panych¹, and Bruno Madore^1
1Department of Radiology, Harvard Medical School, Brigham and Women's Hospital, Boston, MA, United States, ²Department of Radiology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong, China

A frame rate of twenty frames per second or more is often considered necessary to properly resolve breathing motion for MR-guided therapies. But images with the overall quality, information content and spatial coverage required for effective guidance often cannot be acquired that fast. The present work proposes a system for boosting MR temporal resolution by incorporating ultrasound (US) measurements with high temporal resolution. Experiments showed that predicted MR images could be used to accurately localize anatomical targets in in-vivo liver data, in the presence of breathing motion.