Electronic poster

Myocardial Function Human & Experimental Studies

Hall B Monday 14:00-16:00 Computer 28

14:00 3552. Free Breathing Navigator Gated Cine Cardiac MR at 3T: Feasibility Study in Patients.

Chika Obele¹, Christopher Sibley², Jatin Matta¹, Roderic I. Pettigrew¹, Ahmed M. Gharib<sup>1

1</sup>Integrative Cardiovascular Imaging Section, The National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States; ²Radiology and Imaging Sciences Department, National Institutes of Health.

We demonstrate the feasibility of obtaining free-breathing cine images utilizing a single respiratory navigator gating technique. This method was made possible by utilizing the high signal-to-noise ratio (SNR) available at 3T to apply parallel imaging methods allowing the acquisition of up to 30 cardiac phases within clinically acceptable imaging time. Compared to traditional breath-holding techniques this methods showed no statistical difference in qualitative and quantitative imaging parameters, thereby, could be used as an alternative for children and patients who are unable to hold their breath.

14:30 3553. Pericardial Fat Overlaying the Left Ventricle: A Better Indicator of Left Ventricular Function

Ning Hua¹, Zhongjing Chen¹, Sherman Bigornia¹, Alkystis Phinikaridou¹, Ye Qiao¹, Caroline Apovian¹, Hernan Jara¹, Frederick Ruberg¹, James Hamilton<sup>1

1</sup>Boston University, Boston, MA, United States

We imaged 40 metabolic syndrome (MetS) subjects as well as 17 healthy controls using MRI to determine if left ventricular (LV) function would be better correlated with LV fat instead of total pericardial fat. We found that in MetS subjects, stroke volume, cardiac output(CO), wall mass, end-diastolic volume and early filling (E) rate were inversely related to LV fat but not RV fat. The total pericardial fat was only correlated with CO and E-rate. This study suggests that LV pericardial fat rather than total pericardial fat might better correlate to LV function, the mechanism of which remains to be defined.

15:00 3554. Real-Time 3D Visualization of the Heart

Joseph Yitan Cheng¹, Juan M. Santos^1,2, John M. Pauly<sup>1

1</sup>Electrical Engineering, Stanford University, Stanford, CA, United States; ²HeartVista, Inc., Los Altos, CA, United States

The lack of proper visual guidance greatly impairs and lengthens cardiac procedures, such as atrial fibrillation therapy. In this work, we present a practical approach for fast data acquisition and 3D visualization. Acquisition is achieved with a fast multi-slice spiral sequence, and the visualization is achieved with a simple tissue segmentation and surface rendering. With the introduced depth perception, we provide real-time visual feedback for better control in interventional cardiac treatment.

15:30 3555. Assessment of Cardiac Remodelling After Myocardial Infarction in Diabetic Mice Using Self-Gated MRI

Kristine Skårdal¹, Natale Rolim¹, Ole Christian Eidheim², Marius Widerøe¹, Ulrik Wisløff¹, Pål Erik Goa³, Marte Thuen<sup>1

1</sup>Department of Circulation and Medical Imaging, Norwegian University of Science and Technology, Trondheim, Norway; ²Department of Laboratory Medicine, Children's and Women's Health, Norwegian University of Science and Technology, Trondheim, Norway; ³Department of Medical Imaging, St. Olavs University Hospital, Trondheim, Norway

Type II diabetic patients suffer from higher susceptibility to develop post myocardial infarction (MI) heart failure. By adapting a self-gated FLASH to a murine model of the diabetic heart, we obtained multiple slices of the left ventricle and assessed changes in cardiac physiology post MI. Diabetic MI mice displayed decreased cardiac contractility and increased end-systolic volume, while non-diabetic MI mice presented increased end-diastolic volume with preserved ejection fraction. These data suggest that imaging of murine hearts is achievable using a self-gated FLASH, and the results are accurate enough to detect differences in functional analysis between genotypes and interventions.

Tuesday 13:30-15:30 Computer 28

13:30 3556. Radial Tagging for Assessment of Circumferential Myocardial Function

Melanie S. Kotys¹, Xiaopeng Zhou², Scott D. Flamm², Randy M. Setser<sup>2

1</sup>MR Clinical Science, Philips Healthcare, Cleveland, OH, United States; ²Imaging Institute, Cleveland Clinic, Cleveland, OH, United States

Myocardial tags applied in radial orientation using selective saturation bands may have distinct advantages over SPAMM methods for routine clinical examinations. We compared radial tagged images with 4-16 tag lines and grid tagged images in five volunteers. Analysis revealed that radial tags persisted longer than grid tags and had a comparable first acquired cardiac phase. There was no significant difference in end systolic strain or rotation and 12 radial tag lines had the least variation in both measures. Application of radial tags appears to be as efficient as SPAMM tagging with the potential for clinical analysis of circumferential myocardial function.

14:00 3557. Investigation of High Fat Diet Effects on Myocardial Trygliceride and Function in Mice

Marzena Wylezinska¹, Jordi L. Tremoleda¹, Jelena Anastasovska², Willy Gsell¹, Jimmy Bell<sup>2

1</sup>Biological Imaging Centre, Imaging Sciences Department, MRC Clinical Sciences Centre, Imperial College, London, United Kingdom; ²Metabolic Imaging Group, MRC Clinical Sciences Centre, Imperial College, London, United Kingdom

The aim was to investigate the effect of high fat diet on myocardial triglyceride and function in preclinical model. Male C57/Bl6 mice were maintained on a high (21%) fat (HF n=6) or a normal (3%) fat diet (C, n=5). Using MRI left ventricular ejection fraction (LVEF) was measured, while localized 1H MRS was used to estimate lipids content in the interventricular septum in animals. Lipid content was significantly increased in HF group, while trend was observed in LVEF decrease in HF group. These preliminary results suggest that high fat diet may have implications on myocardial lipid content and cardiac function.

14:30 3558. In Vivo Cardiac MRI Detects Differential Response to Partial and Complete Akt1 Deficiency

Katrien Vandoorne¹, Inbal E. Biton², Alon Harmelin², Michal Neeman<sup>1

1</sup>Biological Regulation, Weizmann Institute, Rehovot, Israel; ²Veterinary Resources, Weizmann Institute, Rehovot, Israel

The PKB/Akt family of intracellular protein kinases regulates cellular growth, proliferation, survival and metabolism. It is known that Akt1/PKBalpha controls heart size and function. Baseline left ventricular structure and function of Akt1/PKBalpha; null, heterozygote and wild type mice, were assessed using retrospectively reconstructed FLASH cine scans with the aid of navigator scans. Here, we showed in vivo, that LV mass and cardiac output are reduced in knockout animals. This reduction is consistent with the reduced body weight. Surprisingly, cardiac hypertrophy observed here by MRI of heterozygote mice, and noted also previously by ultrasound, was resolved in the full Akt1 knockout.

15:00 3559. Measurement of Changes in Left Ventricular Volume and Strain During Isovolumic Relaxation

June Cheng-Baron¹, Kelvin Chow¹, Ben T. Esch², Jessica M. Scott², Mark J. Haykowsky², John V. Tyberg³, Richard B. Thompson<sup>1

1</sup>Biomedical Engineering, University of Alberta, Edmonton, AB, Canada; ²Physical Therapy, University of Alberta, Edmonton, AB, Canada; ³Cardiac Sciences, University of Calgary, Calgary, AB, Canada

Left ventricular (LV) volume estimated using ventricular dimensions or surface markers have shown increasing volume during isovolumic relaxation, despite closed mitral and aortic valves. The goal of this study is to explain and interpret this volume increase in the context of ventricular relaxation. We measure a 4.6 mL mean increase in LV volume, which is correlated with changes in principle myocardial strains and compensated for by the descent of the mitral leaflets towards the apex. The motion of the leaflets and conformational changes in the LV during isovolumic relaxation likely reflect LV pressure decline and the development of ventricular suction.

Wednesday 13:30-15:30 Computer 28

13:30 3560. Interventricular Synchrony in Chronic Thrombo-Embolic Pulmonary Hypertension Recovers After Endarterectomy

Gert Jan Mauritz¹, J. Tim Marcus¹, Jochem Bosboom¹, Anton Vonk Noordegraaf<sup>1

1</sup>VU University Medical Center, Amsterdam, Netherlands

The aim of this study is to assess whether the Left-Right (L-R) mechanical synchrony in Chronic Thrombo-Embolic Pulmonary Hypertension recovers after pulmonary endarterectomy. Nine patients were included, and underwent MRI myocardial tagging at baseline before, and 1 year after endarterectomy. The L-R delay in peak myocardial circumferential shortening decreased from 95 ± 61 ms at baseline, to 2 ± 47 ms after endarterectomy (p < 0.05). Cardiac output increased from 3.7 ± 0.9 lit/min, to 4.8 ± 0.6 lit/min (p<0.01). The L-R resynchronization and functional RV recovery are in line with reverse RV remodeling after endarterectomy.

14:00 3561. Effect of Physiological Variation of Heart Rate on Quantitative Cardiac T2 Mapping

Marion de Roquefeuil^1,2, Anne Menini^1,2, Jean-Marie Escanyé³, Pierre-Yves Marie³, Jacques Felblinger<sup>1,2

1</sup>U947, INSERM, Vandoeuvre-lès-Nancy, France, France; ²IADI, Nancy-Université, Nancy, France, France; ³Department of Nuclear Medicine, CHU, Nancy, France

Heart Rate (HR) variation is around 30 % during healthy subject breath-holds necessary for cardiac MR acquisition. As MR system is synchronized with R peaks, image contrast depends on HR evolution. Especially, cardiac T2 mapping used in heart transplantations and pathologies follow up is biased by HR variation. We propose a method to compensate this systematic error and to improve diagnostic quality: a RR-adjusted corrective factor applied on SE signal in k-space.

14:30 3562. Cardiac Torsion and Strain in Fatigued Primary Biliary Cirrhosis Patients Investigated by 3T Cardiac Tagging Show Evidence of Accelerated Ageing Processes

Kieren Grant Hollingsworth¹, David Emerys Jones², Roy Taylor¹, Guy A. MacGowan³, Julia Lindsay Newton⁴, Andrew Mark Blamire<sup>1

1</sup>Newcastle Magnetic Resonance Centre, Newcastle University, Newcastle upon Tyne, Tyne and Wear, United Kingdom; ²Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, Tyne and Wear, United Kingdom; ³Cardiology, Freeman Hospital, Newcastle upon Tyne, Tyne and Wear, United Kingdom; ⁴Institute for Ageing and Health, Newcastle University, Newcastle upon Tyne, Tyne and Wear, United Kingdom

Primary biliary cirrhosis (PBC) is an autoimmune liver disease affecting females from middle age. After our previous observation that PBC patients have impaired cardiac energetics compared to matched controls while preserving normal cardiac morphology, the same cohort was studied with cardiac tagging at 3T to assess cardiac torsion and strain. Those PBC patients with severe fatigue were found to have significant increases in myocardial peak torsion and reduction in peak strain which have previously been seen to be typical of healthy ageing. This suggests that cardiac changes in fatigued PBC patients may reflect an accelerated ageing process.

15:00 3563. Magnetic Resonance Imaging (Mri) Characterization of the Functional and Morphological Changes in Heart and Lung After Myocardial Infarction in Mice

Hasan Alsaid¹, Weike Bao¹, Mary V. Rambo¹, Gregory A. Logan¹, David J. Figueroa¹, Stephen C. Lenhard¹, Charles J. Kotzer¹, Mark E. Burgert¹, Beat M. Jucker<sup>1

1</sup>GlaxoSmithKline, 709 Swedeland Rd, King of Prussia, PA, 19406, United States

In this study, MRI was used for the first time to non-invasively and serially assess cardiac dysfunction and lung congestion in a chronic heart failure model, myocardial infarction (MI), in mice. Cardiac and lung MRI were performed at baseline then every three days up to 13 days post-MI. MRI results revealed that MI induced significant pulmonary congestion/edema as detected by increased MRI signal intensity and was associated with increased lung volume and decreased cardiac function. Additionally, significant correlations were observed between lung signal intensity, lung volume, ejection fraction, left ventricular mass and lung wet weight/body weight ratio.

Thursday 13:30-15:30 Computer 28

13:30 3564. MRI of Longitudinal Myocardial Strain Using Multislice Cine DENSE with Through-Plane Displacement Encoding

Xiao Chen¹, Xiaodong Zhong, ^1,2, Frederick H. Epstein<sup>3

1</sup>Biomedical Engineering, University of Virginia, Charlottesville, VA, United States; ²MR R&D Collaboration, Siemens Healthcare, Atlanta, GA, United States; ³Radiology, University of Virginia, Charlottesville, VA, United States

The purpose of the present study was to develop a cine DENSE pulse sequence for quantitative imaging of longitudinal motion, where two adjacent short-axis slices are encoded for through-plane (longitudinal) displacement and are simultaneously acquired. Displacement trajectories measured from the two slices are used to calculate longitudinal strain. By acquiring both slices within a single breathhold, a fixed and consistent distance between the slices is maintained, which enables the accurate calculation of longitudinal strain from the measured longitudinal displacement fields. The sequence and theory were evaluated and demonstrated in normal volunteers.

14:00 3565. Feasibility of CINE Myocardial T₂^* Mapping Using Susceptibility Weighted Gradient-Echo Imaging at 7.0 T

Fabian Hezel¹, Tobias Frauenrath¹, Wolfgang Renz², Jeanette Schulz-Menger^1,3, Thoralf Niendorf<sup>1,3

1</sup>Berlin Ultrahigh Field Facility, Max-Delbrueck Center for Molecular Medicine, Berlin, Germany; ²Siemens Healthcare, Erlangen, Germany; ³Experimental and Clinical Research Center (ECRC), Charité Campus Buch, Humboldt-University, Berlin, Germany

This study is designed to demonstrate the promise of susceptibility weighted 2D CINE FLASH and T2* Mapping of the heart at 7T.

14:30 3566. Longitudinal Functional and Structural Characterization of Inducible Heart Specific SOD2 Knock-Out Mice by Cardiac MRI

Thomas Kaulisch¹, Heiko G. Niessen¹, David Kind¹, Michael Neumaier¹, Julia Tillmanns¹, Lothar Kussmaul², Simon Melov³, Detlef Stiller<sup>1

1</sup>In-Vivo Imaging Unit, Dept. of Drug Discovery Support, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach, BW, Germany; ²Dept. of CNS Diseases Research, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach, BW, Germany; ³Buck Institute for Age Research, Novato, CA, United States

Oxidative stress induced by reactive oxygen species (ROS) plays an important role in heart diseases. Because fatty acid oxidation is carried out in the mitochondria, their dysfunction will have a severe impact on cardiac function. Because ROS are usually reduced by SOD2, a new mouse model (Fsod2H) with inducible knock-down of SOD2 gene was generated. In-vivo imaging was performed from week 32 to 57 of animal age. A significant reduction of heart contractibility and an increase in heart volume were measured for tgSOD2 mice. Overall, MRI allows for longitudinal quantitative assessment of functional and structural changes in the mouse heart.

15:00 3567. Quantitative Assessment of Left Ventricular Function Using Cardiac Phase-Contrast and Cine Magnetic Resonance Imaging Comparison with Pressure-Volume Loops Analysis: In Vivo Validation on a Swine Model

Hung-Yu Lin¹, Fei Wang², Waiel Almoustadi³, Bo Xiang², Trevor Lee³, Rakesh Arora³, Scott B. King², Boguslaw Tomanek², Darren Freed³, Ganghong Tian<sup>2

1</sup>Institute for Biodiagnostics, National Research Council of Canada, Winnipeg, Manitoba, Canada; ²Institute for Biodiagnostics, National Research Coincil of Canada; ³Saint Boniface General Hospital, Winnipeg, Manitoba, Canada

Noninvasive PC-MRI and cine MRI have been recognized as a valuable and accurate technique to evaluate hemodynamics and heart function. Previous clinical studies suggest that evaluation of the passive relaxation properties serves as a useful indicator of quantitative contractility and function without the influence of relative ventricular load. To our knowledge, the correlation of LV function obtained from noninvasive PC-MRI, cine MRI and invasive P-V loops relation has not been investigated and reported. The aim of the present study was to determine the validity of PC-MRI, cine MRI in the assessment of LV function comparing with dynamic P-V loops analysis.

Myocardial Function: Experimental & Human Studies I

Hall B Monday 14:00-16:00 Computer 29

14:00 3568. Transplantation of Murine Embryonic Stem Cell-Derived Cardiomyocytes Improves Cardiac Function in the Infarcted Heart

HuaLei Zhang¹, Hui Qiao¹, Nataliya Petrenko², Vickas Patel², Bin Huang³, Kenneth Boheler⁴, Victor Ferrari², Rong Zhou<sup>1

1</sup>Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States; ²Dept of Medicine(cardiovascular), University of Pennsylvania; ³Department of Radiology, University of Pennsylvania, PA; ⁴National Institute of Aging, NIH

Highly enriched embryonic stem cell derived cardiomyocytes (ESC-CMs) were obtained in large numbers for in vivo study that examined the potential of these cells in the treatment of myocardial infarction. Our data suggest that ESC-CM mediated a teratoma free myocardial repair with significant recovery of regional and global contractile function over the period of 2 months.

14:30 3569. Detecting Real-Time Regional Myocardium Strain Changes Using Fast Strain-Encoded (FSENC) MRI

Ahmed Amr Harouni¹, Tamer A. Basha¹, Monda L. Shehata², Nael Fakhry Osman<sup>1,2

1</sup>Electrical and computer Engineering, Johns Hopkins University, Baltimore, MD, United States; ²Department of Radiology, Johns Hopkins University, Baltimore, MD, United States

Many techniques have been proposed for real-time interactive cardiac MR imaging. However, most of these techniques are limited to only the anatomical information. In this work, we propose to use fast strain-Encoded functional imaging technique to acquire real-time images then use a fully automated segmentation algorithm to provide online anatomical and functional information of regional myocardial regions. This can be useful in real-time monitoring of cardiac strain changes during either stress test, valsalva exercise or interventional operations.

15:00 3570. Cine DENSE MRI with Dual Displacement Encoding

Xiao Chen¹, Alistair Young², Frederick H. Epstein, <sup>1,3

1</sup>Biomedical Engineering, University of Virginia, Charlottesville, VA, United States; ²Anatomy with Radiology, University of Auckland, Auckland, New Zealand; ³Radiology, University of Virginia, Charlottesville, VA, United States

The purpose of the present study was to develop a cine DENSE sequence with dual displacement encoding, where two distinct stimulated echoes with different displacement-encoding frequencies are simultaneously stored along the longitudinal axis, and where either can be recalled at any particular time to to better accommodate a temporal sequence of images with different amounts of displacement and deformation at different times. The sequence was implemented on a 1.5T scanner and was evaluated and demonstrated by using a deformable phantom and by imaging the hearts of normal volunteers.

15:30 3571. MRI Characterization of Cardiac Tissue Scaffold Materials in Vitro and in Vivo

Daniel James Stuckey¹, Hikaru Ishii², Aldo R. Boccaccini², Carolyn A. Carr¹, Judith A. Roether², Qi Zhi Chen², Hedeer Jawad², Damian J. Tyler¹, Nadire N. Ali², Kieran Clarke¹, Sian E. Harding<sup>2

1</sup>Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, Oxon, United Kingdom; ²National Heart and Lung Institute, Imperial College, London, United Kingdom

MRI was used to test three different scaffold materials designed for myocardial tissue engineering. Scaffold location, degradation and effect on cardiac function were measured in vivo at 1 and 6 weeks after grafting of scaffold onto infarcted rat hearts. The rigid TiO₂-PED scaffold induced microvascular occlusion and necrosis adjacent to the scaffold, resulting in reduced cardiac function by six weeks. The PGS scaffold was not detrimental to function, but MRI showed that the material degraded between 1 and 6 weeks in vivo. This study demonstrates the feasibility and importance of using MRI to optimise myocardial tissue engineering strategies.