ISMRM 21st Annual Meeting & Exhibition 20-26 April 2013 Salt Lake City, Utah, USA

ELECTRONIC POSTER SESSION • CARDIOVASCULAR
4434 -4457 Flow Quantification
4458 -4481 MRA
4482 -4504 Cardiac Function & Diffusion
4505 -4527 Myocardial Tissue Characterisation
4528 -4545 Vessel Wall & Coronary Angiography
4546 -4551 Cardiovascular MAI Education
4552 -4575 CV Imaging Technology & Methodology

ELECTRONIC POSTER SESSION • CARDIOVASCULAR
Thursday, 25 April 2013 (13:30-14:30) Exhibition Hall
Flow Quantification

  Computer #  
4434.   1 Flow-Encode Only Phase Contrast Magnetic Resonance Imaging
Erik J. Offerman1, Christopher B. Glielmi2, Michael Markl3, Ioannis Koktzoglou1,4, and Robert R. Edelman1,3
1Radiology, NorthShore University HealthSystem, Evanston, IL, United States, 2Siemens Healthcare, Chicago, IL, United States, 3Radiology, Feinberg School of Medicine, Northwestern Univeresity, Chicago, IL, United States, 4Radiology, Pritzker School of Medicine, University of Chicago, Chicago, IL, United States

 
Flow-encode only (FEO) is a new time-resolved phase contrast (PC) method that benefits from a doubled time resolution over the traditional PC method, and does not require background phase correction. FEO quantifies blood-flow velocity by performing only flow-encoded acquisitions. FEO was compared to the traditional PC method in ten volunteers and two patients with peripheral artery disease. Flow measurements were compared between methods with flow profiles, linear correlation, and Bland-Altman analysis. Net flow, peak flow, reverse flow, and average flow metrics were compared as well. Blood-flow measurements showed no statistically significant difference between methods (paired t-test, p > 0.05).

 
4435.   2 4D MRI Flow Analysis in an In-Vitro System Modelling Continuous Left Ventricular Support: Effect of Cannula Position in the Thoracic Aorta
Christoph Benk1, Alexander Mauch1, Friedhelm Beyersdorf1, Rolf Klemm1, Jan G. Korvink2, Michael Markl3, and Bernd A. Jung4
1Dept. of Cardiovascular Surgery, University Medical Center, Freiburg, Germany, 2IMTEK – Department of Microsystems Engineering, Laboratory for Simulation, Albert-Ludwigs University, Freiburg, Germany, 3Dept. of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States, 4Dept. of Radiology, Medical Physics, University Medical Center, Freiburg, Germany

 
Left ventricular assist devices (LVAD) has become an important treatment option for heart failure patients. However, altered blood flow patterns are suspected to affect perfusion in the aorta or cause structural changes leading to valve dysfunction or thrombus formation. An MR-compatible model system was developed consisting of an aorta connected to a LVAD simulating the pulsatile flow of the native heart. An LVAD was connected to the aorta model using different cannula positions and flow patterns were evaluated in predefined positions. The results indicate that the cannula position strongly influence flow patterns and flow rates in the aorta.

 
4436.   3 Analysis of Gradient Spoiling in Phase Contrast MRI
Yunpeng Zou1,2, Matthew J. Middione3,4, Subashini Srinivasan3, and Daniel B. Ennis1,5
1Department of Bioengineering, University of California, Los Angeles, CA, United States, 2Sino-Dutch Biomedical and Information Engineering School, Northeastern University, Shenyang, China, 3Department of Radiological Sciences, University of California, Los Angeles, CA, United States, 4Biomedical Physics Interdepartmental Program, University of California, Los Angeles, CA, United States, 5Department of Radiological Sciences, University of California Los Angeles, Los Angeles, CA, United States

 
PC-MRI experiments are typically performed using spoiled gradient recalled echo (GRE) experiments in which incremental RF phase cycling and a dephasing gradient are used to eliminate any residual transverse magnetization prior to the application of the subsequent RF pulse. The effect of gradient spoiling on artifact suppression in GRE magnitude images has been studied in detail, but an analysis of gradient spoiling in phase contrast MRI (PC-MRI) phase images has not been described. The objective was to define time-optimal gradient spoiling for GRE-based PC-MRI to reduce the TR and improve temporal resolution.

 
4437.   4 Hemodynamic Forces in the Progression of Intracranial Aneurysm Change as Assessed Using MR-Based Methods
David A. Saloner1, Evan Kao2, Gabriel Acevedo-Bolton2, Andrew Lee2, Petter Dyverfeldt2, and Vitaliy L. Rayz2
1Radiology and Biomedical Imaging, VA/UCSF, San Francisco, CA, United States, 2Radiology and Biomedical Imaging, UCSF, San Francisco, CA, United States

 
MR methods can be used to assess changes in aneurysm morphology over time. In addition vascular geometry and inlet flow conditions that are needed for Computational Fluid Dynamics can be determined using MRA and MR velocimetry. These methods were used in the evaluation of 78 aneurysms that were followed over time. CFD predictions indicate that there is an increased rate of growth in aneurysms where a large fraction of the aneurysm surface is exposed to low wall shear stress.

 
4438.   5 Reproducibility of Flow Measurements in Serial Studies of Patients with Untreated Aneurysms
Gabriel Acevedo-Bolton1, Andrew Lee1, Vitaliy L. Rayz1, Alastair Martin1, and David A. Saloner2
1Radiology and Biomedical Imaging, UCSF, San Francisco, CA, United States, 2Radiology and Biomedical Imaging, VAMC/UCSF, San Francisco, CA, United States

 
MR velocimetry reproducibility was mesured in a cohort of 88 subjects with untreated aneurysms that were evaluated repeatedly over periods of time as long as 7 years. Reproducibility was also measured in exact replicas of the complex geometries of a subset of these subjects. Good agreement was found between experimental and computational flow measurements. In vivo studies were found to be reproducible with an error of measurement of 10%.

 
4439.   6 A Novel Approach to Phase-Contrast Velocity Offset Correction by in-vivo High-SNR Acquisitions
Merlin Fair1, Peter David Gatehouse1, Peter Drivas1, and David N. Firmin1
1Royal Brompton Hospital, London, UK, United Kingdom

 
A modified phase-contrast method gave increased SNR for static tissue for baseline velocity offset correction, using one extra breath-hold after each flow study. In 18 flow studies, this improved accuracy in offset corrections using higher order fits, but gave no significant improvement over the standard linear correction of background offsets.

 
4440.   7 Real-Time, Free-Breathing Measurement of In-Plane Velocities: A Comparison with ECG-Triggered, Segmented, Breath-Hold Acquisition.
Ning Jin1, Juliana Serafim da Silveira2, and Orlando P. Simonetti2,3
1Siemens Healthcare, Columbus, Ohio, United States, 2Department of Radiology, Ohio State University, Columbus, Ohio, United States, 3Department of Internal Medicine, Ohio State University, Columbus, Ohio, United States

 
Velocity measurement based on ECG-triggered, segmented phase-contrast imaging (PC-MRI) is a valuable and accurate technique to assess hemodynamics in a variety of clinical applications. However, this method requires reliable cardiac gating, regular cardiac rhythm, and some means to suppress respiratory motion artifacts. Real-time PC-MRI (RT-PCMRI) overcomes these limitations and can measure hemodynamic variations across cardiac cycles. While the accuracy and utility of through-plane RT-PCMRI has been previously demonstrated, in this study we describe a technique for real-time measurement of in-plane velocities and demonstrate the equivalence of real-time in-plane peak velocity measurements with results obtained using conventional, ECG-triggered, segmented k-space PC-MRI.

 
4441.   8 Real-Time Cardiovascular Phase-Contrast Flow MRI During Valsalva Maneuver
Arun Antony Joseph1, Jan Sohns2, Johannes Kowallick2, Klaus-Dietmar Merboldt1, Joachim Lotz2, and Jens Frahm1
1Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, Göttingen, Niedersachsen, Germany, 2University Medical Center Georg-August-University, Göttingen, Niedersachsen, Germany

 
Real-time PC imaging with highly undersampled FLASH and regularized nonlinear inversion reconstruction was used for imaging Valsalva maneuver. High temporal resolution of 40 ms per phase contrast map aid in visualizing and analyzing the dynamic changes to flow parameters during the Valsalva maneuver. Variations of flow parameters in ascending aorta for through plane flow at preparation, maneuver and rest phases were analyzed.

 
4442.   9 Respiratory-Resolved Flow Effects in the Chest Assessed with Double-Gated 4D Flow MRI
Eric Mathew Schrauben1, Ashley Anderson2, Kevin M. Johnson1, and Oliver Wieben1,3
1Medical Physics, University of Wisconsin - Madison, Madison, Wisconsin, United States, 2Medical Physics, University of Wisconsin - Madison, Madison, WI, United States,3Radiology, University of Wisconsin - Madison, Madison, WI, United States

 
Many strategies are employed to compensate for respiratory motion in PC MR exams, yet its effects on blood flow are often neglected. This study demonstrates the feasibility of a 4D radially-undersampled respiratory resolved acquisition and reconstruction for the characterization of respiratory induced blood flow changes in the great vessels.

 
4443.   10 Improved Visualization and Quantification of 4D Flow MRI Data Using Divergence-Free Wavelet Denoising
Frank Ong1, Martin Uecker1, Umar Tariq2, Albert Hsiao2, Marcus T. Alley2, Shreyas S. Vasanawala2, and Michael Lustig1
1University of California, Berkeley, Berkeley, CA, United States, 2Stanford University, Palo Alto, CA, United States

 
A novel noise reduction processing for 4D flow MRI data using divergence-free wavelet transform is presented. Divergence-free wavelets have the advantage of enforcing soft divergence-free conditions when discretization and partial voluming result in numerical non-divergence-free components and at the same time, provide sparse representation of flow in a generally divergence-free field. Efficient denoising is achieved by appropriate shrinkage of divergence-free and non-divergence-free wavelet coefficients. To verify its performance, the proposed processing was applied on in vivo data sets and was demonstrated to improve visualization of flow data without distorting quantifications.

 
4444.   11 Sparse Sampling Phase Contrast Imaging of the Aorta
Zhiyue J. Wang1,2, Jonathan M. Chia3, David M. Higgins4, Youngseob Seo2,5, and Nancy K. Rollins1,2
1Childrens Medical Center, Dallas, Texas, United States, 2Univeristy of Texas Southwestern, Dallas, Texas, United States, 3Philips Healthcare, Cleveland, OH, United States, 4Philips Healthcare, Guildford, Surrey, United Kingdom, 5Division of Convergence Technology, Korea Research Institute of Standards and Science, Daejeon, Korea

 
This work looks at the feasibility of performing sparse sampling in high resolution phase contrast imaging using a unique subtraction reconstruction algorithm. Images were sparsely sampled at 45, 36, and 30% and compared against a fully sampled image through region of interest analysis. Under sampled data showed slight underestimation of quantitative values while still maintaining an accurate flow curve behavior. Physiologic fluctuations and the intrinsic nature of under sampling, most likely, lead to this discrepancy. Sparse sampling techniques have been shown to be very promising in achieving accurate quantitative data while reducing scan times significantly.

 
4445.   12 A Fast Reduced TE 4D Spiral PC MRI Sequence for Assessment of Flow and Hemodynamics
Mo Kadbi1, M.J. Negahdar1, Melanie S. Traughber2, Peter Martin2, and Amir A. Amini1
1Elect. and Comp. Eng., University of Louisville, Louisville, KY, United States, 2Philips healthcare, Cleveland, OH, United States

 
A 4-D flow MRI has been investigated to quantify carotid artery hemodynamics and to visualize the temoral motion of fluid particles in detail . In addition to comprehensive anatomical and flow information in both in-plane and through-plane directions, 4D flow imaging results in shorter total scan time compared to 3-D flow imaging Conventional 4D PC-MRI based on the Cartesian trajectory results in a very long scan. Herein, a 4D spiral PC MRI technique was designed to reduce the scan time compared to conventional technique. 4D spiral PC MRI has the added advantage of reducing the phase error and signal loss due to long TE.

 
4446.   13 4D Flow Measurements in the Superior Cerebellar Artery at 7 Tesla: Feasibility and Potential for Applications in Patients with Trigeminal Neuralgia
Sebastian Schmitter1, Bharathi D. Jagadeesan2, Andrew W. Grande3, Julien Sein1, Kamil Ugurbil1, and Pierre-Francois Van de Moortele1
1Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States, 2Departments of Radiology and Neurosurgery, University of Minnesota, Minneapolis, MN, United States, 3Departments of Radiology, Neurosurgery and Neurology, University of Minnesota, Minneapolis, MN, United States

 
Trigeminal Neuralgia is characterized by episodic severe facial pain possibly from “pulsatile” compression of the nerve Root Entry Zone of the Trigeminal Nerve (REZ) by the adjacent superior cerebellar artery (SCA). The exact role of pulsatility of SCA loops in the etiology of TN remains unknown since similar anatomical proximity of SCA and REZ can be found in normal individuals and there are no methods to measure the pulsatility of the SCA currently available. Herein we report the feasibility of measuring the Pulsatility Index (PI) of the SCA using 4D MRA in a normal volunteer at 7 Tesla.

 
4447.   14 4D MR Pressure Difference Mapping: Comparison with Echocardiography and Invasive Catheter Measurements
Jelena Bock1, Julia Geiger1, Raoul Arnold2, Daniel Hirtler1, Hans Burkhardt1, and Michael Markl3
1University of Freiburg, Freiburg, Germany, 2University of Heidelberg, Heidelberg, Germany, 3Northwestern University, Chicago, IL, United States

 
Pressure gradients are an important clinical marker for the severity of cardiovascular disease such as aortic valve stenosis or aortic coarctation. It was the aim of this study to evaluate the potential of an optimized data analysis strategy based on 4D flow MRI for the assessment of aortic 3D pressure difference maps compared to the gold standard invasive catheter measurements in patients with aortic coarctation. Differences between MRI, echocardiography and catheter measurements demonstrate the potential of MRI to non-invasively determine pressure gradients in aortic coarctation and indicate the importance of dynamic aortic boundary conditions for accurate pressure difference estimation.

 
4448.   15 Hemodynamic Outcome in Patients After Bicuspid and Tricuspid Valve Sparing Aortic Root Repair: A 4D Flow MRI Study
Edouard Michel Semaan1, Michael Markl1, Bradley D. Allen1, Alex Baker1, Chris Malaisrie2, Patrick McCarthy3, James C. Carr4, and Jeremy D. Collins4
1Radiology Department, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States, 2Surgery Department, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States, 3Surgery-Cardiac Surgery Department, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States,4Radiology Department, Northwestern University, Chicago, Illinois, United States

 
This study evaluates the impact of aortic root repair on aortic hemodynamic flow in subjects with bicuspid and tricuspid aortic valve morphology without stenosis or significant insufficiency using 4D flow MRI. Aortic root repair results in a more homogeneous flow profile, reduced helical flow patterns, and resolution of forward flow jets impacting the aortic wall compared to control subjects matched with pre-surgical thoracic aortic aneurysm size, age, and aortic valve morphology. These changes occur at the expense of increased peak systolic velocities and regurgitation; the long-term impact of these changes on vascular physiology is unknown.

 
4449.   16 Stress-Strain Characterization of a Dynamically-Controlled Cardiac Phantom with Fluid and Structural Dynamics
Nicolas Charalambous1, Kristis Michaelides1, Elias Psimolofitis2, Vasilis Tzangarakis3, Demos Michaelides3, Stelios Angeli4, and Christakis Constantinides4
1Hydrus Ltd, Limassol, Cyprus, 2CNE Limited, Nicosia, Cyprus, 3α-Evresis Diagnostic Center, Nicosia, Cyprus, 4U. of Cyprus, Nicosia, Cyprus

 
Myocardial tissue characterization, pre- and post-implantation or following therapy, has becoming an elusive and active research area in clinical practice and basic science work. Prior efforts have focused on the invasive [Stuyvers 1997] and non-invasive MRI characterization of the left ventricular (LV) muscle elasticity [Kolinpaka 2010] to document energetic status, rates and extent of filling and relaxation [Aletras 1999, Wen 2005]. Diastolic filling, in particular, is regarded as the dynamic outcome of myocardial re-lengthening post-contraction and ventricular flow. The pressure fields developed within the intra-ventricular cavity are the determinants of wall stress and the transmural strain gradients. The temporal evolution of such gradients is ultimately dependent on tissue viscoelasticity and its mechanical material properties. Transmural stress and strain, are therefore, direct manifestations of structure-function, the muscle’s material properties, and the active and passive fiber force generation, as a result of sarcomeric contraction-relaxation, intra-cavity blood pressure changes, and their effects on the endocardial wall [Hu 2003]. This work develops a comprehensive noninvasive imaging protocol for computational modeling, and estimation of global cardiac stress and strain fields of an elastomeric heart of a dynamically controlled cardiac phantom using ex-vivo testing, functional MRI and computational fluid dynamics (CFD). The elicited results are validated based on the computational solutions of the Navier-Stokes (NS) equations for the elastomer and flow velocity fields, in comparison with bench experimentation and phase contrast (PC) MRI.

 
4450.   17 Vessel Segmentation with 4D Flow MRI for the Characterization of Blood Mixing in Single Ventricle Patients After the Fontan Procedure
Kelly Jarvis1, Susanne Schnell1, Ramona Lorenz2, Alejandro Roldán-Alzate3, Kevin M. Johnson3, Maya Gabbour4, Joshua D. Robinson4,5, Cynthia K. Rigsby1,4, and Michael Markl1
1Radiology, Northwestern University Feinberg School of Medicine, Chicago, IL, United States, 2Radiology, University Medical Center Freiburg, Freiburg, Germany, 3Radiology and Medical Physics, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States, 4Medical Imaging and Cardiology, Ann & Robert H. Lurie Children’s Hospital of Chicago, Chicago, IL, United States, 5Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, IL, United States

 
Single ventricle patients have a complex form of congenital heart disease and undergo multiple surgeries, resulting in the Fontan vasculature geometry. There is growing evidence that underlying hemodynamics in the Fontan circulation may play an important role in patient outcome. The aim of this study was to isolate flow at the Fontan connection by integrating anatomical image segmentation into the 4D flow MR analysis work flow for improved flow visualization and mixing quantification.

 
4451.   18 On the Use of K-T Accelerated 4D Flow MRI in the Portal System
Zoran Stankovic1,2, Jury Fink1, Maximilian Russe1, Michael Markl2, and Bernd A. Jung3
1Dept. of Radioloy, University Medical Center, Freiburg, Germany, 2Dept. of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States,3Dept. of Radiology, Medical Physics, University Medical Center, Freiburg, Germany

 
The purpose of this study was to evaluate the utility of k-t parallel imaging for the acceleration of 4D flow MRI in the portal system by systematically investigating the impact of different acceleration factors R on quantification of hemodynamics parameters such as peak velocities, flow rates or wall shear stress. K-t-GRAPPA accelerated 4D flow MRI with a temporal resolution of 82 ms was performed in 16 healthy volunteers with R=3, 5 and 8 and compared to conventional GRAPPA with R=2. Additionally, a k-t accelerated scan with R=5 with a temporal resolution of 41 ms was performed.

 
4452.   19 Relative Pressure Measurement in Thoracic Aorta and Pulmonary Artery of Healthy Volunteers and Repaired Tetralogy of Fallot Patients Using the 4D Flow Sequence of Cardiac Magnetic Resonance
Jesús Urbina1,2, Julio Sotelo2,3, Marcelo Andía2,4, Cristián Tejos2,3, Daniel Hurtado2, Pablo Irarrázabal2,3, and Sergio Uribe2,4
1Medical School, Pontificia Universidad Católica de Chile, Santiago, Santiago, Chile, 2Biomedical Imaging Center, Pontificia Universidad Católica de Chile, Macul, Santiago, Chile,3Electrical Engineering Department, Pontificia Universidad Católica de Chile, Macul, Santiago, Chile, 4Radiology Department, Pontificia Universidad Católica de Chile, Santiago, Santiago, Chile

 
In this work we propose to use 4D Flow sequence to obtain and compare pressure maps in Ao and PA of healthy volunteer and patients with rTOF. rTOF patients had relative pressure differences between maximum and minimum values higher than volunteer in PA (P<0,05). Additionally, relative pressure of the Ao shown in this work had excellent correlation with other published values using 4D Flow and catheterization. The differences of maximum and minimum relative pressures in TOFr patients could be a novel parameter that can be used to study right ventricular function.

 
4453.   20 Improved Efficiency for Respiratory Motion Compensation in 3D Flow Measurements
Mehmet Akçakaya1, Praveen Gulaka2, Tamer A. Basha1, Warren J. Manning1, and Reza Nezafat1
1Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States, 2Samsung Electronics Co., Suwon, Korea

 
Phase contrast (PC) cardiac MR (CMR) is widely used to assess blood flow in cardiovascular disease. Clinically, 2D acquisitions are used for measurements of blood flow. Recently 3D PC CMR has been proposed to characterize all three directional components of blood flow. However, these require long, navigator-gated free-breathing scans, which limits its clinical usage, where accuracy and reproducibility of the flow measurements is important. In this study, we hypothesized that respiratory-gating the central k-space only will yield similar measurements to a fully respiratory-gated acquisition, and evaluated these two gating approaches in terms of quantification of cardiac indices and imaging efficiency.

 
4454.   21 4D Flow MRI Assessment of Cerebral Blood Flow After Extracranial-Intracranial Bypass
Tetsuro Sekine1, Yasuo Amano1, Ryo Takagi1, Yasuo Murai2, Yuriko Suzuki3, and Shinichiro Kumita1
1Radiology, Nippon Medical School, Tokyo, Japan, 2Neurosurgery, Nippon Medical School, Tokyo, Japan, 3Philips Electronics Japan, Tokyo, Japan

 
4D Flow assessment was examined in 19 patients after extracranial-intracranial bypass. Analysis: 1, Blood flow volume (BFV). 2, Direction of blood flow. 3, Pressure gradient at the M1. The flow direction correlates with the type of bypass. The pressure gradient at M1 correlates with the BFV difference between BFV of contralateral ICA plus BA and BFV of bypass.

 
4455.   22 Validation of 4D Flow Shunt Fractions (Qp/Qs) with 2D-PC in Patients with Partial Anomalous Pulmonary Venous Return
Mark L. Schiebler1, Phillip Kilgas1, Elizabeth Janus Nett2, Oliver Wieben2, Shardha Srinivasen3, Petros Anagnostopoulos4, Scott K. Nagle1,5, Scott B. Reeder1,6, and Christopher J. François7
1Radiology, UW-Madison, Madison, Wisconsin, United States, 2Medical Physics, UW-Madison, Madison, Wisconsin, United States, 3Pediatric Cardiology, UW-Madison, Madison, Wisconsin, United States, 4Cardiothoracic Surgery, UW-Madison, Madison, Wisconsin, United States, 5Medical Physics, UW-Madison, Madison, WI, United States, 6Biomedical Engineering, UW-Madison, Madison, WI, United States, 7Radiology, University of Wisconsin-Madison, Madison, Wisconsin, United States

 
Determination of the shunt fraction (Qp/Qs) in patients with partial anomalous pulmonary venous return is needed prior to surgical repair. We found no significant difference between the gold standard 2D PC measurements of Qp/Qs and those derived from 4D flow MRA for 5 patients and 10 normal volunteers. These cases have complex extra cardiac venous connections and atrial septal defects that are more amenable to quantify off line using post processing techniques than they are on the scanner trying to proscribe multiple double oblique 2D PC acquisitions.

 
4456.   23 Quantification of Aortic Pulse Wave Velocity in Preterm Infants Using 4D Phase Contrast MRI
Kathryn M. Broadhouse1,2, Anthony N. Price1,2, Giuliana Durighel1, Anna E. Finnemore1,2, David J. Cox1,2, A. David Edwards1,2, Joseph V. Hajnal1,2, and Alan M. Groves1,2
1Imaging Sciences Department, MRC Clinical Sciences Centre, Imperial College, London, United Kingdom, 2The Centre for the Developing Brain, Imaging Sciences & Biomedical Engineering Division, King's College, London, United Kingdom

 
A significant increase in pulse wave velocity (PWV) has been found in paediatric subjects born prematurely at low birth weight when studied at ~8yrs and may explain the increase in cardiac disease in this population. However PWV data does not extend back to preterm infants. The aim of this study was to assess the feasibility of measuring aortic PWV in preterm and term infants using 4D PC MRI, in order to establish a normative range in this population and facilitate comparison with adult values. PWV velocity in neonates was found to be at the lower end of reported adult ranges.

 
4457.   24 Aortic Stenosis Peak Velocity Assessment by Breath-Hold Fourier Velocity Imaging
Yanqiu Feng1, Kenneth Gilmour2, Taigang He2, Peter Drivas2, Isabelle Roussin2, Raad Mohiaddin2, and David N. Firmin2
1Southern Medical University, Guangzhou, Guangzhou, China, 2Royal Brompton Hospital, London, UK, United Kingdom

 
Phase-contrast peak velocity measurement through cardiac valves has important clinical applications, but is widely known to underestimate peak velocity. This abstract evaluated whether Fourier Velocity Imaging (FVI) in aortic stenoses avoids the underestimation by standard phase-contrast cine imaging (PC), and compares FVI with Doppler echocardiography (US).

 

ELECTRONIC POSTER SESSION • CARDIOVASCULAR
Thursday, 25 April 2013 (14:30-15:30) Exhibition Hall
MRA

  Computer #  
4458.   1 SNR and CNR Performance Comparison in Dixon- Vs. Subtraction-Type Contrast Enhanced MR Angiography
Eric G. Stinson1, Joshua D. Trzasko1, and Stephen J. Riederer1
1Mayo Clinic, Rochester, Minnesota, United States

 
Dixon-based contrast-enhanced MR angiography (CE-MRA) techniques have recently been reported to improve SNR and CNR compared to subtraction-based techniques. Here, a theoretical analysis is performed and compared to numerical and physical phantom results. Dixon CE-MRA shows a signal dependent SNR advantage of a factor of 2 or greater over subtraction CE-MRA and a constant CNR advantage of a factor of about 2 for appropriate TEs. These results indicate that Dixon-type CE-MRA does indeed improve SNR and CNR, in particular at small concentrations of contrast agent, suggesting that Dixon-type CE-MRA may be particularly useful in low contrast dose situations.

 
4459.   2 High Concentration Relaxivities of Four Gadolinium-Based Contrast Reagents in ex Vivo Physiologic Whole Blood and Plasma at 1.5 and 3.0T
Gregory J. Wilson1, Charles S. Springer, Jr.2, Mark Woods2,3, Sarah Bastawrous1,4, Puneet Bhargava1,4, and Jeffrey H. Maki1
1Radiology, University of Washington, Seattle, WA, United States, 2Advanced Imaging Research Center, Oregon Health and Science University, Portland, OR, United States,3Chemistry, Portland State University, Portland, OR, United States, 4Radiology, Puget Sound VAHCS, Seattle, WA, United States

 
To characterize relevant relaxation rates for CE-MRA, we have measured T1, T2, and T2* for four approved contrast agents in ex vivo whole blood and plasma under physiologic conditions and concentrations up to 18 mM at 1.5T and 3.0T. Protein binding and water exchange across the erythrocyte membrane create deviations from a simple linear dependence of R1 (= 1/T1) on contrast agent concentration in whole blood. T2* was found to be substantially shorter in whole blood than in plasma. Accurate relaxation rates help explain diminishing return of contrast agent dose, and allow us to better optimize dosing strategies for CE-MRA.

 
4460.   3 Dynamic and Static MR Angiography of the Supraaortic Vessels at 3.0 T: Intraindividual Comparison of Gd-Based Contrast Agents at Single Dose
Harald Kramer1, Elisabeth Arnoldi1, Christopher J. Francois2, Andrew L. Wentland3, Konstantin Nikolaou1, Bernd J. Wintersperger4, Maximilian F. Reiser1, and Thomas M. Grist2
1Institute for Clinical Radiology, Ludwig-Maximilians-University Munich, Munich, Bavaria, Germany, 2Department of Radiology, University of Wisconsin-Madison, Madison, Wisconsin, United States, 3Department of Radiology, University of Wisconsin - Madison, Madison, Wisconsin, United States, 4Department of Medical Imaging, University of Toronto, Toronto, Ontario, Canada

 
Several different contrast agents exist for MRI and Despite the fact these are all Gadolinium (Gd) based, they feature different characteristics. We performed static and dynamic MRA of the Carotid arteries with 3 different agents at single dose at 3.0T. Qualitative image quality as well as SNR, CNR and vessel sharpness was assessed. At equimolar doses 1.0 molar Gadobutrol demonstrates superior SNR / CNR to Gadobenate dimeglumine and Gadoterate meglumine with subjectively higher image quality in static and dynamic Carotid MRA. The decreased injected volume with Gadobutrol does not result in significantly different edge blurring of vessels.

 
4461.   4 The Flexible Triggered Segmentation Optimizes Thoracic ECG-Gated Contrast Enhanced MR Angiography
Yutaka Natsuaki1, Randall Kroeker2, J. Paul Finn3, Peter Schmitt4, and Gerhard Laub5
1Siemens Healthcare, Los Angeles, CA, United States, 2Siemens Healthcare, Winnipeg, MB, Canada, 3Radiology, University of California Los Angeles, Los Angeles, CA, United States, 4Siemens AG Healthcare, Erlangen, Germany, 5Siemens Healthcare, San Francisco, CA, United States

 
Contrast-enhanced MR angiography (ceMRA) is typically performed without ECG gating, and in cardiothoracic applications, cardiac motion may result in varying degrees of blurring. To alleviate the motion blurring, ECG gating with segmented acquisition (gated ceMRA) can be utilized. However, conventional gated ceMRA is limited by its acquisition inefficiency with the rigid triggered segments, and its spatial resolution and coverage are insufficient. The current work introduces the flexible triggered segmentation, a novel approach that drastically improves scan time efficiency, allows timing flexibility, and enables full-coverage high-resolution gated ceMRA within a single breath hold.

 
4462.   5 A Novel ECG-Gated MRA for Simultaneous Imaging of the Left Atrium and Esophagus in Patients with Atrial Fibrillation
Eugene G. Kholmovski1,2, Sathya Vijayakumar1,2, Douglas Sheffer3, Lowell Chang2,3, Krishna N. Velagapudi2,3, Christopher J. McGann2,3, and Nassir F. Marrouche2,3
1UCAIR, Department of Radiology, University of Utah, Salt Lake City, Utah, United States, 2CARMA Center, University of Utah, Salt Lake City, Utah, United States, 3Department of Cardiology, University of Utah, Salt Lake City, Utah, United States

 
A novel MRA sequence for simultaneous visualization of the left atrium (LA) and pulmonary veins (PVs), and esophagus has been developed. The sequence was compared with conventional MRA sequence in 80 patients study. Quality scores were determined for the following categories: contrast, border sharpness, details of the PVs, LA, LA appendage, and esophagus, and overall image quality. Analysis shown that novel ECG-gated MRA scored significantly higher than non-gated MRA in all categories. New sequence may improve diagnostics and treatment of patients with atrial fibrillation including planning and execution of RF ablations, detection of PV stenosis, and following LA remodeling post-ablation.

 
4463.   6 Equilibrium-Phase Thoracic MR Angiography with Gadofosveset in Healthy Volunteers: Feasibility and Minimal Practical Dose
Charles Y. Kim1, Tobias J. Heye1, Mustafa R. Bashir1, Thomas Gebhard1, Bjorn I. Engstrom1, and Elmar M. Merkle2
1Radiology, Duke University, Durham, NC, United States, 2Radiology, University of Basel Hospital, Basel, CH-4031, Switzerland

 
The purpose of this study was to evaluate the feasibility and minimal practical dose of equilibrium-phase MR angiography of the thoracic vasculature using gadofosveset in healthy volunteers. Thirty healthy volunteers were randomized to receive one of three doses of gadofosveset. Two blinded radiologists assessed the central veins, the pulmonary arteries, and the thoracic aorta. Qualitative and quantitative assessment was performed on each vessel segment. Using a single equilibrium phase acquisition, the central veins, pulmonary arteries, and aorta were well-depicted, even when dose reduction was performed. This strategy may be useful for patients with impaired borderline renal function.

 
4464.   7 Identification of the Artery of Adamkiewicz Artery: The Role of High Spatial and Temporal Resolution MR Angiography in Patients with Indistinct Depiction by MDCT Angiography. -permission withheld
Hideki Ota1, Kei Takase1, Yoshikatsu Saiki2, Hidenobu Sasaki1, Kazuomi Yamanaka1, and Shoki Takahashi1
1Diagnostic Radiology, Tohoku University Hospital, Sendai, Miyagi, Japan, 2Cardiovascular Surgery, Tohoku University Hospital, Sendai, Miyagi, Japan

 
The purpose of this study was to evaluate the use of high spatial and temporal resolution MR angiography at 3.0T in patients with poor or moderate depiction of the artery of Adamkiewicz on MDCT angiography. Confidence grade for its identification were compared between MDCT and MR angiography. MR angiography demonstrated higher detectability with higher confidence of the artery of Adamkiewicz than MDCT angiography. Although MDCT angiography is widely used for preoperative evaluation in patients with aortic disease, additional use of MR angiography helps to localize the artery of Adamkiewicz in patients with indistinct depiction on MDCT examination.

 
4465.   
8 Pre-Operative Perforator Flap MRA for Autologous Breast Reconstruction
Nanda Deepa Thimmappa1, Silvina P. Dutruel1, Mengchao Pei1, Joshua L. Levine2, Julie Vasile3, David Greenspun3, Constance Chen3, Christina Rhode4, Christina Y. Ahn5, Robert Allen3, and Martin R. Prince1
1Radiology, Weill Cornell Medical College, New York, NY, United States, 2Plastic surgery, The Center for the Advancement of Breast Reconstruction at NYEE, New York, NY, United States, 3Plastic & Reconstructive Surgery, New York, NY, United States, 4NewYork-Presbyterian Hospital/Columbia, New York, NY, United States, 5Plastic surgery, NYU Langone Medical Center, New York, NY, United States

 
This retrospective analysis explores the accuracy of MRA mapping of perforator vessels for autologous breast reconstruction finding MRA to be accurate within 1 cm in all 107 patients. With pre-operative MRA, the flap necrosis rate decreased to 3% compared to an historical average of 14% in the literature. Importantly MR also detected occult metastatic disease in 4 patients. Finally, an automated method of calculating perforator coordinates is presented which eliminated typographical errors associated with manual reporting.

 
4466.   9 High Frame Rate CINEMA: An Improvement of Temporal Resolution in Non-Contrast-Enhanced Time-Resolved MR Angiography
Masanobu Nakamura1, Masami Yoneyama1, Takashi Tabuchi1, Atsushi Takahara2, Makoto Obara2, Taro Takahara3, and Satoshi Tatsuno1
1Yaesu clinic, Tokyo, Japan, Japan, 2Philips Electronics Japan, Tokyo, Japan, 3Tokai University School of Engineering, Kanagawa, Japan

 
Recently, a new technique was presented for non-contrast volumetric time-resolved MRA (Contrast inherent INflow Enhanced Multi phase Angiography; CINEMA) [3]. This technique requires no catheter insertion or contrast agent and provides useful qualitative information on the dynamic filling by the temporal resolution of 200msec in intracranial vessels. However, temporal resolution of this technique is not satisfactory to visualize complex flow patterns such as cerebral aneurysm and AVM. In this study we present a CINEMA sequence with k-t BLAST [4] that produces high temporal resolution non-contrast time-resolved MR Angiograms (CINEMA-HERO). We investigate non-contrast time-resolved MRA with a modified CINEMA sequence with feasibility study results in healthy volunteers and cerebrovascular disease patients.

 
4467.   10 MR Portography Using Non-Contrast-Enhanced Time-Spatial Labeling Inversion Pulse (Time-SLIP) -Comparison Between 3T and 1.5T-
Hiroki Matoba1, Katsumi Nakamura1,2, Akiyoshi Yamamoto1, Masafumi Ueda1, Daiji Uchiyama1, and Mitsue Miyazaki3
1Radiology, Tobata Kyoritsu Hospital, Kitakyushu, Fukuoka, Japan, 2Radiology, Hikari Central Hospital, Hikari, Yamaguchi, Japan, 3Toshiba Medical Research Institute USA, Vernon Hills, IL, United States

 
Time-SLIP using 3T-MRI clearly demonstrates the portal veins with higher CNR than that 1.5T.

 
4468.   11 Feasibility of 3D Balanced SSFP-ASL of the Kidneys at 3.0T -permission withheld
Koji Fujimoto1, Aki Kido2, Kyoko Takakura2, Hajime Sagawa2, Shigeaki Umeoka2, Naotaka Sakashita3, Tokunori Kimura3, Yasutaka Fushimi2, and Kaori Togashi2
1Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University, Kyoto, Japan, 2Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan, 3Toshiba Medical Systems Corporation, Otawara, Tochigi, Japan

 
Because of the higher risk for NSF, there is an increased requirement to non-invasively evaluate the function of the diseased kidneys. We investigated feasibility of 3D-bSSFP MRA for the kidney by comparing with FFE readout. 3D-ASTAR-ASL was performed for five healthy volunteers at Toshiba 3.0T MRI system. Inversion time (TI) between the saturation pulse and readout varied from 800, 1200, 1600, 2000, 2400 msec. bSSFP was superior to FFE both for quantitative analysis (contrast ratio of the kidney/vertebra, and intestines/vertebra) and qualitative analysis (visualization of the renal perfusion, effectiveness of background suppression, and degree of misregistration) at any TI.

 
4469.   
12 Adaptive Efficiency-Optimized Self Navigation (ADIOS) for Free-Breathing Non-Contrast Abdominal MRA
Yibin Xie1,2, Zhaoyang Fan1, Yutaka Natsuaki3, Gerhard Laub4, Rola Saouaf1, and Debiao Li1
1Cedars-Sinai Medical Center, Los Angeles, California, United States, 2University of California, Los Angeles, Los Angeles, California, United States, 3Siemens Medical Solutions, Los Angeles, California, United States, 4Siemens Healthcare, Los Angeles, California, United States

 
Non-contrast MRA based on bSSFP and slab-selective inversion is an attractive method for imaging abdominal arteries without contrast agents. However current free-breathing methods suffer from issues including complicated setup, prolonged scan and navigator saturation artifacts, limiting this technique from becoming clinical routine. An Adaptive Efficiency-Optimized Self Navigation (ADIOS) method is developed in this work utilizing motion information derived from imaging volume. Scan efficiency is maintained with an automatic thresholding algorithm. Volunteer study results show comparable image quality, simplified setup, and absence of navigator artifacts.

 
4470.   13 Non-Contrast-Enhanced Abdominal MRA Using Velocity-Selective Saturation and Multiple Inversion Recovery
Hattie Z. Dong1, Taehoon Shin1, and Dwight G. Nishimura1
1Electrical Engineering, Stanford University, Stanford, CA, United States

 
A new non-contrast-enhanced method based on velocity-selective saturation and multiple inversion recovery (VS-MIR) was developed for magnetic resonance angiography (MRA) in scan times as short as a single breath-hold. VS-MIR leads to excellent background suppression while relaxing the in-flow requirements for vessel contrast. MRA results with this method in the abdominopelvic region demonstrated good vessel contrast over a wide superior-inferior range.

 
4471.   14 Non-Contrast MR Hepatic Arteriography Using 3T-MRI and Time-SLIP: Initial Experiences -permission withheld
Naoki Kanata1, Takeshi Yoshikawa2,3, Nobukazu Aoyama4, Yoshiharu Ohno2,3, Yasusuke Kyotani4, Saori Satou5, Tomonori Kanda1, Hisanobu Koyama1, Mizuho Nishio2,3, and Kazuro Sugimura1
1Division of Radiology, Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan, 2Advanced Biomedical Imaging Research Center, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan, 3Division of Functional and Diagnostic Imaging Research, Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan, 4Center of Radiology and Radiation Oncology, Kobe University Hospital, Kobe, Hyogo, Japan, 5Toshiba Medical Systems Corporation, Otawara, Tochigi, Japan

 
The assessment and classification of anatomy of hepatic artery is an essential step for both diagnosis and management of various diseases in the upper abdomen. Development of non- invasive imaging techniques for this purpose is an urgent problem. Our results suggested that anatomy of hepatic artery can be assessed and classified using non-contrast MR arteriography using Time-SLIP technique at 3T-MRI.

 
4472.   15 Evaluation of a Novel Non-Contrast-Enhanced MRI Imaging Technique for Diagnosis and Characterisation of Deep Venous Thrombosis (DVT).
David J. Bowden1, Andrew N. Priest1, Claire Smith1, Ilse Joubert1, Sally Hunter1, Martin John Graves1, Trevor Baglin2, and David J. Lomas1
1Radiology, Cambridge University Hospitals NHS Foundation Trust, Cambridge, Cambs, United Kingdom, 2Haematology, Cambridge University Hospitals NHS Foundation Trust, Cambridge, Cambs, United Kingdom

 
Ultrasound (US) imaging represents the gold standard in the evaluation of lower limb deep venous thrombosis (DVT), however there is considerable inter-observer variability in the characterisation of thrombi, in particular distinguishing acute from chronic thrombosis. Several MRI methods have demonstrated promise and may be superior to ultrasound in this respect. We present initial data from a novel multi-parametric MR technique utilised in 8 patients with US-confirmed DVT which accurately defines the extent of thrombus and defines the signal characteristics of acute thrombus.

 
4473.   16 Fresh Blood Imaging (FBI) of Peripheral Arteries at 3T MRI - Comparison with 1.5T -
Akiyoshi Yamamoto1, Katsumi Nakamura1,2, Hiroki Matoba1, Masafumi Ueda1, Daiji Uchiyama1, and Mitsue Miyazaki3
1Radiology, Tobata Kyoritsu Hospital, Kitakyushu, Fukuoka, Japan, 2Radiology, Hikari Central Hospital, Hikari, Yamaguchi, Japan, 3Toshiba Medical Research Institute USA, Vernon Hills, IL, United States

 
FBI at 3T clearly demonstrated great depiction of lower extremity arteries with higher CNR, especially in the smaller and more peripheral arteries which could not be depicted well at 1.5T-FBI.

 
4474.   17 Non-Enhanced T1w Imaging of the Lower Extremity Arteries at 7 Tesla
Anja Fischer1,2, Sören Johst1,2, Stephan Orzada1,2, Mark E. Ladd1,2, Kai Nassenstein1, Thomas C. Lauenstein1, and Stefan Maderwald1,2
1Department of Diagnostic and Interventional Radiology and Neuroradiology, Essen, Nordrhein-Westfalen, Germany, 2Erwin L. Hahn Institute for Magnetic Resonance Imaging, Essen, Nordrhein-Westfalen, Germany

 
The aim was to investigate the feasibility of non-enhanced T1-weighted MRA of the lower extremity arteries. Ten healthy volunteers were examined on a 7 T MR system utilizing a custom-built 16-channel transmit / receive coil. Three non-enhanced sequences were acquired, providing a hyperintense delineation of the arterial vasculature from pelvis to feet. Best image quality was found for the popliteal segment. Artifacts could be successfully reduced with phonocardiogram gating. Our results demonstrate high quality imaging of the lower extremity arteries with non-contrast-enhanced T1w MRA at 7 T in healthy subjects, with a superiority of triggered Turbo-FLASH imaging.

 
4475.   18 Non-Contrast High Resolution MR Venography of Lower Extremity Perforating Veins -permission withheld
Jun Isogai1, Takashi Yamada2, Tomoko Miyata3, and Mitsue Miyazaki4
1Shuwa General Hospital, Kasukabe, Saitama, Japan, 2Hasuda Hospital, Hasuda, Saitama, Japan, 3Toshiba Medical Systems Corp., Saitama, Saitama, Japan, 4Toshiba Medical Research Institute, Vernon Hills, IL, United States

 
MR venography for the lower extremity has been reported using two-dimensional (2D) time-of-flight (TOF) and direct gadolinium-enhanced MRA. However, TOF methods suffer from limited images, whereas contrast-enhanced methods require a large amount of contrast agent and add a superimposition between arteries and veins. Due to the recent concerns of Gadolinium-related Nephrogenic Systemic Fibrosis (NSF), non-enhanced and non-invasive MRA solutions have gained interest. An anatomical map of complex venous system provides valuable evaluation of lower extremity varicosities related to incompetent perforating veins.

 
4476.   
19 Non-Contrast Enhanced MR Angiography (NCE-MRA) of the Foot Using Flow Sensitive Dephasing (FSD) Prepared Steady-State Free Precession (SSFP) in Patients with Diabetes
Zhaoyang Fan1, Xin Liu2, Na Zhang2, Qi Yang3, Fei Feng4, Pengcheng Liu4, Dehe Weng5, and Debiao Li1
1Cedars-Sinai Medical Center, Los Angeles, CA, United States, 2Shenzhen Institutes of Advanced Technology,Chinese Academy of Sciences, Shenzhen, Guangdong, China,3Xuanwu Hospital, Capital Medical University, Beijing, China, 4Peking University Shenzhen Hospital, Shenzhen, Guangdong, China, 5Siemens Shenzhen, Shenzhen, China

 
A NCE-MRA technique using steady-state free precession (SSFP) and flow-sensitive dephasing (FSD) magnetization preparation has been recently proposed for peripheral noncontrast (NCE) MRA. The purpose of this study was to prospectively assess the diagnostic performance of the NCE-MRA technique in patients with diabetes, using conventional CE-MRA as the reference standard. In 38 healthy volunteers and 38 diabetic patients, NCE-MRA showed significant higher image quality scores than CE-MRA. In addition, NCE-MRA provided comparable SNR and CNR in dorsal artery and lateral plantar artery compared to CE-MRA and significant higher in pedal artery. Diagnostic accuracy was excellent by using NCE-MRA.

 
4477.   20 High-Resolution MR Imaging and Angiography of Fingers Using a Dedicated Phased Array Coil at 3T
Wingchi Edmund Kwok1,2, Zhigang You1, Gwysuk Seo3, and Johnny Monu3
1Imaging Sciences, University of Rochester, Rochester, NY, United States, 2Rochester Center for Brain Imaging, University of Rochester, Rochester, NY, United States,3Department of Imaging Sciences, University of Rochester, Rochester, NY, United States

 
To achieve high-resolution finger MR imaging and angiography of both the distal and proximal interphalangeal joints, we developed a dedicated phased array RF receive coil at 3T. It supported imaging with isotropic resolution of 200 microns and angiography with resolution much higher than previously reported, revealing detailed anatomical structures and blood vessels inside the finger. With this coil, the imaged finger orients along the magnet bore. This provides comfort of use to the subject, minimizing motion and allowing longer scan time. Our technique should be useful for the diagnosis, treatment assessment and pathogenesis studies of arthritis and systemic sclerosis.

 
4478.   21 Three-Dimensional Cine Phase Contrast Image Can Replace Two-Dimensional Cine Phase Contrast MR Imaging for the Assessments of Pulmonary Artery Velocities and Their Related Parameters.
Masaki Terada1, Yasuo Takehara2, Haruo Isoda3, Tuyoshi Shimizu4, Tetsuya Wakayama5, and Marcus T. Alley6
1Radiology, Iwata City Hospital, Iwata-shi, Shizuoka, Japan, 2Radiology, Hamamatsu Univ. Hospital, Hamamatsu, Shizuoka, Japan, 3Radiological Sciences, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan, 4R tech, Hamamatsu, Shizuoka, Japan, 5GE Healthcare, Hino, Tokyo, Japan, 6stanford university, Stanford, CA, United States

 
Good agreements are present between 3D and 2D cine PC MR imaging for evaluation of pulmonary arterial flow biomarkers. We can replace 2D cine PC MR imaging with 3D cine imaging.

 
4479.   22 Influence of Slice-Selective Tag Thickness for Non-Contrast-Enhanced Pulmonary MR Venography Based on ECG-Gated 3D Time-Spatial Labeling Inversion Pulse (Time-SLIP) Technique
Nobukazu Aoyama1, Yoshiharu Ohno2,3, Mizuho Nishio2,3, Hisanobu Koyama4, Takeshi Yoshikawa2,3, Sumiaki Matsumoto2,3, Katsusuke Kyotani1, Saori Satou5, Hideaki Kawamitsu1, Satoru Takahashi1,4, and Kazuro Sugimura4
1Center forRadiology and Radiation Oncology, Kobe University Hospital, Kobe, Hyogo, Japan, 2Advanced Biomedical Imaging Research Center, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan, 3Division of Functional and Diagnostic Imaging Research, Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan, 4Division of Radiology, Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan, 5Toshiba Medical Systems, Ohtawara, Tochigi, Japan

 
2D or 3D time spatial labeling inversion pulse (time-SLIP) techniques is clinically applied as one of the non-contrast-enhanced pulmonary MR angiography in routine clinical practice. This technique has been suggested as having the capability of separation between pulmonary artery and vein, although the separation of pulmonary vein from artery is more difficult than latter from former. In addition, no one has assessed the influence of slice-selective Tag pulse thickness for time-SLIP technique. The purpose of this study was to prospectively and directly compare the influence of slice-selective Tag thickness for pulmonary MR venography using time-SLIP technique at in vivo study.

 
4480.   23 Accelerated Supra-Aortic Artery Imaging Without Contrast Agent Using Combined Compressed Sensing and Parallel Imaging
Naoyuki Takei1, Kevin F. King2, Masayoshi Sugimura3, Koji Yoneyama3, Takayuki Masui3, and Hiroyuki Kabasawa1
1GE Healthcare, Hino, Tokyo, Japan, 2GE Healthcare, Waukesha, WI, United States, 3Seirei Hamamatsu General Hospital, Hamamatsu, Shizuoka, Japan

 
In Non-Contrast Enhanced MR Angiography (NCE-MRA), accelerated scanning helps to add into established clinical routine protocol for screening and follow-up. Compressed sensing (CS) is a promising technique to accelerate scanning for NCE-MRA which has sparse image. In this work, the combination of CS and parallel imaging was applied to NCE-MRA and demonstrated feasible. Volunteer scan was performed as acceleration factor of CS+PI was changed. The CS +PI sequence reduced scan time down to 1:17 with net acceleration 10.8 identifying the main arteries. In conclusion, CS+PI improves supra-aortic artery depiction and achieves higher acceleration compared to PI only.

 
4481.   24 Application of PLS-DA Method in Separation of Venous and Arterial Phase in 4D CE-MRA Data
Siamak Salari Sharif1, Ewart Mark Haacke1, Joseph J. Hewett2, and Michael Arata2
1MR Innovations Inc., Detroit, MI, United States, 2Synergy Health Concepts, Newport Beach, CA, United States

 
In contrast-enhanced MR-angiography (CE-MRA), often, it is desired to extract a single phase; venous or arterial, for further processing or visualization. This task can be very complicated especially in patients with venous abnormalities as the flow is accompanied with various delays or is obstructed, leading to inability to identify a clear arterial phase in the image for subtraction. Therefore, we developed an algorithm based on partial least-squares discriminant analysis to isolate the venous/arterial phase in 4D CE-MRA. The advantage of our method is its ability to handle highly correlated MRI datasets, as well as capturing the variability in contrast enhancement.

 

ELECTRONIC POSTER SESSION • CARDIOVASCULAR
Thursday, 25 April 2013 (13:30-14:30) Exhibition Hall
Cardiac Function & Diffusion

  Computer #  
4482.   25 Full-Cycle Cine DENSE for Assessment of Systolic and Diastolic Myocardial Function
Bhairav B. Mehta1, Andrew D. Gilliam2, Michael Salerno1,3, and Frederick H. Epstein1,4
1Department of Biomedical Engineering, University of Virginia, Charlottesville, VA, United States, 2A.D. Gilliam Consulting, Providence, RI, United States, 3Department of Medicine, Cardiology Division University of Virginia, Charlottesville, VA, United States, 4Department of Radiology, University of Virginia, Charlottesville, VA, United States

 
Heart failure with preserved ejection fraction (HF-PEF) accounts for more than half of all the heart failure cases. Quantification of diastolic function is becoming as important as quantification of systolic function. Echocardiography is commonly used to assess diastolic function but has limitations affecting its measurement accuracy. Strain and strain rate measurement using cine DENSE MRI has advantages over echocardiographic techniques and could improve the diagnosis of diastolic dysfunction. Previous cine DENSE sequences have primarily imaged systole. Here we modified a cine DENSE sequence to image entire cardiac cycle with sufficient SNR to compute accurate systolic and diastolic displacements, strains, and strain rates.

 
4483.   26 Segmental Tissue Phase Mapping Analysis of Biventricular Heart Function
Marius Menza1, Bernd Jung1, Adriana Komancsek1, Jeff Snyder1, and Daniela Föll2
1University Hospital Freiburg, Medical Physics, Freiburg, Baden Württemberg, Germany, 2University Heart Center Freiburg, Cardiology and Angiology I, Freiburg, Baden Württemberg, Germany

 
The evaluation of the right ventricular (RV) function has prognostic impact on patients with heart failure or pulmonary hypertension. MR tissue phase mapping was used to evaluate biventricular segmental velocities in 10 healthy volunteers. Basal radial velocities of the RV were higher than in the LV (left ventricle). The highest RV velocities were found in long-axis direction of the basal free wall in systole and diastole. A comprehensive analysis of RV velocities might improve patient management in future.

 
4484.   27 Evaluation of Highly-Accelerated Non-Gated Cardiac Cine MRI in Tachycardia
Elwin Clark Bassett1, Edward V.R. DiBella2,3, Eugene G. Kholmovski2,3, Brent Donald Wilson3, Christopher J. McGann3, Nassir F. Marrouche3,4, and Daniel Kim2,3
1Physics, University of Utah, Salt Lake City, Utah, United States, 2UCAIR, University of Utah, Salt Lake City, Utah, United States, 3CARMA, University of Utah, Salt Lake City, Utah, United States, 4Internal Medicine, University of Utah, Salt Lake City, Utah, United States

 
The current gold standard for imaging left ventricular function is electrocardiogram gated cine MRI with balanced steady-state of free precession imaging, which provides excellent myocardium-to-blood contrast. However, it yields non-diagnostic quality images in patients with arrhythmias because data acquisition is synchronized to cardiac rhythm and spread over multiple heart beats. We have developed an 8-fold accelerated non-gated cardiac cine sequence using k-t SPARSE-SENSE. We will evaluate this pulse sequence for assessment of cardiac function in the context of tachycardia, where high temporal resolution is critically important for diagnostic confidence.

 
4485.   28 Movement Abnormalities in the Left Ventricle of Thalassemia Major Patients
Antonella Meloni1, Vincenzo Positano1, Pier Paolo Bitti2, Antonella Carollo3, Letizia Gulino1, Antonino Vallone4, Chiara Tudisca5, Elisabetta Chiodi6, Massimo Lombardi1, and Alessia Pepe1
1CMR Unit, Fondazione G. Monasterio CNR-Regione Toscana and Institute of Clinical Physiology, Pisa, Italy, 2Servizio Immunoematologia e Medicina Trasfusionale, O. San Francesco, Nuoro, Italy, 3Servizio Talassemia-U.O. Pediatria Talassemia, Az. Osp. "Sant'Antonio abate", Trapani, Italy, 4Istituto di Radiologia Az. Osp. "Garibaldi", Presidio Ospedaliero Nesima, Catania, Italy, 5Istituto di Radiologia, Policlinico "Paolo Giaccone", Palermo, Italy, 6Servizio Radiologia Ospedaliera-Universitaria, Arcispedale “S. Anna” di Ferrara, Ferrara, Italy

 
Movement abnormalities in the left ventricle (LV) are not really frequent in thalassemia major patients (6%) and are predominant in the medium anterior, anterolateral and septal segments. Movement abnormalities are associated with age, myocardial iron overload, LV dilation and dysfunction and myocardial fibrosis.

 
4486.   29 Quantification of Left Ventricular Twist During Free-Breathing with SPAtial Modulation of Magnetization (SPAMM) and Fourier Analysis of STimulated Echoes (FAST)
Meral L. Reyhan1,2, Hyun Grace Kim1, and Daniel B. Ennis1,3
1Department of Radiological Sciences, University of California Los Angeles, Los Angeles, CA, United States, 2Biomedical Physics Interdepartmental Program, University of California Los Angeles, Los Angeles, California, United States, 3Biomedical Physics Interdepartmental Program, University of California Los Angeles, Los Angeles, CA, United States

 
Left Ventricular (LV) twist is an imaging biomarker for global LV dysfunction, which is often measured from breath-held tagged cardiac MRI. We hypothesized that significant differences exist in LV twist measurements derived from images acquired during breath-holding, free-breathing with averaging, and respiratory bellows gated free-breathing. Bellows derived estimates of LV twist were significantly lower than breath-held. No significant differences in LV twist were detected between breath-held and free-breathing with averaging. Breath-held consistency can be variable during clinical studies, therefore bellows gating may be a more accurate biomarker of LV dysfunction in patients with limited breath-hold capabilities.

 
4487.   30 Analysis of Neonatal Cardiac Function in Infants with and Without Patent Ductus Arteriosus
Kathryn M. Broadhouse1,2, Anthony N. Price1,2, Giuliana Durighel1, Anna E. Finnemore1,2, David J. Cox1, A. David Edwards1,2, Joseph V. Hajnal1,2, and Alan M. Groves1,2
1Imaging Sciences Department, MRC Clinical Sciences Centre, Imperial College, London, United Kingdom, 2The Centre for the Developing Brain, Imaging Sciences & Biomedical Engineering Division, King's College, London, United Kingdom

 
The aim of this study was to quantify ventricular dimension and function in “healthy” neonates. Then compare patent ductus arteriosus (PDA) infants to this normative range to determine the impact of shunt volume. 2D SSFP stacks providing full coverage of the left ventricle were acquired in neonates with and without PDA to assess the impact of shunt volume on left ventricular morphology and function. Shunt volume was calculated from phase contrast sequences acquired during the same MRI scan. Although left ventricular output and left ventricular mass were significantly increased in PDA infants, ejection fraction remained within the normal range.

 
4488.   31 Left Ventricular Function in a Single Breathhold with 3D Radial CINE BSSFP and 3D Through-Time Radial GRAPPA
Kestutis Barkauskas1, Vidya Nadig2, Bruce S. Spottiswoode3, Sven Zuehlsdorff3, and Nicole Seiberlich1
1Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio, United States, 2Heart and Vascular Center, Metro Health Hospital, Cleveland, Ohio, United States,3Cardiovascular MR R&D, Siemens Medical Solutions, Chicago, Illinois, United States

 
This work applies 3D Through-time Radial GRAPPA to reconstruct images depicting cardiac motion acquired with an ECG-gated, 3D radial cine bSSFP sequence using an angularly-undersampled stack-of-stars cylindrical trajectory during a single breathhold. A total of 10 repetitions of fully-sampled 3D radial data acquired during free-breathing formed the calibration reference. Bland-Altman analysis of ejection fraction in 10 healthy volunteers showed that differences between the proposed 3D radial approach – which required less total scan time and only a single breathhold – and a clinical standard 2D segmented cine multi-breathhold acquisition were not statistically significant (mean +/- 1.96*SD of bias: 0.7 +/- 5.5%).

 
4489.   32 Assessing Cardiac Kinetics Using Highly Accelerated Free Breathing 2D Through-Time Radial GRAPPA Compared to Cartesian Real-Time and Segmented Cine Imaging
Jeremy D. Collins1, Bruce S. Spottiswoode2, Haris Saybasili3, Mark A. Griswold3,4, Nicole Seiberlich3, L. Cort Sommerville5, Keyur Parekh1, Michael Markl6,7, and James C. Carr5
1Radiology, Northwestern University, Chicago, IL, United States, 2Cardiovascular MR R&D, Siemens Healthcare, Chicago, IL, United States, 3Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States, 4Radiology, Case Western Reserve University, Cleveland, OH, United States, 5Radiology, Northwestern University, Chicago, Il, United States, 6Radiology, Northwestern University, Chiago, IL, United States, 7Biomedical Engineering, Northwestern University, Chicago, IL, United States

 
This pilot study evaluates the clinical feasibility of highly accelerated radial GRAPPA real-time bSSFP acquisitions for left ventricular diastology, comparing to accelerated Cartesian real-time and segmented bSSFP acquisitions. Real-time GRAPPA acquisitions with effective temporal resolutions as low as 25 msec were clinically feasible, with adequate image quality to identify the blood pool-myocardial boundary with clear separation of diastolic filling phases. Image quality was limited for trabecular assessment, however. The real-time GRAPPA acquisitions were more accurate for diastolic assessment than Cartesian real-time or Cartesian segmented acquisitions compared to echocardiography. Work is ongoing to assess beat-to-beat quantitative differences in left ventricular diastology.

 
4490.   33 Reference Ranges for Biventricular Volumes and Ejection Fraction and for Left Ventricular Mass in Adult Thalassemia Intermedia Patients Without Myocardial Iron Overload
Antonella Meloni1, Vincenzo Positano1, Daniele De Marchi1, Cristina Salvatori2, Gaetano Giuffrida3, Angelo Peluso4, Gianluca Valeri5, Gennaro Restaino6, Letizia Gulino1, Massimo Lombardi1, and Alessia Pepe1
1CMR Unit, Fondazione G. Monasterio CNR-Regione Toscana and Institute of Clinical Physiology, Pisa, Italy, 2Fondazione G. Monasterio CNR-Regione Toscana, Pisa, Italy, 3Ospedale "Ferrarotto", Divis. Clinicizzata di Ematologia, Catania, Italy, 4Microcitemia - Azienda Unità Sanitaria Locale TA/1, Presidio Ospedaliero Centrale, Taranto, Italy, 5Dipartimento di Radiologia, Azienda Ospedaliero-Universitaria Ospedali Riuniti "Umberto I-Lancisi-Salesi", Ancona, Italy, 6Department of Radiology, Catholic University of the Sacred Heart, Campobasso, Italy

 
Reference ranges for biventricular volumes and ejection fraction and for LV mass specific to adult thalassemia intermedia (TI) patients were defined. These new reference ranges are important for avoiding a misdiagnosis of cardiomyopathy in TI patients.

 
4491.   34 A Qualitative and Quantitative Assessment of Real-Time Cardiac Functional Imaging Using Through-Time Radial GRAPPA
Vidya Nadig1, Victoria Yeh2, Gunhild Erstad Aandal3, Prabhakar Rajiah3, Trevor Jenkins4, Abdus Sattar5, Mark A. Griswold3,6, Vikas Gulani6,7, Robert Chapman Gilkeson3, and Nicole Seiberlich6
1Cardiology, MetroHealth Medical Center at Case Western University, Cleveland, OH, United States, 2Case Western Reserve University School of Medicine, Cleveland, OH, United States, 3Dept. of Radiology, Case Western Reserve University and University Hospitals of Cleveland, Cleveland, OH, United States, 4Cardiology, University Hospitals of Cleveland, Cleveland, OH, United States, 5Epidemiology and Biostatistics, Case Western Reserve University, Cleveland, OH, United States, 6Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States, 7Dept. of Radiology, Case Western Reserve University, Cleveland, OH, United States

 
Temporal resolutions <50 ms can be achieved using through-time radial GRAPPA for CMR, obviating need for gating or breathholding. In this study, 41 subjects underwent functional cardiac imaging using standard breathhold cine and real-time imaging (with through-time radial GRAPPA). Bland-Altman analysis of LVEF from the two methods showed 39/40 of measurements within 95% limits of agreement, and the mean difference was -1.9%. Radiologists’ rating showed >90% of qualitative parameters for both methods were in the excellent or good visibility range. This indicates that real-time imaging could replace breathhold cine, and be used for patients with arrhythmia or difficulty breathholding.

 
4492.   35 Quantification of Left Ventricular Twist in Patients with Becker and Duchenne Muscular Dystrophy
Meral L. Reyhan1,2, Nancy Halnon3, J. Paul Finn1, and Daniel B. Ennis1,2
1Department of Radiological Sciences, University of California Los Angeles, Los Angeles, CA, United States, 2Biomedical Physics Interdepartmental Program, University of California Los Angeles, Los Angeles, California, United States, 3Department of Pediatrics, David Geffen School of Medicine, Los Angeles, CA, United States

 
Becker and Duchenne Muscular Dystrophy (MD) are common inherited neuromuscular disorders that often develop into cardiomyopathy with posterobasal myocardial involvement and mitral regurgitation. Left Ventricular (LV) twist, defined as the difference in rotation between the apex and base of the heart, has been suggested as an imaging biomarker of ventricular dysfunction. In this study, LV twist, torsion, CL-shear angle, and systolic twist-per-volume slope have been investigated in patients with Becker and Duchenne Muscular Dystrophy. A decrease in LV twist within the B/DMD patients corresponding to an increasing myocardial fibrosis was observed. Apparent decreases in LV twist, torsion, CL-shear, and twist-per-volume rate indicate an impairment of the rotational mechanics in these subjects relative to non-age-matched controls.

 
4493.   36 High Resolution 3D Imaging of Post-Mortem Human Fetal Hearts
Eleftheria Pervolaraki1, Steven Reynolds2, Adriana Bucur2, Alejandro Frangi3, Richard Anderson4, Martyn Paley2, and Arun Holden1
1Faculty of Biological Sciences, University of Leeds, Leeds, Yorkshire, United Kingdom, 2Academic Radiology, University of Sheffield, Sheffield, Yorkshire, United Kingdom,3Mechanical Engineering, University of Sheffield, Sheffield, Yorkshire, United Kingdom, 4MRC Centre for Reproductive Health, Universityy of Edinburgh, Edinburgh, East Lothian, United Kingdom

 
High resolution 3D FLASH imaging of post mortem fetal human hearts around 20 week gestation was performed at 9.4T with 58 micron isotropic spatial resolution. Muscle and Purkinje fibers could be segmented in spiral formation.

 
4494.   37 3D High-Resolution Diffusion Tensor Imaging of Heart ex-vivo After Myocardial Infarction in Porcine Model -permission withheld
Farhad Pashakhanloo1, Michael Schär2, Roy Beinart3, M. Muz Zviman3, Henry Halperin4, Susumu Mori5, Neville D. Gai6, David A. Bluemke6, Elliot R. McVeigh1, and Daniel A. Herzka7
1Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, MD, United States, 2Philips Healthcare, Cleveland, Ohio, United States, 3Department of Medicine, Cardiology, Johns Hopkins University, School of medicine, Baltimore, MD, United States, 4Department of Medicine, Cardiology, Johns Hopkins University, Baltimore, MD, United States, 5Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University, School of Medicine, Baltimore, MD, United States, 6Radiology & Imaging Sciences, National Institutes of Health, Bethesda, MD, United States, 7Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, United States

 
High resolution DTI is a promising tool to study the myofiber remodeling in different disease models, specifically myocardial infarction (MI). Most studies of microstructure utilize either high field magnets and small animals hearts or pieces of large animal hearts. To our knowledge, this is the first study that incorporates sub-millimeter 3D DTI to study the remodeling around the infarct area in large animal models and suitable for whole human heart imaging. The extent of microstructural remodeling illustrated by this method is critical information in the pathophysiology of infarct and could be used to predict further electromechanical dysfunction developed after MI.

 
4495.   38 Improved Tractography of the Human Heart in vivo by Motion Correction of Multi-Breathold Diffusion Tensor MRI
Choukri Mekkaoui1, Sonia Nielles-Vallespin2, Marcel Parolin Jackowski3, Timothy G. Reese4, Peter David Gatehouse2, David N. Firmin2, and David E. Sosnovik4
1Harvard Medical School - Massachusetts General Hospital - Athinoula A Martinos center for Biomedical, Boston, MA, United States, 2CMR Unit, Royal Brompton Hospital, London, London, United Kingdom, 3University of São Paulo, São Paulo, São Paulo, Brazil, 4Harvard Medical School - Massachusetts General Hospital - Athinoula A Martinos center for Biomedical, Charlestown, MA, United States

 
The physiological motion inherent to multibreathold in vivo Diffusion Tensor MRI (DTI) acquisitions impacts the estimation of diffusion based-indices as well as accurate tractography of myofiber architecture. We therefore developed a novel automated motion correction scheme to improve the accuracy of in vivo DTI-tractography in the heart. An average SNR increase of 21% and a reduction in the propagation angle by up to 33% were observed after motion correction, indicating more accurate quantification of diffusion based-indices and more coherent fiber tracts. This will be particularly important for free breathing navigator-based DTI of the heart.

 
4496.   39 Sheet Tractography Provides a Multi-Dimensional Representation of Architecture in Normal and Infarcted Hearts
Choukri Mekkaoui1, Marcel Parolin Jackowski2, Timothy G. Reese3, and David E. Sosnovik3
1Harvard Medical School - Massachusetts General Hospital - Athinoula A Martinos center for Biomedical, Boston, MA, United States, 2University of São Paulo, São Paulo, São Paulo, Brazil, 3Harvard Medical School - Massachusetts General Hospital - Athinoula A Martinos center for Biomedical, Charlestown, MA, United States

 
Diffusion Tensor MRI (DTI) has shown that the orientation of the secondary and tertiary eigenvectors in the diffusion tensor correspond to the orientation of the myolaminar sheets in the heart. Myofiber tractography methods, however, have traditionally relied solely on the primary eigenvector to determine fiber trajectory. Here, we extend tractography in the heart by using the secondary and tertiary eigenvectors to reconstruct multi-dimensional tractographic sheets. We show that the rotation of these sheets defined by the torsion angle, is reduced in remodeled hearts.

 
4497.   40 Fast-Track Cardiac Diffusion Tensor Imaging with Compressed Sensing Based on a Novel Circular Cartesian Undersampling
Archontis Giannakidis1, Gerd Melkus2, Jing Liu2, David A. Saloner2, Sharmila Majumdar2, and Grant T. Gullberg1,2
1Radiotracer Development and Imaging Technology, Lawrence Berkeley National Laboratory, Berkeley, CA, United States, 2Radiology and Biomedical Imaging, University California San Francisco, San Francisco, CA, United States

 
A novel 3D Cartesian under-sampling scheme is applied to reduce acquisition time in the Diffusion Tensor MRI of an excised rat heart. Results show that acceleration of factors up to 6 may be achieved without substantial impairment of accuracy.

 
4498.   41 Model Based Automated 4D Analysis for Real-Time Free-Breathing Cardiac MRI
Bogdan Georgescu1, Nicole Seiberlich2, Tommaso Mansi1, Xiaoguang Lu1, Ali Kamen1, Vidya Nadig3, Dorin Comaniciu1, and Mark A. Griswold2
1Imaging and Computer Vision, Siemens Corporation, Corporate Technology, Princeton, New Jersey, United States, 2Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio, United States, 3MetroHealth Heart and Vascular Center, Case Western Reserve University, Cleveland, Ohio, United States

 
We propose a data-driven automated method to fit a parameterized 4D cardiac model of the left and right ventricles while simultaneously correcting for spatial slice mis-alignment. The method provides quantitative estimates of the ventricles morphology and dynamics and it can be applied to both standard breath-hold short axis CMR stacks as well as to a recently developed real-time free-breathing protocol using an undersampled radial trajectory and reconstructed using through-time radial GRAPPA. Initial results show successful slice re-alignment and quantitative measurements on both protocols are in good agreement with the ground-truth.

 
4499.   42 An Efficient Approach for Analysis of Real-Time Cine for LV Function Quantification -permission withheld
Yin Wu1, Na Zhang1, Fan Yang1, Yucheng Chen2, and Yiu-Cho Chung1
1Paul C. Lauterbur Research Center for Biomedical Imaging, Shenzhen Key Laboratory for MRI, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong, China, 2Cardiology Division, West China Hospital, Sichuan University, Chengdu, Sichuan, China

 
Real-time free-breathing cine imaging benefits LV function quantification of cardiac patients. Respiratory motion may mismatch thoracic positions of multiple slices in the cines and leads to errors in volumetric measurement. In this study, we proposed a simple but effective approach to identify ED and ES phases at end-expiration graphically from real-time free-breathing cines. Eight healthy volunteers were scanned using the real-time cine imaging and processed with the proposed method with conventional breath-hold cines as reference. Results showed that the real-time cine gave LV function measurements comparable to the standard protocol. The proposed method is an efficient way to analyze real-time cine.

 
4500.   43 Computer Assisted Branch Cut Placement for Computing 3D+t Biventricular Strain from Tagged MRI
Ming Li1,2, Bharath Ambale Venkatesh3, Himanshu Gupta4, Steve G. Lloyd4, Louis J. Dell'Italia4, and Thomas Stewart Denney Jr1,2
1AU MRI Research Center, Auburn University, Auburn, AL, United States, 2Electrical and Computer Engineering Department, Auburn University, Auburn, AL, United States, 3Johns Hopkins University, Baltimore, MD, United States, 4Department of Medicine, Division of Cardiovascular Disease, University of Alabama at Birmingham, Birmingham, AL, United States

 
Myocardial strain from tagged magnetic resonance imaging is an important parameter of cardiac mechanical function. In previous work, three-dimensional biventricular strain throughout cardiac cycle was reconstructed using displacement measurements obtained by unwrapping harmonic phase. Ideally, multiples of 2ð can be added to regions to unwrap a phase image, but noise and artifacts can create inconsistencies in the phase and cause unwrapping methods to fail. Previous work used manually-placed branch cuts to resolve these inconsistencies. In this abstract, we present an algorithm to automatically place branch cuts in both long and short axis tagged cardiac images and compute 3D+time biventricular strain.

 
4501.   44 Semi-Automated Segmentation of the Entire Left Ventricle from 3D Cine DENSE MRI Using Guide-Point Modeling
Daniel Alejandro Auger1, Xiaodong Zhong2, Frederick H. Epstein3, Ernesta M. Meintjes1, and Bruce S. Spottiswoode4
1MRC/UCT Medical Imaging Research Unit, Department of Human Biology, University of Cape Town, Cape Town, Western Cape, South Africa, 2MR R&D Collaborations, Siemens Medical Solutions, Atlanta, Georgia, United States, 3Departments of Radiology and Biomedical Engineering, University of Virginia, Charlottesville, Virginia, United States,4Cardiovascular MR R&D, Siemens Medical Solutions, Chicago, Illinois, United States

 
Demarcating the left ventricle (LV) from surrounding anatomical structures is an essentail step during the assessment of ventricular fucntion. Currently, this is done manually. This is time consuming, and the LV outline is left to the users interpretation. This work presents a semi-automatic segementation algorithm for 3D cine DENSE MRI. Using user defined guide points, a 3D LV geometrical model, and the inherent properties of cine DENSE, these methods improve the time required for segmentation by 10 fold, while showing promising results.

 
4502.   45 Helix Angle (HA) Healthy Statistical Average Technique for HA Quantification in vivo Cardiac Diffusion Tensor Imaging
Pedro Ferreira1, Sonia Nielles-Vallespin2, Peter David Gatehouse1, Ranil de Silva1, Jennifer Keegan1, Peter Speier3, Thorsten Feiweier4, Timothy G. Reese5, Tevfik Ismail1, Andrew Scott1, Choukri Mekkaoui5, David E. Sosnovik5, and David N. Firmin1
1BRU, Royal Brompton Hospital, London, United Kingdom, 2National Heart Lung and Blood Institute (NHLBI), National Institutes of Health (NIH), Bethesda, Maryland, United States,3MR Application & Workflow Development, Siemens, Erlangen, Germany, 4MR Application & Workflow Development, Siemens AG, Erlangen, Germany, 5Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, United States

 
A healthy average HA map was synthesised from a dataset of 10 healthy volunteers, matching the myocardial shape of the DTI data being analysed. This map allows for a direct pixel-by-pixel comparison of the cardiac fibres’ orientation in vivo. This technique was subsequently applied to evaluate the improved accuracy of in vivo cardiac DTI data sets based on numbers of averages, together with mean diffusivity and fractional anisotropy quantitation.

 
4503.   46 Virtual Short Axis: A Novel Method for Computing Left Atrial Volumes from Two and Four Chamber MRI
Nikhil Jha1,2, Chun Schiros3, Nouha Salibi4, Himanshu Gupta3, Steven Lloyd3, Louis J. Dell'Italia5, and Thomas Stewart Denney1,2
1AU MRI Research Center, Auburn University, Auburn, AL, United States, 2Electrical and Computer Engineering, Auburn University, Auburn, AL, United States, 3Division of Cardiology, University of Alabama Birmingham, Birmingham, AL, United States, 4MR R&D, Siemens Healthcare, Malvern, PA, United States, 5Division of Cardiology, University of Alabama at Birmingham, Birmingham, AL, United States

 
Quantification of left atrial (LA) volumes throughout the cardiac cycle is important to assess atrio-ventricular coupling. The area-length method is based on areas and lengths of the atrium in four chamber and two chamber views, but does not account for differences in LA shape. The serial short-axis method is more accurate, but requires acquisition of additional short-axis slices. We present and validate a new method for computing LA volumes from standard four and two chamber views, which computes “virtual” short-axis LA contours based on four and two chamber contours and sums the “virtual” slice volumes to compute a total volume.

 
4504.   47 Improved Navigator Based Diffusion Tensor MRI of the Human Heart in vivo
Pedro Ferreira1, Sonia Nielles-Vallespin2, Peter David Gatehouse1, Ranil de Silva1, Jennifer Keegan1, Peter Speier3, Thorsten Feiweier4, Timothy G. Reese5, Tevfik Ismail1, Andrew Scott1, Choukri Mekkaoui5, David E. Sosnovik5, and David N. Firmin1
1BRU, Royal Brompton Hospital, London, United Kingdom, 2National Heart Lung and Blood Institute (NHLBI), National Institutes of Health (NIH), Bethesda, Maryland, United States,3MR Application & Workflow Development, Siemens, Erlangen, Germany, 4MR Application & Workflow Development, Siemens AG, Erlangen, Germany, 5Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, United States

 
Novel post-processing techniques were applied to a prospective navigator protocol to allow in vivo DTI of the heart to be performed. 7 healthy volunteers were scanned using both navigator and breath-hold diffusion-weighted stimulated-echo single-shot EPI protocols. A post-processing interface was developed to allow the rejection of bad frames, followed by an automatic image registration algorithm before averaging. Mean diffusivity, fractional anisotropy, and helix-angle maps were derived. Statistical analysis showed no significant differences between the breath-hold and the new navigator protocol. This is a further step towards in vivo free breathing cardiac DTI.

 

ELECTRONIC POSTER SESSION • CARDIOVASCULAR
Thursday, 25 April 2013 (14:30-15:30) Exhibition Hall
Myocardial Tissue Characterisation

  Computer #  
4505.   25 Late Gadolinium Enhancement Imaging Using Spiral Readouts at 3T
Iain Thomas Pierce1,2, Jennifer Keegan1,2, Peter Drivas3, Peter David Gatehouse1,2, and David N. Firmin1,2
1NHLI, Imperial College London, London, United Kingdom, 2NIHR Royal Brompton Cardiovascular Biomedical Research Unit, Royal Bromton Hospital, London, United Kingdom, 3NIHR Royal Brompton Cardiovascular Biomedical Research Unit, Royal Brompton Hospital, London, United Kingdom

 
A comparison of standard Late Gadolinium Enhancement using Cartesian data acquisition against a similarly designed spiral readout sequence at 3T, in 12 volunteer patients. Mid, basal and apical short axis images were acquired with the spiral sequence after a 2D stack of standard LGE scans. Measurements of Left Ventrical blood pool SNR and LV blood pool – myocardium CNR were found to significantly increase when using the spiral sequence, mainly due to optimised flip angles. The shorter acquisition window allowed by the spiral readout may also reduce edge artefacts and motion blurring.

 
4506.   26 MR Diffusion Estimation of Intramyocellular Lipid Droplets in Myocardium
Victor B. Xie1,2, Peng Cao1,2, Shu-Juan J. Fan1,2, and Ed X. Wu1,2
1Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Hong Kong SAR, China, 2Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong SAR, China

 
Intramyocellular lipid serves as an important source of cellular energy for heart and it is mostly stored as lipid droplets. Lipid droplet size may be a useful biomarker for cardiac diseases. In this study, distribution of IMCL droplet size was investigated by measuring ADC in different parts of heart and different layers of myocardium, then droplet size was estimated from MR diffusion signal decays acquired at two diffusion times. ADC was documented to be relatively homogeneous within myocardium. Lipid droplet size was estimated and result was in good agreement with TEM measurement.

 
4507.   27 Magnetization Transfer Encoded Steady State Cardiac Imaging of Fibrotic Development in Mice
Moriel Vandsburger1, Katrien Vandoorne1, and Michal Neeman1
1Weizmann Institute of Science, Rehovot, None, Israel

 
The emergence of fibrotic tissue in the heart typically occurs either following myocardial infarction (MI) or accompanying heart failure. Fibrotic collagen generates significant magnetization transfer (MT) effects across a broad frequency range with surrounding water molecules. We sought to exploit the MT properties of collagen, using a novel free breathing retrospectively gated MT-encoded steady state cardiac cine method, in order to quantitatively and non-invasively image fibrotic scar formation following MI in mice.

 
4508.   28 Measurement of Spin-Spin Relaxation of Myocardial Lipids and Water at 3T by Optimized Clinical 1H MRS Protocol.
Martin Krssák1,2, Veronika Rackayova3, Gert Reiter4, Marek Chmelik5, Yvonne Winnhofer1, Siegfried Trattnig5, Anton Luger1, and Michael Krebs1
1Division of Endocrinology and Metabolism, Department of Intrenal Medicine III, Medical University of Vienna, Wien, Austria, 2Centre of Excellence High Field MR, Department of Radiology, Medical University of V ienna, Wien, Azerbaijan, 3Comenius University, Bratislava, Slovakia, 4Siemens Healthcare, Graz, Austria, 5Centre of Excellence High Field MR, Department of Radiology, Medical University of Vienna, Wien, Austria

 
Optimized 1H MRS protocol allowed for the measurement of spin spin relaxation times of lipid and water resonance lines in the myocardium of healthy volunteers (n=6). Using the PRESS sequence sufficient SNR has been achieved to quantify the water and methylene resonances in the range of echo times from 30 to 100 ms. Estimated T2 time for water (36.8±3.4 ms) is in agreement with previous MRI based results and T2 methylene lipid group (52.2±6.8 ms) is somewhat shorter than those measured in skeletal muscle at 3T.

 
4509.   29 A Comparative Study of Myocardial T1 Maps and PSIR Images in Measuring Extracellular Volume Fraction at 3T
Mao-Yuan Marine Su1, Lian-Yu Lin2, Chin-Cheng Chang3, Jiunn-Lee Lin2, and Wen-Yih Isaac Tseng1,4
1Department of Medical Imaging, National Taiwan University Hospital, Taipei, Taiwan, 2Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan,3Department of Internal Medicine, National Taiwn University Hospital, Taipei, Taiwan, 4Center for Optoelectronic Biomedicine, National Taiwan University College of Medicine, Taipei, Taiwan

 
In this study, we examined the compatibility of myocardial T1 maps and reconstructed images of phase-sensitive inversion recovery (PSIR) in measuring extracellular volume fraction (ECV) at 3T. Patients with systolic heart failure (SHF) showed significant higher ECV than patients with diastolic heart failure (DHF) and healthy volunteers (Control) which measured from T1 maps (0.31±0.03 vs. 0.28±0.02, p=0.004; 0.31±0.03 vs. 0.27±0.03, p = 0.003) and PSIR images (0.30±0.03 vs. 0.22±0.03, p<0.001; 0.30±0.03 vs. 0.22±0.04, p<0.001). There was no significant difference on ECV measurement between DHF and Control for both methods. A significant correlation was found on ECV measurement between two methods (r = 0.50, p = 0.001). In conclusion, PSIR images provide compatible measurement of myocardial ECV as T1 maps at 3T.

 
4510.   30 Quantitative MRI Assessment of LV Structural Remodeling and Fibrosis Formation in Canine Models of Chronic Atrial Fibrillation
Kyungpyo Hong1,2, Matthias Koopmann1, Ravi Ranjan1,3, Eric C. Huang4, Eugene G. Kholmovski1,5, Sathya Vijayakumar1,5, Christopher J. McGann1,3, Derek J. Dosdall1,3, Nassir F. Marrouche1,3, and Daniel Kim1,5
1CARMA Center, University of Utah, Salt Lake City, Utah, United States, 2Department of Bioengineering, University of Utah, Salt Lake City, Utah, United States, 3Internal Medicine, University of Utah, Salt Lake City, Utah, United States, 4Department of Pathology, University of California, Davis Medical Center, Sacramento, California, United States, 5UCAIR, Department of Radiology, University of Utah, Salt Lake City, Utah, United States

 
Atrial fibrillation (AF) causes left ventricular (LV) dysfunction, which is thought to be caused by structural remodeling and fibrosis. However, LV dysfunction induced by AF is under-diagnosed clinically, and its mechanisms are not clearly understood. Late gadolinium enhanced (LGE) cardiac T1 mapping enables assessment of LV structural remodeling and fibrosis development. We sought to study the LV fibrosis induced by AF in a canine model with chronic AF. Our data show that LV fibrosis increases with days after the onset of irregular rhythm. Our results are corroborated with the histological assessment of myocardial fibrosis.

 
4511.   31 Investigation of Cardiac Malate-Aspartate Shuttle at High Workload Using Hyperpolarized [1,2-13C2]pyruvate
Albert P. Chen1, Angus Z. Lau2,3, Yi-ping Gu2, Marie A. Schroeder4, Jennifer Barry5, and Charles H. Cunningham2,3
1GE Healthcare, Toronto, ON, Canada, 2Imaging Research, Sunnybrook Health Sciences Centre, Toronto, ON, Canada, 3Dept. of Medical Biophysics, University of Toronto, Toronto, ON, Canada, 4Dept. of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom, 5Imaging Research, Sunnybrook Research Institute, Toronto, ON, Canada

 
This study demonstrated that changes in α-ketoglutarate derived glutamate could be monitored non-invasively and independently from PDC flux using hyperpolarized [1,2-13C2]pyruvate at different cardiac workloads. A reduction in the glutamate to bicarbonate ratio may indicate a limited transport of reducing equivalent across mitochondria membrane via malate-aspartate shuttle at high cardiac workload.

 
4512.   32 Fusion of T1-Mapping and Semi Quantitative Perfusion (T1Per-Fusion) Imaging Provides Additional Insight Into Myocardial Tissue Viability
Matthias Alexander Dieringer1,2, Marcel Prothmann2, Florian von Knobelsdorff-Brenkenhoff1,2, Andreas Greiser3, Christina Eichhorn4, Thoralf Niendorf1,5, and Jeanette Schulz-Menger1,2
1Berlin Ultrahigh Field Facility (B.U.F.F.), Max-Delbrueck Center for Molecular Medicine, Berlin, Germany, 2Working Group on Cardiovascular Magnetic Resonance, Experimental and Clinical Research Center (ECRC), Berlin, Germany, 3Siemens AG, Erlangen, Germany, 4Max-Delbrueck Center for Molecular Medicine, Berlin, Germany, 5Experimental and Clinical Research Center (ECRC), a cooperation of the Charité Medical Faculty and the Max-Delbrueck Center for Molecular Medicine, Berlin, Germany

 
Cardiovascular MR (CMR) offers the unique capability for non-invasive characterization and differentiation of myocardial tissue. Viability imaging including detection of myocardial infarction is usually based on late Gadolinium enhanced (LGE) imaging. To deliver more precise information about pathogenesis and classification of cardiac disorders, quantitative MR imaging is promising to characterize stage and progress of complex pathophysiological processes. We propose a method that combines quantitative T1 and semi quantitative perfusion imaging to enable intra-individual assessment of impact and progress of cardiac diseases on myocardial tissue viability. The technique is presented on two patients with chronic myocardial infarction.

 
4513.   33 Conductive Channel Identified by Contrast-Enhanced Magnetic Resonance Imaging Predicts Ventricular Tachyarrhythmia in Patients with Systolic Heart Failure
Lian-Yu Lin1, Mao-Yuan Marine Su2, Jien-Jiun Chen3, Juey-Jen Hwang1, Chuen-Den Tseng1, Yih-Sharng Chen4, Hsi-Yu Yu4, Jiunn-Lee Lin1, and Wen-Yih Isaac Tseng2
1Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan, 2Department of Medical Imaging, National Taiwan University Hospital, Taipei, Taiwan,3Cardiovascular center, National Taiwan University Hospital Yun-Lin Branch, Douliu, Taiwan, 4Department of Surgery, National Taiwan University Hospital, Taipei, Taiwan

 
This study evaluates whether the conductive channel (CC) identified by late gadolinium-enhanced cardiac magnetic resonance (LGE-CMR) image is associated with ventricular tachyarrhythmia/ventricular fibrillation (VT/VF) in patients with systolic heart failure (HF). Patients with systolic HF were included and the CC in the left ventricular wall was identified, and it was compared between groups with or without VT/VF attack and between groups with or without mortality. Our results showed that the CC identification was significantly associated with VT/VF, whereas the CC together with the percentage of the core scar region were associated with total mortality.

 
4514.   34 Changes of Myocardial Lipid Content and Left Ventricular Function in the Course of Acute Hypoglycemia and Inhibition of Lipolysis.
Martin Krssák1,2, Yvonne Winnhofer1, Peter Wolf1, Drazenka Jankovic1, Sabina Baumgartner-Parzer1, Rodrig Marculescu3, Michael Wolzt4, Siegfried Trattnig2, Anton Luger1, and Michael Krebs1
1Division of Endocrinology and Metabolism, Department of Intrenal Medicine III, Medical University of Vienna, Wien, Austria, 2Centre of Excellence High Field MR, Department of Radiology, Medical University of Vienna, Wien, Austria, 3Department of Laboratory Diagnostics, Medical University of Vienna, Wien, Austria, 4Department of Clinical Pharmacology, Medical University of Vienna, Wien, Austria

 
Proton MRS and MRI were used to follow the myocardial lipid content (MYCL) and left ventricular ejection fraction (LVEF) in the course of acute hypoglycemia and 24h follow up in young healthy male volunteers (n=8). Lipolysis was alternatively inhibited to distinguish the effects of hypoglycemia and counter-regulation induced lipolysis. Acute hypoglycemia did not reduce the LVEF and MYCL, but MYCL decreased in 24h follow up measurement. Inhibition of adipose tissue lipolysis w/o insulin action was accompanied by decrease of MYCL and LVEF. We conclude that MYCL stores play a major role for the maintenance of myocardial function.

 
4515.   35 Assessment of Lesion Characteristics Post RF Ablation Procedure in a Chronic Canine Model of Atrial Fibrillation
Sathya Vijayakumar1,2, Ravi Ranjan2, Derek J. Dosdall2, Kyungpyo Hong2,3, Daniel Kim1,2, Nassir F. Marrouche2, and Eugene G. Kholmovski1,2
1UCAIR, Dept. of Radiology, University of Utah, Salt Lake City, Utah, United States, 2CARMA, Dept. of Cardiology, University of Utah, Salt Lake City, Utah, United States,3BioEngineering, University of Utah, Salt Lake City, Utah, United States

 
This work examines the contrast kinetics of post radio-frequency ablation lesions in the myocardium of a pacemaker induced atrial fibrillation canine model. We image these dogs, immediately after ablation procedure for a duration of 2.5 hours and repeat imaging every week after.

 
4516.   36 Myocardial and LV Blood T1 Measurement Using 3.0T MOLLI: Importance of Heart Rate Correction
Shinichi Takase1, Masaki Ishida1, Shiho Isoshima1, Tsunehiro Yamahata1, Akira Kamigiri1, and Hajime Sakuma1
1Department of Radiology, Mie University Hospital, Tsu, Mie, Japan

 
3-3-5 MOLLI underestimates true tissue T1 as heart rate (HR) and T1 increase. Fifteen volunteers were scanned by 3-3-5 MOLLI at 3.0T and divided into two groups by a cutoff HR of 70bpm. Compared to lower HR group, higher HR group gave significantly smaller myocardial and blood T1. T1 HR correction formula was obtained by phantom study separately. After HR correction, myocardial and blood T1 were substantially augmented in both groups resulting in smaller T1 differences between the groups. HR-corrected T1 measurement with 3-3-5 MOLLI at 3.0T allows for accurate myocardial and blood T1 quantification regardless of HR and T1.

 
4517.   37 Novel Detection of Intramyocardial Hemorrhage Following Acute Myocardial Infarction by T2 Mapping
Nilesh R. Ghugre1,2, Venkat Ramanan1, Mihaela Pop1, Jennifer Barry1, Kim A. Connelly3, and Graham A. Wright1,2
1Physical Sciences Platform, Sunnybrook Research Institute, Toronto, ON, Canada, 2Medical Biophysics, University of Toronto, Toronto, ON, Canada, 3Division of Cardiology, St. Michaels Hospital, Toronto, ON, Canada

 
T2 mapping techniques [M=M0.exp(-t/T2)] can detect the occurrence of hemorrhage after acute myocardial infarction but can be confounded by opposing effects from edema. We hypothesized that the M0 term may provide additional information beyond T2 for identifying the hemorrhagic sites. The study involved a porcine model (N=6) with imaging at day 2 post-infarction. Hemorrhagic sites could not be distinctly identified on T2 maps, however M0 maps demonstrated signal voids that were spatially correlated with those identified as hemorrhage on T2* maps. T2 and M0 maps together provide complementary information that may potentially be valuable in simultaneously characterizing both the inflammatory and hemorrhagic state of tissue post-AMI.

 
4518.   38 Radiofrequency Ablation Characterization: Comparison of Multi-Contrast Late Enhancement and Late Gadolinium Enhancement Sequences
Haydar Celik1, Venkat Ramanan1, Jennifer Barry1, Sudip Ghate1, Vivian Leber1, Mohammed Shurrab2, Samuel Oduneye1, Nilesh R. Ghugre1, Eugene Crystal2, and Graham A. Wright1
1Imaging Research, Sunnybrook Research Institute, Toronto, ON, Canada, 2Arrhythmia Services, Sunnybrook Research Institute, Toronto, ON, Canada

 
Cardiologists treat arrhythmias, which are the results of abnormal electrical pulses in heart, by creating radiofrequency ablation (RFA) lines under the guidance of x-ray. Although x-ray is accurate for catheter visualization, its soft tissue contrast is insufficient to visualize RFA lesions. The late Gd-DTPA enhancement (LGE) method has been used for characterization of RFA lesions. Here, the multi-contrast late enhancement (MCLE) technique was proposed for a more robust characterization of the RFA lesions. The MCLE method provides images with varying contrast and quantitative T1* and steady-state maps, derived from these MCLE images.

 
4519.   39 Comparison of Instant Thrombolysis Plus Early PCI and Primary PCI in STEMI Patients, View of CMR Early After Reperfusion Therapy
Heng Ge1, Jun Bo1, Haiyan Ding2, Robert Manka3, Zheng Li1, Jianrong Xu1, and Ben He1
1Cardiology, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China, 2Center for Biomedical Imaging Research, Tsinghua University, Bei Jing, China,3Cardiology, University hospital Zurich, Zurich, Switzerland

 
This abstract demonstrated preliminary CMR results from an ongoing randomized study comparing efficacy of instant thrombolysis plus early PCI against primary PCI in STEMI patients. CMR data suggested overall equal outcomes between the two treatments regarding to the left ventricular function, necrosis size and microvascular dysfunction. This supports the usage of instant thrombolysis plus early PCI strategy as a reasonable alternative reperfusion modality for STEMI patients.

 
4520.   40 3D Saturation Recovery Imaging for Free Breathing Myocardial T1 Mapping
Markus Henningsson1, Rene M. Botnar1, and Tobias Voigt2
1Division of Imaging Sciences and Biomedical Engineering, King's College London, London, United Kingdom, 2Clinical Research Europe, Philips Research, London, United Kingdom

 
2D SAturation-recovery single SHot Acquisition (SASHA) has recently been proposed to provide more accurate myocardial T1 mapping. In this work we extend the 2D SASHA sequence to 3D and enable free breathing data acquisition by introducing respiratory navigation. The proposed sequence is compared to breath held 2D SASHA and 2D Modified Look-Locker Inversion recovery (MOLLI) in a T1 phantom and 7 healthy volunteers. Free breathing 3D SASHA provides T1 values in excellent agreement with 2D SASHA in vivo and in the phantom experiments.

 
4521.   41 Analysis of T1, T2 and T1lower case Greek rho Spin Lock Field Dependency in Myocardial Infarction Tissue Using HRMAS Spectroscopy at 11.7 T
Joep van Oorschot1, Mohammed Kaplan2, Marc Baldus2, Peter R. Luijten1, and Jaco J.M. Zwanenburg1
1Radiology, UMC Utrecht, Utrecht, Utrecht, Netherlands, 2Bijvoet Center, Utrecht University, Utrecht, Utrecht, Netherlands

 
After myocardial infarction (MI) scarring fibrosis is formed. In this study T1, T2 and T1ρ were studied with HRMAS spectroscopy after myocardial infarction. Two weeks after occlusion of the left coronary artery of a landrace pig, two tissue samples were extracted from infarcted and healthy heart muscle tissue. The medium T2 component (~30ms) was significantly higher in infarcted tissue, which can be explained by cell death after MI. For higher spin lock frequencies (>500 Hz), T1ρ was significantly higher in infarcted tissue. This suggests that a T1ρ-weighted sequence with high spin-lock field is promising for endogenous detection of myocardial fibrosis.

 
4522.   42 Assessment of Non-Linearities in Cardiac Perfusion Measurements Using Low-TI AIF Images
Felix Schwab1, Lena Vomacka1, Daniel Theisen1, Maximilian F. Reiser1, and Olaf Dietrich1
1Institute for Clinical Radiology, Ludwig-Maximilian-University Hospital Munich, Munich, Bavaria, Germany

 
This abstract investigates the potential of Low TI saturation recovery sequences to assess non-linearities in cardiac perfusion analyses. The corresponding sequences appear to be well described by a linear approximation and demonstrate that standard clinical protocols are afflicted with significant non-linearities and thus overestimate perfusion parameters. Arterial input functions calculated from the low TI protocols can circumvent this problem.

 
4523.   43 Quantitative Myocardial Perfusion Imaging: Comparison of SR-TurboFLASH and SR-TrueFISP at 1.5T and 3.0T
Stefan Weber1, Inci Davulcu1, Christoph Düber2, Karl Friedrich Kreitner2, and Laura Maria Schreiber1
1Department of Radiology, Section of Medical Physics, Mainz University Medical Center, Mainz, Germany, 2Department of Radiology, Mainz University Medical Center, Mainz, Germany

 
Contrast-enhanced magnetic resonance myocardial perfusion imaging is a very promising concept for the noninvasive detection of coronary artery disease. The Aim of this work was to investigate and compare the two for myocardial perfusion imaging established pulse sequences SR-TurboFLASH and SR-TrueFISP at 1.5T and 3.0T. The pulse sequences and field strengths were compared with regard to SNR and CNR as well as for their intra-observer variability in absolute quantification of the myocardial blood flow. SR-TrueFISP at 3.0T yielded highest SNR and CNR values as well as the lowest intra-observer variability.

 
4524.   44 MRI Perfusion Indices During the Evolution of Microembolized Myocardial Infarct
Maythem Saeed1, Jessica Murayama1, Carol Stillson1, Loi Do1, Steven W. Hetts2, and Mark W. Wilson1
1Radiology and Biomedical Imaging, UC San Francisco, San Francisco, Ca, United States, 2Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, Ca, United States

 
The aims were to chronologically monitor and compare myocardial perfusion in swine subjected to infarct with and without coronary microemboli release. Gradient echo pulse sequences were used to monitor Gd-DTPA passage in LV and measure infarct size at 3 days and 5 weeks after interventions. Microemboli in pre-existing infarct induced progressive perfusion deficit, increased incidence of microvascular obstruction, and infarct size. MR indices of myocardial perfusion provide valuable information on the effects of coronary microemboli in pre-existing AMI and hypertrophied remote myocardium. The high sensitivity of MR perfusion makes it a powerful tool in evaluation of new distal filtration devices.

 
4525.   45 In Vivo Performance of Myocardial Background Suppression
Terrence Jao1, Hung Phi Do2, and Krishna S. Nayak3
1Biomedical Engineering, University of Southern California, Los Angeles, California, United States, 2Department of Physics, University of Southern California, Los Angeles, California, United States, 3Electrical Engineering, University of Southern California, Los Angeles, California, United States

 
Myocardial arterial spin labeling (ASL) is a technique for measuring myocardial perfusion and perfusion reserve through the subtraction of labeled and non-labeled images. Imperfect subtraction caused by cardiac or respiratory motion will lead to measurement error. In this work, we examine the potential for myocardial background suppression using a saturation-double-inversion-recovery preparation that is compatible with ASL experiments. In six volunteers, myocardial signal was suppressed to 1.14% ± 1.24% of its equilibrium value.

 
4526.   46 Accurate Quantitative Myocardial Perfusion Using Single Cycle T1 Mapping
David Chen1, Behzad Sharif1, and Debiao Li1
1Cedars Sinai Medical Center, Los Angeles, CA, United States

 
Quantitative myocardial perfusion MRI depends on accurate determination of the arterial input function. By calculating blood and myocardial T1 values during the first pass, CA concentration can be estimated accurately, overcoming the signal saturation problem. This method requires only a single scan which minimizes both scan time and setup time.

 
4527.   47 Comparison of Fully Quantitative and Semi-Quantitative Measure of Women’s Myocardial Perfusion Reserve for Detection of Microvascular Coronary Dysfunction
David Chen1, Behzad Sharif1, Afsaneh Haftbaradaran1, Melody Zaya1, Chrisandra Shufelt2, Puja Mehta1, Daniel S. Berman1, Louis EJ Thomson1, Debiao Li1, and Noel Bairey Merz1
1Cedars Sinai Medical Center, Los Angeles, CA, United States, 2Cedars Sinai Medical Center, Los Angeles, California, United States

 
Myocardial perfusion reserve (MPR) acquired using first-pass cardiac MRI is a measure of the severity of microvascular coronary dysfunction (MCD) in subjects with signs and symptoms of ischemia but no obstructive coronary artery disease (CAD). Semi-quantitative measures (upslopes) have been used to analyze MPR data in the previous work. In this work, we propose using a fully quantitative myocardial blood flow (MBF) analysis to evaluate whether MPR is different between subjects with MCD and normal controls. MPR measured by quantitative MBF analysis provides better detection of MCD than that using semi-quantitative upslopes.

 

ELECTRONIC POSTER SESSION • CARDIOVASCULAR
Thursday, 25 April 2013 (13:30-14:30) Exhibition Hall
Vessel Wall & Coronary Angiography

  Computer #  
4528.   
49 Free-Breathing Whole-Heart Coronary MRI: An Image-Based Motion Compensation Integrated Into Compressed-Sensing Reconstruction
Christoph Forman1,2, Robert Grimm3, Jana Hutter2,3, Jakob Wasza3, Martin Kraus2,3, Joachim Hornegger2,3, and Michael O. Zenge4
1Pattern Recognition Lab, Friedrich-Alexander-University Erlangen-Nürnberg, Erlangen, Germany, 2Erlangen Graduate School in Advanced Optical Technologies (SAOT), Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany, 3Pattern Recognition Lab, Department of Computer Science, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany, 4Healthcare Sector, Siemens AG, Erlangen, Germany

 
In the current work, a method to compensate for respiratory motion by incorporating a motion model into a compressed sensing reconstruction is presented. Therefore, the input data were binned into respiratory phases first and, then, all bins with sufficient data were reconstructed iteratively using a weighted CS reconstruction. Based on these sub-volumes, a motion model was determined using non-rigid inverse-consistent registration. Finally, the resulting deformation fields were used in the reconstruction of a combined dataset without motion artifacts. Compared to the original weighted CS reconstruction the images feature more signal and a sharper delineation of the coronary arteries.

 
4529.   50 Computer-Aided Diagnosis Scheme for Detecting Significant Stenosis on Whole Heart Coronary MR Angiography Based on Signal Intensity and Luminal Diameter -permission withheld
Ryohei Nakayama1, Masaki Ishida1, Nobuo Nakako1, Motonori Nagata1, Kakuya Kitagawa1, and Hajime Sakuma1
1Department of Radiology, Mie University School of Medicine, Tsu, Mie, Japan

 
A computer-aided diagnosis (CAD) was developed for detecting significant stenosis on whole heart coronary MRA. Coronary arterial segments were automatically classified according to AHA model. At each voxel on the centerline, a classifier based on the Mahalanobis distance for the changes of signal intensity and luminal diameter was employed for distinguishing between arteries with and without stenosis. In 34 patients with suspected coronary artery disease, the sensitivity and specificity of the CAD were 80% and 81%. The CAD scheme developed in this study showed high diagnostic performance and will have a substantial impact on interpretation of coronary MRA.

 
4530.   51 Coronary MRA at 3 Tesla – a Qualitative Comparison of a Novel Adiabatic T2-Preparation with Classic MLEV4
Wolfgang G. Rehwald1,2, Christoph Jensen2, Elizabeth R. Jenista2, David C. Wendell2, Enn-Ling Chen2, and Raymond J. Kim2
1Cardiovascular MR R&D, Siemens Healthcare, Durham, NC, United States, 2Cardiology, Duke University, Durham, NC, United States

 
Non-contrast coronary MRA at 3T relies on a B1-, B0-, and motion-insensitive T2-preparation to accurately depict coronary anomalies and stenoses. We previously developed an adiabatic T2-preparation fulfilling these requirements. In the current study, we compared its performance to the clinical standard MLEV4. We scored the depiction quality of six representative coronary segments and the visibility of selected proximal artery segments, and tested for statistical differences. The adiabatic module provided significantly improved image quality in the selected segments, and detected significantly more of the proximal coronary segments. Visual inspection of curved MPRs obtained from the same data confirmed our results.

 
4531.   52 Gadofosveset Optimization for Self-Navigated Coronary MR Angiography
Mark A. Ahlman1, Scott Penzak2, Fabio Raman1, Jianing Pang3, Songtao Liu1, Debiao Li3, and David A. Bluemke1
1Radiology and Imaging Sciences, National Institutes of Health, Bethesda, Maryland, United States, 2Pharmacy, National Institutes of Health, Bethesda, Maryland, United States,3Bioengineering, Cedars-Sianai Medical Center, Los Angeles, California, United States

 
We proposed and validated a mathematically derived injection protocol for an intravascular contrast agent (Gadofosveset) that results in near constant blood T1 time over 5-6 minutes. Such an injection protocol should be idea for a 3D radial coronary MRA sequence with self-navigation. Using this model, we give evidence for proof-of-concept of the clinical applicability of our injection technique in humans.

 
4532.   53 Preventing Unwanted Blurring Due to Incomplete Breath-Hold at Long Breath-Hold Coronary MRA; Usefulness of New Elliptical Centric Acquisition(CENTRA Plus)
Hideo Ono1, Masami Yoneyama1, Taro Takahara2, Thomas C. Kwee3, Masanobu Nakamura1, Takashi Tabuchi1, and Masaharu Hirano4
1Yaesu Clinic, Tokyo, Japan, 2Tokai University School of Engineering, Kanagawa, Japan, 3University Medical Center Untrecht, Utrecht, Netherlands, 4Tokyo Medical University Hospital, Tokyo, Japan

 
Recently, single breath-hold Whole Heart Coronary MRA has emerged thanks to the acceleration of data acquisition. However, the limited scan time during the breath-hold period results in poor signal-to-noise ratio and spatial resolution. We may be able to get higher resolution images with longer scan times of, for example, around 30 sec, but this kind of protocol is unrealistic and reduces the success rate of the examination in case of incomplete breath-holding. Our hypothesis is that the new method of ellipsoid centric acquisition (CENTRA plus) may be tolerable for this kind of fail in breath-hold which happens in the latter half of the scanning.

 
4533.   54 Highly Accelerated Multi-Contrast Carotid Imaging Using Sharable Information
Wenchuan Wu1, Hua Guo1, Chun Yuan1,2, George Randy Duensing3, and Feng Huang4
1Center for Biomedical Imaging Research, Department of Biomedical Engineering,School of Medicine, Tsinghua University, Beijing, China, 2Department of Radiology, University of Washington, Seattle, WA, United States, 3Philips Healthcare, Gainesville, FL, United States, 4Philips Healthcare, Beijing, China

 
In this study, sharable information from multi-contrast carotid scans were extracted and applied to improved partially parallel imaging. Preliminary results show that proposed method can achieve superior image quality than traditional PPI method, and diagnostic information were mostly preserved during the reconstruction.

 
4534.   55 Dynamic Fast Spin Echo Imaging of the Carotid Arteries
Mari Elyse Boesen1,2, Jerome Yerly2,3, Michel Louis Lauzon2,4, Robert Marc Lebel2,5, and Richard Frayne2,4
1Physics & Astronomy, University of Calgary, Calgary, AB, Canada, 2Seaman Family MR Research Centre, Foothills Medical Centre, Calgary, AB, Canada, 3Electrical and Computer Engineering, University of Calgary, Calgary, AB, Canada, 4Radiology and Clinical Neurosciences, University of Calgary, Calgary, AB, Canada, 5Applied Sciences Laboratory, General Electric Healthcare, Calgary, AB, Canada

 
A time-resolved black blood acquisition can provide simultaneous morphological and distensibility analyses in the carotid arteries. A retrospectively gated fast spin echo sequence was applied at the carotid bifurcation to examine cross sectional area change over the course of the cardiac cycle. Carotid distension was measured using an automated segmentation routine over twelve cardiac phases. The same datasets were also reconstructed statically and a reduction in motion artifact was observed due to the non-uniform sampling scheme used.

 
4535.   56 Comparison of Carotid Plaque Characteristics Between Japanese and Midwest American Caucasian Patients with Coronary Artery Disease: A 3.0T MRI Study.
Hideki Ota1, J. Kevin DeMarco2, Minako Wakayama3, David C. Zhu2, Kei Takase1, and Shoki Takahashi1
1Diagnostic Radiology, Tohoku University Hospital, Sendai, Miyagi, Japan, 2Radiology, Michigan State University, East Lansing, MI, United States, 3Cardiology, Sendai Red Cross Hospital, Sendai, Miyagi, Japan

 
The purpose of this study was to compare carotid plaque characteristics in Japanese (Asian) and Midwest American (Caucasian) patients with advanced atherosclerosis. Twenty-two Japanese and 32 American men with asymptomatic >50% carotid stenosis and history of coronary artery disease underwent multi-contrast carotid MR imaging. After adjusting for baseline demographic characteristics as possible confounders, Japanese patients more commonly had complicated AHA-type VI plaque, hemorrhage and larger necrotic core than Americans. The present results indicate that the development of carotid atherosclerosis appears different between the two populations with advanced atherosclerosis.

 
4536.   57 Detection of Thoracic Aorta Atherosclerotic Disease Using Simultaneous Non-Contrast Angiography and IntraPlaque Hemorrhage (SNAP) MR Imaging Technique -permission withheld
Le He1, Xihai Zhao1, Rui Li1, Jinnan Wang2, and Chun Yuan1,3
1Center for Biomedical Imaging Research, Department of Biomedical Engineering, Tsinghua University, Beijing, China, 2Philips Research North America, Briarcliff Manor, NY, United States, 3Department of radiology, University of Washington, Seattle, WA, United States

 
Atherosclerotic disease in the thoracic aorta has been linked to an increased risk of thromboembolic events (such as embolic stroke or ischemic bowel) and an increased risk of mortality and stroke, especially for asymptomatic at-risk patients. It is very important to reliably identify aortic plaques. But the thoracic aorta located deep in the chest, it is difficult to directly evaluate the vessel wall condition with high resolution images. In this study, new MR was optimized and evaluated for the screening of the thoracic aorta atherosclerotic plaques.

 
4537.   58 High Resolution Three Dimensional Intracranial Arterial Wall Imaging at 3T Using SNR-Optimized T1 Weighted SPACE
Lei Zhang1,2, Qing Zhai3, Na Zhang1,2, XiaoXin Tong3, Xin Liu1,2, and Yiu-cho Chung1,2
1Paul C. Lauterbur Research Center for Biomedical Imaging, Shenzhen Institution of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong, China,2Shenzhen Key Laboratory for MRI, Shenzhen, Guangdong, China, 3Department of Neurology, Peking University Shenzhen Hospital, Shenzhen, Guangdong, China

 
Intracranial atherosclerosis is a major cause of ischemic stroke. T1w-SPACE can be used to image vessel wall of intracranial arteries. However, scan time, spatial coverage and contrast compete with each other in this technique. Here, Bloch equation simulation was performed to understand the relationships among these key imaging parameters. Results were verified by volunteer study. In patients, a shorter than optimal TR was need to increase anatomical coverage. Intracranial plaques were successfully identified by pre- and post-contrast T1w-SPACE. This technique may be a clinically useful tool for screening intracranial arterial disease in patients with high risk of ischemic stroke.

 
4538.   59 Quantitative Evaluation of the Current Status of Carotid Artery Imaging at 7T with Respect to 3T
Wouter Koning1, Hanneke Bluemink1, Tijl A. van der Velden1, Michel Italiaander1, Peter R. Luijten1, Jaco J.M. Zwanenburg1, and Dennis W. J. Klomp1
1University Medical Center, Utrecht, Utrecht, Netherlands

 
MRI of the carotid arteries at 7T was evaluated and quantitatively compared to 3T. High resolution turbo spin echo images of a series volunteers were acquired at both field strengths for qualitative comparison. Intrinsic SNR and T2 in the vessel wall was measured for quantitative comparison.

 
4539.   60 Diffusion Weighted Imaging (DWI) in the Rabbit Model of Atherosclerosis: Characterization and Quantification of Water Diffusion in Six-Month Old Aortic Plaque
Philip M. Robson1,2, Claudia Calcagno1,2, Sarayu Ramachandran1,2, Venkatesh Mani1,2, and Zahi A. Fayad1,2
1Translational and Molecular Imaging Institute, Mount Sinai School of Medicine, New York, New York, United States, 2Radiology, Mount Sinai School of Medicine, New York, New York, United States

 
We investigate in vivo diffusion weighted imaging in the rabbit model of atherosclerosis at 3 T using SE-DW single-shot EPI, with 12 different b-values equally spaced up to 600 s/mm2, and 16 slices in a 20-minute protocol. The average diffusion coefficient was 1.19x10-3 mm2/s and the average two-tailed span of the 90% confidence interval for the diffusion coefficient was 0.3x10-3 mm2/s, which is sufficient to distinguish normal vessel wall, lipid core, and free water. DWI is a feasible technique for quantitative characterization of atherosclerotic plaque in the NZW rabbit model in vivo and may provide important information about high-risk plaques.

 
4540.   61 Multisequence Whole-Brain Intracranial Vessel Wall Imaging at 7.0 Tesla MRI
Anja G. van der Kolk1, Jeroen Hendrikse1, Manon Brundel2, Geert Jan Biessels2, Ewoud J. Smit1, Fredy Visser1,3, Peter R. Luijten1, and Jaco J.M. Zwanenburg1,4
1Department of Radiology, University Medical Center Utrecht, Utrecht, Netherlands, 2Department of Neurology, University Medical Center Utrecht, Utrecht, Netherlands, 3Philips Healthcare, Best, Netherlands, 4Image Sciences Institute, University Medical Center Utrecht, Utrecht, Netherlands

 
Intracranial atherosclerosis is an important cause of ischemic stroke. Imaging techniques depicting the intracranial arterial vessel wall and its pathology are therefore important, like the Magnetization-Preparation Inversion Recovery (MPIR)-TSE sequence at 7.0 Tesla MRI. However, this sequence has small coverage, limiting assessment of peripheral arteries. In this study we adapted the MPIR-TSE sequence to obtain whole-brain coverage, with different contrasts weightings. These new sequences were able to depict vessel walls throughout the brain, at a level of detail almost equal to the limited-coverage sequence, and can be used both in future studies regarding intracranial arterial pathology, and in clinical practice.

 
4541.   62 Fast Relaxation Time Mapping in Human Carotid Artery Wall Using Black Blood DANTE 2D Turbo Spin Echo
Linqing Li1, Luca Biasiolli2, Matthew D. Robson2, Karla L. Miller1, and Peter Jezzard1
1FMRIB Centre, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom, 2Department of Cardiovascular Medicine, University of Oxford, Oxford, United Kingdom

 
DANTE prepared 2D-TSE has previously been demonstrated effective application of fast BB imaging. In this work, we first derived a highly simplified linear equation M=M0[1-1/2(T1/T2)1/2] from the longitudinal Bloch equation at steady state of DANTE pulses. Equation was then verified to be applicable when DANTE pulse train is interspersed with readout modules. Finally, in-vivo BB experiments for T1 and T2 mapping demonstrate that DANTE-TSE has potential to be applied as fast (3measurements in 10minutes with 39slices), high resolution (0.6×0.6×2mm) and robust (insensitive to susceptibility in both preparation and readout module) imaging tool for relaxation time mapping carotid artery walls.

 
4542.   63 Numerical Simulations of Carotid MRI: How Accurately Can We Quantify Atherosclerotic Plaque Components in vivo?
Harm Nieuwstadt1, Tom Geraedts2, Martine Truijman3, Eline Kooi3, Aad van der Lugt1, Ton van der Steen1, Jolanda Wentzel1, Marcel Breeuwer2, and Frank Gijsen1
1Erasmus MC, Rotterdam, Zuid Holland, Netherlands, 2Philips Healthcare, Best, Noord Brabant, Netherlands, 3Maastricht University Medical Centre, Maastricht, Limburg, Netherlands

 
Numerical simulations of carotid MRI were performed to assess the accuracy in segmentation of plaque components. We simulated an in vivo T1W contrast-enhanced carotid MRI protocol and evaluated it by comparison with clinical patient images. Plaque geometries derived from histological data were used as input for the MRI simulations. We found that manual segmentation of the luminal area, vessel wall area and LRNC area showed excellent correlation and inter observer agreement. FC’s smaller than 0.6 were severely overestimated in thickness and quantified inaccurately, while the thickness of FC’s larger than 0.6 mm was assessed reliably.

 
4543.   64 Correlation Between Inflammation as Assessed with 18F-FDG PET and Microvasculature as Assessed with Dynamic Contrast-Enhanced MRI in Carotid Atherosclerotic Plaques
Martine Truijman1,2, Robert Kwee1, Michaela Gaens1,3, Raf van Hoof1,3, Evelien Hermeling1,3, Stefan Vöö3,4, Rob van der Geest5, Tobien Schreuder6, Narender van Orshoven7, Be Meems8, Felix Mottaghy4, Robert J. van Oostenbrugge3,9, Werner Mess2, Joachim E. Wildberger1, Walter H. Backes1, M.J.A.P. Daemen10, Jan Bucerius3,4, and Eline Kooi1,3
1Radiology, MUMC, Maastricht, Netherlands, 2Clinical Neurophysiology, MUMC, Maastricht, Netherlands, 3Cardiovascular Research Institute Maastricht, MUMC, Maastricht, Netherlands, 4Nuclear Medicine, MUMC, Maastricht, Netherlands, 5Radiology, Leiden University Medical Center, Leiden, Netherlands, 6Neurology, Atrium Medical Center, Heerlen, Netherlands, 7Neurology, Orbis Medical Center, Sittard, Netherlands, 8Neurology, Viecuri, Venlo, Netherlands, 9Neurology, MUMC, Maastricht, Netherlands, 10Pathology, Amsterdam Medical Center, Amsterdam, Netherlands

 
Identifying vulnerable atherosclerotic plaques in symptomatic patients with moderate (30-69%) carotid artery stenosis can contribute to clinical decision making in performing a carotid endarterectomy. Inflammation, assessed with 18F-FDG PET and microvasculature, assessed with dynamic contrast-enhanced (DCE-MRI), are important features of a vulnerable plaque. The purpose of this study is to investigate the correlation between these two features to study whether these imaging modalities are interchangeable or provide additional information. We found a weak but significant positive correlation between mean Ktrans and mean SUV, meaning that these techniques are not interchangeable.

 
4544.   65 COCOA and Its Combination with Prospective Motion Compensation for Robust Carotid MRI
Feng Huang1, Xihai Zhao2, Le He2, George Randy Duensing3, and Chun Yuan2,4
1Philips Healthcare, Beijing, Beijing, China, 2Center for Biomedical Imaging Research, TsingHua University, Beijing, Beijing, China, 3Philips Healthcare, Gainesville, FL, United States,4University of Washington, Seattle, Washington, United States

 
Due to the long acquisition time, the image quality of Carotid MRI is vulnerable to involuntary motions. COCOA, as a retrospective method, can suppress the random motion artifacts, such as swallowing; but cannot totally remove strong motion artifacts, such as serious head motion. Prospective motion detection and data re-acquisition method is efficient for strong random motion artifacts, but could have residual motion artifacts to balance acquisition efficiency and motion correction. The combination of retrospective and prospective motion compensation method is proposed. Preliminary results demonstrate that the proposed method can consistently and dramatically reduce motion artifacts with moderately prolonged acquisition time.

 
4545.   66 Characterization of Coronary Plaque Using MPRAGE at 3T MRI : Comparison with MDCT and IVUS Findings
Yoshiaki Morita1, Naoaki Yamada1, Reiko Fujiwara2, Yasuhide Asaumi2, Hiroki Sakamoto2, Teruo Noguchi2, Suzu Kanzaki1, Masahiro Higashi1, and Hiroaki Naito1
1Department of Radiology, National Cerebral and Cardiovascular Center, Suita, Osaka, Japan, 2Division of Cardiology, National Cerebral and Cardiovascular Center, Suita, Osaka, Japan

 
In carotid plaque, it is widely known that T1WI high signal is associated with complicated plaque (AHA type IV) and recent cerebrovascular events. In this study, we evaluated the characterization of coronary plaque using inversion-recovery-based 3D T1-weighted imaging (alternatively known as magnetization-prepared rapid acquisition with gradient-echo {MPRAGE}) compared with the CT and IVUS findings that are related to vulnerable plaque in previous studies. Hyperintense plaque on MPRAGE was strongly associated with low CT density, positive remodeling, ultrasound attenuation and increase in lipid area on IB-IVUS. The results suggest that MPRAGE has a potential as marker for plaque vulnerability.

 

ELECTRONIC POSTER SESSION • CARDIOVASCULAR
Thursday, 25 April 2013 (14:30-15:30) Exhibition Hall
Cardiovascular MAI Education

  Computer #  
4546.   49 Non Invasive Imaging of Pulmonary Arterial Hypertension and Other Causes of Pulmonary Hypertension: Clinical State of the Art -permission withheld
Venkata Meduri1, Dheeraj Gopireddy1, Naila Qazi2, Chris Francoise1, and Mark L. Schiebler1
1Radiology, University of Wisconsin-Madison, Madison, WI, United States, 2Radiology, University of Wisconsin-Madion, Madison, WI, United States

 
Familiarity with both the clinical manifestations and the myriad of imaging findings associated with pulmonary arterial hypertension can help to suggest the diagnosis. MRA is playing a greater role in the evaluation of PAH, and may help to monitor therapy non-invasively. This presentation is designed to educate these findings in a clinically-relevant manner.

 
4547.   50 Magnetic Resonance Guidance of Cardiac Resynchronization Therapy
Peter Bernhardt1, Daniel Walcher1, Ludwig Binner1, Axel Bornstedt1, Wolfgang Rottbauer1, and Volker Rasche1
1University of Ulm, Ulm, BW, Germany

 
Cardiac magnetic resonance imaging has been established for visualization of global and regional ventricular function, myocardial viability, and coronary vein anatomy. Cardiac resynchronization therapy has been shown to improve quality of life in patients with severe impairment of cardiac function and asynchronic contraction. However, about 1/3 of these patients do not benefit. Adding the information provided by magnetic resonance imaging is supposed to improve cardiac resynchronization therapy and decrease the number of non-responders due to suboptimal patient selection and suboptimal left ventricular lead placement.

 
4548.   51 "Electrocardiogram (ECG) Made Easy for Radiologists ": A Correlation Between Cardiac MRI Findings and Corresponding ECG Findings in Various Cardiac Diseases.
Dheeraj Reddy Gopireddy1, Venkata Meduri1, Naila Qazi1, Christopher Francois1, and Scott B. Reeder1
1Radiology, University of Wisconsin, Madison, Wisconsin, United States

 
Electrocardiogram (ECG) provides valuable information regarding the electrophysiology of the heart in complex cardiac diseases. Understanding some basic and typical ECG concepts in these clinical entities can enhance and aid in accurate imaging diagnoses made by radiologists. We made an attempt to correlate between the typical ECG and corresponding radiological findings in various cardiac disease, using MRI as the primary imaging modality. Many interesting cases are illustrated using anatomical and ECG correlation as the primary theme of this educational poster. Additional ECG interpretation skills have helped us understand the language commonly spoken by clinicians especially cardiologists thereby nurturing a strong professional relationship.

 
4549.   52 MRI Evaluation of Diffuse Myocardial Diseases -permission withheld
Yasuo Amano1, Masaki Tachi1, Hitomi Tani1, Tadashi Machida1, Minako Takeda1, and Makoto Obara2
1Nippon Medical School, Tokyo, Tokyo, Japan, 2Philips Healthcare Asia Pacific, Tokyo, Tokyo, Japan

 
Delayed-enhancement MRI is useful for detection of myocardial scarring, but cannot identify diffuse myocardial diseases because of its binary contrast between normal and scarred myocardium. The aim of this educational exhibit is to demonstrate MRI techniques that can identify the diffuse myocardial diseases and to exhibit some types of myocardial diseases with diffuse myocardial tissue damages.

 
4550.   53 The Genealogy of ARVD - A Review of the Development of Guidelines for the Diagnosis of Arrhythmogenic Right Ventricular Dysplasia -permission withheld
Tessa Sundaram Cook1, Francisco Contijoch2, and Saurabh Jha1
1Radiology, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania, United States, 2University of Pennsylvania School of Engineering and Applied Sciences

 
Task force guidelines for arrhythmogenic right ventricular dysplasia were developed in 1994 and revised in 2010. This presentation reviews the evolution of the guidelines, particularly with respect to cardiac MRI criteria. Additionally, the presentation critically reviews literature related to the new criteria.

 
4551.   54 Cardiac MRI in the Diagnosis and Management of Asymptomatic Cardiac Involvements in Rheumatic Diseases. -permission withheld
Yasuyuki Kobayashi1, Hitomi Kobayashi2, and Masaharu Hirano3
1Radiology, Kawasaki, Kanagawa, Japan, 2Itabashi Chuo Medical Center, Itabashi-ku, Tokyo, Japan, 3Cardiaology, Tokyo Medical College, Sinjyuku-ku, Tokyo, Japan

 
Subclinical myocardial involvements, as detected by Cardiac MRI, are prevalent in the Rheumatic disease patients without cardiac symptoms. Cardiac MRI is very useful to assess and manage the cardiac involvements in asymptomatic patients with rheumatic disease.

 

ELECTRONIC POSTER SESSION • CARDIOVASCULAR
Thursday, 25 April 2013 (13:30-14:30) Exhibition Hall
CV Imaging Technology & Methodology

  Computer #  
4552.   73 Implementation of a Robust Method to Derive Unbiased T1 Maps from MOLLI Sequence and Bloch Equations Simulations.
Benjamin Marty1,2, Alexandre Vignaud3, Andreas Greiser4, and Pierre G. Carlier1,2
1NMR Laboratory, Institute of Myology, Paris, France, 2NMR Laboratory, CEA, I2BM, MIRCen, Fontenay-aux-Roses, France, 3CEA, I2BM, NeuroSpin, Gif-sur-Yvette, France,4Siemens AG, Erlangen, Germany

 
The MOLLI sequence has been widely used in CMR protocols for diagnosis and quantification of diffuse myocardial fibrosis but is known to underestimate high T1 values. Bloch equations simulations show that the T1 values derived from MOLLI are quite sensitive to sequence parameters (bSSFP readout scheme, nominal flip angle, inversion efficiency) but also to the tissue T2, using the standard post-processing procedure. In this study, we proposed a robust approach to derive unbiased T1 maps using the simulations, experimental data points of the MOLLI sequence and the acquisition of T2 and B1 maps.

 
4553.   74 in vivo Detection of Cardiac Fibrotic Tissue Without Contrast Agent
Xeni Deligianni1, Nadine Kawel-Boehm2, Theresa Dellas Buser2, Jens Bremerich2, Oliver Bieri1, and Francesco Santini1
1Department of Radiology, Division of Radiological Physics, University of Basel Hospital, Basel, NA, Switzerland, 2Department of Radiology and Nuclear Medicine, University of Basel Hospital, Basel, NA, Switzerland

 
Detection of myocardial fibrosis with MR is usually performed with late gadolinium enhancement (LGE). Fibrosis is characterized by increased presence of collagen. We present a new positive contrast technique based on a 2D submillisecond echo time spoiled gradient echo sequence as a possible alternative to LGE. One healthy volunteer and one patient were scanned at a 1.5T scanner and results were compared to LGE. The agreement of the results with the LGE findings indicate that the proposed method could have high clinical potential since the administration of contrast agent could be omitted and it is also specific to chronic myocardial infarction.

 
4554.   75 Right Ventricular Velocities Over the Entire Cardiac Cycle Measured with High Resolution Spiral Phase Velocity Mapping: Results, Reproducibility and Comparison with the Left Ventricle
Robin Simpson1,2, Jennifer Keegan1,2, and David N. Firmin1,2
1Imperial College London, London, England, United Kingdom, 2Royal Brompton Hospital, London, England, United Kingdom

 
Right ventricular (RV) velocities are difficult to measure because of the thin, asymmetrical RV free wall. This study presents results from a phase velocity mapping sequence which uses spiral k-space trajectories and retrospective cardiac gating to allow the acquisition of images with high enough resolution to analyse the RV. Measurements are shown to be reproducible and small temporal features can be detected. Left ventricular velocities can be extracted from the same images, allowing a comparison of the velocities and their timings between the ventricles. This could be useful for pathologies involving both intra and inter ventricular dyssynchrony.

 
4555.   76 Block LOw-Rank Sparsity with Motion Guidance (BLOSM) for Accelerated Dynamic MRI
Xiao Chen1, Michael Salerno2,3, Craig H. Meyer1, and Frederick H. Epstein1
1Biomedical Engineering, University of Virginia, Charlottesville, Virginia, United States, 2Medicine, University of Virginia, Charlottesville, Virginia, United States, 3Radiology, University of Virginia, Charlottesville, Virginia, United States

 
Several accelerated imaging techniques utilizing k-t undersampling have been proposed to model dynamic CMR behavior with a few spatiotemporal basis functions to reconstruct images. These algorithms are sensitive to respiratory motion and perform poorly when both signal intensity and object position and shape change during image acquisition. We propose a novel method that divides the images into blocks and tracks the blocks’ motions to exploit increased sparsity (Block LOw-rank Sparsity with Motion guidance). The simplified dynamics in the smaller, motion-compensated blocks can be better described by a limited number of basis functions, making the method insensitive to complex dynamics.

 
4556.   77 Single-Shot Spiral First-Pass Perfusion Imaging: Full Heart Coverage with High Temporal Resolution
Yang Yang1, Craig Meyer1,2, Frederick H. Epstein1,2, Christopher Kramer2,3, and Michael Salerno1,3
1Biomedical Engineering, University of Virginia, Charlottesville, VA, United States, 2Radiology, University of Virginia, Charlottesville, VA, United States, 3Medicine, University of Virginia, Charlottesville, VA, United States

 
We demonstrate the for the first time the successful application of a single-shot spiral first-pass myocardial perfusion imaging technique enabling rapid full heart coverage for adenosine stress perfusion imaging, with high spatial and very high temporal resolution.

 
4557.   78 Navigator Artefact Reduction in 3D Late Gadolinium Enhancement Imaging
Jennifer Keegan1, Peter Drivas2, and David N. Firmin1,3
1Cardiovascular Biomedical Research Unit, Royal Brompton and Harefield NHS Trust, London, United Kingdom, 2Cardiovascular Biomedical Research Unit, Royal Brompton Hospital, London, United Kingdom, 3Imperial College, London, United Kingdom

 
Navigator-gated 3D late gadolinium enhancement (LGE) imaging demonstrates the degree and distribution of atrial scarring both before and after RF ablation of atrial fibrillation. An artefact originating from the slice-selective navigator-restore pulse is frequently present in the right pulmonary veins, obscuring the vein and atrial walls and making quantification of enhancement difficult. We describe a simple sequence modification to remove this artefact and demonstrate its application in 9 patients.

 
4558.   79 Optimized Three Dimensional Sodium Imaging of the Human Heart on a Clinical 3T Scanner
Neville D. Gai1, Carlos Rochitte2, Marcelo Nacif3, and David A. Bluemke1
1Radiology & Imaging Sciences, National Institutes of Health, Bethesda, MD, United States, 2Heart Institute - InCor - University of São Paulo Medical School, São Paulo, SP, Brazil,3Radiology Department of Faculdade de Medicina, Universidade Federal Fluminense, Niterói, RJ, Brazil

 
Sodium imaging provides a direct window into cell viability. In the heart, tissue viability after an ischemic event is an important determinant in the decision to intervene with corrective measures. Sodium MRI of the heart is challenging due to extremely poor SNR and motion artifacts. In this work, we explore a 3D stack of spirals trajectory for imaging the entire human heart on a clinical 3T scanner. Optimization of sequence parameters based on Bloch simulations (and factors affecting the point spread function) makes sodium imaging the entire heart possible within a reasonable scan time (< 8 min).

 
4559.   80 Precision in T1-Mapping and Estimation of Quality Maps
Peter Kellman1, Andrew E. Arai1, and Hui Xue2
1NHLBI, NIH, Bethesda, MD, United States, 2Siemens Corporate Research, Princeton, NJ, United States

 
The sensitivity for detecting abnormal elevation of T1 is limited by the precision of T1 estimates, which is a function of the number and timing of measurements along the T1-recovery curve, the signal-to-noise ratio, tissue T1, and the method of fitting. It is proposed to produce a map calibrated in T1 units that represented the standard deviation (SD) of the T1 estimate, by transforming the SD of residual fitting error into the SD of the estimated parameters. Estimate of the T1 parameter error based on fit residuals is derived analytically, and validated by Monte-Carlo simulation. In-vivo examples demonstrate potential utility.

 
4560.   81 Improved Late Gadolinium Enhancement Cardiac MRI for Patients with Implanted Cardiac Devices
Shams Rashid1, Stanislas Rapacchi1, Kyung H. Sung1, Marmar Vaseghi2, Kalyanam Shivkumar2, J. Paul Finn1, and Peng Hu1
1Radiological Sciences, University of California Los Angeles, Los Angeles, CA, United States, 2Cardiac Arrhythmia Center, University of California Los Angeles, Los Angeles, CA, United States

 
Recent studies show that cardiac MRI,including LGE MRI, can be safely performed in patients with implanted cardiac devices (ICDs and pacemakers). However, the current LGE sequence suffers from hyperintensity artifacts, which prevent diagnostic utility of the images or give rise to false detection of scar tissue. We designed a new LGE sequence which utilizes a wideband inversion pulse that can resolve these artifacts. We used both the standard LGE sequence and our new sequence to image a volunteer and two ICD patients, and demonstrated that our new sequence can correct the artifacts and prevent incorrect assessment of myocardial scar.

 
4561.   82 Fast Simultaneous T1 and T2 Mapping of the Heart
Francesco Santini1, Nadine Kawel-Boehm2, Jens Bremerich2, and Oliver Bieri1
1Division of Radiological Physics, University of Basel Hospital, Basel, BS, Switzerland, 2Department of Radiology and Nuclear Medicine, University of Basel Hospital, Basel, BS, Switzerland

 
This study presents a new MR method using inversion recovery balanced steady-state free precession (IR-bSSFP) for relaxometry of the cardiac muscle. The method enables the simultaneous acquisition of perfectly coregistered T1 and T2 maps in a single breathhold. The method is validated in healthy volunteers and its intersubject and intrasubject variability is assessed.

 
4562.   83 Calculation of Optimal TI Value for 3D LGE-MRI of the Left Atrium
Eugene G. Kholmovski1,2, Sathya Vijayakumar1,2, and Nassir F. Marrouche2,3
1UCAIR, Department of Radiology, University of Utah, Salt Lake City, Utah, United States, 2CARMA Center, University of Utah, Salt Lake City, Utah, United States, 3Department of Cardiology, University of Utah, Salt Lake City, Utah, United States

 
A novel method for calculation of optimal TI value for LGE-MRI of the left atrium has been developed and validated. The results of the patient studies shown a great improvements in quality of LGE images of LA when this method was used to calculate inversion time of the scan.

 
4563.   84 How Different Data Acquisition Techniques Impact to the Selected Curve Fitting Models and the Cardiac T2* Measurements
Suwit Saekho1,2 and Uten Yarach3
1Radiological Technology, Chiang Mai university, Muang, Chiang Mai, Thailand, 2Biomedical Engineering Center, Chiang Mai university, Muang, Chiang Mai, Thailand, 3Chiang Mai university, Muang, Chiang Mai, Thailand

 
Free breathing technique for Cardiac T2* measurements could be a useful technique in non-cooperative patients. No study guarantees that this technique will provide the same results as that of the standard breath-hold. We compared the 2 techniques in 2 different fitting models, Simple Mono Exponential (SME) and Offset models. The study was done with 14 normal, and 54 Thalassemia volunteers. The results showed that Offset model exhibited 3 false positives with breath-hold technique in normal group. However in term of clinical applications, both data acquisition techniques and fitting models can separate iron overload to the non iron overload groups equally.

 
4564.   85 3D Late Gadolinium Enhancement Imaging with Dynamic-TI in Patients with Atrial Fibrillation
Jennifer Keegan1, Peter David Gatehouse1, Sonya V. Babu-Narayan1,2, Ricardo Wage1, Shouvik Haldar3, and David N. Firmin1,2
1Cardiovascular Biomedical Research Unit, Royal Brompton and Harefield NHS Trust, London, United Kingdom, 2Imperial College, London, United Kingdom, 3Cardiology, Royal Brompton and Harefield NHS Trust, London, United Kingdom

 
3D late gadolinium enhancement (LGE) imaging is performed with single R-wave gating to reduce the acquisition duration, but image quality in patients with atrial fibrillation (AF) is poor due to inconsistent longitudinal magnetisation recovery between cardiac cycles. Image quality could potentially be improved by implementing a dynamic-TI algorithm. Three-D data were acquired in 7 patients with variable heart rates (6 prior to RF ablation of AF), both with and without the dynamic-TI algorithm. We show that dynamic adaptation of the inversion time with each cardiac cycle results in less ghosting and improved image quality in this difficult patient population.

 
4565.   86 Self-Navigated Three-Dimensional Cardiac T2 Mapping at 3T
Ruud B. van Heeswijk1,2, Davide Piccini3,4, Hélène Feliciano1,2, Juerg Schwitter5, and Matthias Stuber1,2
1Department of Radiology, University Hospital (CHUV) and University (UNIL) of Lausanne, Lausanne, Switzerland, 2Center for Biomedical Imaging (CIBM), Lausanne, Switzerland,3Department of Radiology, University Hospital (CHUV) and University of Lausanne (UNIL) / Center for Biomedical Imaging (CIBM), Lausanne, Switzerland, 4Advanced Clinical Imaging Technology, Siemens Healthcare IM S AW, Lausanne, Switzerland, 5Center for Cardiac Magnetic Resonance and Cardiology Service, University Hospital of Lausanne (CHUV), Lausanne, Switzerland
 
 
4566.   87 Interleaved PET Data Sorting for Improved Image Quality in Combined PET/MR
Richard Laforest1, Ju-Chieh Cheng1, Agus Priatna2, Man Chun Jeffrey Lau1, Shivak Sharma1, and Pamela K. Woodard1
1Radiology, Washington University Medical School, St.Louis, MO, United States, 2Siemens, St.Louis, MO, United States

 
The abstract will present a novel methodology for sorting cardiac PET gating data applied to cardiac PET/MRI imaging. The proposed technique will improve tradiational PET gating technique for a better temporal match to cardiac CINE MR and improved statistics for individual phase images.

 
4567.   88 Towards Real-Time 3D Phase-Contrast Flow MRI
Arun Antony Joseph1, Dirk Voit1, Sebastian Schätz1, Klaus-Dietmar Merboldt1, and Jens Frahm1
1Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, Göttingen, Niedersachsen, Germany

 
A method for real time 3D phase contrast imaging with highly undersampled FLASH and regularized nonlinear inversion reconstruction was developed. Flow in different directions was analyzed through invitro and invivo studies. 3D phase contrast maps were obtained in real-time for multiple cardiac cycles without ECG gating common in Cine 3D phase contrast MRI.

 
4568.   89 High Throughput Cardiac MRI Using Interleaved Breath-Hold Cardiac Cine and Free-Breathing Coronary MR Angiography: Initial Results
Markus Henningsson1, Reza Nezafat2, Peter Koken3, Giel Mens4, and Rene M. Botnar1
1Division of Imaging Sciences and Biomedical Engineering, King's College London, London, United Kingdom, 2Harvard Medical School, Boston, MA, United States, 3Philips Research, Hamburg, Germany, 4Philips Healthcare, Best, Netherlands

 
Scans using multiple breath-holds are inefficient because no data is acquired while the subject is breathing freely between breath-holds. In this work we investigate a new framework for interleaving a free-breathing coronary MRA dataset during the patient recovery period between breath-holds of a cardiac cine scan. This result in a shorter total scan time of nearly 50% compared to if the free-breathing and breath-held scan were acquired without interleaving. The proposed framework has potential to greatly improve throughput in cardiac MRI by allowing for a more efficient use of breath-held and free-breathing scans.

 
4569.   90 Arrhythmia Insensitive Rapid Cardiac T1 Mapping Pulse Sequence: in vivo Study
Michelle Fitts1,2, Elodie Breton3, Eugene G. Kholmovski2,4, Derek J. Dosdall2,5, Sathya Vijayakumar2,4, Kyung P. Hong1,2, Ravi Ranjan2,5, Nassir F. Marrouche2,5, Leon Axel6, and Daniel Kim2,4
1Bioengineering, University of Utah, Salt Lake City, Utah, United States, 2CARMA Center, University of Utah, Salt Lake City, Utah, United States, 3ICube, Strasbourg University, Strasbourg, Alsance, France, 4UCAIR, Department of Radiology, University of Utah, Salt Lake City, Utah, United States, 5Internal Medicine, University of Utah, Salt Lake City, Utah, United States, 6Department of Radiology, New York University, New York, New York, United States

 
We propose an arrhythmia-insensitive, rapid (AIR) cardiac T1 mapping pulse sequence based on saturation recovery, which is insensitive to heart rate and rhythm conditions, for quantification of diffuse fibrosis. We compared its performance against the conventional cardiac T1 mapping inversion recovery based method, MOLLI, which is sensitive to heart rate and rhythm conditions and requires a long breath-hold duration. In vivo studies demonstrated that T1 measurements made by MOLLI and AIR were strongly correlated, but in poor agreement. Our AIR pulse sequence may be clinically useful for assessment of diffuse myocardial fibrosis in patients.

 
4570.   91 High Resolution Cardiac T1 Mapping Using an Adaptive Data Acquisition Algorithm Combining Navigator Gating and Compressed Sensing
Bhairav B. Mehta1, Xiao Chen1, Christopher M. Kramer2,3, Michael Salerno1,2, and Frederick H. Epstein1,3
1Department of Biomedical Engineering, University of Virginia, Charlottesville, VA, United States, 2Department of Medicine, Cardiology Division University of Virginia, Charlottesville, VA, United States, 3Department of Radiology, University of Virginia, Charlottesville, VA, United States

 
MOLLI has limited spatial resolution because of its breathhold constraint. Higher spatial resolution may improve T1-mapping of thin structures. The ANGIE sequence uses navigator gating to remove the breathhold constraint and CS to accelerate data acquisition. For high-quality CS reconstruction, the sampling pattern should be incoherent, and to minimize scan time, a stopping criterion should be based on image quality and T1 estimation. We developed an ANGIE sequence that adapts to navigator rejection of data by recalculating, in real-time, a sampling pattern that is well-suited for CS, and halts data acquisition when data are sufficient for CS reconstruction and precise T1 estimation.

 
4571.   92 Improved Signal-To-Noise Ratio in Late Gadolinium Enhancement Imaging by Using Respiratory-Navigator-Rejected K-Space Lines
Mehmet Akçakaya1, Jaime L. Shaw2, Thomas H. Hauser1, and Reza Nezafat1
1Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States, 2Cedars-Sinai Medical Center, University of California, Los Angeles, CA, United States

 
3D late gadolinium enhancement (LGE) MRI is acquired in a segmented fashion over multiple heartbeats, which necessitates respiratory motion compensation. Prospective navigator (NAV) is commonly used, where k-space lines acquired immediately after the NAV signal are used for image reconstruction only if NAV is within a pre-defined gating window, whereas those outside the window are rejected and re-acquired, and the rejected lines are not utilized further. Sub-optimal SNR is another challenge in high-resolution LGE imaging. In this study, we sought to develop and evaluate a technique that utilizes the NAV-rejected k-space lines for improved SNR in high-resolution 3D LGE.

 
4572.   93 Influence of Off-Resonance in Myocardial T1-Mapping Using SSFP Based MOLLI Method
Peter Kellman1, Daniel A. Herzka2, Andrew E. Arai1, and Michael Schacht Hansen3
1NHLBI, NIH, Bethesda, MD, United States, 2Biomedical Engineering, Johns Hopkins University, Baltimore, MD, United States, 3NHLBI, National Institutes of Health, Bethesda, MD, United States

 
The frequency dependence of SSFP imaging is well known and results in dark band artifacts. Myocardial T1-mapping methods such as MOLLI use single shot SSFP readout and are prone to error in T1-measurement that is frequency dependent. A low excitation flip angle is used in MOLLI to reduce errors that result from influence of readout and improve T1-measurement accuracy. It may be less well appreciated that an additional significant frequency-dependent error in T1 results at relatively small off-resonance frequency deviations that are typically observed in the SSFP passband.

 
4573.   94 Whole-Heart Quantification of Myocardial Perfusion with Spiral Pulse Sequences
Yang Yang1, Sujith Kuruvilla2, Christopher Kramer2,3, Craig Meyer1,3, and Michael Salerno2,3
1Biomedical Engineering, University of Virginia, Charlottesville, VA, United States, 2Medicine, University of Virginia, Charlottesville, VA, United States, 3Radiology, University of Virginia, Charlottesville, VA, United States

 
We demonstrated the successful application of whole ventricular coverage absolute quantitative first-pass myocardial perfusion imaging using accelerated spirals in healthy volunteers. This sequence can acquire 8 short axis slices in 480ms enabling full ventricular coverage at heart rates up to 125 BPM.

 
4574.   95 Optimal Flip Angle for Balanced SSFP Cardiac Cine Imaging
Subashini Srinivasan1,2 and Daniel B. Ennis1,3
1Department of Bioengineering, University of California, Los Angeles, California, United States, 2Department of Radiological Sciences, University of California, Los Angeles, California, United States, 3Department of Radiological Sciences, University of California Los Angeles, Los Angeles, California, United States

 
Cine balanced SSFP is the clinical standard for cardiac structural and functional imaging due to its high blood-myocardium contrast compared to spoiled GRE imaging. The literature indicates that the optimal flip angle required for the maximum blood-myocardium contrast is 54˚ for imaging at 1.5T, but simulations didn’t account for flowing blood. Our Bloch simulations of stationary myocardium and flowing blood indicate that a flip angle of ~130˚ is required for maximum blood-myocardium contrast and agree with in vivo results up to ~80°. The highest available flip angle, subject to SAR limitations, should be used for balanced SSFP cardiac cine imaging.

 
4575.   96 Centric and Reverse-Centric Trajectories for Undersampled 3D Saturation Recovery Cardiac Perfusion Imaging
Haonan Wang1, Ganesh Adluru2, Eugene G. Kholmovski2, Jian Xu3, Neal K. Bangerter1, and Edward V.R. DiBella2
1Electrical & Computer Engineering, Brigham Young University, Provo, UT, United States, 2Utah Center for Advanced Imaging Research, University of Utah, Salt Lake City, UT, United States, 3Siemens Healthcare, New York, NY, United States

 
First-pass myocardial perfusion imaging provides a powerful noninvasive method for characterizing ischemic heart disease. 3D myocardial perfusion techniques have a number of advantages over 2D techniques. However, 3D imaging is inherently slower, so accelerated acquisition schemes exploiting compressed sensing and parallel imaging are used, often in conjunction with fast saturation-recovery sequences. In highly accelerated imaging, the magnetization does not reach a steady state, and image contrast is strongly influenced by k-space trajectory. In this study, we compare image contrast in a highly-accelerated 3D saturation-recovery sequence using a centric phase encode ordering vs. a reverse centric ordering.