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Peter Roland Seevinck¹, Wouter Bult¹, J Frank Nijsen¹, Maarten A. Vente¹, Remmert R. Roos¹, Alfred D. van het Schip¹, Chris J.G. Bakker¹

¹University Medical Center, Utrecht, Netherlands

Transcatheter arterial embolization with radioactive holmium-166 microspheres (HoMS) is a promising treatment option for liver cancer, in which accurate assessment of the radionuclide biodistribution is of major importance for treatment planning and dosimetry. Therefore, highly-loaded HoMS have been designed exhibiting high sensitivity on MRI. In this study, we demonstrated test dose detection, biodistribution prediction and the feasibility to quantify local HoMS dose in an ex vivo rabbit liver. Highly-loaded HoMS might allow the detection of extra-hepatic shunting, accurate treatment planning and dosimetry, opening the way to perform fully MR-guided transcatheter hepatic arterial embolization radiation therapy in the near future.

David Arthur Woodrum¹, Thomas Link², Wesley D. Gilson², ³, Brad P. Barnett², Li Pan², ³, Christine H. Lorenz², ³, Di Qian², Dara L. Kraitchman², Jeff WM Bulte², Aravind Arepally²

¹Mayo Clinic, Rochester, Minnesota, USA; ²Johns Hopkins University School of Medicine, Baltimore, Maryland, USA; ³Siemens Corporate Research, Baltimore, Maryland, USA

Magnetic resonance (MR)-trackable magnetocapsules (MCs) were created to simultaneously immunoprotect pancreatic beta cells and non-invasively monitor portal vein delivery and engraftment using MR imaging (MRI). The purpose was to demonstrate the feasibility of MRI guided delivery and monitoring of islet cell transplantation with MCs containing human islets in a swine model. The magnetocapsules were clearly visualized as magnetic susceptibility-induced hypointensities within entire liver and were trackable with standard MRI scanners. Follow-up MR imaging at 4 and 8 weeks post-transplantation demonstrated no changes in MR appearance of capsules with measurable Human C-peptide confirming the functional status of the transplant graft.

Wesley D. Gilson¹, ², Merdim Sonmez¹, ³, Cengizhan Ozturk³, David Woodrum⁴, Dorota Kedziorek², Di Qian², Bradley Barnett², Jeff WM Bulte², Christine H. Lorenz¹, ², Elliot R. McVeigh², Robert J. Lederman³, Aravind Arepally², Dara L. Kraitchman²

¹Siemens Corporate Research, Baltimore, Maryland, USA; ²Johns Hopkins University, Baltimore, Maryland, USA; ³National Institutes of Health, Bethesda, Maryland, USA; ⁴Mayo Clinic, Rochester, Minnesota, USA

The aim of this study was to investigate the use X-ray and MR image fusion for guiding delivery of stem cells contained in X-ray visible microcapsules (XCaps).  Phantom studies were performed to evaluate targeting capabilities.  For in vivo studies, cine and contrast-enhanced viability MR images were acquired in a canine with a myocardial infarction.  Myocardium and infarct segmentation was performed and fused with live X-ray fluoroscopic images to guide delivery of 15 XCaps injections to peri-infarcted and infarcted tissue.  XCaps were readily visible under X-ray, and delivery was possible using conventional endovascular devices with conventional physiological monitoring.

Dingxin Wang¹, Sumeet Virmani¹, Gayle Woloschak¹, Tatjana Paunesku¹, Riad Salem¹, Reed Omary¹, Andrew Larson¹

¹Northwestern University, Chicago, Illinois, USA

In this study, we present a quantitative four-dimensional TRIP-MRI technique (serial iterative 3D volumetric perfusion imaging) with rigorous B1+ field calibration and dynamic tissue R1 measurement for intra-procedural assessment of liver tumor perfusion reductions during transcatheter arterial embolization (TAE).

Yuichiro Matsuoka¹, Yoshinori Morita², Hiromu Kutsumi², Hiroaki Miyasho³, Makiya Matsumoto⁴, Takayuki Miyamoto⁵, Etsuko Kumamoto⁴, Takeshi Azuma², Kagayaki Kuroda¹

¹Institute of Biomedical Research and Innovation, Kobe, Japan; ²Kobe University School of Medicine, Kobe, Japan; ³Olympus Medical Systems Corp., Hachioji, Japan; ⁴Kobe University, Kobe, Japan; ⁵Intervention Technical Center Co., Ltd., Kobe, Japan

The final goal of this study is to establish MR endoscope system, which can implement MR imaging and endoscopy simultaneously and provide MR images superimposed on scope view as navigation. In this paper, the capability to depict anatomical structure and blood vessel in gastric wall in vivo experiment was examined with the developed intracavitary RF coil for 1.5-T MRI. Four or five layers in gastric wall and vascularity in submucosa and muscularis were depicted. The usefulness and ability of MR imaging to support diagnostic endoscopy and also ESD was demonstrated.

Shashank Sathyanarayana¹, Michael Schar², ³, Paul A. Bottomley³

¹Johns Hopkins University, Baltimore, USA; ²Philips Medical Systems, USA; ³Johns Hopkins University, USA

RF transmission and reception by modified miniature internal probes can inherently localize the MRI signal to the probe-head, creating a true MRI endoscope. The method is tested in a kiwifruit and in an intact porcine aorta at 3T with in-plane resolution down to 100µm and 1.5mm “slice”-width.  A local peak SAR of 0.5W/kg associated with an 0.1ºC temperature rise over ten minutes is seen during heat-testing of the endoscope in a gel phantom. MRI endoscopy can be used for efficient, real-time, high resolution internal imaging with intrinsically lower SAR than encountered with conventional body-coil excitation at 3T.

Zion Tsz Ho Tse¹, Haytham Elhawary¹, Marc Rea¹, ², Aleksandar Zivanovic¹, Collin Besant¹, D McRobbie², Ian Young¹, N de Souze³, Brian L. Davies¹, Michael Lamperth¹

¹Imperial College London, London, UK; ²Charing Cross Hospital, London, UK; ³Royal Marsden NHS Foundation Trust, Surrey, UK

An MR compatible 5 DOF haptic system has been developed for transrectal prostate biopsy and tissue palpation diagnosis, incorporating force feedback and replication to the operator at a master console during needle insertion. Tissue stiffness can be measured along the needle trajectory, which can aid diagnosis of suspected cancerous tissue. An in vitro experiment is shown to distinguish a phantom tumour and a normal lamb liver based on the force profile captured during needle insertion. Fiducial tracking technology has been integrated into the system for real-time tracking of the biopsy needle, probe and slice orientation with accuracy of 0.2mm.

Kevin Lister¹, Kokes Rebecca¹, Bao Zhang², Rao P. Gullapalli², Jaydev P. Desai¹

¹University of Maryland, College Park, Maryland, USA; ²University of Maryland School of Medicine, Baltimore, Maryland, USA

Initial results from the design and operation of a prototype MRI-compatible single degree of freedom robot for automated RFA/biopsy probe advancement with haptic feedback, along with a series of experiments proving MRI-compatibility and functionality of the device are presented.   Phantom studies show a strong correlation between the force feedback signals from a biopsy probe and the tissue interfaces within the phantom which was confirmed using MRI guided imaging.  The work presented in this paper is the first step toward the development of a robotic system with multiple degrees of freedom for RFA/biopsy of tumors under continuous MR imaging.

Yong-Lae Park¹, Santhi Elayaperumal¹, Bruce Lewis Daniel¹, Elena Kaye¹, Kim Butts Pauly¹, Richard J. Black², Mark R. Cutkosky¹

¹Stanford University, Stanford, California , USA; ²Intelligent Fiber Optic Systems Corporation, Santa Clara, California , USA

Bragg grating sensors in an optical fiber can provide information about the forces and bending geometry of catheters, needles, and other devices to reach targets in MRI guided interventions. We present the results of early experiments with an instrumented biopsy needle, which show high force sensitivity, immunity to the electromagnetic field and no imaging artifacts.

Steffen Weiss¹, Sascha Krueger¹, Oliver Lips¹

¹Philips Research Europe, Hamburg, Germany

MR real-time slices cannot display out-of-slice sections of devices. Here, a method for real-time imaging of a thin slice and simultaneous visualization or tracking of devices in a volume is presented. Volume visibility of the device is achieved by the transmission of hard pulses with the device. Signal reception with the active device during real-time 2D imaging is used to reconstruct the projection of the device onto the imaging slice and to display it as a color overlay. The method combines high contrast MR imaging of the anatomy in a thin slice with continuous volume visibility of devices as appreciated in X-ray fluoroscopy.