Electronic Posters : Molecular Imaging
Click on to view the abstract pdf and click on to view the video presentation.
Targeted Molecular Imaging

Monday May 9th
Exhibition Hall  14:00 - 16:00 Computer 60

14:00 3688.   Evaluation of a Targeted Nanoglobular Gd Chelate for MRI Molecular Imaging of Prostate Tumor in an Orthotopic Mouse Model 
Mingqian Tan1,2, and Zheng-Rong Lu1
1Case Western Reserve University, Cleveland, Ohio, United States, 2National Chromatographic Research and Analysis Center, Dalian Institute of Chemical Physics, The Chinese Academy of Sciences, Dalian, Liaoning, China, People's Republic of

A cyclic peptide CLT1-targeted nanoglobular Gd(III)-based contrast agent was evaluated in male mice bearing orthotopic xenograft tumor with MRI. The r1 and r2 relaxivities of the CLT1 targeted agent were 11.63 and 15.73 mM-1s-1 per Gd(III) chelate at 1.5T, respectively. Peptide CLT1 has shown significant accumulation in tumor as compared to a control peptide. The CLT1 targeted contrast agent resulted in strong contrast enhancement in the orthotopic prostate tumor for in vivo MR molecular imaging, while little enhancement was observed in the tumor with the control agent. The results demonstrated that the CLT1-targted nanoglobular contrast agent is effective for in vivo cancer MR molecular imaging in an orthotopic mouse tumor model.

14:30 3689.   Targeting of Matrix Metalloproteinase-2 activation with Gd-NBCB-TTDA-MMP-2 for detection of vulnerable atherosclerotic plaques using a novel molecular MR Imaging in vivo 
Chiao-Yun Chen1,2, Twei-Shiun Jaw1,2, Hua-Lin Wu3, Guey-Yueh Shi3, Yun-Ming Wang4, Gin-Chung Liu1,2, and Yu-Ting Kuo1,2
1Department of Medical Imaging, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan, 2Department of Radiology, Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan, 3Department of biochemistry & Molecular Biology, College of Medicine & cardiovascular Research Cancer, National Cheng Kung Univerisity, Taiwan, 4Department of Biological Science and Technology, National Chiao Tung University, Hsinchu, Taiwan

We have successfully synthesized and characterized a novel gadolinium-based MR contrast agent, Gd-NBCB-TTDA-MMP-2, formed of a peptide with a high affinity for MMP-2 .Our study demonstrated that Gd-NBCB-TTDA-MMP-2 can be a useful MR contrast agent for in vivo detection of MMP-2 activity in atherosclerosis at a molecular pathologic level. Because evaluation of the MMP-2 content and activity may aid in the prediction of the vulnerability of atherosclerotic plaques to rupture and thrombosis, using Gd-NBCB-TTDA-MMP-2 enhanced MR imaging to assess MMP-2 activity may allow identification of unstable plaques and contribute substantially to preclinical and clinical evaluation of atherosclerosis.

15:00 3690.   Quantitative molecular MR imaging of U87 brain tumor angiogenesis using a novel RGD Gd-based emulsion 
Benjamin Marty1, Françoise Geffroy1, Boucif Djemai1, Benoit Theze2, Aline Perrin1, Caroline Robic3, Marc Port3, Philippe Robert3, Denis Le Bihan1, Franck Lethimonnier1, and Sébastien Mériaux1
1CEA/DSV/I2BM/Neurospin, Gif-sur-Yvette, France, 2CEA/DSV/I2BM/SHFJ, Orsay, France, 3Research Division, Guerbet, Roissy Charles de Gaulle, France

Molecular magnetic resonance imaging is an increasingly used tool to investigate tumors angiogenic activity. Here we used a high relaxivity Gadolinium based (Gd-based) emulsion grafted with RGD peptides to target αvβ3 protein over-expressed during tumor angiogenesis induced in mice brain. This study proposes to quantify the Gd-based emulsion concentration by acquiring dynamic T1 maps. Thanks to this methodology we are able to detect and quantify the accumulation of contrast agent in the tumor after its intravenous injection. A proof of concept of its binding was obtained in vivo with brain tumors induced in nude mice, and was confirmed by histology.

15:30 3691.   Atherosclerotic MR Molecular Imaging Strategy with Superparamagnetic Iron Oxide on a Human Clinical Scanner – Rabbit Model 
David C Zhu1, Kheireddine El-Boubbou2, George S Abela3, Ruiping Huang3, Medha Kamat2, and Xuefei Huang2
1Radiology and Psychology, Michigan State University, East Lansing, MI, United States, 2Chemistry, Michigan State University, 3Medicine, Michigan State University

Atherosclerotic plaques are formed through the accumulation of macrophages, lipids, and fibrous connective tissue underneath the endothelium lining in arterial walls. CD44 is a cell surface receptor at macrophages which tend to accumulate at atherosclerotic plaques. In this work, hyaluronic acid (HA) was bonded to dextran coated SPIO nanoparticles (DESPIONs). The synthesized HA-DESPIONs were used to target CD44 at macrophages and were able to highlight atherosclerotic plaques in MRI. With HA-DESPION as an example, here we summarize our molecular imaging strategy of a rabbit model on a human clinical scanner.

Tuesday May 10th
  13:30 - 15:00 Computer 60

13:30 3692.   Molecular MRI Allows the Detection of Activated Platelets in a New Mouse Model of Coronary Artery Thrombosis 
Mirko Meißner1, Daniel Dürschmied2, Irene Neudorfer2, Constantin von zur Mühlen2, and Dominik von Elverfeldt1
1Dept. of Radiology / Medical Physics, University Medical Center Freiburg, Freiburg, Germany, 2Dept. of Cardiology and Angiology, University Medical Center Freiburg, Freiburg, Germany

The final event leading to myocardial infarction is adhesion and activation of platelets after rupture of an atherosclerotic plaque. Platelets then aggregate, culminating in thrombotic occlusion of the coronary artery. We examined the feasibility of molecular MRI for the detection of non-occluding coronary artery thrombosis in mice, by using MPIOs targeted to activated platelets. Hypointense regions in the MR images were co-localised with MPIO accumulation in thrombi, as confirmed by histology.

14:00 3693.   Non-Invasive Assessment of Disease Activity in Lupus Nephritis by MRI-Based Molecular Imaging 
Siranush Anna Sargsyan1, Kendra M. Hasebroock2, Brandon Renner2, Brian Larsen3, Conrad Stoldt3, V. Michael Holers2, Joshua M. Thurman2, and Natalie Serkova2
1Medicine, University of Colorado Denver, Aurora, Colorado, United States, 2University of Colorado Denver, 3University of Colorado Boulder

Lupus nephritis is characterized by immune-complex deposition as well as complement C3 activation within the glomeruli of the kidney. Percutaneous renal biopsy is the gold standard for monitoring disease activity, yet less invasive methods of obtaining biopsy information are needed. We have developed a non-invasive method for detecting tissue-bound iC3b/C3d using MRI and superparamagnetic iron oxide (SPIO) nanoparticles linked to the iC3b/C3d binding region of complement receptor type 2 (CR2). We found that CR2-targeted SPIO nanoparticles caused a reduction in the T2-relaxation time in nephritic kidneys corresponding to the peak glomerular iC3b deposition and disease severity.

14:30 3694.   Molecular Probes for Targeting and Imaging of Epidermal Growth Factor Receptor on Head and Neck Cancer Cells 
Chiwei Hung1, Yuan-Chia Kuo1,2, Jiachen Zhuo3, Srinivasa R Raghavan2,4, Janet E Baulch1, Rao Gullapalli3, Mohan Suntharalingam1, and Warren D D'souza1,2
1Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, MD, United States, 2Fischell Department of Bioengineering, University of Maryland, College Park, MD, United States, 3Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland Medical Center, Baltimore, MD, United States, 4Department of Chemical and Biomolecular Engineering, University of Maryland, College Park, MD, United States

A multifuctional molecular probe was investigated for the targeting and imaging of the epidermal growth factor receptors on head and neck tumor cells by combining a paramagnetic contrast agent, Gadolinium, with a monoclonal EGFR targeting antibody. Our research showed that this probe was able to target EGFR on the cancer cell and showed an increase in contrast under MR imaging. It may be used to provide the diagnostic feedback of the ongoing targeted therapy with concurrent RT.

Electronic Posters : Molecular Imaging
Click on to view the abstract pdf and click on to view the video presentation.
Novel Contrast Agents & Labels

Monday May 9th
Exhibition Hall  14:00 - 16:00 Computer 61

14:00 3695.   Development of iron oxide nanoparticles for MRI-SPECT-Optical Imaging of sentinel lymph nodes 
Renata Madru1, Pontus Kjellman2, Pontus Svenmarker3, Karin Wingårdh1, Sarah Fredriksson2, Anders Örbom1, Stefan Andersson-Engels3, Christian Ingvar4, Linda Knutsson1, Johan Olsrud5, Jimmy Lätt5, Freddy Ståhlberg1, and Sven-Erik Strand1
1Medical Radiation Physics, Lund University, Lund, Sweden, 2Genovis AB, Lund, Sweden, 3Physics, Lund University, Lund, Sweden, 4Surgery, Skane University Hospital, Lund, Sweden, 5Center for Medical Imaging and Physiology, Skane University Hospital, Lund, Sweden

In this study a superparamagnetic iron oxide (SPIO) based contrast agent with magnetic, radioactive and fluorescent properties has been developed. The final aim is to be able to image the sentinel lymph node (SLN) thereby guiding the surgeon to find SLN in breast cancer and malignant melanoma patients.

14:30 3696.   Novel Mn-Porphyrin Contrast Probe for Molecular MR Imaging of Glial Reactivity in the Rat Brain 
Timothy J Amrhein1, Talaignair N Venkatraman1, Haichen Wang2, Ines Batinic-Haberle3, and Christopher D Lascola1
1Radiology, Duke University Medical Center, Durham, NC, United States, 2Anesthesiology, Duke University Medical Center, Durham, NC, United States, 3Radiation Oncology, Duke University Medical Center, Durham, NC, United States

The paramagnetic superoxide dismutase mimetric MnTnHex-2-PyP5+ exhibits sufficient lipophilicity to allow for its accumulation within the brain despite an intact blood brain barrier. MR phantom experiments demonstrated their considerable T1 relaxation properties. Subsequently, a spreading depression rat model of microglial activity with an intact blood brain barrier demonstrated increased T1 relaxation within the experimental hemisphere after the administration of MnTnHex-2-PyP5+. This finding was successfully blocked via competitive inhibition with PK11195, a potent ligand of peripheral-type benzodiazepine receptors specific to activated microglia, suggesting a mechanism for localization and potential specificity for early brain injury states.

15:00 3697.   A nanoemulsion based CEST agent for hyperpolarized 129Xe 
Todd K Stevens1,2, Richard M Ramirez1,2, and Alexander Pines1,2
1Chemistry, UC Berkeley, Berkeley, CA, United States, 2Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States

In this study, a novel and highly sensitive 129Xe CEST contrast agent based on perfluorocarbon nanoemulsions is presented. CEST spectra for nanoemulsion droplet diameters ranging from 160 nm to 310 nm were used to demonstrate the dependence of the xenon exchange rates on the xenon diffusion transit times associated with the different sized droplets. Bloch modeling of the data allowed for determination of the escape probability of xenon atoms arriving at the surfactant boundary of the droplets (1.3%). Droplets of 210 nm and 310 nm diameters were detected at concentrations as low as 1 pM and 100 fM, respectively.

15:30 3698.   A Novel Dual MRI-Fluorescent Contrast Agent to Track T-Cells for In-Vivo Imaging 
Li Liu1, Qing Ye1, Yijen L Wu1, Chih-Lung Chen2, Wen-Yuan Hsieh2, Hsin-Hsin Shen2, T. Kevin Hitchens1, Brent Barbe1, Haosen Zhang1, Shian-Jy Wang2, and Chien Ho1
1Pittsburgh NMR Center for Biomedical Research, Carnegie Mellon University, Pittsburgh, PA, United States, 2Material and Chemical Research Laboratory, Industrial Technology Research Institute, Hsinchu, Taiwan

In this study, we develop a novel dual MRI-fluorescent contrast agent, which is a cationic nano-sized superparamagnetic iron oxide particle coated with polyethylene glycol, with high transverse relaxivity (around 250 s-1mM-1) and T-cell labeling efficiency (over 90%). Labeling of T-cells with ITRI-IOPC-NH2 does not perturbing T-cell functions. After i.v. injection of ITRI-IOPC-NH2–labled-T-cells, localized hypointensity can be detected at the rejecting heart of a rodent transplantation model by in-vivo MRI and ex-vivo MRM.

Tuesday May 10th
  13:30 - 15:30 Computer 61

13:30 3699.   Simultaneous T1 and MR temperature monitoring in case of release of gadoteridol from thermosensitive liposomes during HIFU session 
Marc Derieppe1, Matthieu Lepetit-Coiffé1, Mariska De Smet2, Silke Hey1, Yasmina Berber1, and Chrit Moonen1
1Laboratory for Molecular and Functional Imaging, UMR 5231 CNRS / University Bordeaux 2, Bordeaux, France, 2Department of Biomedical NMR, Eindhoven University of Technology, Eindhoven, Netherlands
The characterization of the spatial and temporal biodistribution of drugs is of special interest to optimize in vivo local drug delivery. This study proposes the near real-time monitoring by simultaneous T1 mapping and MR thermometry (Look-Locker sequence) of the release induced by HIFU of Gd-HPDO3A encapsulated in thermo-sensitive liposomes in a gel of polyacrylamide. This gel was enriched with Silica to ensure acoustic compatibility. A local decrease of T1 at the focal point was observed, whereas the dynamic T1 map showed no decrease.

14:00 3700.   A Dysprosium-based PARACEST Agent for in-vivo Temperature MRI: Dy3+-DOTAM-Gly-Lys 
Alex Xuexin Li1, Mojmir Suchy1,2, Joseph S. Gati1, Robert H.E. Hudson2, Ravi S. Menon1,3, and Robert Bartha1,3
1Robarts Research Institute, The University of Western Ontario, London, ON, Canada, 2Department of Chemistry, The University of Western Ontario, London, ON, Canada,3Department of Medical Biophysics, The University of Western Ontario, London, ON, Canada

A Dy3+-DOTAM-Gly-Lys PARACEST contrast agent with a bound water chemical shift (~ -670 ppm) well beyond the endogenous magnetization transfer (MT) window was used for temperature mapping. The endogenous MT effect did not decrease the CEST sensitivity of bound water, and an accurate and precise temperature image was generated from this compound in solution and bovine serum albumin. This compound may be effective for temperature mapping with a temperature sensitivity 20 times larger than that for europium-based agents.

14:30 3701.   Monitoring of Iron-PLLA Particle Loaded MSCs after Intramuscular Injection in the Rat Model @ 3T 
Volker Rasche1, Natalie Fekete2, Axel Bornstedt1, Jian Zhu3, Ina Vernikouskaya3, Martin Urban4, Katharina Landfester4, Gerlinde Schmidtke-Schrezenmeier2, and Hubert Schrezenmeier2
1Internal Medicine II, University Hospital Ulm, Ulm, Germany, 2Institute for Transfusion Medicine, University Hospital Ulm, 3Internal Medicine II, University Hospital Ulm,4Max-Planck-Institute for Polymer Research

Recently the use of Poly-L-Lactic Acid (PLLA) iron loaded nanoparticles for MSC labeling was suggested. These particles were tested for in vivo monitoring of MSC trafficking in rats. The MSCs could be followed over 9 days in vivo with high sensitivitiy.

15:00 3702.   Novel hydroxytryptophan-based Gd chelating substrate for imaging myeloperoxidase activity. 
Alexei A Bogdanov1, Yang Xie2, and Mohammed S Shazeeb2
1Radiology, UMASS Medical School, Worcester, MA, United States, 2UMASS Medical School

Myeloperoxidase (MPO) is one of the imaging targets that has clear outcome- predictive value in myocardial infarction and stroke. We previously synthesized and tested several paramagnetic complexes of mono- and bis- amides of macrocyclic and linear chelates that “sense” MPO activity. We report a novel paramagnetic reducing substrate of MPO resulting in enzyme-mediated increase of Gd relaxivity. Bis-HTrp-DTPA(Gd) has high water solubility and undergoes MPO-specific conversion into protein - reactive intermediates. We anticipate it to be an efficient sensor for in vivo imaging of MPO activity due to potential binding to tissue proteins in inflammatory lesions

Wednesday May 11th
  13:30 - 15:00 Computer 61

13:30 3703.   In vivo labelling of xenografted B16 melanoma cells with a thiol-responsive Gd(III) based MRI contrast agent 
Eliana Gianolio1, Valeria Menchise2, Giuseppe Digilio3, Evelina Cittadino4, Carla Carrera4, Valeria Catanzaro4, and Silvio Aime4
1Università di Torino, Torino, Italy, 2CNR - IBB, Italy, 3Università del Piemonte Orientale, Italy, 4Università di Torino, Italy

Mammalian cells display a large number of reactive protein thiols on the extracellular side of the plasma membrane (Exofacial Protein Thiols, EPTs). These EPTs are quite reactive and can be chemically labeled by suitably designed MRI contrast agents. Compound Gd-DO3A-PDP can efficiently label B16 melanoma cells both ex vitro and in vivo (xenografted tumor) as a function of the levels of EPTs shown by cells.

14:00 3704.   Synthesis and characterization of D-glucuronic acid coated dysprosium oxide nanoparticles for magnetic resonance imaging (MRI) contrast agent 
Krishna Kattel1, Ja Young Young Park1, Wenlong Xu1, Eun Jung Lee1, Han Gyeol Kim1, and Gang Ho Lee*2
1Department of Chemistry, Kyungpook National University, Daegu, Gyeongsangbuk-do, Korea, Republic of, 2Department of Chemistry, Kyungpook National University, Daegu, Gyeongsangbuk-do

We developed a simple one-step synthesis of D-Glucuronic acid surface-modified ultra small Dy2O3 nanoparticles. It is characterized by using MP-XRD ,TEM, FT-IR spectrophotometer,TGA,SQUID magnetometer and Magnetic Resonance Imaging(MRI) instrument. The resulting data suggest that ligand-coated ultra-small Dy2O3 nanoparticles will be extremely valuable for target specific biomedical applications such as MRI contrast agents.

14:30 3705.   Water-soluble MnO nanocolloid for a molecular T1 MR imaging: A facile one-pot synthesis, in vivo T1 MR images, and account for relaxivities 
Eun Jung Lee1, Ja Young Park1, Wenlong Xu1, Krishna Kattel1, Han Gyeol Kim1, and Gang Ho Lee1
1Department of Chemistry, Kyungpook National University, Daegu, Gyeongsangbuk-do, Korea, Republic of

A facile one-pot synthesis of a water-soluble MnO nanocolloid (i.e., D-glucuronic acid-coated MnO nanoparticle) is presented. The MnO nanocolloid showed a high longitudinal water proton relaxivity of r1 = 7.02 s-1 mM-1 with the r2/r1 ratio of 6.83 due to five unpaired S-state electrons of Mn(II) ion (S = 5/2) as well as a high surface to volume ratio of the MnO nanoparticle. High contrast in vivo T1 MR images were obtained for various organs, showing the capability of the MnO nanocolloid as a sensitive T1 MRI contrast agent.

Electronic Posters : Molecular Imaging
Click on to view the abstract pdf and click on to view the video presentation.
Cell Tracking & Gene Responders

Monday May 9th
Exhibition Hall  14:00 - 16:00 Computer 62

14:00 3706.   In vivo quantification of particle based and gene based MRI reporters in the rodent brain 
Janaki Raman Rangarajan1, Greetje Vande Velde2, Caroline Guglielmetti3, Ruth Vreys3, Marleen Verhoye3, Tom Dresselaers2, Annemie Van Der Linden3, Uwe Himmelreich2, and Frederik Maes1
1Medical Image Computing - ESAT/PSI, K.U. Leuven, Leuven, Belgium, 2Biomedical NMR unit, K.U. Leuven, Belgium, 3Bio-Imaging Lab, University of Antwerp, Belgium

Iron-oxide based particles or MRI reporter genes (e.g. ferritin) can be used for labeling and visualization of endogenous stem cells in the rodent brain. While the quantification of hypo-intense contrast induced by these MRI reporters using parametric T2-maps is often constrained by their low resolution and are sensitive to B1 inhomogeneity, we have developed an image analysis pipeline for regional quantification from 3D T2*-weighted MRI. We demonstrate its potential for in vivo assessment of both iron-oxide particle based and gene based MRI reporters, which creates new opportunities for large scale in vivo imaging studies, including longitudinal follow-up within the same animal.

14:30 3707.   Gadolinium-catalyzed single walled carbon nanotubes as advanced magnetic resonance imaging contrast agents: cell labeling and biodistribution studies 
Pramod Kumar Avti1, Henry Bryant2, Youssef Zaim Wadghiri3, Joseph Frank2, Kenneth Shroyer4, and Balaji Sitharaman5
1Biomedical Engineering, Stony Brook University, Stony Brook, New York, United States, 2Frank Laboratory, Radiology and Imaging Sciences, National Institutes of Health, Bethesda, MD 20892, United States, 3Radiology, New York University, Langone Medical Center, New York, New York 10016, United States, 4Pathology, Stony Brook University Medical Center, Stony Brook, New York 11794-8691, United States, 5Biomedical Engineering, Stony Brook University Medical Center, Stony Brook, New York 11794-5281, United States
We report the in vitro cell labeling and in vivo biological response of novel water-solubilized gadolinium-catalyzed single-walled carbon nanotubes (Gd-SWCNTs). The Gd-SWCNT show 25-fold greater relaxivities (at 1.5 T, r1 (Gd-SWCNT) = 126 mM-1s-1 vs. r1(Magnevist) = 4.5 mM-1s-1, [Gd3+] = 0.2 mM), and are uptaken by NIH 3T3 cells at Gd-SWCNT concentrations upto 25 ìg/ml without inducing cytotoxicity. Intravenous injection of the Gd-SWCNT into rats (dosage = 0.5 mg/kg) reveal distribution into various organs with no signs of inflammation or tissue architectural damage. In conclusion, Gd-SWCNTs show potential for future development as magnetic labels for cellular MRI.lower case Greek mu

15:00 3708.   Small and ultra-small nanoparticles of manganese oxide (SPMnO, USPMnO) for positive contrast in cellular MRI 
Marc-André Fortin1,2, Mélanie Tremblay1, Jean Lagueux2, Mathieu Létourneau1, Luc Faucher1, and Dario Rojas1
1Engineering Materials, Université Laval, Québec, Québec, Canada, 2Axe métabolisme, santé vasculaire et rénale, Centre hospitalier universitaire de Québec (CHUQ), Québec, Québec, Canada

Ultra-small MnO nanocrystals were used to label cancer cells. To enhance the ingestion efficiency, the particles were coated with thiol-containing molecules. This strategy also allowed to tune the contrast agent from agglomerates (SPMnO) to individual nanoparticles (USPMnO). For both products, the cell labeling efficiency and MR contrast effect were compared with Mn2+. Labeling cells with (U)SPMnO is efficient, while preserving the viability of cells. Pellets containing as low as 10000 cells were visualized in 1T MRI. The strong positive contrast enhancement effect, normalized to the amount of Mn internalized in the cells, could be preserved over many division cycles.

15:30 3709.   In-vivo monitoring of therapeutic effects on bacterial infection using high-field 19F-MRI 
Volker Sturm1, Tobias Hertlein2, Thomas Christian Basse-Lüsebrink1, Knut Ohlsen2, and Peter Michael Jakob1
1Experimental Physics 5, University of Würzburg, Würzburg, Germany, 2Institute for Molecular Infection Biology, University of Würzburg, Würzburg, Germany

In the last few years, several methods have been developed to non-invasively monitor the time course of bacterial infections. In this context, MRI has proven its potential to image edema and infections by utilization of MR-markers. Perfluorocarbon (PFC) markers internalized by macrophages migrating to the site of inflammation allow background-free inflammation localization. The present study examined PFC markers to evaluate the efficacy of therapeutic measures in time course.

Tuesday May 10th
  13:30 - 15:30 Computer 62

13:30 3710.   Imaging of inflammation in the peripheral nervous system by 19F MRI 
Thomas Christian Basse-Luesebrink1, Gesa Weise2, Carsten Wessig2, Peter Michael Jakob1, and Guido Stoll2
1Experimental Physics 5, University of Wuerzburg, Wuerzburg, Bavaria, Germany, 2Neurology, University of Wuerzburg, Wuerzburg, Bavaria, Germany

Inflammatory cells play an important role in the pathophysiology disorders of the nervous system. Iron oxide-based contrast agents are commonly used to visualize neuroinflammation by magnetic resonance imaging (MRI). Unfortunately, local hemorrhages, blood pool effects and passive diffusion of iron oxide particles through a defective blood-nerve barrier can hamper the information gained. In contrast to iron oxide contrast agents, 19F markers have shown their potential in unambiguous imaging of labeled cells. In the present study, 3D 19F chemical shift imaging (CSI) was applied in- and ex vivo to visualize macrophage infiltration in focal peripheral nerve demyelination using a lysolecithin model.

14:00 3711.   Tracking Metastatic Tumor Cells in Lymphatics in Mice Xenograft Model by MR Imaging 
ting liu1, Haiju Zhou2, Rui Xia1, Jichun Liao1, Hui Wang1, Hua Ai3, Feng Bi2, and Fabao Gao1
1Department of Radiology, West China Hospital£¬Sichuan University, CHENGDU, SICHUAN, China, People's Republic of, 2Department of Oncology, West China Hospital£¬Sichuan University, CHENGDU, SICHUAN, China, People's Republic of, 3National Engineering Research Center for Biomaterials£¬Sichuan University, CHENGDU, SICHUAN, China, People's Republic of

To investigate the mechanism of tumor lymphatic metastases, we inoculated subcutaneously with USPIO labeled and unlabeled LOVO cells in foot pad, groin or axillary area of nude mice, respectively, to develop a model system for tracking metastatic tumor cells in lymphatic system with MR cellular imaging in live mice. MR T2/ T2* weighted image showed the primary tumor growth and the draining lymphatic architecture, as well as the USPIO labeled tumor cells metastasized into regional lymph node at 8 days P.I. And histological finding confirmed MR imaging results and revealed a close relationship between tumor lymphatic metastasis with lymphangiogenesis.

14:30 3712.   Characterization of USPIO nanoparticles for non invasive monitoring of inflammation in tissue engineered tissue vascular graft using in vivo MRI 
Halima Chahboune1,2, Jamie Harrington3, Jason Criscione2, Ragy Ragheb2, Narutoshi Hibino3, Toshiharu Shinoka3, Christopher Breuer Breuer3, and Tarek Fahmy4
1Diagnostic Radiology, Yale University, New HAven, CT, United States, 2Biomedical Engineering, Yale University, New HAven, CT, United States, 3Interdepartmental Program in Vascular Biology and Therapeutic, Yale University, New HAven, CT, United States, 4Biomedical Engineering, Yale University, New HAven, United States

Magnetic Resonance Imaging (MRI) is a non-invasive method potentially well suited for monitoring cells grafts to identify and map the fate of transplanted cells. This study reports the use of ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles to noninvasively monitor and map the fate of labeled macrophages seeded onto a biodegradable scaffold used as venous conduit. The results demonstrate that the seeded cells do not actually become incorporated into the neovessel, but instead are important for inciting an inflammatory remodeling process, through the recruitment of host cells, that is critical for the development of the neovessel.

15:00 3713.   Quantification of Iron Oxide Nanoparticles in Cellular MRI: Assessment of Free vs. Cell-Internalized Fraction 
Olivier M Girard1, Rose Ramirez1, Stephanie McCarty1,2, Elamprakash N Savariar3, and Robert F Mattrey1
1Department of Radiology, University of California, San Diego, CA, United States, 2New York Medical College, Valhalla, NY, United States, 3Department of Pharmacology, University of California, San Diego, CA, United States

Iron oxide nanoparticles (IONPs) are widely used in cellular MRI because of their strong magnetic properties. However quantification of absolute concentration still remains a challenge because relaxivities depend on IONP distribution within a given sample. Recent works on susceptibility mapping have suggested that susceptibility measurements could be used for IONP quantification. Here we study IONP samples that contain a mixture of free- and cell-internalized- IONPs. We investigate multiple MR characteristic parameters (T1, T2, T2* and lower case Greek chi) in order to extract absolute IONP concentration as well as free vs. internalized IONP fractions.

Wednesday May 11th
  13:30 - 14:00 Computer 62

13:30 3714.   Silica-Coated Superparamagnetic Iron oxide Nanoparticles Are More Durable for Labeling Mesenchymal Stem Cells Than Poly(Ethylene Glycol)-Coated Counterparts: Pilot in-vivo Assay Results 
Yi-Xiang Wang1, K C Leung2, T Quercy-Jouvet2, H H Wang3, C P Chak2, S Lin3, D F Wang3, D W Au4, P C Leung5, and K P Fung5
1Department of Imaging and Interventional Radiology, The Chinese University of Hong Kong, Shatin, NT, Hong Kong, 2Center of Novel Functional Molecules, Department of Chemistry, The Chinese University of Hong Kong, Hong Kong, 3Department of Imaging and Interventional Radiology, The Chinese University of Hong Kong, Hong Kong,44Department of Biology and Chemistry, City University of Hong Kong, Kowloon, Hong Kong, 5Institute of Chinese Medicine, The Chinese University of Hong Kong, Hong Kong

Silica has good biocompatility and hydrophilicity. When silica is coated outside the SPIO core, the silica shell may be able to act as a stabilizer, limiting the effect of intracellular enzymes and acids on the core particles. In this study, an attempt was made to compare the transfecting agent-free mesenchymal stem cell (MSCs) labeling using SPIO with different coatings, with a view to study the durability and retainability of these SPIOs in MSCs. The preliminary results in this study suggest silica coating offers better protection to its SPIO core compared with biodegradable PEG coating when the nanomaterials are within MSCs.