Electronic Posters: Cardiovascular

Thursday 13:30-14:00 Computer 39

13:30 3740. Comparison of Techniques for the Measurement of Tissue-Blood Partition Coefficients in Healthy and Infarcted Myocardium

James W. Goldfarb^1,2, Wenguo Zhao<sup>1

1</sup>Saint Francis Hospital, Roslyn, NY, United States; ²Program in Biomedical Engineering, Stony Brook University, Stony Brook, NY, United States

The purpose of this study was to investigate the temporal dynamics a two-compartment tissue-blood partition coefficient and compare it to estimates using a three-compartment model. In 25 individuals with chronic myocardial infarctions, blood Gd-concentration was modeled with a bi-exponential and myocardial tissue Gd-concentration with a three-compartment model. It was found that the measurement of the tissue-blood partition coefficient based on the ratio of T1 relaxation time differences is time dependent.. The measurement of the tissue-blood partition coefficient using a three compartment model yields similar values between infarcted and viable myocardium. T1 relaxation differences are likely due to a third trapping compartment.

Molecular Imaging in Cardiovascular Disease & Cancer

Hall B Monday 14:00-16:00 Computer 40

14:00 3741. A DNA-Targeted Gadolinium Chelate to Selectively Enhance Acutely Injured Myocardium

Shuning Huang¹, Hushan Yuan², Howard Chen³, Guangping Dai¹, Lee Josephson², David E. Sosnovik<sup>1,3

1</sup>Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, United States; ²Center for Translation Nuclear and Molecular Imaging, Massachusetts General Hospital, Charlestown, MA, United States; ³Center for Molecular Imaging Research, Massachusetts General Hospital, Charlestown, MA, United States

Delayed enhancement of gadolinium cannot discriminate acute and chronic injury since both produce similar changes in the pharmacokinetics of small gadolinium chelates, such as Gd-DTPA. Here, we demonstrated that the acute myocardial infarction can be distinguished from both subacute and chronic myocardial injury by utilizing a DNA-targeted gadolinium chelate (Gd-TO).

14:30 3742. 21 Tesla Rat Heart Magnetic Resonance Microimaging by Paramagnetic Anti-Troponin Bound Polyethylene Based Iron-Oxide Nanoparticles and Image Processing

Rakesh Sharma^1,2, Kiran Shetty, <sup>3

1</sup>FAMU-FSU College of Engineering,, CIMAR, National High Magnetic Field Laboratory, Tallahassee, FL, United States; ²Center of Nanomagnetics and Biotechnology, Florida State University & TCC, Tallahassee, FL, United States; ³NHMFL, Florida State University, Tallahassee, FL, United States

The 21T MR microimaging by using first time troponin nanoparticles enhances the visualization of cardiac muscles fiber and offers technical advancement in future. Diffusion weighting offers the fiber tracking and functional analysis. Image processing offers heart probabilistic atlas and maps.

15:00 3743. Optimization of Ultrashort TE Imaging for Angiography and Molecular Imaging of Iron-Oxide Nanoparticles

Ravi Teja Seethamraju¹, Sonia Nielles-Vallespin², Shuning Huang³, David E. Sosnovik<sup>3,4

1</sup>MR R and D, Siemens Medical Solutions, USA Inc., Charlestown, MA, United States; ²Cardiovascular MR, Royal Brompton Hospital, London, United Kingdom; ³Radiology, Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, United States; ⁴Center for Molecular Imaging Research, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States

Iron oxide based USPIOs inherently exhibit T1 shortening apart from their traditional T2 properties. This property is best utilized at ultrashort echo times. We demonstrate how a single UTE sequence can produce both angiographic images as well as molecular quantitation.

15:30 3744. PEGylated Nano-Peaches: A Novel Multimodality Platform for Imaging of Atherosclerosis

Andrei Maiseyeu¹, Georgeta Mihai¹, Marcus A. Badgeley¹, Orlando P. Simonetti¹, Jeffrey A. Deiuliis¹, Chandan K. Sen¹, Sampath Parthasarathy¹, Sanjay Rajagopalan<sup>1

1</sup>Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States

Novel "peach-like" nanoparticle (NP) contrast agents were manufactured, characterized and tested. In-vitro studies showed preferential uptake of NPs by macrophages while in-vivo studies in ApoE-deficient mice revealed protracted signal enhancement of atherosclerotic plaque. Proper design and ease of fabrication of these nanostructures makes them very versatile as either T1 or T2 MRI contrast agents. These NPs loaded with fluorescein or near-infrared emitting quantum dots represent attractive tools for multimodality imaging of atherosclerosis.

Tuesday 13:30-15:30 Computer 40

13:30 3745. 3.0T MRI of Auto-Transplantation of Bone Marrow-Derived Stem-Progenitor Cells: Toward Cell-Based Repair of Injured Arteries

Yanfeng Meng^1,2, Feng Zhang¹, Tiffany Blair¹, Huidong Gu¹, Hongqing Feng¹, Jinnan Wang³, Chun Yuan¹, Zhaoqi Zhang², Bensheng Qiu¹, Xiaoming Yang<sup>1

1</sup>Radiology, University of Washington, Seattle, WA, United States; ²Radiology, Beijing Anzhen Hospital, Beijing, China; ³Clinical Sites Research Program, Philips Research North America, Briarcliff Manor, NY, United States

This study was to validate the feasibility of using clinical 3.0T MRI to monitor the migration of auto-transplanted bone marrow cells (BMC) to the injured arteries of near-human-sized animals. BMCs were extracted endogenously, labeled with Feridex and/or PKH26, and then auto-transplanted back to the same animal. Post-cell transplantation 3.0T T2-MRI showed Feridex-created MR signal voids along the injured iliofemoral artery segments, which were not seen in the control arteries. Histology, including Prussian blue and dextran immunofluorescent staining as well as PKH26 fluorescence, confirmed the MRI findings. This study establishes groundwork for clinical 3.0T MRI of cell-based repair of injured arteries.

14:00 3746. A Multi-Echo Technique for Positive Contrast Detection of SPIO-Labeled Cells at 9.4T

Philip Lee¹, Johannes Riegler², Bingwen Zheng¹, Anthony Price², Mark F. Lythgoe², Xavier Golay<sup>3

1</sup>Singapore Bioimaging Consortium, Biomedical Sciences Institute, Singapore, Singapore; ²Centre for Advanced Biomedical Imaging, University College London, London, United Kingdom; ³Institute of Neurology, University College London, London, United Kingdom

Migration of super-paramagnetic labeled cells critically affects the success of therapeutic cell studies. Detection with T2* weighted MRI is normally implemented. But direct association of signal voids with SPIOs-labeled cells is erroneous, as they could originate from magnetic field inhomogeneities or partial volume effects. This study highlights the use of a multiple-echo ultra-short echo time (MUTE) sequence for positive contrast visualization of injected mononuclear cells. 5x105 and 2.5x105 of MNCs were directly injected into the left myocardium wall at the apex and mid-ventricle respectively and the heart was subsequently excised for MRI. Subtraction between the UTE (TE=0.208ms) and ECHO (TE=2.56ms) images exploited the transverse relaxation effect of iron, generating contrast-to-noise ratio of 19.6 and 22.7 respectively.

14:30 3747. In Vivo SWIFT Imaging of SPIO Labeled Stem Cells Grafted in the Heart

Rong Zhou¹, Djaudat Idiadilitum², Curt Corum², Hualei Zhang¹, Jia Zhong¹, Hui Qiao¹, Steen Moeller², Michael Garwood<sup>2

1</sup>Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States; ²Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States

We demonstrate the first in vivo cardiac image by ECG-gated SWeep Imaging with Fourier Transformation (SWIFT). Myocardium anatomies are well-visualized on 3D SWIFT magnitude images. The positive contrast on SWIFT imaginary image facilitates the detection of SPIO-containing cells while the magnitude image provides anatomical reference without requirement for additional reference image. These data suggest that SWIFT might be an alternative to currently available positive contrast methods, attractive especially in cardiovascular applications.

15:00 3748. High-Resolution MR Angiogenesis Mapping with Integrin-Targeted Ultralow Gadolinium-Manganese Nanocolloids

Dipanjan Pan¹, Anne Schmieder¹, Angana Senpan¹, Shelton D. Caruthers¹, Samuel A. Wickline¹, Gregory M. Lanza<sup>1

1</sup>C-TRAIN and Division of Cardiology, Washington University in St. Louis, Saint Louis, MO, United States

High-resolution MR Angiogenesis Mapping with Integrin-targeted Ultralow Gadolinium-Manganese Nanocolloids

Wednesday 13:30-15:30 Computer 40

13:30 3749. RGD-Functionalized Superparamagnetic Nanoemulsions for Target-Specific Imaging of Tumor Angiogenesis

Lisette Helene Deddens¹, Peter A. Jarzyna², Arjan W. Griffioen³, Zahi A. Fayad², Rick Michiel Dijkhuizen¹, Willem JM Mulder<sup>2

1</sup>Image Sciences Institute, University Medical Center Utrecht, Utrecht, Netherlands; ²Imaging Science Laboratories, Mount Sinai School of Medicine, New York, United States; ³Angiogenesis Laboratory Amsterdam, VU Medical Center, Amsterdam, Netherlands

Nanoemulsions represent an attractive delivery platform for hydrophobic compounds since they improve their bioavailability and make their intravenous administration possible. This abstract demonstrates that the nanoemulsion platform, developed for passive delivery of hydrophobic compounds to tumor tissue, is also very suitable for targeted applications. Data show the applicability of αvβ3-specific RGD nanoemulsions in targeting tumor angiogenesis visualized by MRI, fluorescence microscopy and immunohistochemistry.

14:00 3750. Angiogenesis and Cell Tracking with Iron Oxide-Labeled Tumor Cells: Correlation Between Cell Growth and the Formation of the Tumor Vascular Bed Using High Resolution Magnetic Resonance (MR) Angiography, T1, T2 and T2* Mapping and Histology

Piotr A. Wielopolski¹, Gyula Kotek¹, Sandra van Tiel¹, Gabriela Doeswijk¹, Lejla Alic², Gabriel P. Krestin¹, Bernsen Monique<sup>1

1</sup>Radiology, Erasmus Medical Center, Rotterdam, zuid-holland, Netherlands; ²Informatics and Radiology, Erasmus Medical Center, Rotterdam, zuid-holland, Netherlands

To correlate super paramagnetic iron oxide (SPIO) labeled tumor cell growth and distribution with high resolution magnetic resonance (MR) angiography, T1, T2 and T2* parametric mapping and histology

14:30 3751. Targeted New Peptide Based Nanoparticles Toward High EGFR Expressing Cancer Cells for MRI

Ming-Hung Chen¹, Gin-Chung Liu^2,3, Twei-Shiun Jaw^2,4, Yu-Ting Kuo^2,3, Chiao-Yun Chen^2,3, Yun-Ming Wang<sup>1

1</sup>Department of Biological Science and Technology, National Chiao Tung University, Hsinchu, Taiwan; ²Department of Medical Imaging, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan; ³Department of Radiology,Faculty of Medicine,College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan; ⁴Department of Radiology,Faculty of Medicine,College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan

In this study, the various core sizes of manganese ferrite nanoparticles (MnFe2O4) conjugated with D4 peptide (MnFe2O4-PEG-D4) were synthesized. The high relaxivity MnFe2O4 nanoparticles were obtained by thermal decomposition of Iron acetylacetonate and manganese acetylacetonate in hydrophobic solution at high boiling process. The surface of MnFe2O4 nanoparticles were coated with polyethylene glycol (PEG) and EGFR peptide ligand (D4: Leu-Ala-Arg-Leu-Leu-Thr) to improve their dispersion and ability to target EGFR. The negative signal enhancement of EGFR expressing cancer cells (SKBR-3 and PC-3) were significantly higher than that of low EGFR expressing cells (HEK-293).

15:00 3752. In Vivo Detection of a PARACEST Agent in Mouse Brain Tumors

Alex Xuexin Li¹, Mojmir Suchy², Chunhui Li¹, Claire Poppe¹, Joseph Gati¹, Susan Meakin¹, Robert H.E. Hudson², Ravi S. Menon¹, Robert Bartha<sup>1

1</sup>Robarts Research Institute, London, ON, Canada; ²The University of Western Ontario

A methodology to detect the on-resonance paramagnetic chemical exchange effects (OPARACHEE) of a PARACEST contrast agent: Tm³⁺-DOTAM-Glycine (Gly)-Lysine (Lys) in a mouse brain tumor model was developed. The OPARACHEE effect was isolated from the relaxation effects induced by the PARACEST agent using a control image and an OPARACHEE image. Isolated OPARACHEE contrast (1-3%) was observed in all animals. Immediately after contrast agent injection OPARACHEE contrast was observed and maintained at 1~2% in the hour following injection.

Thursday 13:30-15:30 Computer 40

13:30 3753. A Targeted Nanoglobular Manganese(II) Chelate Conjugate for Magnetic Resonance Cancer Molecular Imaging

Mingqian Tan¹, Eun-Kee Jeong², Zheng-Rong Lu<sup>1

1</sup>Case Western Reserve University, Cleveland, OH, United States; ²University of Utah, Salt Lake City, UT, United States

A peptide targeted nanoglobular Mn(II)-DOTA conjugate was designed and synthesized as MRI contrast agent for cancer molecular imaging. The target specific contrast agent comprised of 2 peptides and 42 Mn(II) chelates on the surface of the G3 nanoglobule with a defined structure. The T1 and T2 relaxivities at room temperature are 3.13 and 8.14 mM-1sec-1 per Mn(II) chelate at 3T, respectively. The targeted nanoglobular contrast agent specifically bound to tumor tissue and resulted in significant tumor contrast enhancement in tumor-bearing mice as compared to a non-targeted control at a dose as low as 0.03 mmol-Mn/kg .

14:00 3754. Multi-Functional Nanocontrast Agents for In Vivo Probing on Non-Small Cell Lung Cancer in MR and Optical Molecular Imaging

Ching-Tang Chen¹, Chia-Hao Su², Yi-Chien Lu¹, Ang Yuan³, Jyh-Horng Chen<sup>1

1</sup>Interdisciplinary MRI/MRS Lab, Department of Electrical Engineering, National Taiwan University, Taipei, Taiwan, Taiwan; ²Center for Translational Research in Biomedical Science, Chang Gung Memorial Hospital, Kaohsiung, Taiwan; ³Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan, Taiwan

Molecular imaging has become an indispensable technology in cancer research and clinical use. The goal of this study is to combine magnetic resonance imaging and optical imaging system with multifunctional contrast agent to detect xenograft non-small cell lung cancer (NSCLC) murine model.

High temperature solution phase reaction led to 8 nm ultrasmall superparamagnetic iron oxide (USPIO, Fe³O⁴), and the CdS-capped CdTe_xSe_1-x alloyed quantum dot was synthesized to near-IR emitting nanoparticles. Aqueous iron oxide and near-IR quantum dot nanoparticles were conjugated with anti-epideremal growth factor receptor (EGFR) antibody as the biomedical probe to detect the NSCLC tumor. Variation of T2 relaxation time was obtained from MRI for nano-contrast agent quantification. Prussian blue staining imaging showed different targeting efficiency in A549 and CL1-0 in vitro. T2 and T2* MR imaging showed significant signal decrease (>30%) in vivo. It was proved caused by nano-probe targeting by using both histological cytochemistry staining. Multifunctional nanocontrast agent could hopefully not only serves as cancer detection and treatment but also used to predict disease prognosis in the future.

14:30 3755. The Use of Cellular MRI and Magnetic Particles to Study Cancer Stem Cells

Emeline Julie Ribot¹, Carmen Simedrea², Patricia McGowan², Ann Chambers², Paula J. Foster<sup>1

1</sup>Imaging Laboratories, Robarts Research Institute, London, Ontario, Canada; ²Medical Biophysics, University of Western Ontario, London, Ontario, Canada

In this abstract, we describe technology developed in our labs for tracking stem-like cancer cells (CSC), in a mouse model of breast cancer metastasis to the brain, using MRI and magnetic particles. A human breast cancer cell line was sorted by flow cytometry into two distinct populations: CD44high/CD24low and CD44low/CD24high, representing the CSC-like and non-CSC cells, respectively. The sorted cell populations can be labeled efficiently and without toxicity with the iron agent MoldayION Rhodamine B. Labeled CSC can be detected in vivo in images of the mouse brain after injection into the left ventricle of the heart in nude mice.

15:00 3756. Development of Cationic Gd(III) Chelate as Potential Tumor-Selective MRI Contrast Agent

Chang-Tong Yang¹, Cai-Xian Yong¹, Chew-Yuan Tuang², Young-Tae Chang², Kai-Hsiang Chuang<sup>1

1</sup>Laboratory of Molecular Imaging, Singapore Bioimaging Consortium, Agency for Science,Technology and Research, Singapore, Singapore; ²Laboratory of Bioimaging Probe Development, Singapore Bioimaging Consortium, Agency for Science,Technology and Research, Singapore, Singapore

We developed a new Gd(III) chelate by conjugating GdDO3A with 2-(diphenylphosphoryl)ethyldiphenylphosphonium cation -- Gd(DO3A-xy-TPEP)+ to form a cationic MRI contrast agent. This contrast agent has been synthesized and characterized in vitro and in vivo. In vitro cell viability showed insignificant cytotoxicity at low [Gd] concentrations up to 0.2 mM. The in vitro T1 relaxivity measured at 7.0 T is about 50% higher than that of clinically used Gd-DTPA and Gd-DOTA. In vivo imaging study in mice demonstrated longer tissue retention especially in the liver. It indicated that Gd(DO3A-xy-TPEP)+ could potentially be used to detect tumor which generally has larger negative mitochondrial transmembrane potential.

Human MRA

Hall B Monday 14:00-16:00 Computer 41

14:00 3757. Clinical Evaluation of Peripheral Vascular Disease Using a Hybrid Approach: Unenhanced Quiescent Interval Single Shot and Low-Dose TWIST MR Angiography

Philip Anthony Hodnett^1,2, Ioannis Kokztzoglou³, Timothy Scanlon, Jeremy Collins⁴, John Sheehan, Eugene Dunkle, James C. Carr, Robert Edelman

¹Northwestern University, Chicago, IL, United States; ²Northshore University Healthcare System, Chicago, IL, United States; ³Northshore University Healthcare System, United States; ⁴Northwestern University, United States

Imtroduction:The purpose of this study was to test the hypothesis that a hybrid technique employing a new unenhanced MRA technique, quiescent interval single shot (QISS) in combination with a low-dose time resolved (TWIST)of the calf provides comparable diagnostic accuracy to the standard hybrid approach using low-dose TWIST of the calf and high-dose stepping table CE-MRA. Materials and Methods:20 prospective patients referred for evaluation of peripheral arterial disease underwent unenhanced and combined low-dose time-resolved (TWIST)evaluation followed by standard hybrid stepping table bolus chase MRA. Results:The combined unenhanced QISS technique and low-dose time resolved (TWIST ) calf study resulted in an overall sensitivity of 97.4%, specificity of 98.3%, a negative predictive value of 98.7% and a positive predictive value of 96.7% using CE-MRA as the reference standard. Cohen kappa analysis for inter-rater indicates almost perfect agreement (©§= 0.86) between the hybrid approach of unenhanced QISS and TWIST and standard hybrid CE-MRA. Conclusion: This hybrid strategy permits a dramatic reduction in contrast agent dosage with no loss of diagnostic accuracy.

14:30 3758. "Does Higher R1 Relaxivity Transfer in Improved Vessel Enhancement of the Run-Off Vasculature?" - Evaluation of Macrocylic Gadolinium Chelates for Peripheral MR-Angiography at 3 T by an Inter-Individual Comparison of Gadobutrol Vs Gadoterate Meglumine, Bo

Ulrike I. Attenberger¹, Matthias Voth², Andre Luckscheiter³, Stefan Haneder¹, Stefan O. Schoenberg⁴, Henrik J. Michaely<sup>1

1</sup>Department of Clinical Radiology and Nuclear Medicine, University Medical Center Manheim, Mannheim, Germany; ²Bayer Schering AG, Berlin, Germany; ³University of Heidelberg, Heidelberg, Germany; ⁴Department of Clinical Radiology and Nuclear Medicine, University Medical Center Manheim , Mannheim, Germany

Since nephrogenic systemic fibrosis (NSF) has been linked to gadolinium-chelate administration in patients with impaired renal function, contrast agent dose and chelate stability have attracted broad attention. Numerous studies have demonstrated linear compounds to be the least stable, whereas the macrocyclic compounds are the most stable. With the approval of gadobutrol, a double concentrated macrocyclic gadolinium chelate became available, characterized by the highest R1-relaxivity among the macrocyclic gadolinium chelates. The aim of this study was to evaluate the enhancement characteristics of gadobutrol and gadoterate meglumine, both injected at a dose level of 0.07 mmol/kg BW, for peripheral MR-angiography.

15:00 3759. Non Contrast MRA of the Renal Artery: Comparison of Respiratory Triggered IFIR and ECG Gated IFIR with Autovoice Guidance for Respiration

Takayuki Masui¹, Motoyuki Katayama¹, Kimihiko Sato¹, Hiroki Ikuma¹, M Sugimura¹, M Ishii¹, Naoyuki Takei², Mitsuharu Miyoshi<sup>2

1</sup>Radiology, Seirei Hamamatsu General Hospital, Hamamatsu, Japan; ²Japan Applied Science Laboratory, GE Healthcare Japan, Hino, Japan

Non-contrast (NC) MRAs including inflow inversion recovery (IFIR) FIESTA have shown promising results for demonstration of the renal arteries but might show irregularity in the most peripheral parts of the renal arteries. The purpose was to evaluate effect of autovoice guiding respiratory cycle with ECG gating (IFIR with autovoice) on the quality of NC MRA for demonstration of renal arteries in comparison with contrast MRA. MRA using IFIR with autovoice could provide best image quality of the peripheral renal arteries when autovoice successfully guided respiration. Contrast MRA might miss the optimal timing for selective visualization of the renal arteries.

15:30 3760. Two-Station Time-Resolved 3D Contrast-Enhanced MRA with Real-Time Station Switching

Casey Peter Johnson¹, Clifton R. Haider¹, Eric A. Borisch¹, Roger C. Grimm¹, Phillip J. Rossman¹, Thomas C. Hulshizer¹, Jake C. Snell¹, James F. Glockner¹, Stephen J. Riederer<sup>1

1</sup>Department of Radiology, Mayo Clinic, Rochester, MN, United States

The purpose of this work was to improve bolus-chase MRA techniques by imaging multiple stations with both high spatial and temporal resolution. A highly-accelerated (14x) CAPR acquisition, previously demonstrated for single-station MRA of the calves, was adapted for this purpose. As part of the implementation, a system was developed to reconstruct the CAPR images in real time and allow for visually-guided station switching. Vasculature of the thighs and calves of volunteers was imaged with 1.0 mm isotropic resolution and frame times as low as 2.5 seconds. High-quality arterial frames were consistently acquired in both stations while avoiding venous contamination.