Klaas Paul Pruessmann¹, Benjamin Emanuel Dietrich¹, and Christoph Barmet^1
1Institute for Biomedical Engineering, University and ETH Zürich, Zurich, Zurich, Switzerland

In this work, field measurements with an NMR field probe are explored as a means of observing cardiovascular dynamics. Using an optimized probe and custom-built transmit and receive hardware, field measurements were performed at different position on a volunteer’s chest. The measurements were found to reveal detailed and highly periodic field dynamics at the cardiac frequency, indicating that these reflect actual dynamics of heart motion and blood flow.

Paul A. Yushkevich¹, Hui Sun¹, Federico M. Sukno², Catalina Tobon-Gomez², Hongzhi Wang¹, and Alejandro F. Frangi^2
1PICSL, Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States, ²CISTIB, Universitat Pompeu Fabra, CIBER-BBN, Barcelona, Spain

This new approach overcomes some of the challenges in automatic cardiac MRI segmentation of by modeling the myocardium using a deformable model that explicitly describes the skeleton of the myocardium and its thickness. This geometrical model is coupled with an appearance model and statistical shape prior learned from training data. The proposed approach achieves high accuracy compared to manual segmentation on end-diastole MR images of patients with common pathologies.

Hui Xue¹, Saurabh Shah², Andreas Greiser³, Christoph Guetter¹, Christophe Chefdhotel¹, Marie-Pierre Jolly¹, Sven Zuehlsdorff², Jens Guehring¹, and Peter Kellman^4
1Imaging and Visualization, Siemens Corporate Research, Princeton, NJ, United States, ²CMR Research and Development, Siemens Medical Solutions USA, Inc., Chicago, IL, United States,³Imaging & IT Division, Siemens AG, Healthcare Sector, Erlangen, Germany, ⁴National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland, United States

The state-of-art technique for cardiac T1 mapping is the modified Look-Locker Inversion Recovery (MOLLI) which acquires multiple images across several heart-beats. Its clinical applicability is often limited by frequent myocardial motion because of imperfect breath-hold or varying R-R interval. A fully automated motion correction directly utilizing MOLLI images is highly challenging due to significantly varying image contrast. We therefore propose a novel registration algorithm based on estimating motion-free synthetic images presenting similar contrast to original MOLLI data by solving a variational energy minimization problem. The validation was performed in vivo on a large cohort of patient datasets.

Carla S Gil¹, Niall Colgan¹, A J Bakermans², B J van Nierop², G J Strijkers², H C van Assen³, and Kathleen M Curran^1
1School of Medicine and Medical Sciences, University College of Dublin, Dublin, Belfield, Dublin 16, Ireland, ²Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, Netherlands, ³Biomedical Image Analysis, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, Netherlands

The purpose of this paper is to register ex-vivo cardiac diffusion tensor images using affine transformations and the preservation of the principal direction reorientation strategy. We have successfully registered cardiac DTI and compared five different similarity measures: relative anisotropy difference, modulus difference, tensor difference, normalized tensor difference and principal direction difference. Results indicate that the principal direction difference is superior to the other similarity measures, followed by the normalized tensor difference and tensor difference. For cardiac DTI registration, measures sensitive to the full tensor perform better than scalar derived measures.

Gilion Hautvast¹, Carol Salton², Michael Chuang^2,3, Marcel Breeuwer^1,4, Christopher O'Donnell^3,5, and Warren Manning^2
1Philips Healthcare, Best, Netherlands, ²Beth Israel Deaconess Medical Center, Boston, MA, United States, ³National Heart, Lung and Blood Institute, Framingham, MA, United States,⁴Eindhoven University of Technology, Eindhoven, Netherlands, ⁵Massachusetts General Hospital, Boston, MA, United States

In this work we examine cine CMR data derived from a large, community-based cohort to determine: 1) the contribution of the basal LV slice(s) at ED to LV volumes and EF and 2) the effect of manual correction of automatically-detected LV contours on global LV functional parameters. Our results show that automatic myocardial contour detection for determination of LV volumes and EF is feasible and accurate in a large, population-based sample of adults. After inclusion of basal slice data, further manual corrections to the automatically-detected contours have minimal effect on the final outcome of global functional parameters.

Christopher J McGann¹, Eugene G Kholmovski¹, Joshua J.E. Blauer¹, Sathya Vijayakumar¹, Thomas S Haslam¹, Joshua E Cates¹, Nazem W Akoum¹, Edward V.R. Dibella¹, Nathan S Burgon¹, Alton J Alexander¹, Marcelinus Prastawa¹, Dennis Parker¹, Rob MacLeod¹, and Nassir F Marrouche^1
1CARMA Center, Salt Lake City, Utah, United States

When LGE imaging is performed immediately post-ablation, heterogeneous injury is seen with both bright (hyperenhancing) and dark (non-enhancing) lesions. The relationship between the acute injuries seen on LGE and late scar formation has not been well studied. Ten patients presenting for AF ablation underwent 3D LGE MRI immediately post ablation (IPA) and three months post-ablation (3moPA) on a 3T scanner. The IPA injuries were evaluated and categorized as either hyperenhancing (HE) or non-enhancing (NE) lesions and compared to scar 3moPA. The NE lesions demonstrate 'no-reflow' characteristics and may improve prediction of final scar at 3 months.

Wei Zha¹, Steven Lloyd², Himanshu Gupta², Louis Dell’Italia², and Thomas S. Denney^1
1ECE, Auburn University, Auburn, AL, United States, ²Medicine and Radiology, University of Alabama at Birmingham, Birmingham, AL, United States

This abstract derives a relationship between ejection fraction as a function of wall thickening, radius thickness ratio, longitudinal shortening and circumferential shortening. Validated using cine and tagged MRI of 458 human subjects, the derived expression suggests that in hypertension, the preserved ejection fraction in the presence of reduced circumferential shortening can be explained by the geometric effects of concentric remodeling.

Anthony N Price¹, Shaihan J Malik¹, Kathryn M Broadhouse¹, Francesco Padormo¹, Giuliana Durighel¹, David J Cox¹, A David Edwards¹, Alan M Groves¹, and Jo V Hajnal^1
1Robert Steiner MRI Unit, Imaging Sciences Department, MRC Clinical Sciences Centre, Hammersmith Hospital, Imperial College London, London, United Kingdom

Cardiac MRI has the scope to significantly advance understanding of circulatory function in newborn infants. Previously, image quality in these infants has been degraded by respiratory and whole body motion since infants are not sedated or anesthetised during scanning. In this study imaging was performed with monitoring of respiratory and whole body motion using a pressure sensor placed on the abdominal wall. Real time SSFP imaging was utilised to demonstrate that abdominal pressure sensing accurately predicts diaphragmatic position. Rejection and binning of k-space data according to whole body motion and respiratory phase produced significant improvements in cine SSFP image quality.

Wenbo Liu^1,2, Niranjan Balu², Xihai Zhao¹, Huijun Chen², Chun Yuan^1,2, Huilin Zhao³, Jianrong Xu³, Guangzhi Wang¹, and William S. Kerwin^2
1Biomedical Engineering & Center for Biomedical Imaging Research, School of Medicine, Tsinghua University, Beijing, China, People's Republic of, ²Radiology, University of Washington, Seattle, WA, United States, ³Radiology, Shanghai Jiao Tong University, Shanghai, China, People's Republic of

To evaluate the use of 3D gradient echo imaging techniques to identify plaque components, we sought to compare performance of an automatic segmentation algorithm based on Morphology-Enhanced Probabilistic Plaque Segmentation (MEPPS) using traditional 2D spin echo images versus 3D gradient echo images. The results show in principle a protocol based on 3D gradient echo contrast weightings provides sufficient information to quantitatively characterize calcification, necrotic core, and loose matrix in carotid atherosclerotic plaque. The advantage of this approach is especially well represented by the 3D visualization results. The isotropic segmentation results permit visualization of plaque structure in arbitrarily reformatted cuts.

Suwit Saekho^1,2, Uten Yarach¹, Petai Buttakote¹, Siriphan Luxsakhum¹, Arintaya Phrommintikul³, and Nipon Chattipakorn^4
1Radiological Technology, Chiang Mai University, Muang, Chiang mai, Thailand, ²Biomedical Engineering Center, Chiang Mai University, Muang, Chiang Mai University, Thailand, ³Internal Medicine, Chiang Mai University, Muang, Chiang Mai, Thailand, ⁴Cardiac Electrophysiology Research and Training Center, Chiang Mai University, Muang, Chiang Mai, Thailand

Accuracy, reproducibility and selected curve fitting model for the T2* measurement depend on SNR and resolution of MR images. Currently, single breath-hold technique has been used in most centers. The limitation of this technique is that acquisition time is constrained by the breath-holding capability in each individual resulting in limited SNR and resolution on images. We propose free-breathing technique to assess myocardial T2* employing a navigator pre-pulse to reduce motion artifact. This technique improved the resolution and SNR by approximately 40% resulting in better inter-study and intra-observer reproducibility, as well as less dependent to the curve fitting algorithms.

Hui Xue¹, Ding Yu², Saurabh Shah³, Christoph Guetter¹, Marie-Pierre Jolly¹, Orlando P. Simonetti², Peter Kellman⁴, and Jens Guehring^1
1Imaging and Visualization, Siemens Corporate Research, Princeton, NJ, United States, ²The Ohio State University, Columbus, Ohio, United States, ³CMR Research and Development, Siemens Medical Solutions USA, Inc., Chicago, IL, United States, ⁴National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland, United States

Recent development in cardiac MR shows that improved SNR can be achieved by averaging the motion-corrected free-breathing images using non-rigid image registration. To motion correction induced artifacts, previous studies heuristically exclude some frames from final averaging. However, non-rigid image registration can lead to variant accuracy for different frames and different regions within a frame. We therefore propose a novel image combination algorithm, computing optimal weights for image combination by minimizing the total amount of deformation brought into the averaging. Compared to uniform averaging, our approach achieves good noise suppression and provides better tolerance to artifacts possibly introduced by motion correction.

Pietro Valsecchi¹, Christof Karmonik^2,3, Jean Bismuth², Mark G Davies², Dipan J Shah², Bill E Kline¹, and Alan B Lumsden^2
1ExxonMobil Upstream Research Company, Houston, TX, United States, ²The Methodist DeBakey Heart & Vascular Center, Houston, TX, United States, ³The Methodist Hospital Neurological Institute, Houston, TX, United States

High post-treatment mortality rates in DeBakey type III aortic dissections (AD) (20% in 3 years after hospital discharge) necessitates a better understanding of biomechanical properties of true (TL) and false lumen (FL) wall for the development of effective treatment. In an effort to create synergy between know-how in the energy industry and the medical community, we took advantage of established seismology techniques to estimate stiffness of the AD intra-luminal septum (IS) using the wall pressure wave. From this, Young's modulus of the IS was found to be approximately a factor 50 lower compared to literature values for healthy aortic wall.

Martin Ugander¹, Hui Xue², Jens Guehring³, Saurabh Shah⁴, Li-Yueh Hsu¹, Andrew E Arai¹, and Peter Kellman^1
1National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, United States, ²Siemens Corporate Research, Princeton, NJ, United States, ³Siemens AG Healthcare Sector, Erlangen, Germany, ⁴Siemens Medical Solutions, Chicago, IL, United States

T1 mapping is emerging as a tool for quantitative assessment of myocardial disease. Quantitative T1 mapping can be undertaken using a Modified Look-Locker Inversion-recovery (MOLLI) sequence. We developed a fully automated motion-correction algorithm for MOLLI images. In 649 paired image comparisons from 178 patients, automated T1 map image quality following motion correction was assessed by a physician as unchanged in 91.8% of cases, improved in 7.6% of cases and worsened in 0.6% of cases. Automated motion correction in MOLLI imaging improves the image quality of both pre-contrast and post-contrast T1 maps of the heart in clinical patients.

Johann Baptist Drexl¹, Ola Friman², Anja Hennemuth², Jelena Bock³, Michael Markl³, and Horst Karl Hahn^1
1Fraunhofer MEVIS, Bremen, Bremen, Germany, ²Fraunhofer MEVIS, ³Department of Radiology, Medical Physics, University Hospital Freiburg, Germany

In this work, we evaluate Jenkinson's PRELUDE phase unwrapping method on phase contrast magnetic resonance imaging flow data of the human aorta. For the evaluation, we used aquired data from a volunteer as well as a simple digital phantom. We set up an image processing pipeline employing PRELUDE, and finally evaluate the performance of the method qualitatively and quantitatively using the misclassification rate and execution speed as metrics.

Samuel Ting¹, Yu Ding², Yiu-Cho Chung³, and Orlando P. Simonetti^1,2
1Department of Biomedical Engineering, The Ohio State University, Columbus, OH, United States, ²Dorothy M. Davis Heart & Lung Research Institute, The Ohio State University, Columbus, OH, United States, ³Siemens Medical Systems, Columbus, OH, United States

Real-time cardiac cine images acquired in settings where minimal acquisition time or patient conditions eliminate the possibility of breathhold or triggering techniques contain high levels of noise. We apply the Karhunev-Loeve Transform to real-time cine images for peak velocity measurement to reduce noise and compare our results to those obtained using spatial four- and eight- neighbor averaging. Filtering via the Karhunen-Loeve Transform successfully reduces signal noise while leading to a smaller affect on the peak velocity measurement compared to that of spatial averaging.

Bernard Chiu¹, Vijay Shamdasani², Robert Entrekin², Chun Yuan¹, and William S Kerwin^1
1Radiology, University of Washington, Seattle, WA, United States, ²Ultrasound Investigations, Philips Healthcare, Bothell, WA, United States

Due to the cost effectiveness of US, it is beneficial to establish a screening strategy in which US is used to identify subjects suspicious of having vulnerable plaques, who are then further studied using MRI. To evaluate the viability of such screening strategy, it is crucial to establish to what extent US can predict subsequent MRI findings. To make this assessment possible, we developed a MR-US registration technique that establishes the spatial correspondence of different plaque components. Our registration method has an average error below 1mm. Also, we found a good correspondence between hyperechoic structures and calcifications in US images.

Pairash Saiviroonporn¹, Vip Viprakasit², Thananya Boonyasirinant³, John C Wood⁴, and Rungroj Krittayaphong^3
1Radiology Department, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand, ²Haematology/Oncology Division, Department of Pediatrics and Thalassemia Center, Faculty of Medicine Siriraj Hospital, Mahidol University, ³Division of Cardiology, Department of Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University, ⁴Divisions of Cardiology, Department of Pediatrics, Children’s Hospital Los Angeles, Keck School of Medicine, University of Southern California, United States

The study compared the observer variability of the conventional Region-Based (RB) to the typical and proposed Pixel-Wise (PW) methods for cardiac T2* analysis in thalassemia patients. Fifty thalassemia major patients were enrolled for the study. Short axis bright- and black-blood sequences were acquired and analyzed using the RB and PW methods. Regions were defined using the whole interventricular septum (WS) or partial septum (PS). The proposed Pixel-Wise method using median of T2* values calculated from PS region provided lower intra- and inter-observer variability as compared to the conventional Region-Based or typical Pixel-Wise methods on both scanning techniques.

Cristobal Arrieta^1,2, Sergio Uribe^2,3, Vicente Parot^1,2, Pablo Irarrazaval^1,2, Carlos Sing-Long², and Cristian Tejos^1,2
1Department of Electrical Engineering, Pontificia Universidad Catolica de Chile, Santiago, RM, Chile, ²Biomedical Imaging Center, Pontificia Universidad Catolica de Chile, Santiago, RM, Chile,³Department of Radiology, Pontificia Universidad Catolica de Chile, Santiago, RM, Chile

Cardiac performance is typically evaluated from left ventricle volume estimations obtained by segmenting cardiac MRI data. This segmentation is usually done by a tedious manual process, that shows low reproducibility. Different authors have proposed the use of Level-Sets to automate this process. Due to the presence of multiple objects in the image, Level-Sets normally require shape constrains that are built from a training procedures. Training-based segmentations tend to fail with severely abnormal anatomies. We propose the use of Level-Sets with Preserved Topology. Compared to manual segmentations we achieved equally accurate and more reproducible segmentations without training, even in abnormal patients.

Pairash Saiviroonporn¹, Vip Viprakasit², Thananya Boonyasirinant³, Archrob Khuhapinant⁴, John C Wood⁵, and Rungroj Krittayaphong^3
1Radiology Department, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand, ²Haematology/Oncology Division, Department of Pediatrics and Thalassemia Center, Faculty of Medicine Siriraj Hospital, Mahidol University, ³Division of Cardiology, Department of Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University, ⁴Haematology/Oncology Division, Department of Internal Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University, ⁵Divisions of Cardiology, Department of Pediatrics, Children’s Hospital Los Angeles, Keck School of Medicine, University of Southern California, United States

This study investigated inter-site observer variability of the Pixel-Wise (PW) method for cardiac T2* analysis in thalassemia patients using the mono-exponential with constant fitting (offset) model as well as to compare the offset model to the mono-exponential with median report (MPS). The inter-site variability of the offset model on the PW method provided acceptable CV on both scanning technique and was comparable to the conventional method. When comparing the offset to MPS method, the variability was also comparable to previous report for the black-blood technique but substantially higher for the bright-blood technique due to the discrepancy at low T2* range.

Huijun Chen¹, Jie Sun¹, William S Kerwin¹, Niranjan Balu¹, Daniel S Hippe¹, Daniel Isquith¹, Yunjing Xue¹, Suzanne Peck¹, Chun Yuan¹, Kevin O'Brien¹, and Xue-Qiao Zhao^1
1University of Washington, Seattle, WA, United States

Inflammation plays an important role in both atherosclerotic plaque progression and rupture. Kinetic parameters derived from DCE-MRI (K^trans and v_p), has been proved to correspond with permeability and blood supply, which are related to inflammatory processes. However, the inter-scan reproducibility of these kinetic parameters in atherosclerotic plaque has not been investigated for multi-center studies, which is essential for prospective studies. In this study, we established the reproducibility of K^trans and v_p and analyzed the sample size needed to detect changes of these parameters, using 3T scanners in a multi-center design.

Ye Qiao¹, David A. Steinman², Qin Qin¹, Maryam Etesami¹, Michael Schär^1,3, Brad C, Astor¹, and Bruce A. Wasserman^1
1The Johns Hopkins Hospital, Baltimore, MD, United States, ²University of Toronto, Toronto, ON, Canada, ³Philips Healthcare, Cleveland, OH, United States

Only a few studies have attempted to image intracranial atherosclerosis by MRI, all using a 2D black blood MRI technique. This approach is suboptimal for imaging intracranial vessel walls given the small size and inherent curving course of these vessels. We developed a 3D high-resolution Volumetric ISotropic TSE Acquisition (VISTA) sequence (0.5 isotropic) for evaluating intracranial vessels at 3.0T to minimize the partial volume effects and signal constraints of 2D sequences. Our sequence provides reliable measurements of intracranial vessel wall size and may make it possible to discern pathological changes from the normal vessel wall.

Robert Kwee¹, Paul Hofman¹, Ed Gronenschild², Robert van Oostenbrugge², Werner Mess², Johannes ter Berg³, Cees Franke⁴, Arthur Korten⁵, Bé Meems⁶, Jos van Engelshoven², Joachim Wildberger², and Eline Kooi^2
1Maastricht University Medical Center, Maastricht, Limburg, Netherlands, ²Maastricht University Medical Center, Netherlands, ³Orbis Medical Center Sittard, Netherlands, ⁴Atrium Medical Center Parkstad Heerlen, Netherlands, ⁵Laurentius Hospital Roermond, Netherlands, ⁶VieCuri Medical Center, Netherlands

In TIA/stroke patients with carotid stenosis, we found no associations between carotid plaque characteristics and ipsilateral white matter lesion severity and progression over a one-year period. This suggests that there is no causal relationship between carotid plaque vulnerability and the occurrence of white matter lesions.

Michaela Elisabeth Gaens¹, Stefan Rozel¹, Matthijs Lipperts^1,2, Robert M. Kwee¹, Karolien Jaspers¹, Mat J. A. P. Daemen¹, Joachim E. Wildberger¹, Walter H. Backes¹, and Marianne Eline Kooi^1
1Department of Radiology, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University Medical Center, Maastricht, Netherlands, ²Department of ICMT, Atrium Medical Center, Heerlen, Netherlands

Dynamic contrast-enhanced MRI can be used to determine pharmacokinetic parameters of carotid plaques. These parameters are connected with plaque properties such as neovascularization, an indicator for plaque vulnerability. In this study, three known models (Tofts, Extended Tofts, Patlak) were compared with regard to their ability to describe DCE-MRI data acquired for 29 patients with moderate (50-69 %) carotid stenosis. Comparison of overall fit error and uncertainties in estimated parameter values show that the Patlak model is most suited to describe data acquired with the presently used scan protocol.

Chengcheng Zhu¹, Zhongzhao Teng¹, Umar Sadat¹, Victoria E Young¹, Martin J Graves¹, Zhiyong Li^1,2, and Jonathan H Gillard^1
1Department of Radiology, University of Cambridge, Cambridge, Cambridgeshire, United Kingdom, ²School of Biological Science & Medical Engineering, Southeast University, Nanjing, Jiangsu, China, People's Republic of

The rupture of atherosclerotic carotid plaque is one of the main causes of ischemic cerebrovascular events such as stroke. Carotid plaque rupture/ulceration is often located in the region proximal to the maximum stenosis. We aim to quantify both the morphological and mechanical features along the plaque to identify high risk factors for rupture.

Seong-Eun Kim¹, Eun-Kee Jeong¹, Xianfeung Shi², Gerald S Treiman³, and Dennis L Parker^1
1Utah Center for Advanced Imaging Research, Department of Radiology, University of Utah, Salt Lake City, Utah, United States, ²Brain Research Institute, University of Utah, ³Department of Veterans Affairs, VASLCHCS, Salt Lake City, Utah

Atherosclerotic plaque characterization by MRI is generally based on the signal intensities and morphological appearance in multi-contrast images, but conventional contrast images are unable to provide the full quantification of high risk plaque components. Iron has consistently been found in higher concentrations in atherosclerotic plaque compared to tissue. Iron may be incorporated into hemoglobin or bound to the storage proteins ferritin and hemosiderin. It has been reported that intraplaque T2* measurement distinguished symptom-producing from non-symptom producing plaques in patients. In this work we introduce simultaneous measurement of T1 and T2* of atherosclerotic plaque using a novel sigleshot sequence, 2D ss-SGSTEPI.

Diederik Frank van Wijk¹, Raphael Duivenvoorden¹, D F Enklaar¹, Rob J van der Geest², Eric de Groot¹, Erik S.G Stroes¹, and Aart J Nederveen^3
1Vascular Medicine, Academic Medical Center, Amsterdam, Netherlands, ²Radiology, Leiden University Medical Center, Leiden, Netherlands, ³Radiology, Academic Medical Center, Amsterdam, Netherlands

Early detection of atherosclerotic plaques that are prone for rupture can improve preventive strategies in clinical practise. MRI has the promise to identify plaque morphological characteristics that are the hallmark of the vulnerable plaque. Here, we show that high and low spatial resolution measurements change the accuracy and reproducibility of different parameters of the atherosclerotic plaque in a population with carotid atherosclerosis.

Yunjing Xue¹, Daniel S Hippe¹, Hunter R Underhill¹, Marina S Ferguson¹, Niranjan Balu¹, Rui Li², Huijun Chen¹, Li Dong³, Feiyu Li⁴, Gador Canton¹, and Chun Yuan^1
1Vascular Imaging Laboratory, Radiology, University of Washington, Seattle, WA, United States, ²Center for Bio-Medical Imaging Research, Tsinghua University, Beijing, China, People's Republic of, ³Department of Radiology, Beijing Anzhen Hospital, Beijing, China, People's Republic of, ⁴Department of Radiology, Peking University First Hospital, Beijing, China, People's Republic of

Carotid bifurcation geometry has been identified implicated as a risk factor for the development of atherosclerotic plaque. Geometrical factors associated with flow propertiesfeatures can be assessed from 3D models derived from either bright blood or black blood MRI. Reproducibility of these geometrical parameters is important for longitudinal studies of risk assessment. While reproducibility of black-blood derived geometry has been previously reported, bright blood reproducibility is unknown. We show that geometric parameters assessed by bright blood MRI are comparable to those derived from black blood MRI.

Jinnan Wang¹, Huijun Chen², Gregory J Wilson³, Niranjan Balu², William S Kerwin², Chun Yuan², and Peter Boernert^4
1Clinical Sites Research Program, Philips Research North America, Seattle, WA, United States, ²University of Washington, ³Philips Healthcare, ⁴Philips Research Europe

Dynamic contrast enhanced MRI has been used to quantify the inflammation in atherosclerotic plaques. The current technology of using mere bright or black blood contrast images, however, can not achieve the required high temporal resolution for AIF and high spatial resolution for vessel wall. In this abstract, an inverleaved Black and Bright blood DCE MRI was proposed. A novel LOBBI sequence was used to eliminate the signal intereference between Black and Bright blood images and the technique was validated in a flow phantom experiment.

Robert Kwee¹, Robert van Oostenbrugge², Werner Mess², Martin Prins², Rob van der Geest³, Johannes ter Berg⁴, Cees Franke⁵, Arthur Korten⁶, Bé Meems⁷, Jos van Engelshoven², Joachim Wildberger², and Eline Kooi^2
1Maastricht University Medical Center, Maastricht, Limburg, Netherlands, ²Maastricht University Medical Center, Netherlands, ³Leiden University Medical Center, Netherlands, ⁴Orbis Medical Center Sittard, Netherlands, ⁵Atrium Medical Center Parkstad Heerlen, Netherlands, ⁶Laurentius Hospital Roermond, Netherlands, ⁷VieCuri Medical Center Venlo, Netherlands

We investigated the natural course of carotid plaque progression in TIA/stroke patients with ipsilateral <70% carotid stenosis, by using serial multisequence magnetic resonance imaging. The results of our study show that there is inward plaque remodeling over a 1-year period, while features of plaque vulnerability generally remain unchanged.

Jian Zhu^1,2, Axel Bornstedt¹, Genshan Ma², Nico Merkle¹, Naifeng Liu², Wolfgang Rottbauer¹, and Volker Rasche^1
1Internal Medicine II, University of Ulm, Ulm, Germany, ²Department of Cardiology, Zhongda Hospital, Nanjing, Jiangsu, China, People's Republic of

In this study, the use of a fast gradient echo sequence with T2 preparation is investigated for generating a T2 weighted image contrast similar to a multi-spin echo approach. The sequence has been applied to volumetric imaging of the carotid artery wall and compared to the conventional multi-spin echo technique. Using the suggested technique enabled a significant reduction of the image acquisition time up to a factor of three, with almost maintained image contrast.

Stephanie Elaine GarWai Chiu¹, Alan R Moody^1,2, James Q Zhan², and General Leung^1
1Medical Biophysics, University of Toronto, Toronto, Ontario, Canada, ²Medical Imaging, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada

Intraplaque hemorrhage (IPH) detected with T1-weighted MRI has been shown to predict future ischemic events in both symptomatic and asymptomatic carotid patients. Despite the clinical relevance of IPH, there are few animal IPH models and an absence of data concerning MRI of IPH in such animal models. This study explores the suitability of a rabbit model of intraplaque-delivered red blood cells for MRI studies of in vivo IPH and presents evidence of MRI-detected IPH in this model using high resolution, T1-weighted sequences.

Jihong Sun^1,2, Xubin Li¹, Hongqing Feng¹, Huidong Gu¹, Tiffany Blair¹, Jiakai Li¹, Yanfeng Meng¹, Feng Zhang¹, and Xiaoming Yang^1,2
1Image-Guided Bio-Molecular Interventions Section, Radiology, University of Washington School of Medicine, Seattle, WA, United States, ²Radiology, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China, People's Republic of

Interleukin-10 (IL10) gene-transduced-bone marrow cells (BMC) were labeled with Feridex, and then transplanted into atherosclerotic ApoE-/- mice. In vivo MRI presented signal voids of the aorta walls due to the migration of the IL10/Feridex-BMCs into atherosclerotic lesions. Subsequent histologic measurements showed that the average size of atherosclerotic lesions in the mouse group with IL10/Feridex-BMC transplantation was significantly less than those in control mouse groups with Feridex-BMC transplantation or no BMC transplantation. This study demonstrates the potential of using in vivo MRI to track IL10/Feridex-BMCs recruited to atherosclerotic lesions, where IL10 genes may function to prevent the progression of atherosclerotic lesions.

Jinnan Wang¹, Niranjan Balu², Gregory J Wilson³, Chun Yuan², and Peter Boernert^4
1Clinical Sites Research Program, Philips Research North America, Seattle, WA, United States, ²University of Washington, ³Philips Healthcare, ⁴Philips Research Europe

High field MRI provides a unique approach to characterize atherosclerotic plaques with improved SNR and new contrast. The unavailability of global T/R coil on high field systems due to homogeneity issues, however, limits its further application in black blood imaging. No current BB techniques works without global excitation due to inflow effects. This abstract proposes a new imaging that achieves effective BB with only local excitation and a flow phantom experiment is also conducted for validation.

Diederik Frank van Wijk¹, S Gonçalves², Raphael Duivenvoorden³, D F Enklaar³, Paul F. Groot², J. B. Warntjes^4,5, Erik S Stroes³, and Aart J Nederveen^2
1Vascular medicine, Acedemic Medical Center, Amsterdam, Netherlands, ²Radiology, Academic Medical Center, Amsterdam, Netherlands, ³Vascular Medicine, Academic Medical Center, Amsterdam, Netherlands, ⁴Center for Medical Imag Science and Visualization, Linköping University, Linköping, Sweden, ⁵SyntheticMR AB, Linköping, Sweden

The cornerstone for preventive treatment strategies of patients at increased risk for an atherosclerotic event is early recognition of the prone to rupture plaque. MRI has recently shown to identify morphological characteristics, such as the intraplaque haemorrhage and the lipid rich necrotic core, which are considered to be important components of the vulnerable plaque. Absolute T2 values can accurately discriminate and indentify different tissues in a wide range of conditions and patients. Here, we used MR relaxometry to determine the absolute T2-values of two repetitive measurements in human carotid plaques.

Sarah Anne Peel¹, Tarique Hussain¹, Marina Cecelja², Abeera Abbas³, Gerald Greil¹, and René M Botnar^1
1Division of Imaging Sciences and Biomedical Engineering, King's College London, London, London, United Kingdom, ²NIHR Comprehensive Biomedical Research Centre, Guy's and St Thomas' NHS Foundation Trust / King's College London, United Kingdom, ³Academic Department of Surgery, Cardiovascular Division, King's College London, United Kingdom

The quadruple inversion recovery (QIR) pre-pulse was originally developed for carotid vessel wall imaging without cardiac triggering. As aortic blood flow varies considerably during the cardiac cycle, we hypothesize that ECG-triggering may improve blood suppression when applying the QIR sequence in the aorta. The QIR pre-pulse was successfully combined with ECG-triggering and small FOV 'zoom' imaging to accelerate the scan time without fold over artifacts. The zoom QIR-TSE sequence was used to image the abdominal aorta in volunteers both before and after contrast administration. The ECG-triggered QIR images show improved blood suppression and image quality compared to un-triggered scans.

Dongxiang Xu¹, Jinnan Wang², Jie Sun³, and Chun Yuan^3
1Radiology, University of Washington, Seattle, WA, United States, ²Philips Research North America, ³University of Washington

Atherosclerosis is the number one killer in the world. Previous studies have shown that intraplaque hemorrhage (IPH) into the carotid atherosclerotic plaque is a major factor causing plaque instability and progression. Thus, IPH is critical to evaluation of carotid atherosclerotic disease. The Slab-selection Phase-sensitive Inversion-recovery MRI sequence has improved IPH evaluation compared to others imaging sequences. Using this technique, we developed an enhanced mean-shift model to auto-detect IPH and applied it to in vivo MRI data. The statistical analysis results show this algorithm has 100% sensitivity, 95% specificity and a high correlation with human evaluation

Seong-Eun Kim¹, Eun-Kee Jeong¹, Xianfeng Shi², Gerald S Treiman³, and Dennis L Parker^1
1Utah Center for Advanced Imaging Research, Department of Radiology, University of Utah, Salt Lake City, Utah, United States, ²Brain Research Institute, University of Utah, ³Department of Veterans Affairs, VASLCHCS, Salt Lake City, Utah

To improve the sensitivity and specify of plaque component identification in ADC maps a high resolution 3D DWI technique is desirable. 3D ss-IV-STEPI technique has been developed to acquire a high resolution DWI of a localized region such as the carotid artery. This technique acquires the total k-space of a limited 3D volume after a single diffusion-preparation. Inner volume technique is used to reduce the time required for EPI readout of each complete k-space and reduce blurring and susceptibility artifacts. In this work we present the first in vivo high resolution 3D DWI of the atherosclerosis plaques using the 3D-ss-IV-STEPI.

Hisanori Kosuge¹, Toshiro Kitagawa¹, Masaki Uchida², Lars Liepold², David Morris³, Peter E Prevelige Jr.³, Trevor Douglas², and Michael V McConnell^1
1Cardiovascular Medicine, Stanford University, Stanford, CA, United States, ²Chemistry and Biochemistry, Montana State University, Bozeman, MT, United States, ³Microbiology, The University of Alabama at Birmingham, Birmingham, AL, United States

Protein cage nanoparticles (PCNs) have shown promise for molecular/cellular imaging of cardiovascular disease and cancer. PCNs incorporating iron oxide have been used as susceptibility agents for MRI, but T1-shortening agents are preferred clinically. The PCN structure can incorporate targeting peptides and can also enhance the T1 effect of Gd by slowing rotational correlation time and by providing multiple Gd binding domains. We demonstrate that Gd-based PCNs show strong r1 values in vitro plus signal enhancement in vivo of carotid and aortic vascular disease, with low Gd dosing.

Michel A Bartoli¹, Frank Kober¹, Patrick J Cozzone¹, and Monique Bernard^1
1Centre de Resonance Magnetique Biologique et Medicale, Faculte de Medecine, Universite de la Mediterranee, Marseille, Provence, France

The elastase perfusion mouse model is one of the most reliable animal models of Abdominal Aortic Aneurism formation. This MRI study at 11.75T aimed at evaluating the reliability of longitudinal in vivo aortic diameter and wall thickness measurements in mice after aortic perfusion with elastase or with heat-inactivated elastase in control animals. Vessel diameter was significantly greater in elastase-perfused mice compared to controls with both the optic grid measurement and the MRI measurement of the outer diameter. Aortic wall area was significantly greater in elastase mice compared with control mice. Optic and MRI measurements showed good correlation.

Tarique Hussain¹, Sarah Peel¹, Abeera Abbas¹, Matthew Waltham¹, Gerald Greil¹, and Rene Botnar^1
1King's College London, Westminster, London, United Kingdom

In this study, the Abdominal Aortic aneurysm is used as a model to show the ability of Zoom-accelerated Quadruple inversion Recovery to demonstrate post-contrast enhancement of the fibrous cap. The technique has been implemented here for cardiovascular imaging by adapting timing for ECG-gating. The advantage over traditional techniques is that exactly the same inversion times are used before and after contrast administration. This removes the implicit quantification bias of traditional sequences.

Qi Liu^1,2, Qi Yang³, Zhaoyang Fan¹, and Debiao Li^1,4
1Cedars-Sinai Medical Center, Los Angeles, CA, United States, ²Northwestern University, Chicago, IL, United States, ³Xuanwu Hospital, Beijing, China, People's Republic of, ⁴UCLA, Los Angeles, CA, United States

Despite the benefits of SWI vessel wall imaging, namely blood flow independence, three dimensional coverage, and sensitivity to calcification, the accuracy of SWI in morphological measurement has yet to be addressed. Here we compared SWI with the reference method, single slice DIR turbo spin echo (TSE), on measuring femoral artery lumen and wall size.

Peter Fries¹, Florian Custodis², Andreas Müller¹, Roland Seidel¹, Alexander Massmann¹, Arno Bücker¹, and Günther Schneider^1
1Clinic of Diagnostic and Interventional Radiology, Saarland University Hospital, Homburg, Saarland, Germany, ²Department of Cardiology, Saarland University Hospital, Homburg, Saarland, Germany

The aim of this study was to compare the aortic distensibility (AD) in wild-type (C57/BL6, n=6)) and cholesterol fed ApoE-knock-out mice (ApoE-/-, n=6), a model of atherosclerosis, by means of cine MRI at 9.4 T. A self-gated cine sequence (Intragate®) was acquired perpendicular to the ascending aorta. AD was defined as the difference of the cross-sectional vessel area at endsystole and enddiastole. ApoE-/- mice demonstrated a significantly lower AD and a larger cross-sectional vessel areas at enddiastole. The reduced AD in this model of lipid induced atherosclerosis may be evaluated in vivo with MRI at 9.4 T.

James F Glockner¹, and Christine U Lee^1
1Radiology, Mayo Clinic, Rochester, MN, United States

Low b-value DWI was assessed as an alternative technique for demonstrating mural edema in patients with large vessel vasculitis. The robust black blood effect, significant increased signal intensity in patients with active disease, and rapid acquisition times of low b-value DW imagse compared favorably with conventional ecg gated or non-gated fast spin echo acquisitions in this small feasibility study.

Di Qian^1,2, and Paul A Bottomley^1,2
1Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University, Baltimore, Maryland, United States, ²Electrical and Computer Engineering, Johns Hopkins University, Baltimore, Maryland, United States

Fibrous cap thickness is key to assessing vulnerable atherosclerotic plaque. MRI is intrinsically well-suited for plaque imaging, but has lacked the spatial resolution needed to resolve the cap and other pathologies. At 3T, the intravascular loopless MRI detector offers ~4-fold higher signal-to-noise ratio than at 1.5T, and can be made safe from RF heating. Here we investigate its use for identifying plaques for subsequent high-resolution 80µm imaging of lesion and vessel wall morphology in diseased human arterial specimens in vitro, correlating MRI measurements of fibrous caps with histology. Feasibility of the approach is demonstrated in a rabbit aorta in vivo.

Marcelo E Andia¹, and Rene M Botnar^1
1Division of Imaging Sciences and Biomedical Engineering, Kings College London, London, United Kingdom

In this work we present a novel technique for flow-independent vessel wall imaging based on the differences in T2 relaxation time of arterial blood and surrounding tissues using a T2prep prepulse. The technique is based on the acquisition and subtraction of two data sets, one obtained with T2prep(+) and without T2prep(-). This allows nulling the signal of arterial blood while maintaining the signal of muscle and vessel wall. The result of the subtraction results in a flow-independent black blood vessel wall image.

Andrew David Scott^1,2, Jennifer Keegan^1,2, and David Firmin^1,2
1Cardiovascular Magnetic Resonance Unit, Imperial College London, London, United Kingdom, ²Cardiovascular Magnetic Resonance Unit, The Royal Brompton and Harefield NHS Foundation Trust, London, United Kingdom

MR vessel wall imaging is commonly performed with alternate R-wave cardiac gating which improves SNR and robustness to variations in RR-interval, but results in one redundant cardiac cycle in every two. The redundant cardiac cycle has been used to image an additional parallel slice in 2D carotid wall imaging. Beat-to-beat respiratory motion correction (B2B-RMC) can obtain 3D coronary wall images with ~100% respiratory efficiency. We have used the redundant cardiac cycle to acquire an additional 3D volume in coronary vessel wall imaging with B2B-RMC, resulting in simultaneous targeted high resolution left and right 3D coronary vessel wall imaging in ~10minutes.

Jing Liu¹, Thanh D Nguyen¹, Yanchun Zhu¹, Pascal Spincemaille¹, Jonathan W Weinsaft¹, Martin R Prince¹, and Yi Wang^1
1Radiology, Weill Cornell Medical College, New York, NY, United States

A respiratory and cardiac self-gated free-breathing 3D cine SSFP imaging technique provides both water and fat visualization of the coronary arteries. Multi-echo hybrid radial sampling has been approved to be high efficient at data acquisition and robust to motion. It has been exploited for generating self-gating signals without extra cost of scan time, by mapping the k-space center along the slice encoding direction intensity-weighted position information, from which both respiratory and cardiac motions are derived. In this study, data sets at different echo times are exploited for separating water and fat signals. The conventional coronary imaging techniques acquire data during a limited acquisition window at the middle diastolic phase, which requires subject dependent trigger delay. And the preparation pulses such as navigation pulse, fat and myocardium suppression pulses interrupt the steady states and cause artifacts. Our proposed water and fat separation based self-gated cine image technique have the advantages of avoiding the extra requirements and preparation pulses. Combination of the water and fat images improves the coronary artery contrast.

Harsh Kumar Agarwal¹, Peter Koken², Michael Schär³, Jing Yu¹, Allison G Hays¹, Holger Eggers², Robert G Weiss¹, Peter Börnert², and Matthias Stuber^4,5
1Johns Hopkins University, Baltimore, MD, United States, ²Philips Research Laboratories, Hamburg, Germany, ³Philips Healthcare, Cleveland, OH, United States, ⁴Department of Radiology, Centre Hospitalier Universitaire Vaudois and University of Lausanne, Lausanne, Switzerland, ⁵Center for Biomedical Imaging (CIBM), Lausanne, Switzerland

Three Tesla cross-sectional spiral coronary MRI has successfully been used for the measurement of endothelial function in healthy adults and in patients with coronary artery disease. However, increased B0 inhomogeneity at high magnetic field strength may adversely affect the image quality and the quantitative measurements. Therefore, we have combined the 3 point Dixon technique with cross sectional spiral coronary MRI to separate water and fat signal on the one hand and to correct for off-resonance artifacts using sliding window conjugate phase reconstruction on the other hand.

Mehdi Hedjazi Moghari¹, Alan O'connor¹, Warren J Manning¹, and Reza Nezafat^1
1Dept. of Medicine (Cardiovascular Div.), Beth Israel Deaconess Medical Center, Harvard Medical Sch., Boston, MA, United States

Compensating for the heart respiratory motion using prospective navigators prolongs scan time with a non-deterministic total acquisition time. In this study, we propose a new adaptive navigator gating where fixed navigator efficiency is used for enforcing temporal changes in the gating window during the scan.

Taehoon Shin¹, Holden H Wu^1,2, Michael V McConnell^1,2, and Dwight G Nishimura^1
1Electrical Engineering, Stanford University, Stanford, CA, United States, ²Cardiovascular Medicine, Stanford University, Stanford, CA, United States

Correction for respiratory motion remains a major challenge in free-breathing coronary MRA. Motion estimation directly from the heart is potentially superior to conventional diaphragmatic navigator, and several methods based on DC or 1D projection signals have been proposed. We propose a 2D image-based respiratory navigator which allows accurate estimation of SI and AP motion of the heart. Despite the use of 2D images, the navigator acquisition time was significantly shortened by utilizing preserved motion correlation between aliased images. The feasibility of the proposed approach is demonstrated by phantom and in-vivo experiments.

Markus Henningsson¹, Jouke Smink², and Rene M Botnar^1
1Division of Imaging Sciences & Biomedical Engineering, King's College London, London, United Kingdom, ²Philips Healthcare, Best, Netherlands

In this work a novel 2D navigator (2Dnav) is proposed, which prospectively corrects for translational motion in foot-head and left-right direction. The 2Dnav was implemented as a Cartesian bSSFP sequence and used a template matching algorithm for motion estimation. The 2Dnav was compared to a diaphragmatic 1D navigator with a tracking factor of 0.6 at 10 mm gating window and no gating. Visual assessment preferred the 2Dnav over the 1Dnav for no gating while there was no significant difference for a gating window of 10mm.

Markus Henningsson¹, and Rene M Botnar^1
1Division of Imaging Sciences & Biomedical Engineering, King's College London, London, United Kingdom

Self-navigators offers a “model free” alternative to diaphragmatic navigators for respiratory motion correction in coronary MRA. In this study we have investigated the use of a pencil beam 1D navigator (1Dnav) with large diameter (~100mm) and small flip angle (10°) for direct measurements of the respiratory motion of the heart, comparing it to the conventional approach which uses a 1Dnav positioned on the diaphragm and a tracking factor of 0.6. We show that the 1Dnav is feasible for self-navigation and shows improved motion compensation compared to the diaphragmatic 1D navigator.

Davide Piccini¹, Arne Littmann², Sonia Nielles-Vallespin², and Michael O. Zenge^2
1Pattern Recognition Lab, University of Erlangen-Nuremberg, Erlangen, Germany, ²MR Applications and Workflow Development, Healthcare Sector, Siemens AG, Erlangen, Germany

Conventional navigator-gated techniques for coronary MRI are burdened with low scan-time efficiency and sub-optimal precision. Self-navigating methods promise to overcome these limitations using the positional information of the heart directly accessible in the readouts used for imaging. These methods, however, suffer from the presence of signal form chest wall, arms and liver which can render the respiratory motion detection impossible. In the current work, an innovative method to efficiently suppress such unwanted signal is presented and robust self-navigation is achieved. This method was fully integrated into 3D radial whole-heart coronary imaging and was compared with conventional navigator-gated imaging in volunteers.

Mehdi Hedjazi Moghari¹, Dana C Peters¹, Jouke Smink², Lois Goepfert¹, Kraig V Kissinger¹, Beth Goddu¹, Thomas H Hauser¹, Mark E Josephson¹, Warren J Manning¹, and Reza Nezafat^1
1Dept. of Medicine (Cardiovascular Div.), Beth Israel Deaconess Medical Center, Harvard Medical Sch., Boston, MA, United States, ²Philips Healthcare, Netherlands

Conventional navigator gated imaging sequence for left atrial late gadolinium enhancement (LGE) results in blood enhancement artifact. In this study, we investigated a modified free-breathing LGE sequence that minimizes this artifact.

Holden H Wu^1,2, Bob S Hu^2,3, Dwight G Nishimura², and Michael V McConnell^1,2
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 important goals in cardiovascular imaging and MRI is a promising modality for addressing this critical need. In this work, we present a 3D whole-heart free-breathing coronary MRI technique based on the 3D cones readout trajectory, which enables a high degree of scan time reduction compared to 3D Cartesian encoding and exhibits greater robustness to motion/flow. In addition, 2D navigator images are acquired directly over the heart to compensate for respiratory motion and multiple cardiac phases are resolved to support retrospective selection of the best phase for visualization.

Mehdi Hedjazi Moghari¹, Beth Goddu¹, Kraig K Kissinger¹, Lois Goepfert¹, Warren J Manning¹, and Reza Nezafat^1
1Dept. of Medicine (Cardiovascular Div.), Beth Israel Deaconess Medical Center, Harvard Medical Sch., Boston, MA, United States

In this study, respiratory motion of pulmonary veins (PV) with respect to that of the right-hemi-diaphragm (RHD) is investigated. Tracking factors between PV and RHD’s respiratory motions of 19 subjects are calculated to be 0.45 and shown to be subject-dependent.

Doug Stanton¹, Neha Dobhal¹, Michele Casanova², Mehdi Hedjazi Moghari², Ameet Jain¹, Robert Manzke¹, Warren J Manning², Chris Hall¹, and Reza Nezafat^2
1Philips Research, Briarcliff Manor, NY, United States, ²Dept. of Medicine (Cardiovascular Div.), Beth Israel Deaconess Medical Center, Harvard Medical Sch., Boston, MA, United States

In this study, we present an MR compatible pneumatic heart phantom that can mimic both respiratory and cardiac motions derived from patient’s information.

Tamer Ahmed Basha¹, Mehmet Akcakaya¹, Mehdi H Moghari¹, Kraig V Kissinger¹, Beth Goddu¹, Lois Goepfert¹, Warren J Manning¹, and Reza Nezafat^1
1Dept of Medicine, Cardiovascular Division, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States

We investigated using a radial profile ordering scheme of the randomly sampled k-space in 3D compressed-sensing acquisition. Phantom and in vivo cardiac imaging were performed to evaluate this ordering.

Jingsi Xie^1,2, Xiaoming Bi³, and Debiao Li^1,2
1Northwestern University, Chicago, IL, United States, ²Cedars-Sinai Medical Center, Los Angeles, CA, United States, ³Cardiovascular MR R&D, Siemens Healthcare, Chicago, IL, United States

We developed a TI-independent 2D black blood imaging technique on coronary vessel wall during contrast injection by using PS reconstruction. Dynamic quantitative indices such as Ktrans, Vp can be calculated from these measurements.

Qi Yang¹, Kuncheng Li¹, Xiangying Du¹, Lixin Jin², Jing An², Renate Jerecic², and Debiao Li^3
1Radiology, Xuanwu Hospital, Beijing, Beijing, China, People's Republic of, ²Siemens Healthcare, MR Collaboration NE Asia, ³Cedars-Sinai Medical Center and UCLA, Los Angeles, CA

Contrast enhanced 3T whole heart coronary MR angiography (CMRA) is a reliable method for the detection and exclusion of hemodynamically significant coronary stenosis and has shown high accuracy in one single center trial. With the improvements in spatial resolution, particularly along the z-axis, it is possible to postprocess whole heart CMRA images by using advanced methods such as MIP, curved MPR, and 3D VRT.

David Muccigrosso¹, Adil Bashir¹, Dongsi Lu¹, and Jie Zheng^1
1Washington University School of Medicine, St. Louis, MO, United States

Susceptibility weighted imaging (SWI) can be used to image vessel wall and calcification with less flow artifacts and partial volume effect. The study is to explore the role of SWI approach in the characterization of various major plaque components. Plaque phantoms, coronary artery specimens, and endarterectomy carotid artery specimens were investigated using 3D SWI sequence. Phase images show clear differentiation of hemorrhage and calcification. The finding indicates possibility to use SWI technique to correctly segment major plaque components.

Claudia Prieto¹, Rene Botnar¹, and Tobias Schaeffter^1
1Division of Imaging Sciences and Biomedical Engineering, King's College London, London, United Kingdom

Scan time of coronary MRA can be reduced using radial sampling with long cardiac acquisition windows by exploiting its intrinsic motion insensitivity. However, with this approach, image quality may be hampered due to recovery of epicardial fat signal after a fat-saturation prepulse. Here we propose to use a k-space filtered golden radial acquisition to overcome this problem. Filtering is used to weight selectively the k-space data according to their fat saturation levels while the golden angle approach allows retrospective subject-specific filter adaptation for optimal fat suppression. Significantly improved fat-suppression is shown in a water-fat phantom and right coronary artery images in healthy subjects.

Jonathan Suever¹, Pierre Watson², and John Oshinski^1,2
1Biomedical Engineering, Georgia Institute of Technology / Emory University, Atlanta, Georgia, United States, ²Radiology, Emory University School of Medicine, Atlanta, Georgia, United States

The objective was to quantify periods of low motion of the coronary veins during the cardiac cycle for planning MR coronary venograms. Patients scheduled for cardiac resynchronization therapy (CRT) and patients with coronary artery disease (CAD) were studied. All CRT patients and 32% of CAD patients (all with EF<35%) had a longer systolic rest period. In 77% of patients, cross-sectional area was larger in systole than diastole. The combination of larger vessel areas during systole and the lengthened systolic rest period in CRT patients suggest that systolic imaging would be preferable for coronary vein imaging in CRT patients.

Mehmet Akcakaya*¹, Tamer Basha*¹, Kraig V. Kissinger¹, Beth Goddu¹, Lois Goepfert¹, Warren J. Manning¹, and Reza Nezafat^1
1Dept. of Medicine (Cardiovascular Division), Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States

Use of contrast agents in whole heart coronary MRI is known to increase SNR and CNR. However, to take full advantage of the presence of contrast media, the scan times need to be shortened. In this work, we investigated a prospectively accelerated whole heart contrast-enhanced coronary MRI after a bolus infusion of Gd-BOPTA using low-dimensional-structure self-learning and thresholding (LOST), an improved CS reconstruction.

Davide Piccini¹, Arne Littmann², Hui Xue³, Jens Guehring³, and Michael O. Zenge^2
1Pattern Recognition Lab, University of Erlangen-Nuremberg, Erlangen, Germany, ²MR Applications and Workflow Development, Healthcare Sector, Siemens AG, Erlangen, Germany, ³Imaging and Visualization, Siemens Corporate Research, Princeton, NJ, United States

Conventional navigator-gated techniques for coronary MRI are limited both in scan-time efficiency and precision. Alternative approaches that derive the positional information of the heart directly from the readouts used for imaging achieve up to 100% efficiency, but are limited to 1D rigid respiratory motion correction. In contrast, image registration allows for a more realistic estimation of the underlying 3D motion, but is less efficient. In this work, a hybrid method that combines 1D self-navigation with registration-based affine motion compensation is presented. This method was implemented for 3D radial whole-heart coronary MRI and was compared with a navigator-gated approach in volunteers.

Ek Tsoon Tan¹, Luca Marinelli¹, Thomas K Foo¹, and Christopher J Hardy^1
1GE Global Research, Niskayuna, NY, United States

Standard breath-held 3D CMRA uses linear phase-encoding, and is challenging because of variation in patients’ cardiac quiescent period and breath-holding abilities. Flexible phase-encoding allows for acquisition window and breath-hold duration to be flexibly adjusted, and can provide 25-30% reduction in acquisitions due to removal of k-space corner samples. A novel and compact flexible-linear scheme was tested in balanced SSFP CMRA. Compared to linear phase-encoding (14 heart-beats), flexible phase-encoding in vivo provided either reduced acquisition window by 30% (14 heart-beats) or a reduced breath-hold duration (9 heart-beats).

Andrew David Scott^1,2, Jennifer Keegan^1,2, Raad H Mohiaddin^1,2, and David Firmin^1,2
1Cardiovascular Magnetic Resonance Unit, Imperial College London, London, United Kingdom, ²Cardiovascular Magnetic Resonance Unit, The Royal Brompton and Harefield NHS Foundation Trust, London, United Kingdom

Autopsy studies have shown that the coronary vessel wall thickens with age. There is, however, a need for a non-invasive, radiation free technique for assessing the coronary wall in longitudinal studies of disease. Beat-to-beat respiratory motion correction (B2B-RMC) is a highly efficient technique (typically >99% efficient) for respiratory motion correction in MR coronary vessel wall imaging. We studied 21 healthy subjects using dark blood prepared high resolution (0.7x0.7x3.0mm) 3D spiral imaging with B2B-RMC. For the first time using non-invasive imaging, we demonstrate significantly increasing coronary vessel wall thickness and wall/outer wall ratio (W/OW) with age in healthy subjects.

Ahmed Klink¹, Steve Davis Dickson¹, David Izquierdo¹, Jason Bini², Eric Lancelot³, Jesus Mateo⁴, Phlippe Robert⁵, Claire Corot³, and Zahi A Fayad^6
1Radiology, Translational and Molecular Imaging Institute, New York, NY, United States, ²Radiology, Translational and Molecular Imaging Institute, New York, 10029, United States, ³Guerbet, Paris, France, ⁴Epidemiology, Atherothrombosis and Imaging, CNIC, Madrid, Spain, ⁵Research Department, Guerbet, Paris, France, ⁶Radiology, Translational and Molecular Imaging Institute, New York, United States

Effects of statins on the inflammation/macrophage burden in atherosclerotic rabbits were monitored with PET and USPIO-enhanced MRI on combined PET/MRI system. USPIO-enhanced MRI was achieved using P904, a short circulating USPIO demonstrated to be uptaken by macrophages in the plaque while radioactive labeled glucose (FDG) was used to assess macrophage metabolic activity with PET.

Yi He¹, Zhaoqi Zhang¹, Qinyi Dai¹, Jing An², Lixin Jin³, Renate Jerecic³, and Debiao Li^4
1Department of Radiology, Beijing Anzhen Hospital, Capital Medical University, Beijing, China, People's Republic of, ²Siemens Mindit Magnetic Resonance, Siemens Healthcare, MR Collaboration NE Asia, Shenzhen, China, People's Republic of, ³Siemens Limited China, Siemens Healthcare, MR Collaboration NE Asia, Shanghai, China, People's Republic of, ⁴Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, United States

This study evaluated the ability of black blood coronary arterial wall MRI to identify the coronary artery plaque, using intravascular ultrasound (IVUS) as the golden standard. The vessel cross-sectional area (CSA), luminal CSA, maximal wall thickness, plaque burden of MRI cross-section coronary wall imaging in 19 patients were compared with IVUS. And It showed a good agreement between IVUS and MRI with regard to extent of wall thickening although MRI overestimated plaque burden and degree of luminal stenosis, which is the difference in spatial resolution between techniques.