|Developments in MR-Guided Interventions|
Highly-Loaded Holmium Microspheres for Test Dose
Detection and Biodistribution Prediction in Internal Radiation Therapy
of Liver Malignancies
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.
MR Guided Islet Cell Transplantation
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.
X-Ray Fusion with MRI for Delivery of
Encapsulated Stem Cell Therapeutics
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.
Monitoring Liver Tumor Embolization in VX2 Rabbits:
Four-Dimensional Transcatheter Intraarterial Perfusion (TRIP) MR Imaging
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).
Imaging of Anatomical Structure and Blood Vessels in
Porcine Gastric Wall by MR Endoscope
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.
MRI Endoscopy at 3T
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 100Ám and 1.5mm ôsliceö-width. A local peak SAR of 0.5W/kg associated with an 0.1║C 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.
A 5 Degree of Freedom Haptic System for
Transrectal Prostate Biopsy and Tissue Palpation with MR Image Guidance
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.
MRI Compatible Robotic System with Haptic Feedback
for RF Ablation/Biopsy Under Continuous MRI
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.
MRI-Compatible Haptics: Feasibility of Using Optical
Fiber Bragg Grating Strain-Sensors to Detect Deflection of Needles in an
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.
2D-Real-Time MR Imaging and Simultaneous X-Ray-Like
Volume Visualization of Devices
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.