Traditional Poster Session - Cardiovascular
  Myocardial Tissue Characterization & Spectroscopy 1111-1129
  Myocardial Function: Experimental Models & Human Studies 1130-1137
  Myocardial Perfusion & Non Contrast MRA 1138-1154
  Coronary MRA & Vessel Wall 1155-1171
  Flow Quantification 1172-1198
  Non Contrast & Contrast MRA 1199-1218
  CV Imaging Methodology Technology, Image Processing & Other 1219-1255
  Miscellaneous Cardiovascular 1256-1265
     

Myocardial Tissue Characterization & Spectroscopy
Click on to view the abstract pdf. Click on to view the poster (Not all posters are available for viewing.)
 
Monday 7 May 2012
Exhibition Hall  10:45 - 12:45

1111.   Characterising an Inversion-Recovery prepared Steady-State Free-Precession sequence for measuring myocardial T1 relaxation times pre- and post-contrast administration.
R Stephen Nicholas1,2, Stephen J Gandy1,2, and J Graeme Houston3,4
1Medical Physics, NHS Tayside, Dundee, Angus, United Kingdom, 2Medical Physics, University of Dundee, Dundee, Angus, United Kingdom, 3Radiology, NHS Tayside, Dundee, Angus, United Kingdom, 4Clinical Imaging, University of Dundee, Dundee, Angus, United Kingdom

 
This work characterised an Inversion Recovery prepared SSFP used for determining the optimum Inversion Time (TI) in the myocardium after contrast administration. Gel phantoms with known T1 and T2 values were scanned with different simulated heart rates to measure the variation in the optimum TI. The results showed that there is considerable variation in TI. These results were applied in a small cohort of patients to account for heart rate variability in T1 measurements for both pre-and post-contrast TI measurements in normal and hyper-enhanced myocardium. However, significant variability was still observed, particularly in the pre-contrast measurements.

 
1112.   Evaluation of Postcontrast T1-values of the Myocardium and Blood by 3D Look-Locker MRI: Comparison with 2D Look-Locker MRI
Yasuo Amano1, Masaki Tachi1, Yoshiaki Komori2, Yuriko Suzuki2, Tetsuro Sekine1, and Shinichiro Kumita1
1Nippon Medical School, Tokyo, Tokyo, Japan, 2Philips Electronics Japan, Tokyo, Japan

 
Postcontrast 2D Look-Locker MRI is able to detect the diffuse myocardial fibrosis, but covers only one slice. 3D Look-Locker MRI may permit the estimate of postcontrast T1-values of the whole left ventricular myocardium in the 4-chamber view during a single breath-hold, comparable to 2D Look-Locker MRI.

 
1113.   Multi-Slice Saturation-Recovery Look-Locker Method for Rapid T1 Mapping of Mouse Myocardium
Kai Jiang1,2, and Xin Yu1,2
1Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States, 2Case Center for Imaging Research, Case Western Reserve University, Cleveland, OH, United States

 
An ECG-triggered multi-slice saturation-recovery Look-Locker (MSRLL) method was developed for fast cardiac T1 mapping. High temporal resolution (2.5 minutes) was achieved without the aid of parallel imaging or EPI. Phantom and in vivo validations were performed by comparing measured T1 with that using the single-slice Look-Locker method.

 
1114.   Effects of Formalin Fixation on Diffusion Tensor Imaging of Myocardial Tissues
Brian R Watson1, and Edward W Hsu1
1Bioengineering, University of Utah, Salt Lake City, Utah, United States

 
Contrary to some tissues, little is known regarding the effects of fixation on Diffusion Tensor Imaging of cardiac specimens. Our goal was to systematically assess the effects of fixation, including factors such as specimen preparation, time of fixation, fixation duration, and fixative type, on DTI derived parameters measured in myocardial specimens. Utilizing canine hearts, we found that unfixed tissues lose fractional anisotropy(FA) and mean diffusivity(MD) over time. Also, we significantly show that fixed myocardium lost FA and MD due to fixation. In contrast, KCl did not significantly effect FA. These results help provide guidelines for future cardiac studies.

 
1115.   In vivo cardiac 31P-MRS in a mouse model of heart failure
Adrianus J. Bakermans1, Bastiaan J. van Nierop1, Desiree Abdurrachim1, Klaas Nicolay1, and Jeanine J. Prompers1
1Biomedical NMR, Eindhoven University of Technology, Eindhoven, Netherlands

 
3D Image-Selected In vivo Spectroscopy (ISIS) for non-invasive cardiac 31P-MRS was used to investigate the myocardial energy status in a thoracic aortic constriction (TAC) mouse model of heart failure. By maintaining a constant TR, signal contamination from tissue surrounding the heart was minimized. Left ventricular function and morphology were assessed using cine MRI. Decreased ejection fraction and increased myocardial mass were accompanied by a decreased phosphocreatine to ATP ratio in TAC mice, indicating a disturbed energy homeostasis. This non-invasive approach will be useful to investigate cardiac disease progression and the effects of therapeutic strategies in longitudinal study designs.

 
1116.   Two lipid pools detected in the myocardium of rats fed a high fat diet
Vijayasarathi Nagarajan1, Philip William Kuchel1, and S. Sendhil Velan1
1Laboratory of Molecular Imaging, Singapore Bioimaging Consortium, Singapore, Singapore, Singapore

 
We evaluated the myocardial fat content in rats fed with a placebo and a high fat diet. We demonstrated the presence of two lipid pools in the myocardium of the rats with obesity induced by high fat diet. The left ventricular function was significantly reduced in rats fed with high fat diet. The concentration of IMCL in myocardium may be a potential marker for early stages of diabetes.

 
1117.   Manganese-­Enhanced MRI in the Evaluation of Cell-Based Therapy
Paul Jaegu Kim1, Ildiko Toma1, Phillip Harnish2, and Phillip Yang1
1Cardiovascular Medicine, Stanford University, Stanford, CA, United States, 2Eagle Vision Pharmaceutical

 
To date, the underlying mechanism responsible for the restoration of the injured myocardium following transplantation of stem cells has not been clearly identified. Manganese-enhanced MRI (MEMRI) has recently been published as a reliable method of imaging viable myocardium. Utilizing MEMRI, we evaluated the changes in the viability of the injured myocardium to further investigate the underlying mechanism of functional restoration using stem cell therapy. A more sensitive measurement of myocardial restoration is significantly increased MEMRI signal observed in the ESC-RGs vs. control mice (119+.005 cm3 vs .0736+.001 cm3 respectively, p=0.034), indicating improved myocardial viability. Thus, MEMRI shows a significant increase in viable myocardium in ESC-RG transplanted hearts, indicating myocardial restoration.

 
1118.   Detection of Immune Cell infiltration and Visualization of Inflammatory Dilation on Myocardial Disorder Using Fluorescent Magnetic Nanoparticles
Hyeyoung Moon1,2, Hyo Eun Park3, Jongeun Kang1,4, Kiyuk Chang3, and Kwan Soo Hong1,4
1Division of MR research, Korea Basic Science Institute, Cheongwon-Gun, Chungcheongbuk-Do, Korea, Republic of, 2Bio-Analytical Science, University of Science and Technology, Daejeon, Korea, Republic of, 3Department of Internal Medicine, Catholic University, Seoul, Korea, Republic of, 4Graduate School of Analytical science and Technology, Chungnam National University, Daejeon, Korea, Republic of

 
In this study, we investigated whether PEGylated fluorescent magnetic nanoparticles (MNP) could detect the inflammatory areas in experimentally induced autoimmune myocarditis (EAM) rats with in vivo cardiac MRI. In addition, we examined the MNP¡¯s possibility if we apply to clinical research by exploring the inflammatory dilation and therapeutic effect.

 
1119.   MYOCARDIAL MICROINFARCT MEASURMENTS ON MRI, MDCT AND HISTOPATHOLOGY
Maythem Saeed1, Sammir Sullivan1, Loi Do1, and Mark Wilson1
1Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, Ca, United States

 
The objectives were to use DE-MRI and DE-MDCT imaging and light microscopy to determine the relationship and the limits of agreement for measuring myocardial microinfarct. Pigs (n=14) received either 16mm3 or 32mm3 of 40-120µm microemboli. Clinical MRI and MDCT scanners were used 3 days after microembolization. Gd-DTPA and iohexol were used to enhance microinfarct. MRI and MDCT imaging showed systematic underestimation of microinfarct size and area at risk compared with histopathology, which should be considered in evaluating microinfarct using these modalities and may be related to differences in spatial resolution, light microscopy, mismatch between slices and volume averaging effect.

 
1120.   An inducible transgenic mice model of cardiac steatosis; Validation of model and MRS acquisition protocol
Edvin Johansson1, Johan Jirholt2, Katja Madeyski-Bengtson2, and Paul D Hockings1
1PHB Imaging, AstraZeneca R&D Molndal, Molndal, Sweden, 2DS Bioreagents, AstraZeneca R&D Molndal, Sweden

 
A transgenic mice model of cardiomyocyte-specific acyl CoA synthase overexpression, inducible in mature mice and believed to cause myocardial steatosis was investigated. In vivo triglyceride quantification was performed via MRS and validated against analytical chemistry. The agreement between the two techniques was good, and both techniques demonstrated increased myocardial triglyceride levels in ACS overexpressing mice when compared to unmodified mice. The ejection fraction was markedly reduced in ACS overexpressing mice, but this finding requires further investigations in order to rule out factors associated with the transgenic modification, but not directly related to the accumulation of myocardial triglycerides.

 
1121.   Improved Reproducibility of Black-Blood T2-Weighted CMR Assessment of Area at Risk with Myocardial Segmentation from b-SSFP Short-Axis Images
Anders Frodo Stegmann1, Esben Søvsø Szocska Hansen1, W. Yong Kim1,2, and Samuel Alberg Thrysøe1
1MR-Research Centre, Aarhus University Hospital, Skejby, Aarhus N, Denmark, 2Dept. of Cardiology, Aarhus University Hospital, Skejby, Aarhus N, Denmark

 

1122.   Myocardial T2-Mapping and T2-value Measurement using Breath-hold Gradient- and Spin-echo (GRASE) imaging: Comparison with Navigator-gated Spin-echo Imaging
Yasuo Amano1, Yoshiaki Komori2, Masaki Tachi1, Hitomi Tani1, Tetsuro Sekine1, and van Cauteren Marc2
1Nippon Medical School, Tokyo, Tokyo, Japan, 2Philips Electronics Japan, Tokyo, Japan

 
Gradient- and spin-echo imaging (GRASE) with the multishot acquisition = 3, 5, 7 was performed to generate T2-mapping and to measure myocardial T2-value in a single-breath-hold. ECG-gating, black-blood preparation and 5-multiecho-time acquisition (i.e., 20, 30, 40, 50, and 60 ms) were applied to both SE and GRASE. The GRASE with the multishot acquisition = 3 provided the T2-mapping with few artifacts and the myocardial T2-values comparable to those acquired by SE imaging during the acceptable breath-holding time. The interventricular septal myocardium may be appropriate for the T2-value measurement.

 
1123.   MOLLI T1-Mapping for Assessment of Acute Myocardial Infarction and Tako-Tsubo Cardiomyopathy
Donnie Cameron1, David Higgins2, Baljit Jagpal1, Margaret Bruce1, Nishat Siddiqi1, Christian Stehning3, Michael Frenneaux1, Thomas Redpath1, and Dana Dawson1
1The University of Aberdeen, Aberdeen, Scotland, United Kingdom, 2Philips Healthcare, Guildford, United Kingdom, 3Philips Research, Hamburg, Germany

 
Modified Look-Locker Inversion recovery (MOLLI) is a useful tool for measuring T1 values in the myocardium. We applied MOLLI to acute myocardial infarction and acute tako-tsubo cardiomyopathy in order to assess its ability to distinguish normal myocardium from abnormal myocardium. Comparing two patient groups with healthy volunteers, MOLLI showed significant differences in T1 values of infarcted segments as compared to normal segments(p<0.005). Tako-tsubo dyskinetic segments demonstrated significantly higher T1 values than both normal and infarcted myocardium (p<<0.0001 versus normal). These results show that MOLLI sensitively delineates abnormal myocardium and provides superior evaluation compared to T2-weighted assessment.

 
1124.   Increased myocardial extracellular distribution volume in patients with hypertrophic cardiomyopathy as sign for diffuse fibrosis
Wessel P Brouwer1, Emma Baars1, Tjeerd Germans1, Karin de Boer1, Aernout M Beek1, Jolanda van der Velden2, Arthur AM Wilde3, Albert C van Rossum1, and Mark BM Hofman4
1Cardiology, ICaR-VU, VU University Medical Center, Amsterdam, Netherlands, 2Physiology, ICaR-VU, VU University Medical Center, 3Cardiology, Academic Medical Center, Amsterdam, Netherlands, 4Physics and Medical Technology, ICaR-VU, VU University Medical Center, Amsterdam, Netherlands

 
Autopsy studies revealed areas of interstitial fibrosis in hypertrophic cardiomyopathy (HCM), but current late gadolinium enhancement imaging (LGE) is unable to depict diffuse deposition of collagen fibers. Therefore, we used T1 mapping with a Modified Look-Locker Inversion Recovery (MOLLI) pulse sequence to determine the distribution volume (Vdm) for extracellular Gd-DTPA in non enhanced myocardium, which is a measure of interstitial fibrosis. Results showed that LGE positive HCM patients have significantly higher (Vdm) values then LGE negative HCM patients and controls. Besides, pre-hypertrophic HCM mutation carriers had higher (Vdm) then controls, suggesting that interstitial fibrosis occurs early in the disease process.

 
1125.   Assessment of myocardial triglycerides by 2D PRESS echo-planar spectroscopic imaging
Jan Weis1, Morten Bruvold2, Francisco Ortiz-Nieto1, and Håkan Ahlström1
1Department of Radiology, Uppsala University Hospital, Uppsala, Sweden, 2Philips Healthcare, Best, Netherlands

 
Cardiac and respiratory triggered 2D PRESS echo-planar spectroscopic imaging with high spatial resolution was used for the assessment of triglyceride content in the human myocardium. The PRESS volume of interest selection enables smaller field of view and minimizes signal contamination from outside the PRESS box. The proposed data processing approach using magnitude spectra avoids the need for individual phase correction before voxel spectra averaging. High spatial resolution enables evaluation the local triglyceride changes in non-continuous and irregularly shaped volumes of interest.

 
1126.   : Characterization of pulmonary vein stenosis by serial MRI after atrial fibrillation ablation.
Lowell Chang1, Divya Verma1, Eugene Kholmovski2, Sathya Vijayakumar2, Nathan Burgon2, Nassir Marrouche1, and Christopher McGann1
1Cardiology, University of Utah School of Medicine, Salt Lake City, UT, United States, 2Utah Center for Advanced Imaging Research, University of Utah School of Medicine, Salt Lake City, UT, United States

 
Serial cardiac MRI is a useful tool in the characterization of injury of pulmonary veins leading to pulmonary vein stenosis after radiofrequency ablation for atrial fibrillation. Acute edema/inflammation immediate post-ablation can be seen by T2-weighted imaging, while late gadolinium-enhanced imaging show remodeling leading to scar. Pulmonary vein stenosis is best predicted by MRA measurements of baseline pulmonary vein caliber and immediate post-ablation pulmonary vein narrowing.

 
1127.   Measurement of Extracellular Volume Fraction by Cardiac Magnetic Resonance Imaging Detects Diffuse Myocardial Fibrosis in Hypertrophic cardiomyopathy
Aya Kino1, Darshit Thakrar2, Rahul Rustogi2, Brandon Benefield3, Jeremy D Collins2, Daniel Lee2, Lubna Choudhury4, and James C Carr2
1Radiology, Northwestern University, Chicago, IL, United States, 2Radiology, Northwestern University, 3Medicine Cardiology Division, Northwestern, 4Medicine Cardiology Division, Northwestern University

 
The purpose of the study is to demonstrate the HCM patient present higher myocardial extravascular extracellular volume fraction in scar/ fibrosis areas obtained by using a single-shot modified Look Locker inversion recovery sequence (MOLLI) with balanced SSFP MR Sequence.

 
1128.   Cardiovasular MR at 7Tesla: Assessment of the Right Ventricle
Valeriy Tkachenko1, Florian von Knobelsdorff-Brenkenhoff1, Denise Kleindienst1, Lukas Winter2, Jan Rieger2, Tobias Frauenrath2, Matthias A. Dieringer2, Davide Santoro2, Thoralf Niendorf1,2, and Jeanette Schulz-Menger1
1WG Cardiac MRI at ECRC Medical University Berlin, Charité Campus Buch, Berlin, Germany, 2Berlin Ultrahigh Field Facility, Max-Delbrueck Center for Molecular Medicine, Berlin, Germany

 
The assessment of the right ventricle (RV) is a challenge in today's cardiology. CMR at 1.5T is the accepted gold standard for RV quantification. The higher spatial resolution achievable at ultrahigh field strength (UHF) offers the potential to gain new insights into the structure and function of the RV. To approach this goal accurate RV chamber quantification at 7T has to be proven. Consequently this study examines the feasibility of assessment of RV dimensions and function at 7T using improved spatial resolution enabled by the intrinsic sensitivity gain of UHF CMR.

 
1129.   T2-weighted bright peri-infarct edema in late reperfused myocardial infarction
Iacopo Carbone1, Bahare Saidi1, Manuela Mariyadas2, Ilaria Iampieri3, Marco Francone3, and Matthias Friedrich1
1CMR Centre, Montreal Heart Institute, Montreal, Quebec, Canada, 2Department of Internal Medicine II, University of Ulm, Ulm, Germany, 3Department of Radiological, Oncological and Pathological Sciences, "Sapienza", University of Rome, Rome, Italy, Italy

 
In late-reperfused acute myocardial infarction (AMI) there is always a difference between the area at risk (measured with T2-weighted images) and infarct area (measured with late gadolinium enhancement). 41 patients with with late reperfused (>8hours) AMI were enrolled in the study. The mean difference between AAR and IA after 8hours was 9±7.25% and did not significantly increased over time. These data indicate that in late-reperfused MI, the edema surrounding infarcted tissue likely represents reversible tissue injury not related to myocardial salvage. These findings have significant implications for the quantification of myocardial salvage by CMR in patients with late refused MI.
 
Traditional Poster Session - Cardiovascular

Myocardial Function: Experimental Models & Human Studies
Monday 7 May 2012
Click on to view the abstract pdf. Click on to view the poster (Not all posters are available for viewing.)
 
Exhibition Hall  10:45 - 12:45

1130.   Highly Accelerated Cine-MRI in Mouse Hearts Using Compressed Sensing and Parallel Imaging at 9.4T
Tobias Wech1, Victoria Thornton2, Craig A. Lygate2, Stefan Neubauer2, Herbert Köstler1, and Jürgen E. Schneider2
1Institute of Radiology, University of Würzburg, Würzburg, Germany, 2Cardiovascular Medicine, University of Oxford, Oxford, United Kingdom

 
Parallel Imaging (PI) and Compressed Sensing (CS) have been shown to individually provide a three-fold reduction in scan-time for cine MRI in mice whilst providing accurate measurement of the physiologically relevant parameters. We now sought to combine PI and CS to further accelerate cine-MRI in mouse hearts at 9.4T. Fully acquired cine-data sets were retrospectively undersampled (overall acceleration factors combined: 4 up to 16) and subjected to CS and PI reconstruction, followed by image analysis. It is shown that a 3x3-fold acceleration (RCS x RPI) still allows for accurate assessment of cardiac functional values.

 
1131.   Evaluation of cardiac mechanical dyssynchrony with longitudinal strain analysis in 4-chamber cine magnetic resonance imaging
Masateru Kawakubo1,2, Michinobu Nagao3, Seiji Kumazawa4, Akiko Suyama Chishaki4, Hiroshi Honda5, and Junji Morishita4
1Division of Radiology, Department of Medical Technology, Kyushu University Hospital, Fukuoka, Fukuoka, Japan, 2Department of Health Sciences, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Fukuoka, Japan, 3Department of Molecular Imaging & Diagnosis, Department of Clinical Radiology, Graduate School of, Kyushu University, Fukuoka, Fukuoka, Japan, 4Department of Health Sciences, Faculty of Medical Sciences, Kyushu University, Fukuoka, Fukuoka, Japan, 5Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Fukuoka, Japan

 
In order to predict response to cardiac resynchronization therapy (CRT), a longitudinal strain analysis with echocardiography is used in the evaluation of mechanical dyssynchrony. Although analysis with echocardiography is restricted due to the narrow field of view (FOV), four-chamber (4CH) cine magnetic resonance imaging (MRI) has no restrictions due to the FOV and thus should allow a more precise evaluation of cardiac dyssynchrony. The longitudinal strain analysis using MRI has not been investigated in terms of cardiac dyssynchrony. We suggest an evaluation of mechanical dyssynchrony by using longitudinal strain analysis in 4CH cine MRI is useful for selecting CRT patients.

 
1132.   Cardiac MRI reveals progressive abnormalities in heart shape and function in the R6/2 mouse model of Huntington's disease
Stephen J Sawiak1,2, Nigel I Wood3, Guido Buonincontri1, T Adrian Carpenter1, and A Jennifer Morton3
1Wolfson Brain Imaging Centre, University of Cambridge, Cambridge, England, United Kingdom, 2Behavioural and Clinical Neurosciences Institute, University of Cambridge, Cambridge, United Kingdom, 3Department of Pharmacology, University of Cambridge, Cambridge, United Kingdom

 
Although incidence of heart disease is similar amongst those with and without Huntington's disease (HD), 30% of HD patients compared to 2% of non-HD sufferers will die from the disease. We examined the R6/2 mouse using cardiac MRI and found there are progressive abnormalities in morphology and function. We used a simple parameter of LV shape and showed the heart is more bent in disease carriers in this model.

 
1133.   T1lower case Greek rho in infarcted mouse myocardium in vivo
Haja-Sherief N Musthafa1, Galina Dragneva1, Line Lottonen1, Mari Merentie1, Lyubomir Petrov1,2, Tommi Heikura1,2, Elias Ylä-Herttuala1, Seppo Ylä-Herttuala1, Olli Gröhn1, and Timo Liimatainen1
1AI Virtanen Institute For Molecular Sciences, University of Eastern Finland, Kuopio, Finland, 2Ark Therapeutics Ltd., Kuopio, Finland

 
In this study, we measured T1ρ relaxation times in mouse myocardium before and 1, 3, 7, 14 and 21 days after left anterior descending coronary artery ligation. T1ρ was found to increase in infarcted myocardium when compared to the reference myocardium of the same heart. Infarctions were confirmed by cine MRI and histology staining. The increase in T1ρ fits well with the time course of granulation and scar tissue formations opening up the possibilities to follow up the responses of therapeutic agents.

 
1134.   Estimation of Cardiac Elastance and Compliance from Pressure-Volume Tracing During Inflow Occlusion Using Real Time Cardiac Imaging Technique
Francisco Contijoch1, Walter RT Witschey2,3, Melissa M Levack3, Jeremy M McGarvey3, Gerald A Zsido3, Manabu Takebe3, Norihiro Kondo3, Christen Dillard3, Kristina Lau3, Hee Kwon Song2, Larry Dougherty2, Joseph H Gorman III3, Robert C Gorman3, and James J Pilla2,3
1Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, United States, 2Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States, 3Department of Surgery, University of Pennsylvania, Philadelphia, PA, United States

 

1135.   Doxorubicin cardiotoxicity in the rat detected with cardiac function MRI and late gadolinium enhancement
Neil Woodhouse1, Howard Mellor2, Jose Ulloa1, Guy Healing2, Jason Kirk2, and Paul Hockings3
1PHB Imaging, AstraZeneca, Alderley Edge, Cheshire, United Kingdom, 2GSA, AstraZeneca, Alderley Edge, Cheshire, United Kingdom, 3PHB Imaging, AstraZeneca, Molndal, Gothenburg, Sweden

 
Doxorubicin induced cardiotoxicity was examined in two groups of male Han-Wistar rats (n = 6/group), Vehicle (0.9 % saline) and Dox (doxorubicin 1.25 mg/kg) using a retrospectively gated IntraGate FLASH multi-slice cine sequence at 4.7T. Gadopentetate was administered as an intravenous bolus to three rats per group. Significant differences in end systolic volume, stroke volume, ejection fraction, and fractional shortening were demonstrated between the Vehicle and Dox groups. There were statistically significant (p=0.001) differences in late gadolinium enhancement after gadopentetate infusion.

 
1136.   COMPARING THE EFFECTS OF ACUTE HOMOGENEOUS MYOCARDIAL INFARCT WITH HETEROGENOUS MICROINFARCT ON LEFT VENTRICULAR FUNCTION USING MRI
Maythem Saeed1, Steven W Hetts1, Loi Do1, and Mark Wilson1
1Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, Ca, United States

 
The purpose was to differentiate the deleterious effects of major-vessel and micro-vessel occlusion on left ventricular function using MRI. Pigs (n=24) were divided into 3 groups: 1) control (no-infarct), 2) subjected to 90min of LAD artery occlusion/reperfusion and 3) subjected to coronary microemboli delivered into the LAD. At 3 days after coronary intervention, cine and viability images were acquired using MRI. The sizes of homogeneous infarct and microinfarct measured were 17±1% and 6.2±0.6% LV mass (P<0.01). Surprisingly, the effect on LV ejection fraction was identical in both interventional procedures, suggesting that different mechanisms govern the decline in LV function.

 
1137.   Evaluation of a Heart Phantom for Cardiac MR Elastography: A Feasibility Study
Shivaram Poigai Arunachalam1, Kevin Glaser1, Richard L Ehman1, and Philip Araoz1
1Radiology, Mayo Clinic, Rochester, Minnesota, United States

 
Previous studies have shown that cardiac MR elastography (CMRE) can assess regional differences in stiffness between infarcted and remote, noninfarcted myocardium in pigs. However, clinical applications of CMRE are challenging given the thin wall and complicated wave propagation of the myocardium. Therefore, realistic phantom studies are necessary to determine the requirements for drivers, imaging sequences and inversion algorithms for CMRE. This paper focuses on evaluating a commercially available heart phantom for CMRE using 2D EPI and 3D GRE MRE pulse sequences. The results demonstrate the feasibility of acquiring volumetric data in the thin myocardial wall of the heart phantom.
 
Traditional Poster Session - Cardiovascular

Myocardial Perfusion & Non Contrast MRA
Click on to view the abstract pdf. Click on to view the poster (Not all posters are available for viewing.)
 
Monday 7 May 2012
Exhibition Hall  10:45 - 12:45

1138.   A model-based approach for deformable registration of ungated cardiac perfusion MRI
Ganesh Adluru1, Alexis Harrison2, Chris McGann2, and Edward V.R. DiBella1
1Radiology, University of Utah, Salt Lake City, UT, United States, 2Internal Medicine, University of Utah, Salt Lake City, UT, United States

 
Cardiac perfusion MRI without ECG gating can be a promising alternative for imaging patients with atrial fibrillation and for imaging at high field strengths. Self-gating techniques can be used to retrospectively bin ungated images into approximate systole and diastole. However cardiac and respiratory motion can still be present in these self-gated images. Here we propose a model-based deformable registration approach that uses a two-compartment contrast model to remove the residual motion. A model reference image for each image in the dynamic sequence is generated and deformable registration using a finite element based method is performed to obtain motion free images.

 
1139.   Quantification of Myocardial Blood Volume and Measurement of Water Exchange with an Intravascular Contrast Agent in Healthy Volunteers
Octavia Biris1,2, Saurabh Shah3, Christopher Glielmi3, Daniel C Lee4, James C Carr1, and Timothy J Carroll1,2
1Radiology, Northwestern University, Chicago, IL, United States, 2Biomedical Engineering, Northwestern University, Evanston, IL, United States, 3Customer Solutions Group, Siemens Medical Solutions USA, Inc., Chicago, IL, United States, 4Feinberg Cardiovascular Research Institute, Northwestern University, Chicago, IL, United States

 
Absolute quantification of myocardial blood volume (ml/100g) may provide important information about myocardial viability in coronary artery disease and in heart transplants, where the formation of fibrotic tissue and global MBV reduction in the myocardium precedes organ rejection. We show a first observation of quantitative myocardial blood volume and water proton exchange in human volunteers with an intravascular contrast agent. Myocardial blood volume was calculated pixel-by-pixel from steady-state T1-weighted signal before and after administration of contrast agent. We show intra- to extra-vascular water exchange in the myocardium to fit a previously published two compartment slow water exchange model.

 
1140.   Iterative three compartment model for Look-Locker cardiac ASL acquisition
Adrienne E Campbell1,2, Anthony N Price3, Mark F Lythgoe1, Roger J Ordidge4, and Dave L Thomas5
1Centre for Advanced Biomedical Imaging, Division of Medicine and Institute of Child Health, University College London, London, United Kingdom, 2Department of Medical Physics and Bioengineering, University College London, London, United Kingdom, 3Robert Steiner MRI Unit, Imaging Science Department, Hammersmith Hostpital, Imperial College London, London, United Kingdom, 4Centre for Neuroscience, University of Melbourne, Melbourne, Australia, 5Department of Brain Repair and Rehabilitation, UCL Institute of Neurology, University College London, London, United Kingdom

 
Look-Locker arterial spin labelling (ASL) is used for the measurement of myocardial perfusion in preclinical studies. Saturation effects from Look-Locker acquisition will become particularly relevant in the heart when acquiring multi-slice ASL data, which requires thicker slice-selective inversions and additional RF pulses. In this study, we have taken the preliminary steps toward developing a 3-compartment iterative ASL model for the heart which includes the effects of the Look-Locker acquisition, in order to model the ASL acquisition.

 
1141.   Spin Labeling Cardiac MR Allows Early Detection of Cardiotoxicity Induced by Doxorubicin
Song Chen1, Jia Zhong1, Hualei Zhang1,2, Hui Qiao1,3, Rachel S. Frank1, Jerry Glickson1, and Rong Zhou1,3
1Laboratories of Molecular Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, United States, 2Department of Bioengineering, University of Pennsylvania, 3Cardiovascular Institute, University of Pennsylvania

 
Doxorubicin (DOX) remains among the most potent and widely prescribed drug for treating breast, blood and pediatric cancers. However, severe cardiotoxicity continues to affect up to 20% of patients receiving DOX. Unfortunately, currently available methods in the clinic cannot predict or discriminate patients who will suffer from cardiomyopathy after exposure to DOX. Here we show spin labeling cardiac MR reveals an early decline in myocardial blood flow in response to DOX when LVEF is still normal. With further investigation, we hope to develop a sensitive, non-invasive prognostic tool to improve cardiac risk stratification in the management of DOX-treated patients.

 
1142.   Single Cardiac Cycle Multipoint T1 Mapping with Radial Acquisition
David Chen1,2, Behzad Sharif1, Louise Thomson1,3, Troy LaBounty1, Rohan Dharmakumar1,3, Daniel Berman1,3, and Debiao Li1
1Cedars Sinai Medical Center, Los Angeles, CA, United States, 2Northwestern University, Evanston, IL, United States, 3University of California, Los Angeles, CA, United States

 
This work describes method to correct for saturation in the arterial input function (AIF) for cardiac perfusion using a multi-shot radially acquired data. Single cardiac cycle resolution T1 mapping is possible with this technique. T1 can then be converted to Gd concentration. This method eliminates the need to acquire two datasets, increasing feasibility for clinical use.

 
1143.   MRI Conditional Pacemakers: The Cooling Effect of Blood Flow in the Heart Chambers
Ramez E. N. Shehada1, Rohan More1, Sassan Rahbari1, Richard Williamson1, and Ali Dianaty1
1CRMD, St. Jude Medical, Sylmar, California, United States

 
MRI conditional pacemaker leads may increase in temperature primarily due to RF-induced heating; however, large segments of the leads reside in blood vessels and can benefit from the cooling effect of the surrounding blood flow. An in-vitro flow setup was developed to simulate in-vivo flow conditions around pacemaker leads and was used to determine the percent temperature reduction in the lead due to blood flow. Blood flow may reduce temperature-rises in the distal end of pacemaker leads by 83-87% and can be used to mitigate moderate heating of the distal segments of MRI conditional pacemaker leads.

 
1144.   Projection Imaging of Myocardial Perfusion: Minimizing the Subendocardial Dark-Rim Artifact
Behzad Sharif1, Rohan Dharmakumar1, Chrisandra Shufelt2, Troy LaBounty2, Louise Thomson2, Noel Bairey Merz2, Daniel S. Berman2, and Debiao Li1
1Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, and University of California Los Angeles, Los Angeles, California, United States, 2Heart Institute, Cedars-Sinai Medical Center, Los Angeles, California, United States

 
Current clinical myocardial perfusion MR methods suffer from image artifacts that reduce diagnostic accuracy, specifically the so-called subendocardial dark-rim artifact (DRA). DRAs are caused by multiple factors and mimic subendocardial perfusion deficits, and are especially limiting since they can reduce the sensitivity/specificity of detecting subendocardial perfusion deficits. In this work, we demonstrate that projection imaging of first-pass cardiac perfusion MR is robust to Gibbs ringing, which is a major cause of DRAs; thereby proposing radial k-space sampling as the preferred acquisition scheme for DRA-free perfusion imaging.

 
1145.   A theoretical model describing the Cine-ASL perfusion mapping technique: steadily-pulsed labeling provides better acquisition efficiency than FAIR
Thibaut Capron1, Thomas Troalen1, Patrick J. Cozzone1, Monique Bernard1, and Frank Kober1
1Centre de Résonance Magnétique Biologique et Médicale (CRMBM), UMR CNRS N°6612, Faculté de Médecine, Aix-Marseille Université, Marseille, France

 
The FAIR-ASL method, applied to the heart, has key limitations due to the relaxation of the labeled magnetization during the experiment. We propose a new steadily-pulsed ASL experimental scheme that allows maintaining the tagged state, simultaneously with cine-imaging. We provide a theoretical description of such a scheme and show a close agreement with the behavior observed in a proof-of-concept experiment carried out in mice heart. The calculations thus allow for a reliable assessment of myocardial perfusion. Furthermore, theory predicts that the acquisition efficiency can be enhanced by a factor of 3 with respect to the widely used FAIR technique.

 
1146.   Quantitative Assessment of the Myocardial Perfusion Reserve at 3.0T – Comparison of SR-TrueFISP and SR-TurboFLASH
Stefan Weber1,2, Karl-Friedrich Kreitner2, and Laura Maria Schreiber1,2
1Section of Medical Physics, Department of Diagnostic and Interventional Radiology, University Medical Center Mainz, Mainz, Rheinland-Pfalz, Germany,2Department of Diagnostic and Interventional Radiology, University Medical Center Mainz, Mainz, Germany

 
The aim of this study was to compare at 3.0T SR-TrueFISP and SR-TurboFLASH pulse sequences for semi-quantitative and absolutequantitative assessment of the myocardial perfusion reserve. No differences were found in SNR and CNR between both pulse sequences. However, SR-TrueFISP yielded superior reproducibility than SR-TurboFLASH as well as absolutequantification using the MMID4 model yielded lower intraobservervariability than the semiquantitative method.

 
1147.   Improved temporal resolution of dynamic oximetry via keyhole acquisition for quantifying reactive hyperemia
Michael C Langham1, and Felix W Wehrli1
1Radiology, University of Pennsylvania, Philadelphia, PA, United States

 
The current temporal resolution of dynamic oximetry is limited to 5s and thus may not be able to resolve potentially important information that could differentiate subtle differences in the vascular reactivity. Reducing TR is not a satisfactory solution since it will lead to unacceptable SNR in reference tissue as well as a minor loss of blood signal due to saturation effect. In this work we implemented and evaluated the keyhole acquisition scheme for improving the temporal resolution of dynamic oximetry by a factor of four without sacrificing SNR and accuracy.

 
1148.   Voxelwise analysis of myocardial blood flow from DCE-MRI data
Andreas Max Weng1, Christian Oliver Ritter1, Sven Zuehlsdorff2, Hui Xue3, Jens Guehring3, Christopher Glielmi2, Meinrad Beer1, Dietbert Hahn1, and Herbert Köstler1
1Institute of Radiology, University of Würzburg, Würzburg, Bayern, Germany, 2MR Research and Development, Siemens Healthcare, 3Corporate Research, Siemens Corporation

 
Absolute quantification of myocardial perfusion is commonly based on a region-of-interest (ROI) analysis in order to achieve a sufficient signal to noise ratio (SNR). 3 T scanners provide the opportunity to acquire dynamic contrast enhanced MRI with higher SNR compared to 1.5 T. This, in turn, may help to absolutely quantify myocardial perfusion not only in ROIs but in every acquired voxel. This study presents first results of a voxelwise myocardial perfusion quantification.

 
1149.   Motion-Induced Dark-Rim Artifact in First-Pass Myocardial Perfusion MR: A Controlled Canine Study
Behzad Sharif1, Rohan Dharmakumar1, Louise Thomson2, Noel Bairey Merz2, Daniel S. Berman2, and Debiao Li1
1Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, and University of California Los Angeles, Los Angeles, California, United States, 2Heart Institute, Cedars-Sinai Medical Center, Los Angeles, California, United States

 
A major limiting factor for specificity and sensitivity of current MP MR methods is the so-called subendocardial dark-rim artifact (DRA), which may mimic perfusion deficits. It is known that DRAs in conventional Cartesian imaging protocols are caused by a combination of factors including Gibbs ringing and cardiac motion effects. In this work, we aimed at improving the analysis of motion-induced DRAs by considering the combined effect of cardiac motion and limited spatial resolution (Gibbs ringing) on both the spatial extent and temporal persistence of the DRA. We performed first-pass MP MR on healthy dogs at moderate to high heart-rates to evaluate the effect of motion on the DRAs in terms of their spatial extent and temporal persistence. In addition, we present initial results for an alternative highly-accelerated radial acquisition and reconstruction scheme that can potentially eliminate the DRA due to motion.

 
1150.   Myocardial perfusion assessment by using contrast-media-free Fourier decomposition MRI
Grzegorz Bauman1, Rajiv Gupta2, and Julien Dinkel2,3
1Dept. of Medical Physics in Radiology, German Cancer Research Center, Heidelberg, Germany, 2Dept. of Radiology, Massachusetts General Hospital, Boston, United States, 3Dept. of Radiology, German Cancer Research Center, Heidelberg, Germany

 
In this work we present a technique for myocardial perfusion assessment by using contrast-agent-free MRI at 3T. In this feasibily study the data were obtained in a group of healthy volunteers. The proposed method is based on fast data acquisition with an interleaved radial gradient echo sequence combined and compressed sensing image reconstruction. Subsequent postprocessing including image registration, segmentation and spectral analysis of signal variations in myocardium was used to generate perfusion-weighted images as well as maps of temporal distribution of the blood flow.

 
1151.   High-Resolution 3D First-Pass Myocardial Perfusion Imaging
Anthony G. Christodoulou1, Haosen Zhang2, Bo Zhao1, Qing Ye2, T. Kevin Hitchens2, Chien Ho2, and Zhi-Pei Liang1
1Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, United States, 2Pittsburgh NMR Center for Biomedical Research, Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, United States

 
This abstract presents a novel method for performing high-resolution 3D first-pass myocardial perfusion imaging. Parallel imaging and sparse sampling are integrated to vastly improve the temporal resolution of first-pass myocardial perfusion imaging. The method is demonstrated in vivo in rats.

 
1152.   Evaluation of fully automated motion corrected first pass myocardial perfusion
Aya Kino1, Andrada R Popescu2, Mauricio S Galizia1, Jeremy D Collins1, Darshit Thakrar1, Rhaul Rustogi1, Christopher Glielmi3, Hui Xue4, Jens Guehring4, Sven Zuehlsdorff5, Daniel Lee6, and James Carr1
1Northwestern University, Chicago, IL, United States, 2Radiology, Children Memorial Hospital, Chicago, IL, United States, 3Siemens Healthcare, Siemens,4Corporate Research USA, Siemens, Princenton, New Jersey, 5Siemens Healthcare, Siemens, Chicago, IL, 6Medicine Cardiology Division, Northwestern University, Chicago, IL

 
The purpose of the study is to evaluate a fully automated motion corrected first pass myocardial perfusion (FPMP) MRI with semi quantitative perfusion parameter maps in patients with suspected ischemic heart disease

 
1153.   Non-Contrast-Enhanced Abdominal Venography Using Inflow Spin Labeling in Combination with Flow Dephased Background Suppression
Hao Shen1, Guang Cao2, Haiyi Wang3, and Jia Wang3
1Applied Science Laboratory, GE Healthcare, Beijing, Beijing, China, 2Applied Science Laboratory, GE Healthcare, HongKong SAR, China, 3Department of Radiology, Chinese PLA General Hospital, Beijing, China

 
Abdominal venography is important in clinical diagnosis of several diseases, but it is difficult to image with the existing MRI technique. In this study, we developed a non-contrast-enhanced abdominal venography using inflow spin labeling in combination with flow dephased background suppression.

 
1154.   NON-CONTRAST-ENHANCED MR ANGIOGRAPHY FOR SELECTIVE EVALUATION OF THE RENAL ARTERY
Bing Wu1, Jiayu Sun2, Changxian Li2, and Zhenlin Li2
1West China Hospital, Chengdu, Sichuan, China, 2West China Hospital

 
To evaluate the diagnostic performance of non-contrast-enhanced MR angiography (NCE-MRA) with contrast-enhanced MR angiography (CE-MRA) in the preoperative assessment of renal artery. Results showed no statistically significant differences between NCE-MRA and CE-MRA for characterization of renal vasculature(P<0.05).
 
Traditional Poster Session - Cardiovascular

Coronary MRA & Vessel Wall
Click on to view the abstract pdf. Click on to view the poster (Not all posters are available for viewing.)
 
Monday 7 May 2012
Exhibition Hall  10:45 - 12:45

1155.   Self-Guided Retrospective Motion Correction (SEGMO) for Free-Breathing Whole-heart Coronary MRA with 100% Acquisition Efficiency
Jianing Pang1,2, Himanshu Bhat3, Behzad Sharif1, Zhaoyang Fan1, Edward Gill1, Troy LaBounty1, James Min1, Louise E.J. Thomson1, John D. Friedman1, Daniel S. Berman1, and Debiao Li1,4
1Cedars-Sinai Medical Center, Los Angeles, CA, United States, 2Northwestern University, Chicago, IL, United States, 3Siemens Medical Solutions USA Inc., Charlestown, MA, United States, 4University of California, Los Angeles, CA, United States

 
A respiratory motion correction method (SEGMO) is proposed for whole-heart coronary MRA. It eliminates the need for a diaphragm navigator, reduces imaging setup time, and has more accurate respiratory motion detection using an affine model. Its inherent 100% gating efficiency ensures a shorter and more fixed scan time compared to conventional navigator gated schemes.

 
1156.   Multi-Phase 3D Cones Coronary MRA with 3D Respiratory Motion Compensation
Holden H Wu1,2, Bob S Hu2,3, Dwight G Nishimura2, and Michael V McConnell1,2
1Cardiovascular Medicine, Stanford University, Stanford, CA, United States, 2Electrical Engineering, Stanford University, Stanford, CA, United States, 3Palo Alto Medical Foundation, Palo Alto, CA, United States

 
Non-invasive coronary angiography is one of the most desired applications of cardiovascular MRI, but is challenged by physiologic motion. In this work, we present new advances in respiratory motion compensation for the 3D cones multi-phase whole-heart imaging technique. Leading and trailing 2D navigator images are acquired every heartbeat in orthogonal planes through the heart to directly track respiration-induced displacement in all three directions (S/I, A/P, L/R). Tracking results are then used to retrospectively compensate all readouts (100% acquisition efficiency) prior to image reconstruction.

 
1157.   Accelerated Whole-Heart Coronary Imaging using Multiple Breath-holds and Compressed Sensing Monitored by Self-navigation
Christoph Forman1,2, Davide Piccini1, Jana Hutter1,2, Robert Grimm1, Joachim Hornegger1,2, and Michael O. Zenge3
1Pattern Recognition Lab, University of Erlangen-Nuremberg, Erlangen, Germany, 2Erlangen Graduate School in Advanced Optical Technologies (SAOT), Friedrich-Alexander-University Erlangen-Nuremberg, Erlangen, Germany, 3MR Application & Workflow Development, Siemens AG, Healthcare Sector, Erlangen, Germany

 
Current research in whole-heart coronary MR imaging is driven by acceleration of scan time. On the one hand, self-navigation was introduced to improve the efficiency of conventional navigator-gated examinations. On the other hand, compressed sensing was proposed for acceleration of data acquisition. In this work, a novel incoherent Cartesian sampling pattern is used for imaging the coronary imaging in multiple breath-holds. Self-navigation properties are exploited for a real-time supervision the respiratory phase during breath-hold. In this way, misregistration of consecutive acquisitions could be avoided. The proposed method was compared with the navigator-gated approach in 4 volunteers.

 
1158.   About the performance of multi-dimensional radial self-navigation incorporating compressed sensing for free-breathing coronary MRI
Gabriele Bonanno1,2, Gilles Puy3,4, Yves Wiaux3,5, Ruud B. van Heeswijk1,2, and Matthias Stuber1,2
1Department of Radiology, University Hospital (CHUV) and University of Lausanne, Lausanne, Vaud, Switzerland, 2Center for Biomedical Imaging (CIBM), Lausanne, Vaud, Switzerland, 3Institute of Electrical Engineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Vaud, Switzerland, 4Institute of the Physics and Biological Systems, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Vaud, Switzerland, 5Institute of Bioengineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Vaud, Switzerland

 
A novel image-based respiratory self-navigation method was developed for free-breathing coronary MRI. Under-sampled radial sub-images are acquired on a beat-to-beat basis, non-linear reconstruction is performed, and motion parameters are extracted for direct motion correction. In a first step, the new algorithm was optimized and evaluated using a numerical simulation of a moving heart. Subsequently, the performance was quantitatively ascertained in an in vivo study that included 12 healthy adult subjects where it was objectively demonstrated that self-navigation incorporating compressed sensing is a powerful tool for motion artifact suppression in radial coronary MRI.

 
1159.   Prospective Navigator Cardiac Triggering for Coronary MRA
Naoyuki Takei1, Yuji Iwadate1, Takayuki Suzuki2, Koji Yoneyama2, Takayuki Masui2, and Hiroyuki Kabasawa1
1Global Applied Science Laboratory, GE Healthcare, Hino, Tokyo, Japan, 2Radiology, Seirei Hamamatsu General Hospital, Japan

 
The purpose of this study was to develop a prospective navigator echo based cardiac triggering for coronary artery imaging (CAI). Echo peak from FID signal acquired using 2D selective navigator pulse with 10mm in diameter that was placed on aortic arch was used for cardiac triggering. The magnitude of echo peak from the FID was displayed on a real-time monitor window. Systole was detected by a rise in echo peak above a threshold. Data was acquired with Balanced Steady State Free Precession (bSSFP) data acquisition with spectral selective inversion pulse for fat saturation (SPIR) with breath hold. The comparison study was performed to a conventional ECG trigger approach on 1.5T. The preliminary results provide a comparable depiction of coronary arteries to ECG without the constraints of scan time, spatial resolution and image quality.

 
1160.   Minimization of Respiratory Motion Artifacts for Whole-Heart Coronary MRI: A Combination of Self-navigation and Weighted Compressed Sensing Reconstruction
Christoph Forman1,2, Davide Piccini1, Jana Hutter1,2, Robert Grimm1, Joachim Hornegger1,2, and Michael O. Zenge3
1Pattern Recognition Lab, University of Erlangen-Nuremberg, Erlangen, Germany, 2Erlangen Graduate School in Advanced Optical Technologies (SAOT), Friedrich-Alexander-University Erlangen-Nuremberg, Erlangen, Germany, 3MR Application & Workflow Development, Siemens AG, Healthcare Sector, Erlangen, Germany

 
Recently, self-navigation techniques were introduced for 3D radial in the field of free-breathing, whole-heart coronary imaging. Radial trajectories intrinsically are insensitve for motion during data acquisition. However, Cartesian sampling is superior to radial trajectories in terms of SNR and hardware limitations, e.g. gradient delays. Thus, we propose the application of respiratory self-navigation on an incoherent, undersampled Cartesian trajectory. The effects of residual respiratory motion are minimized by a weighted data fidelity term, exploiting the information derived from the self-navigation, in iterative image reconstruction. In-vivo experiments were performed on four healthy volunteers and compared to navigator-gated acquisition.

 
1161.   Sensitivity Encoded Isotropic Projection Reconstruction (SNIPR) for Whole-Heart Coronary MRA
Jianing Pang1,2, Behzad Sharif1, Troy LaBounty1, Louise E.J. Thomson1, Daniel S. Berman1, and Debiao Li1,3
1Cedars-Sinai Medical Center, Los Angeles, CA, United States, 2Northwestern University, Chicago, IL, United States, 3University of California, Los Angeles, CA, United States

 
Proposed method combines sensitivity encoding and undersampled projection reconstruction trajectory to greatly accelerate whole-heart coronary MRA. No separate calibration scans are needed since the densely sampled k-space central region allows direct sensitivity map extraction from image data. Results show that the proposed method reduces aliasing, hence allows a shorter scan time by acquiring less k-space samples, while minimizing the reduction in image quality.

 
1162.   An Improved Binning Strategy for 3D Image-Based Respiratory Motion Correction in Whole-Heart Coronary MRA
Davide Piccini1, Arne Littmann2, Hui Xue3, Jens Guehring2, and Michael O. Zenge2
1Pattern Recognition Lab, University of Erlangen-Nuremberg, Erlangen, Germany, 2MR Applications & Workflow Development, Siemens AG, Healthcare Sector, Erlangen, Germany, 3Imaging and Visualization, Siemens Corporate Research, Princeton, NJ, United States

 
In recent approaches implementing image-based 3D respiratory motion correction for interleaved whole-heart coronary MRA, the interleaves are straightforwardly grouped in equally spaced bins on the respiratory cycle. This allows to obtain undersampled images with minimal intra-bin respiratory motion that can be registered to a reference. However, for bins with a low number of interleaves or non-uniform spatial distribution, image quality is degraded by streaking and undersampling artifacts. Hence, image registration might fail and such bins are usually discarded. In this work an optimized binning approach is proposed which maximizes the uniformity of the distribution of the interleaves. With this method 3D affine motion correction is allowed for all bins.

 
1163.   Fast Simultaneous Non-contrast Angiography and intra-Plaque hemorrhage (fSNAP) imaging for atherosclerotic disease with low-resolution reference scan and corrected phase sensitive reconstruction
Huijun Chen1, Jinnan Wang2, Xihai Zhao3, Chun Yuan1, and William S Kerwin1
1University of Washington, Seattle, WA, United States, 2Philips Research North America, United States, 3Department of Biomedical Engineering, Tshinghua University, Beijing, China

 
SNAP sequence has been proposed to image both the luminal stenosis and intraplaque hemorrhage in atherosclerosis patient in one scan. In SNAP, the blood signal presents only negative signal that can be used to generate non-contrast MRA, while all other tissues presents T1-weighted positive signal, providing a good hemorrhage detection tool. However, the phase-sensitive reconstruction in the SNAP sequence requires a full-resolution reference scan, which doubles the scan time. In this study, we propose a fast SNAP (fSNAP) sequence with low resolution reference scan and a corrected phase-sensitive reconstruction to speed up the acquisition without compromising the image quality.

 
1164.   Motion-compensated TSE imaging of the carotid arteries using FID-based navigator gating
Petter Dyverfeldt1, Vibhas S Deshpande2, Tobias Kober3, Gunnar Krueger3, and David Saloner1
1Radiology & Biomedical Imaging, University of California San Francisco, San Francisco, CA, United States, 2Siemens Medical Solutions USA, Inc., San Francisco, CA, United States, 3Advanced Clinical Imaging Technology, Siemens Healthcare Sector IM&WS S, Lausanne, Switzerland

 
Multicontrast-weighted MRI is promising for characterization of carotid plaques, but is hampered by motion artifacts. This study demonstrated initial feasibility of motion-compensated carotid-MRI achieved by a novel approach to FID-based navigator gating. The results demonstrate the potential of the proposed gating-approach to improve the clinical capability of MR imaging of carotid plaques.

 
1165.   Long-term Effects of Red Blood Cell Deposition in an Animal Model of Complicated Atherosclerosis
Stephanie Elaine Gar-Wai Chiu1, James Q Zhan2, and Alan R Moody1,2
1Medical Biophysics, University of Toronto, Toronto, Ontario, Canada, 2Medical Imaging, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada

 
Intraplaque hemorrhage (IPH) may be an important marker of complicated atheroma. IPH was simulated by microinfusion catheter delivery of autologous red blood cells (RBCs) into advanced rabbit abdominal aorta plaques. Histology at 9 weeks after simulated IPH indicated the development of plaque features not previously seen in rabbits undergoing similar atherosclerosis induction without RBC injection. These plaque features include necrotic cores, extravasated RBCs, and iron deposits. T1-weighted MR imaging was able to show varying vessel wall thickness and post-contrast vessel wall enhancement indicative of the large plaque sizes and extensive inflammation and neovascularization.

 
1166.   An Image-Based Navigation Method for Carotid Vessel Wall Imaging
Ioannis Koktzoglou1,2, and Robert R Edelman1
1Radiology, NorthShore University HealthSystem, Evanston, IL, United States, 2The University of Chicago Pritzker School of Medicine, Chicago, IL, United States

 
Swallowing is reported to be greatest source of physiologic motion within the carotid arteries. The purpose of this work was to investigate whether image-based (i.e., 2D) navigators depicting the carotid arteries and adjacent tissue could be used to identify motion and ameliorate image artifacts during three-dimensional carotid vessel wall imaging.

 
1167.   Middle cerebral artery (MCA) vessel wall imaging using T1-enhanced iMSDE
Jinnan Wang1, Niranjan Balu2, Peter Börnert3, and Chun Yuan2
1Philips Research North America, Briarcliff Manor, NY, United States, 2University of Washington, 3Philips Research Europe

 
Intracranial atherosclerotic disease (IAD) represents 9-15% of all the ischemic strokes in US and is suggested as the most common cause of stroke worldwide. The vessel wall imaging of IAD, however, is challenged by blood suppression and outer wall boundary delineation. This study proposed a new T1 enhanced iMSDE sequence for IAD vessel wall imaging and demonstrated its feasibility in a group of subjects.

 
1168.   In vivo assessment of adventitial vasa vasorum in patients with symptomatic carotid plaques: A dynamic contrast-enhanced MRI study.
Jie Sun1, Yan Song2, William S Kerwin1, Huijun Chen1, Dong Li3, Daniel S Hippe1, Min Chen2, Cheng Zhou2, Thomas S Hatsukami4, and Chun Yuan1
1Radiology, University of Washington, Seattle, Washington, United States, 2Radiology, Beijing Hospital, Beijing, China, 3Radiology, Anzhen Hospital, Beijing, China,4Surgery, University of Washington, Seattle, Washington, United States

 
Substantial evidence indicates that adventitial vasa vasorum (VV) is actively involved in the atherogenic process. However, non-invasive methods to study adventitial VV quantitatively are limited. This study characterized adventitial VV in symptomatic patients using dynamic contrast-enhanced MRI (DCE-MRI). Adventitial Ktrans derived from DCE-MRI was found to be closely associated with IPH and clinical symptom status. DCE-MRI provides a noninvasive way to study adventitial VV in patients and may be useful in understanding plaque progression or individual risk stratification.

 
1169.   Intracranial Atherosclerotic Plaque Evaluation Using Three Dimensional Isotropic Multi-Contrast MRI
Dongxiang Xu1, Jinnan Wang2, William S Kerwin1, and Chun Yuan1
1Radiology, University of Washington, Seattle, WA, United States, 2Philips Research North America, Seattle, WA, United States

 
Intracranial atherosclerotic disease (IAD) is one of the most common causes of stroke worldwide. Clinically, IAD is usually diagnosed with angiography based imaging methods to detect luminal narrowing. However, autopsy studies2 show that approximately 40% of IAD does not present with any luminal stenosis but rather only outer wall remodeling, an indicator of progression of plaque burden. To overcome this underestimation of stroke risk, analysis of the intracranial vessel wall (IVW) is crucial. Recent developments in 3D isotropic MR imaging techniques provide sufficient wall contrast in in vivo MR IVW images. Due to the tortuous topology of intracranial vessels, cross sectional images reformatted based on the geometry of the arteries are desirable. However, no approaches have thus far been proposed to effectively analyze IVW images, and most current IVW analysis is still limited to arterial sections that are approximately straight. In this study, we proposed a new approach that allows effective evaluation of atherosclerotic plaques at all locations along intracranial arteries by using 3D isotropic multi-contrast MRI.

 
1170.   On the Generalization of Carotid Vessel Wall MRI Risk Factors across Imaging Centers
Kiyofumi Yamada1, Martine Truijman2, William Kerwin1, Jie Sun1, Yan Song3, Mat Daemen2, Eline Kooi2, and Chun Yuan1
1Radiology, University of Washington, Seattle, Washington, United States, 2Maastricht University Medical Center, Maastricht, Netherlands, 3Radiology, Beijing Hospital, Beijing, China

 
The purpose of this investigation was to understand the cross-center similarities and differences of two independent carotid vessel wall imaging centers. Ten subjects were recruited from each of two imaging centers for multicontrast MRI and plaque compositional analysis. We found good association across centers suggesting similar results regarding the association of risk factors with outcome can be expected across centers. On the other hand, considerable biases between absolute values of quantitative parameters were observed. Thus, in order for risk factors to be translated into clinical practice with appropriate risk thresholds, the source of bias must be ascertained and eliminated.

 
1171.   How thick of Fibrous Cap Can Be Seen in MRI? A Phantom Study
Rui Li1, and Chun Yuan1,2
1Center for Biomedical Imaging Research, School of Medicine, Tsinghua University, Beijing, China, 2Department of Radiology, University of Washington, Seattle, WA, United States

 
Visualization of fibrous cap in atherosclerotic plaque is critical for plaque imaging, since thin fibrous cap means vulnerable plaque. Several studies have shown the capability of high resolution MRf imaging to discriminate fibrous cap and lipid rich necrotic core. However the minimum thickness can be seen has not been investigated yet. This study proposed to find out the answer using a home-designed phantom. In conclusion we found fibrous cap thinner than the acquisition resolution is hardly to be seen with 1/2 contrast hypnosis between fibrous cap and necrotic core.
 
Traditional Poster Session - Cardiovascular

Flow Quantification
Click on to view the abstract pdf. Click on to view the poster (Not all posters are available for viewing.)
 
Monday 7 May 2012
Exhibition Hall  10:45 - 12:45

1172.   
Pre-emphasis Compensation of Oscillatory Phase Offsets in Phase-Contrast Flow Measurements
Julia Busch1, Signe Johanna Vannesjoe1, Daniel Giese1,2, Christoph Barmet1, Klaas Pruessmann1, and Sebastian Kozerke1,2
1Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland, 2Division of Imaging Sciences and Biomedical Engineering, King’s College London, London, United Kingdom

 
Phase-contrast magnetic resonance imaging provides high resolution information about blood flow, however its application in a clinical setting is still limited due to its sensitivity to phase errors. Phase oscillations caused by mechanical vibrations of the gradient coils account for various degrees of phase offsets depending on the echo time point. A generic system-specific pre-emphasis would offer the possibility to compensate for 0th and 1st order phase offsets without the disadvantage of causing additional scan time. Focusing on the mechanical vibrations of the z-gradient it is demonstrated that pre-emphasis can reduce phase errors well below 1% of the encoding velocity.

 
1173.   
Accelerated Aortic Flow Assessment with Compressed Sensing using Sparsity of the Complex Difference Image as an additional constraint
Yongjun Kwak1,2, Seunghoon Nam1,2, Mehmet Akcakaya1, Tamer A. Basha1, Beth Goddu1, Warren J. Manning1, Vahid Tarokh2, and Reza Nezafat1
1Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, United States, 2SEAS, Harvard University, Cambridge, MA, United States

 
One of the major limitations of phase contrast imaging is its long scan time. In this study, we propose an accelerated phase contrast MR approach in which the sparsity of the complex difference (CD) image is used as the sparsifying transform to improve the compressed sensing (CS) reconstruction. The efficacy of the proposed method was demonstrated in both retrospective undersampling and prospective accelerated flow imaging in ascending aorta.

 
1174.   Left Atrial Flow Quantitification in Atrial Fibrillation
Jacob U Fluckiger1, Jeffrey Goldberger1, Daniel Lee2, Richard Lee2, Jason Ng2, James Carr1, and Michael Markl1
1Radiology, Northwestern University, Chicago, Il, United States, 2Cardiology, Northwestern University, Chicago, Il, United States

 
In this work we present preliminary results measuring blood velocity in patients with atrial fibrillation. 4D phase contrast MRI data was collected in 9 patients with AF as well as 10 healthy volunteers. The AF patients had an average velocity that was 39% lower than healthy volunteers.

 
1175.   
Assessing relative energy loss across heart valves using generalized phase-contrast flow measurements
Christian Binter1, Verena Knobloch1, Robert Manka1,2, Andreas Sigfridsson1, and Sebastian Kozerke1
1Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland, 2Cardiac Imaging, University Hospital Zurich, Zurich, Switzerland

 
Aortic valve performance is typically assessed by means of pressure gradients or orifice sizes, which correlate only weakly with the energy loss across the valve. Here a method to directly determine the energy budget of the flow is presented. Using generalized phase-contrast flow measurements with multiple velocity encodings the energy loss due to turbulence and regurgitation can be quantified. By relating these losses to the available kinetic energy of the flow, a parameter for the efficiency of heart valves can be obtained. It is shown that significant differences in energy efficiency between different valve designs and between heart valve patients and healthy controls exist.

 
1176.   A Novel 4D Flow Tool for Comprehensive Blood Flow Analysis
Mehmet A. Gulsun1, Marie-Pierre Jolly1, Jens Guehring2, Christoph Guetter1, Arne Littmann2, Andreas Greiser2, Michael Markl3, and Aurelien F. Stalder2
1Image Analytics and Informatics, Siemens Corporate Research, Princeton, NJ, United States, 2Siemens AG Healthcare Sector, Erlangen, Germany,3Northwestern University, Chicago, Illinois, United States

 
4D Phase Contrast (PC)-MRI is gaining attention for assessing blood flow. Therefore the accuracy and reproducibility of this process becomes critical. We present a comprehensive 4DFlow software package for advanced flow quantification and visualization. This software integrates background phase and velocity aliasing corrections, 4D vascular centerline and lumen segmentation, automated quantification and 3D visualization. Five cases were evaluated giving inter-method and inter-observer errors within 10% of the measured dimension. Results demonstrate that an integrated 4D flow post-processing approach can reduce processing times to a few minutes while enhancing accuracy and objectivity and thus help bring the technique to the clinic.

 
1177.   Comparison of Velocity Vector Fields and Turbulent Kinetic Energy Measured by MRI and Particle Tracking Velocimetry in a Realistic Aortic Phantom
Verena Knobloch1, Christian Binter1, Utku Gulan2, Beat Lüthi2, Peter Boesiger1, and Sebastian Kozerke1
1Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland, 2Institute of Environmental Engineering, ETH Zurich, Zurich, Switzerland

 
Velocity vector fields and Turbulent Kinetic Energy (TKE) were acquired in an elastic and anatomically accurate replica of a human aorta equipped with a mechanical heart valve. Using the MRI acquisition of a multi-point velocity encoded sequence, velocities and TKE were computed with Bayesian parameter estimation. As a reference, both parameters were measured with Particle Tracking Velocimetry in the transparent setup. The comparison of both measurements shows good agreement for velocity and TKE values.

 
1178.   Real time flow with fast GPU reconstruction for continuous assessment of cardiac output.
Grzegorz Tomasz Kowalik1, Jennifer Anne Steeden1, Bejal Pandya1, David Atkinson2, Andrew Taylor1, and Vivek Muthurangu1
1Institute of Cardiovascular Science, UCL Centre for Cardiovascular Imaging, London, United Kingdom, 2Centre for Medical Imaging, UCL Division of Medicine, London, United Kingdom

 
A novel approach for continuous cardiac output quantification during an exercise was developed and implemented on a heterogeneous image reconstruction system. Combination of spiral real-time PCMR sequence with parallel imaging allowed on high-temporal acquisition. Application of a GPU for image processing resulted in almost instantaneous reconstruction. An external computer equipped with the GPU was networked using CORBA technology. This let on seamless processing from a clinician point of view. The implementation was tested and validated against our multi -core CPU

 
1179.   A novel method to calculate vectorial wall shear stress from 4D phase contrast MRI: analytical and in-vivo validation in the common carotid artery at different resolutions
Wouter V. Potters1, Pim van Ooij1,2, Ed vanBavel2, and Aart J. Nederveen1
1Radiology, Academic Medical Center, Amsterdam, Netherlands, 2Biomedical Engineering and Physics, Academic Medical Center, Amsterdam, Netherlands

 
Wall shear stress (WSS) is the tangential force of flowing blood on the vessel wall. Calculation of WSS remains challenging. A novel method is presented to calculate time-resolved vectorial WSS along the entire vessel wall. The method was validated in software phantoms and in-vivo datasets of the common carotid artery at multiple resolutions. Results showed convergence of WSS towards theoretical WSS for the phantom data, which effect was reproduced in in-vivo data.

 
1180.   Single-voxel direct Fourier reconstruction of spiral Fourier velocity encoding data on GPGPUs
Thales Henrique Dantas1, and Joao L. A. Carvalho1
1Department of Electrical Engineering, University of Brasília, Brasília, DF, Brazil

 
Fourier velocity encoding (FVE) may be useful in the assessment of valvular disease and of carotid wall shear stress, as it eliminates partial volume effects that affect phase-contrast imaging. The scan-time of 2DFT FVE is prohibitively long for clinical use, but the spiral FVE method is substantially faster. Spiral FVE reconstruction is time-consuming, due to multidimensionality and non-Cartesian sampling. Using gridding or NUFFT, the entire m(x,y,v,t) matrix is calculated. However, we are typically only interested in the velocity distributions associated with pixels in a small ROI. We propose single-voxel direct Fourier transform (DrFT) on GPGPUs for seemingly instantaneous spiral FVE reconstruction.

 
1181.   Comparison of local against regional elastic properties of the vessel wall in a murine atherosclerosis model by PWV measurements
Alexander Gotschy1,2, Volker Herold1, Elisabeth Bauer2, Gunthard Lykowsky3, Christian Schrodt2, Eberhard Rommel1, Peter M. Jakob1, and Wolfgang R. Bauer1
1Department of Experimental Physics 5, University of Würzburg, Würzburg, Germany, 2Department of Internal Medicine I, University of Würzburg, Würzburg, Germany, 3Research Center Magnetic Resonance Bavaria (MRB), Würzburg, Germany

 
Increased aortic stiffness is known to be associated with atherosclerosis. However, to our knowledge, the local distribution of vascular stiffening has never been investigated in detail. A local indicator for the elasticity of the vessel wall is the Pulse-Wave-Velocity (PWV). In this study we assessed regional and local PWV in the descending aortas of ApoE-/- and control mice and evaluated the correlation of both parameters. Thereby we found that local and regional PWV show a good correlation in control mice but no correlation in ApoE-/- mice. This may indicate that vascular stiffening is very unequally distributed over the vessel.

 
1182.   4D phase contrast MRI in intracranial aneurysms: A comparison with patient-specific computational fluid dynamics with temporal and spatial inflow velocity boundary conditions as measured with 2D phase contrast MRI
Pim van Ooij1,2, Joppe Schneiders1, Henk A. Marquering1,2, Charles B. Majoie1, Ed vanBavel2, and Aart J. Nederveen1
1Radiology, Academic Medical Center, Amsterdam, Netherlands, 2Biomedical Engineering & Physics, Academic Medical Center, Amsterdam, Netherlands

 
4D phase contrast MRI measurements (4D PC-MRI) in intracranial aneurysms are presented and compared with patient-specific computational fluid dynamics in which a 4D velocity profile as measured with through-plane PC-MRI (2D PC-MRI) is prescribed as inflow boundary conditions. Quantitative and qualitative similarities were found. Although the inflow velocity assumption in CFD is minimized by using the 2D PC-MRI measurement, other assumptions cause deviations from measured flow patterns. However, in CFD the resolution is higher and results show more flow details. Thus, for hemodynamic assessment, CFD and 4D PC-MRI complement each other.

 
1183.   Multi-Slice CINE Phase Contrast Pulse Wave Velocity Measurements for Characterising Aortic Cardiovascular Disease
Deirdre B Cassidy1, Stephen J Gandy2,3, Patricia Martin3, R Stephen Nicholas2,3, and J Graeme Houston3,4
1Institute of Cardiovascular Research, Dundee, Angus, United Kingdom, 2NHS Tayside Medical Physics, Ninewells Hospital, Dundee, Angus, United Kingdom, 3NHS Tayside Clinical Radiology, Ninewells Hospital, Dundee, Angus, United Kingdom, 4Institute of Cardiovascular Research, Dundee, Scotland, United Kingdom

 
Aortic stiffening occurs as a result of the pathophysiological contribution of age and atherosclerosis, and is associated with increased risk of cardiovascular events. This can be characterised by measurement of pulse wave velocity (PWV). PWV can be derived from phase contrast MRA using multiple aortic flow waveforms in combination with intra-arterial distance measurements. In this study, the mean PWV was found to be stable on a ‘scan-to-scan’ basis in a cohort of healthy volunteers, and was found to increase significantly with age and cardiovascular disease severity – i.e. the data are consistent with developing aortic stiffness.

 
1184.   Wall shear stress vectors derived from 3D phase contrast MRI at increasing resolutions in an intracranial aneurysm phantom
Pim van Ooij1,2, Wouter V. Potters1, Charles B. Majoie1, Ed vanBavel2, and Aart J. Nederveen1
1Radiology, Academic Medical Center, Amsterdam, Netherlands, 2Biomedical Engineering & Physics, Academic Medical Center, Amsterdam, Netherlands

 
Due to limited resolution and SNR, estimating wall shear stress (WSS) from time-resolved 3D phase contrast MRI is challenging. In this study, a recently in-house developed WSS algorithm is tested on 3D PC-MRI data obtained in an intracranial aneurysm phantom, measured with steady flow at different resolutions. Flow patterns are similar, albeit with more detail at higher resolutions. The maximum and mean WSS increased with increasing resolution. Directions of WSS vectors and regions were similar. More WSS complexity could be observed at higher resolutions. For accurate WSS estimations, resolution must be as high as possible.

 
1185.   Time-resolved 3D MR angiography transit times are inversely proportional to cardiac index
Andy Swift1, Adam Telfer2, Smitha Rajaram2, Robin Condliffe3, Helen Marshall2, Dave Capener2, Judith Hurdman3, Charlie Elliot3, David Kiely3, and Jim Wild2
1University of Sheffield, Sheffield, S.Yorks, United Kingdom, 2University of Sheffield, 3Sheffield Pulmonary Vascular Disease Unit

 
Based on a simple fluid dynamics model of plug flow, we evaluated 3D MR contrast transit times in 59 patients with pulmonary hypertension. Regression curve fitting identified significant inverse proportional relationships between cardiac index and 3D MR angiography measurements. Direct proportional relationships that have been previously reported with pulmonary arterial pressure and resistance were not found to be either physically realistic, or strong in correlation with 3D MR angiography transit times from our plug flow model.

 
1186.   Assessment of Transvalvular Flow Jet Eccentricity in Aortic Stenosis
Julio Garcia1, Lyes Kadem2, Eric Larose1, and Philippe Pibarot1
1Medicine, Laval University, Quebec, Quebec, Canada, 2Concordia University, Montreal, Quebec, Canada

 
Aortic valve eccentricity measurement may be related to valve hemodynamic in patients with aortic stenosis (AS). However, it is difficult to characterize with transthoracic Doppler echocardiography velocity measurements. Flow velocity eccentricity can be estimated from CMR phase-contrast flow velocity measurements using jet displacement and flow velocity angle. The aim of this study is to characterize aortic valve eccentricity on aortic stenosis patients. Aortic flow velocity eccentricity parameters showed to be able to characterize transvalvular flow hemodynamic on AS patients and may provide further information about patient outcome.

 
1187.   High field in-vivo PC-MRI to quantify and compare regional and local pulse-wave velocity in the right common carotid artery in mice
Volker Herold1, Alma Zerneck2, Alexander Gotschy1, Eberhard Rommel1, Wolfgang Rudolf Bauer2, and Peter Michael Jakob1
1Experimental Physics 5, University of Würzburg, Würzburg, Bavaria, Germany, 2Medizinische Universitätsklinik, University of Würzburg

 
Quantification of the vessel wall function in mouse models by estimating the pulse wave velocity (PWV) has emerged as an important predictor of cardiovascular risk. Usually transit-time methods (TT) to quantify the averaged regional PWV and local PWV measurements using QA-methods (Q: volume flow; A: cross-sectional area) are applied. However, no comparison of these techniques have yet been performed with MR-based imaging in particular not in the carotid arteries. In this paper we present a multi-site-TT approach to calculate at the first time the regional PWV in the carotid artery and compare these results with local PWV values

 
1188.   Quantification of Aortic Pulse Wave Velocity in neonates to assess impact of PDA
Kathryn M Broadhouse1, Anthony N Price1, Giuliana Durighel1, Anna E Finnemore1, David J Cox1, Alan M Groves1, A David Edwards1, and Jo V Hajnal1
1Robert Steiner Unit, Imaging Sciences Department, MRC Clinical Sciences Centre, Hammersmith Hospital, Imperial College, London, United Kingdom

 
This study looks at the feasibility of measuring pulse wave velocity (PWV) using PC-MRI in neonates and seeks to identify any changes in PWV associated with patent ductus arteriosus (PDA). PWV was quantified in the aorta between the aortic valve and the descending aorta at the level of the diaphragm in 29 infants. Eight had a PDA determined by echocardiography. Three methods were used to assess PWV; delay between the arrival time, time of maximum gradient and time of peak flow of the 2 flow curves. No significant difference in PWV between control and PDA infants was found.

 
1189.   Accelerated spiral Fourier velocity encoded MRI using SPIRiT parallel imaging
Davi Marco Lyra-Leite1, and Joao L. A. Carvalho1
1Department of Electrical Engineering, University of Brasília, Brasília, Distrito Federal, Brazil

 
Fourier velocity encoding (FVE) eliminates partial volume effects that are an issue in phase-contrast imaging, and may be useful in the assessment of valvular disease and of carotid wall shear stress. Although the scan-time of 2DFT FVE is prohibitively long, the spiral FVE method is substantially faster. The temporal resolution of temporally-accelerated spiral FVE can be improved if spatial aliasing due to undersampling is reduced. This may be achieved using parallel imaging. We investigate the use of the SPIRiT method to accelerate spiral FVE acquisition. We show that SPIRiT is able to completely remove spatial aliasing from the undersampled time-velocity distributions.

 
1190.   Parallelized reconstruction of spiral Fourier velocity encoding MRI data in multicore processors
Rosana Ribeiro Lima1, and Joao L. A. Carvalho1
1Department of Electrical Engineering, University of Brasília, Brasília, DF, Brazil

 
Fourier velocity encoding (FVE) may be useful in the assessment of valvular disease and of carotid wall shear stress, as it eliminates partial volume effects that are an issue in phase-contrast imaging. The scan-time of 2DFT FVE is prohibitively long for clinical use, but the spiral FVE method is substantially faster. FVE can be significantly accelerated using compressed sensing. However, iterative reconstruction of spiral FVE is time-consuming, because of non-Cartesian sampling and multidimensionality. The sequential implementation of reconstruction algorithms underuses the total capacity of multicore processors. We demonstrate a reduction of reconstruction time of spiral FVE data through parallel programming.

 
1191.   Feasibility of mitral valve blood flow quantification by 7D PC-SSFP
Marijn P Rolf1, Mark BM Hofman1, Joost PA Kuijer1, Rob J van der Geest2, Aernout M Beek3, Albert C van Rossum3, and Rudolf M Verdaasdonk1
1Physics and Medical Technology, ICaR-VU, VU University Medical Center, Amsterdam, Netherlands, 2Radiology, Leiden University Medical Center, Leiden, Netherlands, 3Cardiology, ICaR-VU, VU University Medical Center, Amsterdam, Netherlands

 
The feasibility of a new 7D PC-SSFP sequence for mitral regurgitation volume quantification is assessed. The 7D PC-SSFP sequence implementation is based on a balanced SSFP gradient scheme with velocity encoding. Mitral volume flow was determined in ten healthy subjects and in two patients with mitral insufficiency. It was measured directly at the mitral valve using 7D PC-GE and 7D PC-SSFP, and indirectly using aorta flow and left ventricular volumes. Images showed reasonable quality, although occasional respiratory motion artifacts were noted. Regurgitation volumes in healthy subjects were not significantly different from zero and a clear regurgitation was observed in both patients.

 
1192.   A Comparison of the Two and Three Element Windkessel Models in the Non-Invasive Evaluation of Pulmonary Artery Pressure by MRI
Octavia Biris1,2, Sanjiv J Shah3, Michael J Cuttica4, Jeremy D Collins1, James C Carr1, and Timothy J Carroll1
1Radiology, Northwestern University, Chicago, IL, United States, 2Biomedical Engineering, Northwestern University, Evanston, IL, United States, 3Feinberg School of Medicine/Cardiology, Northwestern University, Chicago, IL, United States, 4Feinberg School of Medicine/Pulmonary and Critical Care, Northwestern University, Chicago, IL, United States

 
We show proof-of-principle quantification of pulmonary artery pressure wave forms in patients with pulmonary arterial hypertension, by a three element Windkessel model with phase contrast MRI flow, MRI measured compliance, vascular resistance, characteristic impedance and mean pulmonary arterial pressure as inputs. To increase the resolution of the systolic pressure, we up-sample the flow input to a desired temporal resolution, by Fourier deconvolution with a boxcar function. The pressure wave forms obtained from the three element Windkessel and the up-sampled flow wave form are compared to pressure wave forms obtained by the two element Windkessel, with no re-sampling of flow data.

 
1193.   Quantification of Caval contribution to flow in the Right and Left Pulmonary Artery of Fontan patients with 4D Flow MRI
Pablo Bächler1, Natalia Pinochet1, Israel Valverde2, Sarah Nordmeyer3, Titus Kuehne3, Gerard Crelier4, Claudia Prieto1, Cristian Tejos1, Pablo Irarrazaval1, and Sergio Uribe1
1Pontificia Universidad Católica de Chile, Santiago, Chile, 2King's College London, London, United Kingdom, 3Deutsches Herzzentrum Berlin, Berlin, Germany, 4ETH and University of Zurich, Zurich, Switzerland

 
Measuring the caval contribution to flow in the Right and Left Pulmonary Artery of Fontan patients is of great interest, because uneven flow distribution might lead to Pulmonary Arteriovenous Malformations (PAVMs) decreasing systemic oxygenation. However, quantify the flow distribution with standard methods is difficult when more than one vessel contributes with blood flow, such as in the pulmonary arteries of Fontan patients. We validated a new method to calculate caval contribution based on particles traces from 4D flow data. This method may identify Fontan patients at risk for developing complications secondary to uneven caval flow distribution, such as PAVMs.

 
1194.   Aorto-iliac flow sensitive MRI: Blood Flow pre and post endovascular aortic repair
Maximilian Frederik Russe1, Philipp Blanke1, Wulf Euringer1, Julia Geiger1, Zoran Stankovic1, Bernd Jung1, and Mathias Langer1
1Diagnostic Radiology - Medical Physics, University Hospital, Freiburg, Germany

 
Blood flow patterns are altered in aortic aneurysms. After endovascular aortic repair (EVAR), changes in flow patterns are conceivable, potentially resulting in stent-specific complications such as iliac limb thrombosis due to functional stenosis or proximal neck dilation. Using flow-sensitive MRI and flow visualization, flow patterns were studied in vivo prior and after EVAR. While pre-EVAR aortic blood flow patterns were characterized by vortex-formation and flow deceleration during passage through the aneurysm, post-EVAR blood flow was laminar with similar velocities in the stent body and the aorta proximal to the stent, but with strongly increased velocities in the iliac limbs.

 
1195.   Reduction of Respiration Artifacts in 3D Phase Contrast Imaging with Intermittent Fat Saturation
Marcus T. Alley1, Albert Hsiao1, and Shreyas S. Vasanawala1
1Radiology, Stanford University, Stanford, CA, United States

 
Time-resolved 3-dimensional phase-contrast MR imaging (4D-PC MRI) is typically subject to respiration artifacts that can limit anatomic visualization. Navigator gating and respiratory compensation can be used but result in even longer scan times. Because the lipid signal is very bright and tends to originate from close to the chest wall, we hypothesize that the elimination of this signal will reduce the severity of the resulting respiration artifacts. Here we demonstrate that the inclusion of an intermittent fat saturation pulse in a Cartesian 4D-PC acquisition can reduce the artifact severity and improve vascular visualization with no acquisition time penalty.

 
1196.   Normal values of Wall Shear Stress in the Pulmonary Artery from 4D flow Data
Julio Sotelo1,2, Pablo Bächler2,3, Steren Chabert1,2, Claudia Prieto2,4, Daniel Hurtado5, Pablo Irarrázaval2,4, Cristian Tejos2,4, and Sergio Uribe2,6
1Biomedical Engineering Department, Faculty of Biological Science, Universidad de Valparaíso, Valparaíso, Chile, 2Biomedical Imaging Center, Pontificia Universidad Católica de Chile, Santiago, Chile, 3School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile, 4Electrical Engineering Department, Faculty of Engineering, Pontificia Universidad Católica de Chile, Santiago, Chile, 5Structural Engineering Department, Faculty of Engineering, Pontificia Universidad Católica de Chile, Santiago, Chile, 6Radiology Department, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile

 
In this work we proposed a novel and reproducible method to calculate WSS derived from 4D flow data, in the main pulmonary artery (PA), right PA (RPA) and left PA (LPA), of volunteers and patients with Congenital Heart Diseases (CHD). In volunteers we found a greater WSS in the RPA compared with the LPA, which is probably associated with helical flow pattern in the RPA. Values of WSS obtained in patients with CHD showed increasing values and great variability of WSS. In conclusion, this method may be helpful to identify patient with CHD at risk of developing Pulmonary Arterial Hypertension.

 
1197.   Usefulness of Cardiovascular Magnetic Resonance to Assess Valvulo Arterial Impedance in Aortic Stenosis Patients
Julio Garcia1, Lyes Kadem2, Eric Larose1, and Philippe Pibarot1
1Medicine, Laval University, Quebec, Quebec, Canada, 2Concordia University, Montreal, Quebec, Canada

 
Valvulo arterial impedance (ZVA) is an independent and powerful predictor of poor outcome for patients with aortic stenosis (AS) severity, it is usually computed from transthoracic echocardiography (TTE) measurements. However, there are often discrepancies among the TTE measurements. Cardiovascular magnetic resonance (CMR) may be used to corroborate stenosis severity by computing effective orifice area (EOA), mean pressure gradient (MPG) and ZVA. The aim of this study is to examine the agreement of TTE and CMR for the estimation of EOA, MPG and ZVA in patients with AS. ZVA CMR using corrected MPG had a good concordance with ZVA TTE and was a good predictor of patient outcome after one year follow.

 
1198.   Analysis of the Hemodynamic Parameters of Patients with Pulmonary Arterial Hypertension by MR Phase-Contrast Imaging
Hung-Hsuan Wang1, and Hsu-Hsia Peng2
1National Tsing Hua University, Hsinchu, Taiwan, 2National Tsing Hua University, Taiwan

 
Pulmonary arterial hypertension (PAH) is one of the five categories of pulmonary hypertension (PH). In previous study, hemodynamic parameters of patients with PH, measured by non-invasive phase-contrast magnetic resonance imaging (PC-MRI) and invasive catheterization methods, have been proved with high correlation coefficients. In this study, we aim to acquire windkessel volume (V_wk), acceleration time (T_acce), acceleration volume (V_acce), and other hemodynamic parameters to investigate differences between normal subjects and patients with PAH. Student¡¦s t-test was used to comprehend the significance of the difference between normal subjects and PAH patients.
 
Traditional Poster Session - Cardiovascular

Non Contrast & Contrast MRA
Click on to view the abstract pdf. Click on to view the poster (Not all posters are available for viewing.)
 
Monday 7 May 2012
Exhibition Hall  10:45 - 12:45

1199.   Single-Echo Dixon Imaging for First-Pass Contrast-Enhanced Peripheral Angiography without Subtraction
Holger Eggers1, Liesbeth Geerts-Ossevoort2, Evert-Jan Vonken3, and Tim Leiner3
1Philips Research, Hamburg, Germany, 2Philips Healthcare, Best, Netherlands, 3University Medical Center Utrecht, Utrecht, Netherlands

 
A flexible dual-echo Dixon method was recently demonstrated to permit first-past contrast-enhanced peripheral angiography without subtraction. In this work, the feasibility of replacing it by a single-echo Dixon method is studied. Fat-suppressed images were reconstructed from dual-echo acquisitions in patients, once separately from the first and the second echo with a single-echo Dixon method and once from both echoes with a dual-echo Dixon method. While single-echo acquisitions promise to decrease scan time or increase spatial resolution, they prove to be more prone to flow and swapping artifacts and more sensitive to the choice of echo time(s).

 
1200.   Contrast-enhanced magnetic resonance angiography in management of pulmonary arterio-venous malformations in patients with HHT (Osler disease)
Guenther Schneider1, Arno Buecker1, Alexander Massmann1, and Peter Fries1
1Diagnostic and Interventional Radiology, Saarland University Hospital, Homburg, Germany

 
Purpose of our study was to evaluate CE-MRA for management of pulmonary arterio-venous malformations (PAVM) in patients with hereditary hemorrhagic telangiectasia (HHT). 286 patients (mean-age 45,9 y, male/female = 118/168) with confirmed HHT or first degree relatives underwent screening pulmonary CE-MRA (MultiHance 0.1 mmol/kg bodyweight). Patients with relevant PAVM were referred for DSA. CE-MRA detected 323 PAVM in 97 patients. 74 patients with 263 PAVMs detected on CE-MRA underwent DSA. Significantly fewer PAVMs (205/263 [78%]) were demonstrated on global DSA of which 191 were embolized. Follow-up CE-MRA showed 57 newly developed PAVM in 14 patients (interval 1-6years) and 32 reperfused PAVM in 24 patients (interval 3months-7years). All reperfused PAVMs were confirmed by DSA and reembolized successfully. CE-MRA can be considered method of choice for management of PAVMs in HHT.

 
1201.   MR Imaging improves endoleak detection in patients after endovascular abdominal aneurysm repair
Jesse Habets1, Herman J.A. Zandvoort2, Sandra A. Cornelissen1,3, Frans L. Moll2, L. Wilbert Bartels3, Joost A. van Herwaarden2, and Tim Leiner1
1Radiology, University Medical Center Utrecht, Utrecht, Netherlands, 2Vascular Surgery, University Medical Center Utrecht, Utrecht, Netherlands, 3Image Sciences Institute, University Medical Center Utrecht, Utrecht, Netherlands

 
Endovascular repair for abdominal aortic aneurysm (EVAR) requires life-long postoperative imaging follow-up to detect complications. Prior work has shown that MRI with a blood pool agent with 85% albumin binding is more sensitive than CTA for endoleak detection, especially for slow flow and type II endoleaks. This work found that a gadolinium contrast agent with just 5% albumin binding is highly sensitive for the detection of endoleaks in patients with AAA growth and no or uncertain endoleak on CT angiography.

 
1202.   Technical evaluation of pulmonary artery MRA in routine clinical practice
Rajkumar Yarlagadda1, Mark L Schiebler1, Scott B Reeder1,2, Christopher J Francois1, Thomas M Grist1, and Scott K Nagle1,2
1Radiology, University of Wisconsin, Madison, WI, United States, 2Medical Physics, University of Wisconsin, Madison, WI

 
The largest study to date comparing MRA with CTA for diagnosis of pulmonary embolism (PIOPED III) reported a high technical failure rate of 25% (11-51%) across participating centers. Technical developments since that study have significantly improved the quality of clinical PE MRA examinations. We report here the results of a retrospective image quality evaluation of a high-volume clinical PE MRA practice and suggest the key technical developments that have resulted in greatly improved performance.

 
1203.   Probabilistic MRA Template of the Macaque Putamen for Guiding Convection Enhanced Delivery
Zhan Xu1, Marina Emborg2,3, Do Tromp1, Nagesh Adluru1, Martin Brady4, Raghu Raghavan4, Ken Kubota5, and Andrew L Alexander1,6
1Waisman Laboratory for Brain Imaging and Behavior, University of Wisconsin Madison, Madison, WI, United States, 2Department of Medical Physics, University of Wisconsin Madison, Madison, WI, United States, 3Wisconsin National Primate Research Center, 4Therataxis,LLC, Baltimore, MD, 5Kinetics Foundation, Los Altos, CA, United States, 6Department of Medical Physics and Psychiatry, University of Wisconsin Madison, Madison, WI, United States

 
In our CED research on rhesus macaque monkeys for treatment of Parkinson's disease, the location of infusion spot within brain highly determines the effect of the delivered drug. We generate a probabilistic MRA template of putamen on both hemispheres. By overlaying the template with T1W template, which is generated by another member of our group with identical subjects, we find out blood vessels mainly locate in lateral surface of putamen, there is barely any vessel within. Also a high probability region is found in this MRA template, where we should avoid during infusion in any future subject

 
1204.   Initial experience with blood pool agent enhanced free breathing radial 3D gradient echo VIBE sequence in the detection of pulmonary embolism
Constantine Raptis1, Sanjeev Bhalla2, Kathryn Fowler2, Vamsi Narra2, Rex Parker2, Priatna Agus3, and Pamela Woodard2
1Diagnostic Radiology - Cardiothoracic Imaging Section, Mallinckrodt Institute of Radiology, St. Louis, MO, United States, 2Mallinckrodt Institute of Radiology,3Siemens

 
Pulmonary MRA examinations for pulmonary embolism are often subject to technically inadequate images, with breathing artifact as a particularly important problem. Blood pool contrast agent enhanced free breathing radial VIBE sequences can be used in pulmonary MRA protocols for pulmonary embolism as an adjunct to traditional GRE sequences, and can be of particular value in patients with dyspnea. We present our initial experience with radial VIBE sequences in pulmonary MRA, including SNR and CNR, as well as comparison with other MRI sequences and computed tomography.

 
1205.   Characterization of a novel gadolinium-based high molecular weight polymer as an intravascular MR contrast agent
Anne Kirchherr1, Danielle Franke1, Detlef Stiller2, and Andreas Briel1
1nanoPET Pharma GmbH, Berlin, Germany, 2In-Vivo Imaging, Target Discovery Research, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach, Germany

 
In the present work a blood pool contrast agent (CA) composed of Gd-DTPA conjugated to a biodegradable polymer was synthesized and characterized. The CA showed high contrast efficiency with 2 - 3 times higher relaxivities compared to conventional contrast agents. In vivo experiments in mice showed that the CA remained within the vascular system for a prolonged period of time compared to Gd-DTPA and that it was cleared from the blood through renal excretion with a half-life of 1.9 h. The novel contrast agent can be of use in magnetic resonance angiography and in studies of renal structure and function.

 
1206.   High spatial resolution 3D CE MRA using Extremely small-sized Iron Oxide Nanoparticles(ESION) at 3T MRI
Pan-Ki Kim1,2, Bong-sik Jeon3, Young Ho So4, Eung-Gyu Kim3, and Whal Lee2,5
1Kwangwoon University, Seoul, Korea, 2SNU-Duke Cardiovascular MR Research Center, Seoul, Korea, 3Nano R&D Group, Hanwha Chemical, Daejeon, Korea,4Radiology, Seoul National University Boramae Medical Center, Seoul, Korea, 5Radiology, Seoul National University Hospital, Seoul, Korea

 
Extremely small-sized iron oxide nanoparticles (ESION) recently developed an iron oxide based contrast agent was made of 3 nm-sized nanoparticle. Because of small size iron oxide nanoparticles, ESION has low r2/r1 ratio and long blood circulation time, unlike existing superparamagnetic iron oxide nanoparticles (SPIO), and that can be utilized as T1 contrast agent like a gadolinium based one without nephrogenic system fibrosis. This study was carried out to evaluate whether ESION is clinically useful through the animal study that acquired first-pass MR image and high spatial resolution 3D MR angiograph at steady-state to compare with gadolinium based contrast agent (Gd-DOTA).

 
1207.   Background-Suppressed Hybrid Pulsed and Pseudo-Continuous Labeling Scheme for ASL-Based Carotid MR Angiography
Ioannis Koktzoglou1, NavYash Gupta2,3, and Robert R Edelman1
1Radiology, NorthShore University HealthSystem, Evanston, IL, United States, 2Vascular Surgery, NorthShore University HealthSystem, Evanston, IL, United States, 3The University of Chicago Pritzker School of Medicine, Chicago, IL, United States

 
Pseudo-continuous arterial spin-labeled (pCASL) carotid MR angiography provides excellent arterial-to background contrast but may produce artifacts in patients who move or swallow during the exam. The aim of this work was to describe a self-configuring and hybrid pseudo-continuous and pulsed spin labeling preparation that incorporates background suppression to reduce motion-related artifacts as well as improve vascular contrast-to-noise ratio in pCASL-based carotid MRA.

 
1208.   Non-Contrast-Enhanced Renal Angiography in One Heartbeat
Hattie Zhi Chen Dong1, Shreyas S. Vasanawala2, and Dwight G. Nishimura1
1Electrical Engineering, Stanford University, Stanford, CA, United States, 2Radiology, Stanford University, Stanford, CA, United States

 
Multiple inversion recovery (MIR) preparation combined with alternating TR balanced SSFP is a promising technique for rapid non-contrast-enhanced renal angiography. MIR MRA achieves a high level of background suppression while allowing for flexible selection of inflow times. In this work, we explore practical factors to improve image quality, and demonstrate scans at various orientations and increasing levels of detail. Each image was acquired in one heartbeat, which is highly advantageous for respiratory artifact mitigation and real-time interactive assessment.

 
1209.   Evaluation of Non-contrast Dynamic MRA in Intracranial Arteriovenous Malformation (AVM): Comparison with time of flight (TOF) and digital subtraction angiography (DSA)
Songlin Yu1, Lirong Yan2, Yuqiang Yao3, Shuo Wang4, Mingqi Yang4, Bo Wang5, Yan Zhuo5, Lin Ai6, Xinyuan Miao5, Jizong Zhao4, and Danny J. J. Wang2
1Beijing Tiantan Hospital, Capital Medical University, beijing, beijing, China, 2Department of Neurology University of California Los Angeles Ahmanson-Lovelace Brain Mapping Center, 3Beijing Jishuitan Hospital, Peking university, 4Beijing Tiantan Hospital, Capital Medical University, 5The State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of, 6Beijing Neurosurgical institute

 
Digital subtraction angiography (DSA) remains the gold standard to diagnose intracranial arteriovenous malformations (AVMs) but is invasive. Existing MR angiography (MRA) is suboptimal for assessing the hemodynamics of AVMs. This study evaluated the clinical utility of a novel non-contrast 4D dynamic MRA (dMRA) in the evaluation of intracranial AVMs, through comparison with DSA and time-of-flight (TOF) MRA in 19 AVM patients. DMRA was able to detect 16 out of 19 AVMs, and the ratings of AVM size and location matched those of DSA. The hemodynamic information provided by dMRA improved diagnostic confidence scores by TOF MRA.

 
1210.   Non-Contrast-Enhanced Vein Imaging in the Deep Veins: Impact of Velocity Patterns and Improved Image Quality
Andrew Nicholas Priest1, Martin John Graves1, and David John Lomas1
1Department of Radiology, Addenbrookes Hospital and Cambridge University, Cambridge, United Kingdom

 
MRI has the potential for multi-contrast imaging of venous thrombo-embolism (VTE). Luminal imaging may be performed using ADVANCE-MRV, a recently developed method which relies on suppression of flowing signal using an iMSDE preparation module. It is demonstrated that signal suppression is governed both by the flow velocity and by velocity dispersion. In low-dispersion situations, the signal may oscillate as a function of velocity, leading to signal loss from the subtraction venograms. This effect is investigated in volunteers, and an image combination method is proposed, leading to more uniform vascular images despite flow variations.

 
1211.   3Tesla Inflow Inversion Recovery 3D SSFP for Robust Non-contrast MR Angiography Using Triple Triggering
Naoyuki Takei1, Mitsuharu Miyoshi1, Masayoshi Sugimura2, Takayuki Masui2, and Hiroyuki Kabasawa1
1Global Applied Science Laboratory, GE Healthcare, Hino, Tokyo, Japan, 2Radiology, Seirei Hamamatsu General Hospital, Japan

 
The purpose of this study is to eliminate low and dark flow artifact at descending aorta encountered at 3.0T on 3D Balanced Steady State Free Precession (bSSFP) with slab selective inversion pulse for visualizing renal arteries.@A novel trigger procedure is presented with triple triggers for achieving both carotid and respiratory synchronized data acquisition despite the use of long inversion pulse over 1 second. The comparison study was performed to conventional respiratory trigger alone sequence on 1.5T and 3.0T. Compared to the conventional respiratory trigger the advantage of the proposed approach is robust, uniform and high arterial blood visualization.

 
1212.   Noncontrast MRA using Gated 3D FSE with Hybrid Refocusing Angles
Andrew J Wheaton1, Robert Anderson1, and Mitsue Miyazaki2
1Toshiba Medical Research Institute USA, Mayfield Village, OH, United States, 2Toshiba Medical Research Institute USA, Vernon Hills, IL, United States

 
Noncontrast-enhanced MRA using gated 3D FSE (FBI, NativeSPACE, Trance) relies on the inherent flow sensitivity of FSE. A dark blood image acquired during systole is subtracted from a bright blood image acquired during diastole. The flow sensitivity is a function of refocusing angle; high refocusing angles result in bright large arteries, but diminished branch arteries. The opposite is true for low refocusing angles. This study proposes a hybrid method using high refocusing angle in diastole and low refocusing angle in systole. The resultant angiogram contains bright blood in both small and large arteries with minimal increase in background signal.

 
1213.   Highly accelerated non-contrast enhanced MRA of the renal arteries using iterative reconstruction
Jana Hutter1,2, Robert Grimm1, Christoph Forman1,2, Joachim Hornegger1,2, and Peter Schmitt3
1Pattern recognition lab, Universität Erlangen-Nürnberg, Erlangen, Germany, 2Erlangen graduate school in avanced optical technologies, Erlangen, Germany, 3MR Application & Workflow Development, Siemens AG, Healthcare Sector, Germany

 
Non-contrast enhanced 3D MR angiography of the renal arteries typically needs a long acquisition time. We use an iterative reconstruction algorithm which combines parallel MRI and compressed sensing to accelerate the acquisition time by a factor of up to 9. Different undersampling factors, realized with a dedicated pattern, are applied and reconstructed with our approach. The evaluation shows that a high level of image quality regarding sharpness and contrast in the first and second order branches as well as the maximal visible blood path length is achieved.

 
1214.   Accuracy of PCASL MRA for Quantifying Extracranial Carotid Artery Stenosis
Ioannis Koktzoglou1,2, NavYash Gupta2,3, and Robert R Edelman1
1Radiology, NorthShore University HealthSystem, Evanston, IL, United States, 2The University of Chicago Pritzker School of Medicine, Chicago, IL, United States,3Vascular Surgery, NorthShore University HealthSystem, Evanston, IL, United States

 
Pseudo-continuous arterial spin labeling (PCASL) has been reported to provide better signal to noise ratio than pulsed arterial spin labeling for carotid MR angiography. The purpose of this study was to determine the accuracy of PCASL MRA for quantifying carotid artery stenosis (CAS) in patients with sonographically documented CAS. Accuracy was assessed relative to conventional 3D TOF and contrast-enhanced MRA techniques.

 
1215.   High-Quality Susceptibility Weighted Venography from Multi-echo MR dataset using Linear Phase Model
Ung Jang1, Yura Park1, and Dosik Hwang1
1School of Electrical and Electronic Engineering, Yonsei University, Seoul, Korea

 
The aim of this study is to acquire high-quality SWI-MRv at longer TE by reducing the noise of phase data on the temporal domain of 3D multi-echo datasets for obtaining high-SNR phase mask.

 
1216.   Quiescent-Interval Single-Shot Non-Contrast Enhanced MR Angiography using Two-Point Dixon Fat-Water Decomposition
Daniel V Litwiller1, Mahdi S Rahimi2, Wei Sun3, Ananth J Madhuranthakam4, Dan W Rettmann1, Frank R Korosec5, and Jean H Brittain6
1Global Applied Science Laboratory, GE Healthcare, Rochester, MN, United States, 2Biomedical Engineering, University of Wisconsin, Madison, WI, United States,3MR Engineering, GE Healthcare, Waukesha, WI, United States, 4Global Applied Science Laboratory, GE Healthcare, Boston, MA, United States, 5Medical Physics and Radiology, University of Wisconsin, Madison, WI, United States, 6Global Applied Science Laboratory, GE Healthcare, Madison, WI, United States

 
Quiscent-Interval Single-Shot (QISS) is a recently developed non-constrast MR angiography technique that relies on a signal-saturation-based fat suppression pulse, which is sensitive to B0 and B1 inhomogeneities. In this work, we report a dual-echo bipolar QISS sequence, followed by a two-point Dixon fat-water reconstruction algorithm to synthesize fat-free, water-only images of arterial signal in the lower extremities, demonstrating robust and uniform fat suppression, improved vessel conspicuity and increased signal-to-noise ratio.

 
1217.   Quiescent-Interval Single-Shot Magnetic Resonance Angiography: the use of localized thin-slices as an adjunct to the standard technique
Mauricio S Galizia1,2, Christopher Glielmi3, Ioannis Koktzoglou1, Eugene Dunkle1, James C Carr2, and Robert R Edelman1
1Department of Radiology, NorthShore University HealthSystem, Evanston, IL, United States, 2Department of Radiology, Northwestern University-Feinberg School of Medicine, Chicago, IL, United States, 3Cardiovascular MR R&D, Simens Healthcare, Chicago, IL, United States

 
Ten patients with peripheral arterial disease were imaged with nonenhanced quiescent-interval single-shot (QISS) MRA. Thinner slices were also acquired in the region of the knee. A blinded observer graded image quality in several vessel segments in the proximal calf. The horizontal anterior tibial, the posterior tibial, and the peroneal arteries had higher image quality scores in the thin-slice images. In the horizontal anterior tibial artery, the proportion of nondiagnostic and poor quality images was reduced from 50% to 5%. Acquiring additional thin slices in selected regions when imaging with QISS leads to better image quality and might improve diagnosis.

 
1218.   Optimization of Venous Saturation Pulses for Time-of-Flight MR Angiography at 7 Tesla
Sören Johst1,2, Karsten H Wrede1,3, Mark E Ladd1,2, and Stefan Maderwald1
1Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany, 2Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Germany, 3University Hospital Essen, Department of Neurosurgery, Germany

 
The visibility of the vasculature in TOF MRA highly profits from increased field strengths. The aim of this study was to create a clinical high-resolution 7T TOF MRA protocol with venous saturation, acquirable within a clinically acceptable measurement time. To ameliorate SAR restrictions, we used the VERSE algorithm for both excitation and saturation pulses. The use of standard 90° pulses for venous suppression generally leads to longer TR due to SAR limitations. For α Є [15°, 35°] and TR Є [20 ms, 35 ms], saturation flip angles of αSAT = (α + 15°) lead to acceptable venous saturation.
 
Traditional Poster Session - Cardiovascular

CV Imaging Methodology Technology, Image Processing & Other
Click on to view the abstract pdf. Click on to view the poster (Not all posters are available for viewing.)
 
Monday 7 May 2012
Exhibition Hall  10:45 - 12:45

1219.   
Volume Based Determination of Global Left Ventricular Strain: A Comparison to Tissue Tagging
June Cheng-Baron1, Kelvin Chow1, Joseph J Pagano1, D Ian Paterson2, and Richard B Thompson1
1Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada, 2Division of Cardiology, University of Alberta, Edmonton, Alberta, Canada

 
Current MRI methods used to measure left ventricular strain, including tissue tracking or phase-based methods, require onerous post-processing or specialty pulse sequences. We propose an alternative method for the determination of peak systolic global circumferential, longitudinal and radial strains that does not rely on tissue tracking and is based on basic SSFP cines and left ventricular volume analysis. The purpose of this study is to compare this new method to conventional tissue tagging-derived strains.

 
1220.   Accelerated High Frame Rate Mouse CINE CMR Using Retrospective Triggering and Compressed Sensing Reconstruction
Abdallah G. Motaal1, Rui Castro2, Bram F. Coolen1, Desiree Abdurachim1, Jeanine Prompers1, Luc Florack2, Klaas Nicolay1, and Gustav Strijkers1
1Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, Netherlands, 2Department of Mathematics and Computer Science, Eindhoven University of Technology, Eindhoven, Netherlands

 
Using low temporal resolution Cine CMR has a significant drawback in assessing the heart function, since the details of myocardial deformation go undetected. In this study we introduce the retrospective triggering acquisition scheme in combination with compressed sensing reconstruction to obtain very high frame Cine CMR in an acquisition time shorter than the time needed for a gold standard reconstruction. High acceleration factors were achieved without significant losses in image quality and derived cardiac functional parameters.

 
1221.   3D Determination of Area-at-Risk in Acute Myocardial Infarction
Haiyan Ding1,2, Laura Fernandez-de-Manuel1,3, Michael Schär4,5, Elliot R. McVeigh1, Henry Halperin6, M. Muz Zviman6, and Daniel A. Herzka1
1Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, MD, United States, 2Biomedical Engineering, Tsinghua University, Beijing, China, 3Biomedical Image Technologies Lab, ETSI Telecomunicacion, Universidad Politecnica de Madrid, and CIBER-BBN, Madrid, Spain, 4Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins School of Medicine, Baltimore, MD, United States, 5Philips Healthcare, Cleveland, Ohio, United States, 6Department of Medicine, Cardiology, Johns Hopkins School of Medicine, Baltimore, MD, United States

 
The area of myocardium at risk (AAR) is defined as hypoperfused myocardium at the time of an ischemic episode, such as acute myocardial infarction (MI). To assess AAR, measures of both scar and edema must be combined. Late Gadolinium enhancement (LGE) with phase sensitive inversion recovery (PSIR) is a well-established method of delineating scar. Recently, quantitative 3D T2 mapping has been shown to be a robust method for visualizing edema. In this work it is shown that the combination of 3D respiratory navigator gated T2 Mapping and PSIR make high-resolution whole-heart AAR determination possible.

 
1222.   Real-Time Cardiac Imaging at 7T using a 24-Channel Cardiac Coil
Stefan Maderwald1, Stephan Orzada1,2, Sören Johst1,2, Lena C. Schäfer1,2, Anja Fischer1,2, Thomas Schlosser2, Mark E. Ladd1,2, and Kai Nassenstein1,2
1Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany, 2Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Essen, Germany

 
Real-time sequences for cardiovascular magnetic resonance (CMR) at ultrahigh field strengths (greater than or equal to7 Tesla) could alleviate the need for a robust trigger signal, which fails in a large number of cases due to magneto-hydrodynamic effects. For signal transmission and reception a new custom-built 8 ch Tx / 24 ch Rx coil was used. The pulse sequence is based on a strongly undersampled radial FLASH sequence which is reconstructed with a sliding window approach. Cine-like images were acquired with a temporal resolution between 6 and 106 ms. Acceptable image quality was found for a temporal resolution of 49 ms per image.

 
1223.   Phase sensitive inversion recovery with simultaneous dark fat rendering by virtual chemical inversion
Wolfgang Rehwald1, Elizabeth Jenista2, Deneen Spatz2, Stephen Darty2, Han Kim2, Lowie Van Assche2, Enn-Ling Chen2, and Raymond Kim2
1Siemens Healthcare, Chicago, IL, United States, 2Cardiology, Duke University, Durham, NC, United States

 
Common fat suppression techniques perform poorly in combination with phase sensitive inversion recovery (PSIR). We have developed a technique for fat suppression that results in black-fat PSIR images without additional SAR or acquisition time.

 
1224.   Accelerated Black Blood Imaging Using Self-Calibrated Split-Echo FSE (SCSE-FSE) Imaging
Sabrina Klix1, Fabian Hezel1, Jan Ruff2, and Thoralf Niendorf1,3
1Berlin Ultrahigh-Field Facility, Max-Delbrueck Center for Molecular Medicine, 13125 Berlin, Germany, 2Siemens Healthcare, 91054 Erlangen, Germany,3Experimental and Clinical Research Center (ECRC), Charité Campus Buch, Humboldt-University, 13125 Berlin, Germany

 
The anatomic MR imaging of the heart is mainly with black blood techniques. These techniques improve the segmentation of myocardium from the blood pool. For low-signal representation, a self calibrated split-echo FSE (SCSE-FSE) was proposed and implemented. The aim is to waive a separate reference scan, to shorten measurement times, enhances image quality and reduction of image artefacts. Clinically relevant short axis and four chamber view with double and triple inversion recovery images were acquired. The results of the SCSE-FSE technique by using a acceleration factors of up to R=4 compared with a conventional FSE are suitable for clinical applications.

 
1225.   Highly accelerated in vivo measurement of local pulse wave velocity in mice using a k-t BLAST QA-method
Volker Herold1, Thomas Kampf1, Alexander Gotschy1, Felix Breuer2, Eberhard Rommel1, Wolfgang Rudolf Bauer3, and Peter Michael Jakob1
1Experimental Physics 5, University of Würzburg, Würzburg, Bavaria, Germany, 2Research Center for Magnetic Resonance Bavaria, 3Medizinische Universitätsklinik, University of Würzburg

 
Local elastic properties of the murine arteries such as the pulse-wave-velocity (PWV) can be calculated using PC-MRI to quantify blood-flow (Q) and cross-sectional area changes (A) (QA-method). To calculate the PWV the measured Q and A pulses have to undergo a frequency low pass filtering step. Moreover, a short total measurement time is of paramount interest, in particular with varying cardiac cycles. We present a method which substitutes temporal low pass filtering by temporal undersampled data acquisition followed by a k-t BLAST reconstruction with the benefit of an almost 10 fold acceleration of data acquisition without compromising the PWV calculation.

 
1226.   Free-Breathing 3D Water-Fat Separation and R2* Mapping in the Heart
Valentina Taviani1, Diego Hernando1, Ann Shimakawa2, Jean H. Brittain3, Kevin M. Johnson1, Karl K. Vigen1, and Scott B. Reeder1,4
1Department of Radiology, University of Wisconsin, Madison, WI, United States, 2Global MR Applied Science Laboratory, GE Healthcare, Menlo Park, CA, United States, 3Applied Science Laboratory, GE Healthcare, Madison, WI, United States, 4Department of Medical Physics, University of Wisconsin, Madison, WI, United States

 
R2* mapping in the heart is important to quantify myocardial iron concentration as well as for accurate water-fat separation. However, R2* measurements in the myocardium are hampered by severe susceptibility variations due to the presence of tissue-air interfaces and deoxygenated blood in epicardial veins. In this work we propose a 3D free-breathing technique for water-fat separation and R2* mapping in the heart and we compare our 3D free-breathing approach with a previously reported 2D breath-hold technique. Both phantom experiments and preliminary data in healthy volunteers showed that the 3D free-breathing technique greatly reduced susceptibility-induced variations in R2*.

 
1227.   Cardiac CINE MRI at 7 T using a transmit array
Tomasz Dawid Lindel1, Andreas Greiser2, Patrick Waxmann1, Martin Dietterle1, Frank Seifert1, Ulrich Fontius2, Wolfgang Renz2, Matthias Alexander Dieringer3,4, Tobias Frauenrath3, Jeanette Schulz-Menger4, Thoralf Niendorf3,4, and Bernd Ittermann1
1Physikalisch-Technische Bundesanstalt, Braunschweig & Berlin, Germany, 2Siemens AG Healthcare Sector, Erlangen, Germany, 3Berlin Ultrahighfield Facility (B.U.F.F.), Max-Delbrück-Centrum für Molekulare Medizin, Berlin, Germany, 4Charité–Universitätsmedizin Berlin, Campus Buch, Experimental and Clinical Research Center (ECRC), Berlin, Germany

 
The feasibiltiy of cardiac MRI at 7T using a transmit array was demonstrated. A software solution was implemented for synchronizing the independent array CPUs with the cardiac trigger and CINE images were acquired with a modified product sequence for cardiovascular imaging. Using the 7T system in Tx array or single channel mode with hardwired phase settings produced identical image quality. In this proof-of-principle study the Tx array was used for static B1 shimming only but the concept permits dynamic applications like transmit SENSE as well.

 
1228.   DIR Black-Blood Imaging Using Concentric Rings with Fat/Water Separation
Holden H Wu1,2, Joelle K Barral3, Dwight G Nishimura2, and Michael V McConnell1,2
1Cardiovascular Medicine, Stanford University, Stanford, CA, United States, 2Electrical Engineering, Stanford University, Stanford, CA, United States, 3HeartVista, Inc., Los Altos, CA, United States

 
Black-blood imaging is a crucial technique for visualizing the myocardium and studying the progression of atherosclerosis in the vessel wall. In this work, we present a new double inversion-recovery (DIR) black-blood imaging method based on the non-Cartesian 2D concentric rings trajectory, which requires half the number of readouts compared to 2D Cartesian encoding and supports 2D centric ordering to maximize the effectiveness of the DIR preparation. In addition, the concentric rings are acquired with a time-efficient multi-revolution design to enable fat/water separation for enhanced image contrast. Experimental results from cardiac and carotid imaging demonstrate the performance of this proposed technique.

 
1229.   Monitoring amyloid deposition and therapeutic clearance using equilibrium contrast MRI
Adrienne E Campbell1,2, Anthony N Price3, Stephan Ellmerich4, Paul Simons4, Raya Al-Shawi4, Rupinder Ghatrora5, Tammy L Kalber5, Philip N Hawkins4, Roger J Ordidge6, James C Moon7, Mark B Pepys4, and Mark F Lythgoe5
1Centre for Advanced Biomedical Imaging, Division of Medicine and Institute of Child Health, University College London, London, London, United Kingdom,2Department of Medical Physics and Bioengineering, University College London, London, United Kingdom, 3Robert Steiner MRI Unit, Imaging Sciences Department, Hammersmith Hospital, Imperial College London, London, United Kingdom, 4Wolfson Drug Discovery Unit, Centre for Amyloidosis and Acute Phase Proteins, Division of Medicine, University College London, London, United Kingdom, 5Centre for Advanced Biomedical Imaging, Division of Medicine and Institute of Child Health, University College London, London, United Kingdom, 6Centre for Neuroscience, University of Melbourne, Melbourne, Australia, 7Heart Hospital and Division of Medicine, University College London, London, United Kingdom

 
Equilibrium contrast MRI (EQ-MRI) was applied for the detection and monitoring of systemic amyloidosis in mice. Modest amyloid deposits in the heart were clearly detected by EQ-MRI even when cardiac function was not measureably impaired. An excellent discrimination between amyloidotic and control mice was observed in the liver where amyloid load is substantial. In addition, EQ-MRI was able to monitor the induction of amyloidosis and regression of amyloid deposits following the administration of a novel therapy, indicating the potential of this technique to monitor therapeutically induced amyloid regression.

 
1230.   Motion-Guided Temporally-Constrained Compressed Sensing for Dynamic MRI
Xiao Chen1, Michael Salerno2,3, Patrick F Antkowiak1, and Frederick H Epstein1,2
1Biomedical Engineering, University of Virginia, Charlottesville, VA, United States, 2Radiology, University of Virginia, Charlottesville, VA, United States, 3Cardiology, University of Virginia, Charlottesville, VA, United States

 
Many MR image series present temporal sparsity, in which image signal intensity changes smoothly through time, and such images are inherently suitable for acceleration using compressed sensing (CS) reconstruction. However, object motion between images violates temporal smoothness constraints and significantly degrades the quality of the CS-reconstructed images. To overcome this problem, we propose a general motion-guided CS algorithm which tracks object motion and guides the CS sparsity transform along the direction of motion. Improved image quality was observed using the proposed algorithm in dynamic contrast-enhanced images compared to non-motion guided reconstruction at an acceleration rate of 4.

 
1231.   Fast T2 mapping of the Heart from Highly Undersampled Radial FSE Data Using a Principal Component-Based Reconstruction Algorithm
Tomoe Barr1, Chuan Huang2, Aiden Abidov3,4, Jaspreet Singh3, Bujji Ainapurapu3, Dipak KC3, Scott Squire4, Jean-Philippe Galons4, and Maria I Altbach5
1Biomedical Engineering, University of Arizona, Tucson, AZ, United States, 2Mathematics, University of Arizona, United States, 3Medicine, University of Arizona, United States, 4Radiology, University of Arizona, United States, 5Radiology, University of Arizona, Tucson, AZ, United States

 
T2-weighted imaging is an important modality in cardiac MRI and has been used for the diagnosis of a series of pathologies. Recently, the importance of T2 mapping of the heart has been highlighted. In this work we present a double inversion radial fast spin-echo (DIR-RADFSE) technique combined with a principal component based reconstruction algorithm recently developed for T2 estimation. The method provides motion insensitivity and high spatial and temporal resolution data for the reconstruction of T2 maps from data acquired in a single breath hold.

 
1232.   Susceptibility Corrected Myocardial R2* Quantification with Magnetic Resonance Imaging
Shane A Wells1, Karl K Vigen1, Jeffrey S Nackos1, Scott B Reeder1,2, and Diego Hernando1
1Department of Radiology, University of Wisconsin-Madison, Madison, WI, United States, 2Department of Medical Physics, University of Wisconsin-Madison, Madison, WI, United States

 
Excess myocardial iron can result in sudden death or heart failure, the leading causes of morbidity and mortality in transfusion-dependent thalassemia patients. Accurate and reproducible, non-invasive quantification of myocardial iron is important because effective chelation therapy can be initiated and cardiomyopathy averted. R2* mapping is very sensitive to the presence of tissue iron; however, in the myocardium, its broad use is limited due to macroscopic magnetic field inhomogeneities caused by susceptibility effects, most profound at the myocardial-air interface. The purpose of this work is to demonstrate the feasibility of a background magnetic field correction technique for more consistent R2* mapping.

 
1233.   Is Phonocardiogram Gating a Reliable Alternative to ECG Gating in Clinical Routine for CINE and Velocity-Encoded Phase Contrast Imaging?
Stefan Maderwald1, Stephan Orzada1,2, Lars Haering3, Andreas Czylwik3, Thomas Schlosser2, Mark E. Ladd1,2, and Kai Nassenstein1,2
1Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany, 2Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Essen, Germany, 3Department of Communication Systems, University Duisburg-Essen, Essen, Germany

 
In this study an in-house developed phonocardiogram (PCG) gating device was used to validate the diagnostic accuracy of acoustic triggered sequences in a clinical routine protocol at 1.5T. PCG- and ECG-gated cine imaging sequences for the assessment of LV global and regional function as well as velocity-encoded phase-contrast imaging sequences for flow quantification were compared. 147 consecutive patients were enrolled and evaluated. PCG-gated imaging was successful in 95%, ECG-gated in 100% of all patients. With cine imaging an excellent correlation between PCG and ECG was observed, whereas flow quantification measurements showed a wide limit of agreement for all variables analyzed.

 
1234.   Accelerated cardiac MRI by 2D Fourier Inversion of the Entire Image Sequence
Wei Zha1, Steven Lloyd2, Himanshu Gupta2, Stanley J. Reeves1, and Thomas S. Denney1
1Auburn University, Auburn, AL, United States, 2University of Alabama at Birmingham

 
A fast dynamic imaging method is proposed to shorten the image acquisition. Only the dynamic region in an arbitrary shape that encloses the heart is reconstructed in each timeframe. All other pixels were reconstructed once for the whole image sequence. The phase-encoding direction alternated horizontally and vertically at even and odd timeframes for a more k- space coverage. The undersampling pattern for each timeframe is pre-calculated using a modified sequential backward selection method. Our earlier simulation shows that 40 resized image sequences from different subjects are able to be reconstructed using 44% of the k-t space data reliably and stably.

 
1235.   Quantitative cardiac diffusion imaging using double echo steady-state free precession
Hendrikus J.A. Crooijmans1, Thomas Ruder2,3, Sandra Mathier3, Michael Thali2, and Oliver Bieri1
1Department of Radiology and Nuclear Medicine, Division of Radiological Physics, University of Basel Hospital, Basel, Switzerland, 2Department of Medicine and Imaging, Institute of Forensic Medicine, University of Zürich, Zürich, Switzerland, 3Department of Medicine and Imaging, Institute of Forensic Medicine, University of Bern, Bern, Switzerland

 
Quantitative diffusion imaging using a dwDESS sequence is relaxation time independent. In contrast to other SSFP diffusion imaging methods it uses both primary echo paths. Both direction dependent and direction independent diffusion maps can be generated from dwDESS acquisitions. By means of a procine heart, we have shown that this method can be used to indicate fiber direction within the myocardium. Next to this, we have shown that with dwDESS imaging, it is possible to differentiate between older and acute myocardial infacts in a human post mortem case.

 
1236.   A Method to Remove Heart Rate Dependence with Modified Look Locker Inversion Recovery (MOLLI) T1 Quantification
James W Goldfarb1,2
1Research and Education, St Francis Hospital, Roslyn, New York, United States, 2Biomedical Engineering, SUNY Stony Brook, Stony Brook, NY, United States

 
Phantom experiments across a range of T1-values and heart rates demonstrated an underestimation of longer T1-values at higher heart rates using the conventional MOLLI curve fitting equation. A new fitting equation which includes the effect of incomplete magnetization recovery between inversion pulses provided a significantly better fit to the data and consistent estimates of T1-relaxation times over a range of heart-rates. Measurements in 15 subjects showed a heart rate dependence of T1-estimates of blood in the LV cavity. The new equation provided a significantly better fit (p<0.001) for both myocardial and LV blood T1-estimates without heart rate dependence.

 
1237.   Accelerated 4D Flow Imaging with Compressed Sensing and Radial Undersampling Pattern on Cartesian Grid
Jing Liu1, Petter Dyverfeldt1, Michael Hope1, and David Saloner1
1University of California San Francisco, San Francisco, CA, United States

 
In this study, different undersampling patterns were used to accelerate phase-contrast imaging. Our preliminary results of aorta flow imaging have shown that radial like pattern on Cartesian grid is simple to implement and less sensitive to undersampling artifacts. Image reconstruction with compressed sensing provides good image quality and accurate flow measurements.

 
1238.   Dual inversion recovery pre-pulse improves blood suppression and allows earlier late gadolinium enhancement imaging of atrial scar after radiofrequency ablation
Sarah Anne Peel1, Aruna Arujuna1, James Harrison1, Reza Razavi1, Kawal Rhode1, Jaswinder Gill1, Tobias Schaeffter1, and Rene Botnar1
1Division of Imaging Sciences and Biomedical Engineering, King's College London, The Rayne Institute, London, United Kingdom

 
A good correlation has been found between late gadolinium enhancement using the inversion recovery (IR) pre-pulse and the outcome of radiofrequency ablation for atrial fibrillation. However, scar visualization is hampered by strong residual blood signal. Therefore imaging is often performed 25 minutes after contrast administration to ensure the contrast agent has cleared from blood. In this study, we found that the dual-IR pre-pulse achieved superior blood suppression at an earlier time point compared to the IR pre-pulse and without the need for a Look Locker scan. It can potentially improve scar visualization and reduce total scan time.

 
1239.   Coping with a changing ocean: Real-time cardiac MRI on an animal model with a natural cardiovascular disorder
Christian Bock1, Faruk Dogan1, and Hans O. Pörtner1
1Alfred-Wegener-Institute for Polar and Marine Research, Bremerhaven, Germany

 
Real-time cardiac MRI together with velocity mapping for blood flow quantification in different arteries were applied to study the cardiovascular performance of the marine crustacean Cancer pagurus, an animal model with a natural cardiovascular disorder. The feasibility of MRI for future monitoring of heart functioning and blood flow in a marine crustacean under conditions of ocean warming and acidification could be shown. Real-time cardiac MRI revealed an increase in heart function under conditions of ocean acidification as expected by the end of this century, whereas almost no increase in blood flow of the main arteries could be observed.

 
1240.   In vivo Cardiac Diffusion MRI via Second Order Motion Compensated Diffusion Weighted Driven Equilibrium Balanced Steady State Free Precession (SOMOCO-DW-DE bSSFP)
Christopher Nguyen1,2, Zhaoyang Fan2, Rohan Dharmakumar2, Troy LaBounty3, James Min3, Daniel Berman3, and Debiao Li2,4
1Biomedical Engineering Interdepartmental Program, University of California, Los Angeles, Los Angeles, CA, United States, 2Departments of Biomedical Sciences and Imaging, Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States, 3Cedars-Sinai Medical Center, Los Angeles, CA, United States, 4Department of Bioengineering, University of California, Los Angeles, Los Angeles, CA, United States

 
Cardiac diffusion MRI (CDMRI) has the potential to identify acute myocardium ischemia and assess the chronic change of myofiber orientation after a myocardial infraction. Serious technical challenges such as cardiac motion and clinical hardware limitations restrict the technique in vivo. We propose a novel application of DW driven equilibrium balanced steady-state free precession (DW-DE-bSSFP) to include second order MOCO (SOMOCO) that not only allows for longer Tdiff and acceptable b-values, but also takes advantage of the high SNR of bSSFP. We show the feasibility of applying SOMOCO-DW-DE-bSSFP for in vivo CDMRI within clinically human limited MR parameters in healthy volunteers.

 
1241.   Design, Implementation, Application and Evaluation of a MR Compatible Left Ventricle Model
Matthias Alexander Dieringer1,2, Thiago de Quadros1,2, Jan Hentschel1, Werner Hoffmann3, Thoralf Niendorf1,2, and Jeanette Schulz-Menger1,2
1Berlin Ultrahigh Field Facility, Max-Delbrueck Center for Molecular Medicine, Berlin, Germany, 2Experimental and Clinical Research Center (ECRC), Charité Campus Buch, Humboldt-University, Berlin, Germany, 3Metrology in Medicine, Physikalisch-Technische Bundesanstalt, Berlin, Germany

 
The development and validation of MR sequences require a high degree of reproducibility including phantom experiments that mimic in vivo. This study demonstrates the design, implementation, application and evaluation of a comprehensive left ventricle model. The model is designed to resemble motion patterns and flow dynamics of a beating heart, as well as signal characteristics and relaxation times of myocardial tissue.

 
1242.   Removing the Phase-Sensitive Reconstruction Artifacts in Phase-Sensitive Inversion Recovery (PSIR) Sequence
Huijun Chen1, Jinnan Wang2, Chun Yuan1, and William S Kerwin1
1University of Washington, Seattle, WA, United States, 2Philips Research North America, United States

 
Phase-Sensitive Inversion Recovery (PSIR) has been widely used in cardiac imaging to detect infarcts by providing consistent high contrast between infarcts and normal myocardium. Recently, it has been shown as an improved intraplaque hemorrhage detection tool with good blood suppression and as a possible MRA tool in carotid atherosclerosis imaging. However, considerable amount of reconstruction artifacts can be found in PSIR sequence acquired short Inversion Time (TI). In this abstract, we sought to analyze the cause of these artifacts and propose a solution.

 
1243.   In Vivo Evaluation of a Novel Left Ventricular Mechanical Assist Device Using Cardiac MRI
Jeremy R McGarvey1,2, Kevin J Koomalsingh1,2, Norihiro Kondo2, Manabu Takebe2, Walter R.T. Witschey2,3, Gerald A. Zsido2, Christen M. Dillard2, Kristina Lau2, Gabrielle Pilla2, Joseph H. Gorman1,2, Robert C. Gorman1,2, and James J. Pilla2,3
1Department of Surgery, University of Pennsylvania Health System, Philadelphia, PA, United States, 2Gorman Cardiovascular Research Lab, Harrison Department of Surgical Research, Glenolden, PA, United States, 3Department of Radiology, University of Pennsylvania Health System, Philadelphia, PA, United States

 
Treatment of ischemic cardiomyopathy remains a complex clinical problem. We have developed an novel MRI-safe left ventricular assist device which is able to apply directed and synchronized force to an infarct area. In vivo cardiac MRI was utilized to evaluate left ventricular function and geometry after device implantation in a porcine ischemic heart failure model. SGFP cine sequences demonstrated a significant increase in ejection fraction and stroke volume while using the synchronized pulsation device when compared to the unassisted ventricle. As such, MRI was effectively used to quantify and characterize ventricular function using a novel mechanical ventricular assist device.

 
1244.   Breath-Held Myocardial T1 Mapping Using Multiple Single-Point Saturation Recovery
Glenn S. Slavin1, Maureen N. Hood2, Vincent B. Ho2, and Jeffrey A. Stainsby3
1GE Healthcare, Bethesda, MD, United States, 2Walter Reed National Military Medical Center, Bethesda, MD, United States, 3GE Healthcare, Toronto, ON, Canada

 
The challenge for cardiac T1 mapping is obtaining sufficient sampling of the T1 relaxation curve in a single breath-hold. Traditional single-point inversion recovery is limited by short delay times and is not feasible in a breath-hold. Multi-point (Look-Locker) inversion recovery is possible in a breath-hold; however, it necessitates both partial Fourier and parallel imaging and long data acquisition windows. Look-Locker imaging also measures “apparent” relaxation times (T1*), rather than true T1. This work demonstrates a cardiac T1 mapping method that measures true T1 in a single breath-hold using multiple single-point saturation recovery with delay times longer than the cardiac cycle.

 
1245.   Dual inversion recovery pre-pulse differentiates contrast uptake from oedema in late gadolinium enhancement imaging of the atrial wall after radiofrequency ablation
Sarah Anne Peel1, Aruna Arujuna1, Reza Razavi1, Kawal Rhode1, Jaswinder Gill1, Tobias Schaeffter1, and Rene Botnar1
1Division of Imaging Sciences and Biomedical Engineering, King's College London, The Rayne Institute, London, United Kingdom

 
Pulmonary vein isolation using RF ablation is an established treatment for patients with atrial fibrillation. Late gadolinium enhancement (LGE) imaging can be performed acutely after ablation using the inversion recovery (IR) pre-pulse. However, the IR pre-pulse generates high signal from areas of oedema as well as contrast uptake. In this study, we showed that the dual-IR pre-pulse only generates high signal from areas of contrast uptake whilst suppressing the signal from fluid and normal atrial wall. This may help differentiate contrast uptake from oedema in LGE imaging to visualize acute damage caused by RF ablation.

 
1246.   Evaluation of divergence-free correction algorithms in high resolution 4-D flow images of cranial vasculature.
Michael Loecher1, Steven Kecskemeti2, Kevin M Johnson1, Patrick Turski3, and Oliver Wieben1,3
1Medical Physics, University of Wisconsin Madison, Madison, WI, United States, 2Physics, University of Wisconsin Madison, Madison, WI, United States, 3Radiology, University of Wisconsin Madison, Madison, WI, United States

 
This study investigates the performance of a finite difference method and a radial basis function algorithm for removing divergence from 4D-flow images. Noise reduction and visualization improvements are compared in a phantom and in vivo by comparing RMSE, noise levels, and streamline lengths. Overall the RBF method performs better, generally reducing noise by around 25% and improving streamline length by around 22%.

 
1247.   AIF Correction for Non-Uniform k-space Data Weighting Effects in First-Pass Cardiac Perfusion MRI
Sohae Chung1, and Leon Axel1
1Center for Biomedical Imaging, Radiology Department, NYU Langone Medical Center, New York, NY, United States

 
To obtain first-pass cardiac perfusion images, a saturation-recovery preparation with TurboFLASH readout can be used to capture the contrast enhancement dynamics. However, when using a SR preparation, non-uniform k-space data weighting in the phase-encoding direction, due to data acquisition during the transition toward the steady state, can lead to a filtering effect. This may lead to systematic overestimation of the image-derived arterial input function (AIF), with a resulting bias in the perfusion calculations. In this work, numerical simulations were used to correct for non-uniform k-space data weighting effects on the AIF.

 
1248.   Artificial intelligent technique for measuring heart volume from MRI images using iterative salient isolated threshold optimization ant algorithm (ISITOAA)
El-Sayed H Ibrahim1, Shannon Birchell2, and Sherif Elfayoumy2
1Department of Radiology, University of Florida, Jacksonville, FL, United States, 2School of Computing, University of North Florida, Jacksonville, FL, United States

 
Manual segmentation of MRI images is inefficient and inconsistent method for measuring ventricular volumes. In this study, new artificial intelligence technique (ISITOAA) is developed and implemented for measuring ventricular volumes. The technique is based on automatic delineation of blood-myocardium border using ant colony optimization with salient isolated thresholding. The technique was implemented on datasets from eight volunteers and the results were compared to manual segmentation. ISITOAA provided both left and right ventricular segmentation in single processing, and provided stability measure of the solution. ISITOAA showed good agreement with the gold standard and was faster and more consistent than manual segmentation.

 
1249.   A Novel Biventricular Active Mesh Model for Measuring Cardiac Function and Geometry from Cine MRI
Chun G Schiros1, Himanshu Gupta2, Steven G. Lloyd2, Louis J Dell'Italia2, and Thomas S Denney Jr.1
1Auburn University, Auburn, AL, United States, 2University of Alabama at Birmingham

 
Approaches for quantifying cardiac function and geometry from cine MRI remain problematic because 1) systolic translocation of the right ventricular (RV) atrio-ventricular annulus is greater than that of the left ventricle (LV), resulting in unequal LV and RV stroke volumes and 2) surface models for measuring ventricular curvatures are usually based on coordinate systems with singularities at the ventricular apexes and assume a circular symmetry that is not applicable in the complex RV. To address these issues, a novel biventricular active mesh model is presented and validated in normal subjects, patients with mitral regurgitation and patients with pulmonary hypertension.

 
1250.   Feasibility of real-time MR based path planning for off-pump cardiac interventions
Erol Yeniaras1, Jason R. Stafford1, John D. Hazle1, and Nikolaos V. Tsekos2
1MD Anderson Cancer Center, Houston, Texas, United States, 2Medical Robotics Lab., University of Houston, Houston, Texas, United States

 
In this work we evaluate the viability of our computational methodology for MR guidance in minimally invasive cardio-thoracic interventions, particularly transapical aortic valve replacement in beating heart. Our system includes the dedicated software modules that operate synergistically for both processing real-time MR images and adjusting on-the-fly the acquisition parameters of scanner to better suit the particular conditions of interventions as they evolve. To verify the efficacy of the approach, safe access to aortic valve annulus via a small incision at the apex of the heart was simulated for 15 subjects.

 
1251.   Semi-Automatic Quantification of Late Enhancement in CT and MRI Images
Anja Hennemuth1, Andreas Mahnken2, Ola Friman3, Markus Huellebrand4, and Heinz-Otto Peitgen4
1Fraunhofer MEVIS, Bremen, Bremen, Germany, 2Department of Diagnostic and Interventional Radiology, University Hospital Aachen, Aachen, Germany, 3Swedish Defence Research Agency, Linkoeping, Sweden, 4Fraunhofer MEVIS, Bremen, Germany

 
Late enhancement (LE) imaging has become the gold standard for detecting necrotic tissue with MRI. The underlying effect of contrast agent accumulation in defective tissue is observed in CT image data as well. The purpose of this work was the comparison of semi-automatically detected LE volumes from CT and MRI data of pigs with inflicted infarctions. Image data was analyzed with a method that combines a mixture model approach and an additional closing step for the inclusion of microvascular obstructions. The comparison of the results regarding location and volume of the segmented regions showed a good agreement.

 
1252.   Noninvasive Pressure Measurement in Patients with Congenital Heart Disease using 4D Phase Contrast MRI
Elizabeth J Nett1, Jie Nguyen2, Kevin M Johnson1, Oliver Wieben1,2, and Christopher J Francois2
1Medical Physics, University of Wisconsin, Madison, Wisconsin, United States, 2Radiology, University of Wisconsin, Madison, Wisconsin, United States

 
In this study, we demonstrated the feasibility of noninvasively quantifying stenosis grade and pressure differences in congential heart disease patients with aortic coarctations or pulmonary artery stenosis using a radially undersampled 4D PC-MRI sequence. Anatomical measurements were compared with CE-MRA and pressure measurements were compared with Doppler ultrasound.

 
1253.   KLT and Wavelet Filtering: reducing noise in highly accelerated dynamic images
Prashanth Palaniappan1, Orlando P. Simonetti2,3, Yu Ding2, Rizwan Ahmad2, Hui Xue4, Ti-chuin Chang4, and Christoph Guetter5
1Department of Electrical and Computer Engineering, The Ohio State University, Columbus, Ohio, United States, 2Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio, United States, 3Department of Radiology, The Ohio State University, Columbus, Ohio, United States, 4Siemens Corporate Research, United States, 5Siemens Corporate Research

 
In our current study, we propose a novel approach to de-noise Real-time (RT) cardiac cine images by combining two well established algorithms: Temporal Karhunen-Loeve Transform (KLT) and Spatial Wavelet Filtering. The combined KLT+wavelet approach is very effective in enhancing image Signal-to-Noise ratio (SNR) while preserving the edge sharpness of the image. This is a fully automatic method that does not require estimation or user selection of any free parameters, nor acquisition of training data. In rate 6 real-time cine images, the proposed approach showed superiority to the 3D wavelet filter in terms of image SNR and edge sharpness. The performance of the proposed approach also increased with increasing frame length.

 
1254.   Choice of Bandpass Filter on Accuracy of Myocardial Deformation Recovery With SinMod
Hui Wang1, Mo Kadbi1, Melanie Troughber2, and Amir Amini1
1University of Louisville, Louisville, KY, United States, 2Philips Medical Systems, Cleveland, Oh, United States

 
Tagged MRI has been an excellent technique for measuring myocardial deformations and cardiac mechanical functions since its development in the late 1980s. In data processing, a number of approaches have been proposed in recent years. Among all, frequency-based methods have become more widely popular for analysis of myocardial displacements . In particular, the SimMod has the following distinct advantages over HARP analysis which has become popular for frequency domain analysis of tagged images. Bandpass filtering the off-center peak of tagged image spectrum is a critical step for accurate recovery of the cardiac motion with SinMod. In this abstract, we compared the performance of three different types of bandpass filters in analyzing myocardial deformation using the SinMod method.

 
1255.   Excess High Noise in Exercise Stress Real-time Cardiac Cine Images
Yu Ding1, Hui Xue2, Ti-chiun Chang2, Christoph Guetter2, and Orlando Simonetti1,3
1Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States, 2Siemens Corporate Research, 3Biomedical Engineering, The Ohio State University

 
Compared to real-time cardiac cine images at rest, the exercise stress real-time cine images show significantly lower SNR. In this abstract, we will demonstrate that the excess high noise level is a motion induced noise. When the motion is severe, every temporal frame cannot be approximated as an instantaneous “snap-shot”. The motion may induce a signal variation which behaves statistically like spatial noise. Using in vivo volunteer study, we found that the apparent noise level in stress MRI raw data with rapid heart rate and breathing is higher than that of the resting real-time cine raw data.
 
Traditional Poster Session - Cardiovascular

Miscellaneous Cardiovascular
Click on to view the abstract pdf. Click on to view the poster (Not all posters are available for viewing.)
 
Monday 7 May 2012
Exhibition Hall  10:45 - 12:45

1256.   magnetic resonance elastography of the human abdominal aorta: a preliminary study
Lei Xu1,2, Jun Chen1, Kevin J Glaser1, Meng Yin1, Phillip J Rossman1, and Richard L Ehman1
1Radiology Department, Mayo Clinic, Rochester, MN, United States, 2Radiology Department, Beijing Anzhen Hospital, Capital Medical University, Beijing, Beijing, China

 
To investigate the feasibility of using MRE for the evaluation of the mechanical properties of the in vivo aortic wall. The feasibility of performing pulse-gated cine MRE technique in the abdominal aorta was assessed in five healthy volunteers. In the study, the waves were well visualized within the lumen of the abdominal aorta in the diastolic phase, but they were not well visualized during systole. A significant correlation between E*t product of aortic wall in the five volunteers and their age was revealed (r2=0.81). The study shows that MRE is feasible for assessing the elastic properties of the abdominal aorta.

 
1257.   Magnetic Resonance Imaging Is More Sensitive Than Computed Tomography Angiography for the Detection of Endoleaks After Endovascular Abdominal Aortic Aneurysm Repair: A Systematic Review
Jesse Habets1, Herman J.A. Zandvoort2, Johannes B. Reitsma3, Frans L. Moll2, L. Wilbert Bartels4, Joost A. van Herwaarden2, and Tim Leiner1
1Radiology, University Medical Center Utrecht, Utrecht, Netherlands, 2Vascular Surgery, University Medical Center Utrecht, Utrecht, Netherlands, 3Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, Netherlands, 4Image Sciences Institute, University Medical Center Utrecht, Utrecht, Netherlands

 
This systematic review and meta-analysis demonstrates that magnetic resonance imaging (MRI) is a more sensitive imaging modality than computed tomography angiography (CTA) for the detection of endoleaks in patients after endovascular abdominal aortic aneurysm repair (EVAR). Blood pooling contrast agents may have additional diagnostic value compared to extracellular gadolinium chelates.

 
1258.   The number of patent calf vessels in contrast-enhanced MRA significantly impacts the patient’s survival
Elke Angelika Lassel1, Gina-Lisa Friese1, Lothar R Pilz2, Stefan O Schoenberg1, and Henrik J Michaely1
1Department of Clinical Radiology and Nuclear Medicine, University Medical Centre Mannheim, Mannheim, Baden-Württemberg, Germany, 2Statistics, Medical Faculty Mannheim at Heidelberg University, Germany

 
The aim of this study was to identify MRA-based factors that influence the patient’s outcome, especially the overall survival, the time to infarct and limb amputation. Based on 124 patients with MRA of the lower extremities with at least 1 year follow-up time the impact of different MR-based and clinical parameters on survival and time to the first cardiovascular event were assessed by a Cox proportional hazard model. The only factor with significant impact on overall survival was the number of patent calf vessels (HR=0.688; p=0.0048) while the time to the first cardiovascular event was dependent on various factors.

 
1259.   High Resolution Contrast Enhanced MR Angiography (CEMRA) at 3.0T in Pediatric Abdominal Organ Transplantation: Initial Results.
Conor P Meehan1, Sarah N Khan1, Maria Ines Boechat1, and J Paul Finn1
1Diagnostic Cardiovascular Imaging, David Geffen School of Medicine, UCLA, Los Angeles, CA, United States

 
High- resolution contrast enhanced MRA (CEMRA) at 3.0T provides consistent, high quality evaluation of vascular anatomy in pediatric transplant patients and can provide comprehensive vascular information prior to and following liver, small bowel and pancreas transplantation. We report the initial findings in 29 consecutive pediatric patients.

 
1260.   Automatic Registration of Multispectral MR Vessel Wall Images of the Carotid Artery
Ronald van 't Klooster1, Marius Staring1, Stefan Klein2, Robert Kwee3, Eline Kooi3, Johan Reiber1, Boudewijn Lelieveldt1, and Rob van der Geest1
1Division of Image Processing, Department of Radiology, Leiden University Medical Center, Leiden, Netherlands, 2Biomedical Imaging Group Rotterdam, Depts. Of Radiology & Medical Informatics, Erasmus MC, Rotterdam, Netherlands, 3Department of Radiology, Cardiovascular Research Institute Maastricht, Maastricht University Medical Center, Maastricht, Netherlands

 
Patient movement during scanning can cause misalignments between multispectral MR images. Correctly aligned images of the carotid artery are needed to accurately classify plaque components inside the vessel wall. Manual alignment of these images is the current procedure but is time-consuming. Automatic image registration can be applied to correct for these misalignments. Various registration techniques were investigated and quantitatively validated with a gold standard. The results show that automatic image registration using a 3D B-spline transform can replace the manual alignment procedure reducing the amount of time needed analyzing carotid vessel wall images.

 
1261.   High-Resolution Three-Dimensional Oblique-Sagittal Black-Blood Magnetic Resonance Imaging in Preoperative Evaluation of Stenting in Atherosclerotic Carotid Stenosis
Qingjun Wang1, Yong Guo2, Jianming Cai3, and Minghua Huang4
1Department of Radiology, Chinese Navy General Hospital, Beijing, Beijing, China, 2Department of Radiology, Chinese Navy General Hospital, China, 3Chinese PLA General Hospital, 4Chinese Navy General Hospital

 
After comparing with digital subtraction angiography (DSA) and high-resolution two-dimensional oblique-sagittal black-blood magnetic resonance imaging (2D-BB-MRI), we evaluated the value of high-resolution three-dimensional oblique-sagittal black-blood magnetic resonance imaging (3D-BB-MRI) in carotid artery stenting (CAS) for atherosclerotic carotid stenosis with cerebrovascular ischemic events. Two radiologists evaluated the maximum stenosis (Max-stenosis), maximum transverse plaque thickness (Max-TPT) and location of maximal lumen stenosis, plaque rupture, degree of maximal lumen stenosis and maximum longitudinal plaque extension (Max-LPE) on MRI images by consensus, and then compared the results with DSA. Our findings showed that the 3D-BB-MRI can provide a good preoperative preparation for CAS.

 
1262.   High Resolution Imaging of Brain Vessels at 7 Tesla
Julien Sein1, Shahram Majidi2, Saqib Chaudry2, Nauman Tariq2, Dingxin Wang1,3, Gregor Adriany1, Eddie Auerbach1, Kamil Ugurbil1, Muhammad Fareed Suri2, and Pierre-Francois Van de Moortele1
1CMRR, University of Minnesota, Minneapolis, Minnesota, United States, 2Zeenat Qureshi Stroke Research Center, University of Minnesota, Minneapolis, Minnesota, United States, 3Siemens Medical Solutions USA, Inc.

 
Brain vessel wall MRI is expected to benefit from gains in SNR and tissue contrast at high magnetic fields. A 7-Tesla human MRI scanner was chosen to investigate both ex-vivo and in-vivo achievable cerebral vessel MR. Ex-vivo samples excised from human cadaver brains in the Circle of Willis area were imaged with the 3D SPACE MR sequence. In vivo, a pool of healthy subjects was scanned at 0.64 mm isotropic resolution with same sequence. Comparison of ex-vivo MR images with virtual histology intravascular ultrasound allowed for distinction of vessel wall boundaries and plaque components on MR images.

 
1263.   4D MRI as the best way to prescribe patient-specific proximal and distal boundaries for numerical modeling
Vitaliy L. Rayz1, Monica Sigovan1, and David Saloner1
1Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California, United States

 
4D MRI data, providing time-resolved velocity measurements in vivo, can be used to prescribe patient-specific boundary conditions for detailed numerical simulations. This approach connects a computational domain to the proximal and distal circulation, eliminating uncertainties of various modeling assumptions commonly used in the flow modeling practice. We have used 4D MRI to prescribe flow boundaries for computations in a cerebral aneurysm and an arteriovenous fistula and compared these results to computations carried out based on specific different assumptions about the distal circulation. The study demonstrates that boundary conditions based on 4D MRI measurements ensure the accuracy of the numerical simulations.

 
1264.   Quantitative MRI as an indirect evaluation tool of the mechanical properties of cardiac tissues
Delphine Perie1, Anthony Foudis1, Gilles Beaudoin2, Guillaume Gilbert3, Nagib Dahdah4, and Daniel Curnier5
1Mechanical Engineering, Ecole Polytechnique de Montreal, Montreal, Quebec, Canada, 2Physics and Biomedical Engineering, CHUM Hopital Saint-Luc, Montreal, quebec, Canada, 3MR Clinical Science, Philips Healthcare, Cleveland, OH, United States, 4Cardiology, CHU Sainte-Justine, Montreal, Quebec, Canada, 5Kinesiology, Universite de Montreal, Montreal, Quebec, Canada

 
The long-term objective is to develop a sensitive and non-invasive technique allowing the early detection and the follow-up of the changes occurring within the mechanical properties of cardiac tissues with cardiomyopathy. We hypothesized that a relationship exists between mechanical properties and MR parameters of cardiac tissues. Porcine hearts were submitted to a quantitative MRI acquisition followed by a tensile test until rupture. The significant relationship found between the Young’s modulus and the MRI parameters T1, FA and ADC is the basis for the development of an indirect tool for the in vivo evaluation of the mechanical properties of cardiac tissues. Kriging is a powerful tool that optimizes theses relationships.

 
1265.   Myocardial T1 Mapping in Swine with Non-ischemic Heart Failure with Comparison to Changes in Specific Collagen Types
Maureen N Hood1,2, Ting Song1,3, Peter Bedocs4, John F Capacchione4, Christine E Kasper2,5, Mark C Haigney6, and Vincent B Ho1
1Radiology & Radiological Sciences, Uniformed Services University, Bethesda, Maryland, United States, 2Graduate School of Nursing, Uniformed Services University, Bethesda, Maryland, United States, 3Global Applied Science Laboratory, GE Healthcare, Bethesda, Maryland, United States, 4Anesthesiology, Uniformed Services University, Bethesda, Maryland, United States, 5Nursing, department of Veteran Affairs, Washington, District of Columbia, United States, 6Cardiology, Uniformed Services University, Bethesda, Maryland, United States

 
T1 mapping may be a promising technique to quantify myocardial changes in heart failure even when the subject cannot hold their breath. T1 mapping using modified look-locker with saturation recovery in this small swine study shows a quantitative difference in T1 value between healthy baseline and heart failure hearts. The immunochemistry suggests a change in amounts of Type I, III and VI collagen in the myocardium between the control and heart failure swine, but more research needs to be done.