Shivaprasad Ashok Chikop¹, Amaresha Shridhar Konar¹, Nithin Vajuvalli¹, Darshan Shivaram Keelara¹, Ashwini Kumnoor¹, Sairamesh raghuraman², Ramesh Venkateshan², and sairam Geethanath^1
1Medical Imaging Research Centre, Dayananda Sagar Institutions, Bangalore, India, ²Wipro GE Healthcare, Bangalore, India

The goal of the work was to build a low cost cardiac phantom that mimics cardiac motion and measure thermometric profile based on applied B1+ fields during MR imaging. The cardiac motion inside the phantom was simulated using the mechanical gear setup. To obtain the thermometric profile of the cardiac phantom 12 probes were inserted into the phantom with required thermal insulation.  The phantom also provides an opportunity to correlate local SAR findings with temperature measurements in the heart phantom. 

Andrew James Patterson¹, Martin John Graves¹, and David John Lomas^1
1Radiology, University of Cambridge & Addenbrooke’s Hospital, Cambridge, United Kingdom

This work describes the development of a novel approach for prescribing cardiac scan plane locations which will benefit cardiac examinations where the anatomy is abnormal (for example, in congenital anomalies). We have developed a desktop sized constrained surface controller which mimics an ultrasound transducer. This enables retrospective reformatting of a 3D localizer image to determine the desired cardiac view. The cardiac scan plane is then prospectively transferred to a 2D CINE bSSFP sequence to enable interactive assessment of cardiac function. Initial testing has established that our approach allows us to replicate standard cardiac views.

Tyler Joseph Spear¹, Tori Stromp¹, Steve Leung², and Moriel Vandsburger^1
1Saha Cardiovascular Research Center, University of Kentucky, Lexington, KY, United States, ²Gill Heart Imaging Center, University of Kentucky, Lexington, KY, United States

This project uses cardiac magnetic resonance to compare cine balance steady state free precession signals between 2D and 3D acquisitions in order to better understand how through-plane motion of tissues impacts the change in signal through the cardiac cycle.  As quantitative techniques become more prevalent and refined, it is imperative to be able understand the evolution of these signals to eliminate results due to physical motion of the heart that would skew the results of otherwise diagnostic tests.

El-Sayed H. Ibrahim¹, Jadranka Stojanovska¹, Scott Swanson¹, Claire Duvernoy¹, and Rodica Pop-Busui^1
1University of Michigan, Ann Arbor, MI, United States

This study evaluates the association between MRI-derived parameteers of cardiac function in Type-1 diabetes (T1DM) at baseline and 3-years follow-up, and compares the results to healthy controls (HC). There were no differences between T1DM and HC at baseline in the measured variables. In T1DM, only left-ventricular (LV) mass-ratio and basal circumferential strain significantly decreased from baseline to follow-up. Mitral early-to-atrial filling-rate (representing diastolic function) increased, and apical torsion decreased from baseline to follow-up, although these differences were not significant. Among the parameters that showed differences between baseline and follow-up, only LV mass-ratio showed significant difference between female and male patients.

Atsushi FUKUYAMA¹, Haruo ISODA², and Shuji KOYAMA^2
1Radiological Sciences, Nagoya University Graduate School of Medicine, Nagoya, Japan, ²Brain & Mind Research Center, Nagoya University, Nagoya, Japan

Our objective is to develop a phantom that can evaluate the image distortion along the body axis objectively, and elucidate the relationship between the occurrence and geometrical position of image distortion in MRA. As a result, the phantom that we have developed has made it possible to evaluate image distortion objectively over a wide range of the trunk. We made clear that when separated from the center of the magnetic field in vertical or horizontal directions, image distortion became larger with the increase in distance. 

Roel LF van der Palen^1,2, Julio Garcia², Alex J Barker², Michael J Rose³, Luciana Young⁴, Arno AW Roest¹, Michael Markl^2,5, Joshua D Robinson^4,6, and Cynthia K Rigsby^3
1Department of Pediatric Cardiology, Willem-Alexander Children and Youth Center, Leiden University Medical Center, Leiden, Netherlands, ²Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States, ³Department of Medical Imaging, Ann & Robert Lurie Children’s Hospital of Chicago, Chicago, IL, United States, ⁴Division of Pediatric Cardiology, Ann & Robert Lurie Children’s Hospital of Chicago, Chicago, IL, United States, ⁵Department of Biomedical Engineering, McCormick School of Engineering, Northwestern University, Chicago, IL, United States, ⁶Department of Pediatrics, Ann & Robert Lurie Children’s Hospital of Chicago, Chicago, IL, United States

Marfan syndrome (MFS) is a connective tissue disease with high risk of aortic dissection/rupture. Two-thirds of dissections originate in the ascending aorta (AAo), one-third in the descending aorta (DAo). Diameter plays an important role in risk stratification. However, aortic dimension alone may not capture the complex changes in aortic geometry that are often encountered in MFS patients, e.g. elongation and changes in overall shape of the aorta. Aortic 3D geometry was systematically investigated in a cohort of children and adolescents with MFS and was compared to an age appropriate control cohort: altered aortic geometry in pediatric MFS patients was detected.

Kristin Mcleod^1,2, Samuel Wall^1,2, Jørg Saberniak^2,3, and Kristina Haugaa^2,3
1Computational Cardiac Modelling Department, Simula Research Laboratory, Oslo, Norway, ²Centre for Cardiological Innovation, Oslo, Norway, ³Department of Cardiology, Oslo University Hospital, Rikshospitalet, Oslo, Norway

Better understanding of the impact that disease has on ventricular shape remodeling and improved tools for quantifying disease severity are needed in complex diseases such as ARVC. We propose a method to automatically characterise right ventricular shape features in ARVC patients using statistical methods applied to shapes extracted from CMR images in a population of 27 ARVC patients. In addition to characterizing the typical shape features in ARVC, the level of severity of any given shape feature (e.g. dilation) can be measured in a new patient to quantify the degree in which that specific feature is present in that patient.

Ivan Cokic¹, Avinash Kali¹, Hsin-Jung Yang¹, Richard Tang¹, Frank S Prato², David Underhill¹, and Rohan Dharmakumar^1
1Cedars-Sinai Medical Center, Los Angeles, CA, United States, ²Lawson Health Research Institute, London, ON, Canada

Hemorrhagic myocardial infarctions (MI) are associated with persistence of iron depositions in the chronic MI phase. These iron deposits have been shown to lead to perpetual recruitment of new monocytes/macrophages into the infarcted territory. Hemorrhagic MI is accompanied by a persistent microvascular obstruction (PMO) but the converse is not true. In this histologically validated cardiac MRI study we demonstrate that even in the absence of hemorrhage, PMO per se can lead to chronic iron-driven inflammatory response. Our findings are expected and lend improved insight into the mechanisms driving heart failure in infarction with PMO.

Sebastian Haberkorn¹, Christoph Jacoby¹, and Ulrich Flögel^1
1Molecular Cardiology, Heinrich Heine University, Düsseldorf, Germany

In the present study, we systematically compared myocardial tissue characterization by Gd-based techniques with intrinsic T1/T2 mapping and their correlation with local cardiac function after experimental myocardial infarction (MI). We found that pre-contrast T1 mapping with variable flip angle analysis carried out 1 day after MI predicts the functional outcome after 21 days at least as reliable as LGE. Compared to the latter technique providing plain signal enhancement, the current approach determines quantitative maps with a large dynamic range, which may pave the way for reliable myocardial tissue characterization without any CA.

Laurence H Jackson¹, Evangelia Vlachodimitropoulou Koumoutsea², Panicos Shangaris³, Thomas M Ryan⁴, Anna L David³, John Porter², Daniel J Stuckey¹, and Mark F Lythgoe^1
1Centre for Advanced Biomedical Imaging, University College London, London, United Kingdom, ²Dept. Haematology, University College London, London, United Kingdom, ³Institute for Women’s Health, University College London, London, United Kingdom, ⁴Dept. Biochemistry and Molecular Genetics, University of Alabama, Birmingham, AL, United States

β-thalassemia major is a common blood disorder causing the production of abnormal red blood cells (RBCs) leading to severe anaemia. Current treatment of the disease consists of regular blood transfusions with the side effect of iron overload. Due to difficulties in producing a representative animal model of the disease, research into experimental therapy has been limited. A recently developed humanised mouse model of thalassemia has the potential to provide a platform for the development of new treatments. Here we determine whether magnetic resonance imaging (MRI) can be used to assess and quantify biomarkers of disease in-vivo.

Scott William Thalman¹, Zhengshi Yang², Ashley Pumphrey², and Moriel Vandsburger^1,2,3
1Department of Biomedical Engineering, University of Kentucky, Lexington, KY, United States, ²Saha Cardiovascular Research Center, University of Kentucky, Lexington, KY, United States, ³Department of Physiology, University of Kentucky, Lexington, KY, United States

Remodeling of the myocardium via hypertrophy and fibrosis increases the risk of adverse cardiac events. Quantitative magnetization transfer weighted imaging has shown promise as a method to identify fibrosis, however the effects of hypertrophy on such measures remains unknown. Using a murine model of chronic Angiotensin-II stimulation characterized by robust hypertrophy with little fibrosis, we demonstrate that despite large increases in myocardial mean cross-sectional area (AngII= 4825μm²±717 vs Saline= 2372μm²±158), no change occurs in the cardioCEST derived measure of magnetization transfer ratio (MTR) (AngII= 30.8%±7.3 vs Saline= 27.2%±8.6). Thus, increases in MTR due to fibrosis are unbiased by concomitant hypertrophy.

Michael S Dodd¹, Vicky Ball¹, and Damian J Tyler^1
1Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom

Doxorubicin can lead to pre-clinical and clinical heart failure and reduced myocardial energetics. Alterations in metabolism potentially play a role in chemotherapy induced heart failure. The aim of this work was to assess the in vivo metabolic phenotype of doxorubicin treated hearts using hyperpolarized MRS. Doxorubicin cardiotoxicity was induced in Wistar rats and 4 weeks later, CINE-MRI and hyperpolarized [1-¹³C]pyruvate MRS was performed.  Doxorubicin resulted in significant wall thinning, and reductions in both cardiac function and volume, all indicative of cardiotoxicity. Interestingly, doxorubicin resulted in significant metabolic alterations; with reductions in both PDH flux and ¹³C label incorporation into alanine.

Christos G. Xanthis^1,2, Panagiotis G. Papadimitroulas³, George C. Kagadis³, and Anthony H. Aletras^1,4
1Lund Cardiac MR Group, Department of Clinical Physiology, Lund University, Lund, Sweden, ²Department of Computer Science and Biomedical Informatics, University of Thessaly, Lamia, Greece, ³Department of Medical Physics, School of Medicine, University of Patras, Patras, Greece, ⁴Laboratory of Medical Informatics, School of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece

In the past, MR simulations were usually confined to incorporation of simplified anatomical models of limited realism and/or simulations of basic MR physics concepts only. The purpose of this study was the incorporation of the XCAT anatomical phantom in MRISIMUL, a high performance multi-GPU simulation platform. Two different CMR applications were studied: the first for heart morphology evaluation and the second for T1 mapping of the heart. Results showed that the incorporation of realistic human anatomical models in a high performance MR simulation platform may benefit the design and optimization of MR protocols and pulse sequences in the future.

Arvin Arani¹, Kevin J. Glaser¹, Shivaram Poigai Arunachalam¹, Phillip J. Rossman¹, David S. Lake¹, Joshua D. Trzasko¹, Armando Manduca¹, Kiaran P. McGee¹, Richard L. Ehman¹, and Philip A. Araoz^1
1Mayo Clinic, Rochester, MN, United States

Noninvasive stiffness imaging techniques (elastography) can image myocardial tissue biomechanics in vivo.  However, for cardiac magnetic resonance elastography (MRE) techniques the optimal vibration frequency for in vivo experiments is unknown. The purpose of this study was to determine the optimal vibration frequency for cardiac MRE in healthy volunteers. Cardiac MRE displacement fields can be imaged with mean OSS-SNR > 1.6 at frequencies as high as 180Hz, however, mean OSS-SNR values and myocardial coverage was shown to be highest at 140Hz across all subjects. This study motivates future evaluation of high-frequency 3D MRE in patient populations.

Shivaram Poigai Arunachalam¹, Arvin Arani¹, Francis Baffour¹, Joseph Rysavy², Phillip Rossman¹, David Lake³, Kevin Glaser¹, Joshua Trzasko¹, Armando Manduca³, Kiaran McGee¹, Richard Ehman¹, and Philip Araoz^1
1Radiology, Mayo Clinic, Rochester, MN, United States, ²Surgery, Mayo Clinic, Rochester, MN, United States, ³Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, United States

Myocardial stiffness is a novel biomarker with both diagnostic and prognostic potential for a range of cardiac diseases such as myocardial infarction which is known to significantly increase stiffness. Magnetic Resonance Elastography (MRE) is a non-invasive imaging technique that can be applied to the heart for in-vivo myocardial tissue characterization.  The purpose of this pilot study was to assess the feasibility of measuring in-vivo stiffness changes in infarcted tissue and compare with remote (i.e. non-infarcted) myocardium in the same pig using 3D MRE.  Results indicate a 3-fold increase in stiffness of the infarct compared to the normal myocardium. 

Eugene G. Kholmovski^1,2, Ravi Ranjan², Sathya Vijayakumar^1,2, Nathan A. Angel², and Nassir F. Marrouche^2
1UCAIR, Department of Radiology, University of Utah, Salt Lake City, UT, United States, ²CARMA Center, University of Utah, Salt Lake City, UT, United States

Catheter RF ablation is a widely accepted procedure for treatment of cardiac arrhythmias. Recently, native (non-contrast) T1-weighted (T1w) MRI was proposed to characterize RF lesions immediately post-ablation. The main aim of this work was to study how the visibility and volume of RF lesions in native T1w MRI changes with time after ablation. We have found that reduction of T1 relaxation time of RF ablated myocardium is transient. The visibility of RF ablation lesions and volume of the corresponding enhanced regions in native T1w MRI drastically reduce few days after ablation.

Teresa Serradas Duarte¹, Till Huelnhagen¹, and Thoralf Niendorf^1,2
1Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany, ²Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max Delbrück Center in the Helmholtz Associaiton, Berlin, Germany

Magnetic susceptibility-based methods are an emerging technique in CMR for myocardial tissue characterization. Making use of UHF MRI, temporally resolved myocardial T₂^* mapping was recently demonstrated. Since susceptibility weighted MRI is highly dependent on main magnetic field homogeneity, B₀ assessment is crucial for interpretation of results. This pioneering study investigates B₀ variation in the heart over the cardiac cycle at 7.0T and its implications for myocardial T₂^* mapping in a cohort of healthy volunteers. Results show that septal macroscopic field inhomogeneities are minor regarding their effects on T₂^*. This provides encouragement for temporally resolved susceptibility-based CMR at UHF.

Li Zhang^1,2, Mihaela Pop^1,2, and Graham A Wright^1,2
1Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada, ²Sunnybrook Health Sciences Centre, Toronto, ON, Canada

Accurate characterization of infarct heterogeneity depends on high spatial resolution imaging¹. This study was performed to evaluate the use of an accelerated multi-contrast late enhancement acquisition (MCLE)²with COmpressed Sensing with Edge Preservation (COSEP) for isotropic spatial resolution imaging to improve characterization of infarct heterogeneity in the clinical setting. We have shown that an isotropic resolution of 2.2mm could be achieved using an accelerated three-dimensional (3D) MCLE acquisition within a single breath-hold in a patient study and the COSEP reconstruction provides improved characterization of infarct heterogeneity compared to an alternative compressed sensing method.

Antonella Meloni¹, Nicola Giunta², Pietro Giuliano², Maria Giovanna Neri¹, Stefania Renne³, Antonino Vallone⁴, Massimiliano Missere⁵, Emanuele Grassedonio⁶, Vincenzo Positano¹, Daniele De Marchi¹, and Alessia Pepe^1
1Fondazione G. Monasterio CNR-Regione Toscana, Pisa, Italy, ²"ARNAS" Civico, Palermo, Italy, ³P.O. “Giovanni Paolo II”, Lamezia Terme (CZ), Italy, ⁴Az. Osp. "Garibaldi" Presidio Ospedaliero Nesima, Catania, Italy, ⁵P.O. “Giovanni Paolo II”, Campobasso, Italy, ⁶Policlinico "Paolo Giaccone", Palermo, Italy

We prospectively assessed the predictive value of MRI for cardiac complications in talassemia intermedia (TI). All our patients underwent MRI examination assessing multi-parametric findings (heart and liver iron, myocardial fibrosis, atrial areas, and biventricular function).

Righ ventricular (RV) hypertrophy identified patients at high risk for arrhythmias and pulmonary hypertension. Both RV hypertrophy and fibrosis detected by LGE were independent predictive factor for cardiac complications.  So, a widespread program using MRI exploiting its multi-parametric potential, including the measurement of RV mass,  can have considerable power for opening the prognosis of TI patients by the early identification and treatment of patients at risk for cardiac complications.

Nilesh R. Ghugre^1,2,3, Venkat Ramanan¹, Jing Yang¹, Idan Roifman³, Mohammad I Zia³, Bradley H Strauss³, Kim A Connelly⁴, and Graham A Wright^1,2,3
1Physical Sciences Platform, Sunnybrook Research Institute, Toronto, ON, Canada, ²Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada, ³Schulich Heart Research Program, Sunnybrook Health Sciences Centre, Toronto, ON, Canada, ⁴Cardiology, St. Michaels Hospital, Toronto, ON, Canada

T1 and T2 relaxation parameters have been instrumental in quantifying both edema and hemorrhage in acute myocardial infarction (AMI). Unlike T2, the combined effect of edema and hemorrhage on T1 has not been well described.  Our study assessed and compared the impact of microvascular obstruction (MVO) and hemorrhage on the sensitivity of T1 and T2 in the quantification of edema. Our study indicated that the capacity of T1 to detect edema is affected by the counteracting influence from hemorrhage. Furthermore, T2 may be more sensitive to edema than T1 in AMI, particularly in the presence of MVO and hemorrhage.

Philip M Robson¹, Marc R Dweck¹, Nicolas A Karakatsanis¹, Maria Giovanna Trivieri², Ronan Abgral¹, Johanna Contreras², Umesh Gidwani², Jagat P Narula², Valentin Fuster², Jason C Kovacic², and Zahi A Fayad^1
1Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States, ²Department of Cardiology, Icahn School of Medicine at Mount Sinai, New York, NY, United States

Cardiac and coronary imaging using hybrid PET/MR is gaining increasing interest.  PET image reconstruction requires knowledge of the PET-photon attenuation of the object in order to produce accurate images of PET tracer activity.  The standard approach for MR-based attenuation correction is breath-hold volumetric imaging to freeze motion of the chest and abdomen.  However, for imaging the heart, alignment of anatomy during PET data collection and attenuation measurement is crucial.  In this work, we propose mapping attenuation using a free-breathing golden-angle radial gradient echo sequence and compare the PET images produced with this novel approach and the standard breath-hold approach.

Bram F Coolen¹, Abdallah G Motaal¹, Wouter V Potters¹, Maarten J Versluis², Gustav J Strijkers³, and Aart J Nederveen^1
1Department of Radiology, Academic Medical Center, Amsterdam, Netherlands, ²Philips Healthcare, Benelux, Netherlands, ³Department of Biomedical Engineering and Physics, Academic Medical Center, Amsterdam, Netherlands

We present a prospectively accelerated 3D black-blood sequence in conjunction with CS reconstruction and show the feasibility of 3D high-resolution carotid vessel wall imaging. Results show that acceleration in combination with CS reconstruction increased SNR efficiency and resulted in improved vessel wall visibility as compared to the full data acquisition. More importantly, high-resolution imaging carotid imaging (0.4-0.5 mm) was shown feasible within a clinically feasible imaging time of 4 min.  

Niranjan Balu¹, Jie Sun¹, Daniel S Hippe¹, Huijun Chen², and Chun Yuan^1
1Radiology, University of Washington, Seattle, WA, United States, ²Tsinghua University, Beijing, China, People's Republic of

We have developed a single sequence (SNAP) for identification of high-risk features such as stenosis, intraplaque hemorrhage and juxtaluminal calcification. However measurement of plaque burden, an early marker for disease, required a separate black-blood scan. In this work, we demonstrate that plaque burden can be measured using an alternate reconstruction (SNAP2). In patients with atherosclerosis, we compare vessel wall area measurements on SNAP2 to established black-blood MRI measurements and show that our method provides results comparable to established plaque MRI methods.

Haikun Qi¹, Shuo Chen¹, Xinlei Pan¹, and Huijun Chen^1
1Center for Biomedical Imaging Research, School of Medicine, Tsinghua University, Beijing, China, People's Republic of

Multi-contrast imaging is needed for comprehensive characterization of atherosclerosis, which often involves a series of separate scans. But the mis-registration between scans due to motion and the long scan time limits its application. So acquisition of multi-contrast images in one scan is preferable. In this study, we developed an inversion recovery prepared 3D golden angle radial sampling sequence enabling flexible posteriori selection of TI time and frame duration for arbitrary-contrast reconstruction. The proposed method may be a one-stop solution for 3D large coverage plaque imaging by providing inherently co-registered multi-contrast images in a single scan within short scan time.

Jianmin Yuan¹, Andrew J Patterson², Ammara Usman¹, Gregory C Makris¹, Zhongzhao Teng¹, Jonathan H Gillard¹, and Martin J Graves^1,2
1Department of Radiology, University of Cambridge, Cambridge, United Kingdom, ²Department of Radiology, Cambridge University Hospitals NHS Foundation Trust, Cambridge, United Kingdom

Carotid neovascularization and lumen surface morphology both play important roles in the progression of atherosclerotic plaque. This study uses a high-spatial and temporal resolution dynamic 3D contrast-enhanced (CE) imaging technique to simultaneously acquire and explore the relationship between the two factors. Results demonstrate that carotid luminal stenosis and appearance of ulceration are correlated with the plaque neovascularization. The study shows the ability to perform high-resolution carotid plaque morphology and functional assessment within a reasonable scanning time.

Hanne Hakkarainen¹, Jaana Rysä², Anna-Kaisa Ruotsalainen¹, Anna-Liisa Levonen¹, and Timo Liimatainen^1,3
1A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland, ²School of Pharmacy, University of Eastern Finland, Kuopio, Finland, ³Imaging Center, Kuopio University Hospital, Kuopio, Finland

High resolution cine-MRI was applied for examining aortic valve function and atherosclerotic plaque accumulation in the valves in mice on a high fat diet. The end systolic images of the aortic valves of these mice showed clear signs of atherosclerotic fat accumulation and dysfunction of the valves. This implies that the cine-MRI method provides a noninvasive tool for monitoring atherosclerotic plaques in the mouse aortic valves.  

Rik PM Moonen¹, Stefan Vöö², Jan Bucerius², Joachim Wildberger¹, and Eline Kooi^1
1Department of Radiology, Maastricht University Medical Center +, Maastricht, Netherlands, ²Department of Nuclear Medicine, Maastricht University Medical Center +, Maastricht, Netherlands

Noninvasive imaging can improve risk stratification in carotid atherosclerosis. Multi-sequence MRI allows visualization of plaque burden and components, while PET can be used to study inflammation. Combining the two modalities with hybrid PET/MRI in a one-stop shop approach may improve assessment of vulnerable plaque.

The goal of this work was to optimize a 3D multi-sequence carotic PET/MRI protocol including 3D MPRAGE, 3D SPACE pre- and post-contrast, and UTE, using simulations and optimization in healthy volunteers.

Feasibility of the protocol was demonstrated in a patient suffering from carotid atherosclerosis (>70% stenosis).

Chaoyue Wang¹, Saifeng Liu², Sagar Buch², Hyun Seok Choi³, Eo-Jin Hwang³, Zhaoyang Fan⁴, and E. Mark Haacke^1,2,5,6
1School of Biomedical Engineering, McMaster University, Hamilton, ON, Canada, ²The MRI Institute for Biomedical Research, Waterloo, ON, Canada, ³Department of Radiology, St. Mary’s Hospital, Seoul, Korea, Republic of, ⁴Department of Radiology, Cedars Sinai Hospital, Los Angeles, CA, United States, ⁵Department of Radiology, Wayne State University, Detroit, MI, United States, ⁶Biomedical Engineering, Northeastern University, Shenyang, China, People's Republic of

Due to complex structures in neck, such as the presence of bone and air, existing methods for neck quantitative susceptibility mapping (QSM) have several limitations. The purpose of this study was to find a reliable method for data collection in order to use QSM to detect carotid plaque and recognize vulnerable features. Therefor, we proposed a multi-echo SWI approach for data collection and regional 2D polynomial fitting method for data processing. Preliminary results show this method is able to image the vessel wall clearly and recognize calcified atherosclerosis and thrombosis by their susceptibility value. 

Hanjing Kong¹, Bo Li¹, Huarui Du¹, Jue Zhang¹, and Li Dong^2
1Peking university, Beijing, China, People's Republic of, ²Anzhen Hospital, Beijing, China, People's Republic of

Multi-contrast weighted imaging methods with a single scan provide efficient means for viewing and characterizing the atherosclerotic plaques. We extend previous studies by establishing a new strategy (CS-BLGDuC) and further reducing scan time with compressed sensing . 16 subjects including 6 healthy volunteers and 10 patients with carotid stenosis were carried out.The scan time of CS-BLGDuC were dramatically reduced compared with conventional 3D TOF and QIR. Superficial vascular calcification was clearly showed in gray blood images. It is feasible for the CS-BLGDuC strategy to depict superficial vascular calcifications and improve scan efficiency without decreasing image quality.

Andrew Nicholas Priest¹, Ian G Murphy¹, and David John Lomas^1
1Radiology, Addenbrookes Hospital and Cambridge University, Cambridge, United Kingdom

This work develops an NCE-MRA technique based on the flow-sensitised dephasing (FSD) method but using a fast-spin echo (FSE) readout to avoid off-resonance artifacts and allow a larger field of view. The flow-preparation module may be velocity-sensitised, acceleration-sensitised or mixed velocity-and-acceleration-sensitised. The FSE readout allows these approaches to be combined with additional flow sensitisation by ‘adaptive refocus’ which reduces the refocusing flip angle in systole. These approaches performed well in healthy volunteers, in particular the velocity-sensitisation  and mixed-sensitisation approaches. Adding adaptive refocus increased venous contamination and thus reduced the arterial image quality. Future work will evaluate these methods in patients.

Dongchan Kim¹, Hyunseok Seo¹, Jaejin Cho¹, Kinam Kwon¹, and HyunWook Park^1
1KAIST, Daejeon, Korea, Republic of

Recently quiescent-interval single-shot (QISS) non-contrast MR angiography (NC-MRA) technique was developed to obtain high-contrast peripheral angiographic images in a reasonable imaging time. QISS enhances contrast between the artery and unwanted signal by saturating signals from background, fat and vein. Thus, QISS needs multiple RF pulses for background saturation, which is limited in perfect saturation due to the inhomogeneity of main magnetic field. In this work, we propose a new MRA technique, which could generate peripheral angiogram without saturation pulses and an external ECG trigger using the velocity-sensitive gradient-echo (GRE) sequence.

Arni Nutting¹, Amos Varga-Szemes², Shahryar Chowdhury¹, Davide Piccini³, and Anthony Hlavacek^1
1Pediatrics, Medical University of South Carolina, Charleston, SC, United States, ²Radiology, Medical University of South Carolina, Charleston, SC, United States, ³Lausanne, Switzerland

We performed a retrospective review of studies obtained using a prototype, self navigated, free breathing 3D SSFP sequence. Scans were reviewed for diagnostic sensitivity of coronary artery origin, diagnostic quality, and were graded for the severity of respiratory or cardiac motion or blood pool inhomogeneity. A diagnostic scan was obtained in 80.7% of cases. Blood pool inhomogeneity was common but very rarely affected diagnosis. The greatest factor affecting diagnostic ability was cardiac motion. We concluded that self-navigated 3D sequences can provide excellent sensitivity in diagnosing coronary origins with significant time savings compared to diaphragm navigated sequences.

Thomas Lindner¹, Naomi Larsen¹, Olav Jansen¹, and Michael Helle^2
1Clinic for Radiology and Neuroradiology, University Hospital Schleswig-Holstein, Kiel, Germany, ²Philips GmbH Innovative Technologies, Research Laboratories, Hamburg, Germany

In the presented study, selective Arterial Spin Labeling and Phase encoded information are obtained in a single acquisition, thereby allowing for artery-selective velocity and flow imaging. From the data, several image contrasts can be derived. First, anatomical images are available. From these, static artery-selective angiograms are obtained, which are processed as binary image masks and applied to the phase encoded images. Thereby, vessel-selective Phase encoded angiograms are created. Furthermore, it is possible to calculate venous-only images by subtraction of the arterial information derived from the ASL measurements from the phase-encoded images.

Simon Reiss¹, Axel Joachim Krafft^1,2,3, Marius Menza¹, Lisa Caroline Besch⁴, Timo Heidt⁴, Christoph Bode⁴, Constantin von zur Mühlen⁴, and Michael Bock^1
1Dept. of Radiology - Medical Physics, University Medical Center Freiburg, Freiburg, Germany, ²German Cancer Consortium (DKTK), University Medical Center Freiburg, Heidelberg, Germany, ³German Cancer Research Center (DKFZ), Heidelberg, Germany, ⁴Department of Cardiology and Angiology I, University Heart Center, Freiburg, Germany

The implantation of bioresorbable Vascular Scaffolds (BVS) is a rapidly evolving technique in the treatment of coronary artery disease. BVS consist of a polylactate-based backbone which is completely dissolved after 2-3 years. Due to the organic material, coronary MRI can be used as a non-invasive technique for post-interventional imaging of arteries treated with BVS, which is not possible for metal stents. In this study, we evaluated the use of 3T MRI in assessing luminal patency after implantation of the BVS, as well as flow measurements for myocardial blood flow quantification as a possible indicator of post-interventional angina.

HoeSu Jung¹, SeokHa Jin¹, DongKyu Lee¹, SoHyun Han¹, and HyungJoon Cho^1
1Ulsan National Institute of Science and Technology, Ulsan, Korea, Republic of

  Transverse-relaxation-based ΔR₂- and ΔR₂^*- micro MRAs are being investigated for imaging cerebral vasculature in rodent brains with increased sensitivity for intracortical arterioles and venules, in conjunction with exogenous blood pool contrast agents. In this study, we simulated extravascular signal decay behaviors of ΔR₂, and ΔR₂^* values for multiple cylindrical models with varying diameters to quantitatively assess both sensitivity and size overestimation issues in micro MRA. The benefits of following synergistic combination of ΔR₂, and ΔR₂^* angiograms along with the UTE-derived positive angiogram were investigated, and corresponding UTE-ΔR₂-ΔR₂^* combined angiogram was applied to normal and C6 glioma tumor model for the verifications.

Toshimasa James Clark¹, Gregory J Wilson², and Jeffrey H Maki^2
1Department of Radiology, University of Colorado Denver, Aurora, CO, United States, ²Department of Radiology, University of Washington, Seattle, WA, United States

CE-MRA spatial resolution is determined by a complex interaction between acquired voxel size, gadolinium injection rate, contrast volume, cardiac output, magnetic field strength, and acquisition duration. R1 relaxivity non-linearity and R2* signal degradation inherent in SPGR acquisitions play important roles in observed signal intensity during bolus passage. Through generation of modulation transfer functions spanning the gamut of parameter values likely to be seen in clinical practice we derive injection rates that produce optimal image contrast and resolution in our model.

Tilman Schubert^1,2, Utaroh Motosugi³, Samir Sharma⁴, Sonja Kinner¹, Shane Wells¹, Diego Hernando¹, and Scott Reeder^1
1Radiology, University of Wisconsin Madison, Madison, WI, United States, ²Clinic for Radiology and Nuclear Medicine, Basel University Hospital, Basel, Switzerland, ³Department of Radiology, University of Yamanashi, Yamanashi, Japan, ⁴Medical Physics, University of Wisconsin Madison, Madison, WI, United States

Ferumoxytol has gained interest as a positive MR-contrast agent in patients with renal failure. However, limited data exist regarding the optimal/minimal dose for MRA applications and optimal scanning parameters. Therefore, this study evaluated image quality with different doses of ferumoxytol with gadolinium as reference. Furthermore, flip angle optimization was performed in the steady state. Relative SNR was found to be significantly higher for gadolinium- compared to ferumoxytol-enhanced MRA during first pass. However, this did not lead to qualitative penalty for ferumoxytol-enhanced MRA. Flip angle-optimization indicated that adapting the flip angle to dose may help to achieve optimal results. 

Salvatore Saporito¹, Ingeborg H.F. Herold ^1,2, Silviu Dovancescu³, Jacques A. den Boer¹, Ronald M. Aarts^1,3, Arthur R. Bouwman², Harrie C.M. van den Bosch⁴, Hendrikus H.M. Korsten ^1,2, Hans C. van Assen¹, and Massimo Mischi^1
1Department of Electrical Engineering, Eindhoven University of technology, Eindhoven, Netherlands, ²Department of Anesthesiology and Intensive Care, Catharina Hospital Eindhoven, Eindhoven, Netherlands, ³Philips Research, Eindhoven, Netherlands, ⁴Department of Radiology, Catharina Hospital Eindhoven, Eindhoven, Netherlands

The assessment of thoracic fluid status is crucial for diagnosis, management, stratification, and follow-up of heart failure patients. Indicator dilution theoretical framework allows absolute volume estimation; magnetic resonance contrast agents have been proposed as indicators, with the advantage of a non-invasive detection. In this pilot study, we investigated the changes in intra-thoracic blood volume (ITBV) measured by cardiac magnetic resonance during fluid shifts induced by a pneumatic leg compression device. Preliminary results on 8 healthy volunteers suggest the sensitivity of the proposed measurement technique; a significant increase in ITBV after the leg compression was observed.

Mahmud Mossa-Basha¹, Matthew Alexander², Jeffrey H. Maki¹, Wendy Cohen¹, Daniel S Hippe¹, Chun Yuan¹, Hannu Huhdanpa¹, and Tobias Saam^3
1Radiology, University of Washington, Seattle, WA, United States, ²Radiology, University of California San Francisco, San Francisco, CA, United States, ³Radiology, Ludwig-Maximilians-Universität München, Munich, Germany

Prompt diagnosis of large artery vasculopathies is important to avoid significant morbidities that can arise from delayed diagnosis.  This is difficult however, as patients frequently present with nonspecific sign and symptoms and luminal imaging techniques are limited in the detection of non-stenotic disease.  Vessel wall imaging is an emerging technique for vasculopathy evaluation throughout the body.  We compare quantitative and qualitative measures of 2D and 3D vessel wall imaging techniques in patients with suspected large artery vasculopathy.

Lara Mrak¹, Christopher J. François¹, Sonja Kinner^1,2, and Mark L. Schiebler^1
1Radiology, UW-Madison, Madison, WI, United States, ²University Hospital Essen, Essen, Germany

The size of the ascending aorta is of critical importance for patient survival as it is directly related to the likelihood of aortic dissection and risk of death.  The traditional imaging method that has been used for this measurement has been computed tomography of the chest. With many more children and young adults now being imaged with contrast enhanced magnetic resonance angiography examinations (CE-MRA) , it is useful to know what the range of variability is for the normal aorta on these exams. We present here age and sex specific values for nomograms of the ascending aorta  derived from non-gated CE-MRA examinations that are indexed to body surface area.

Zhefeng Yu¹, Jianzhong Sun¹, Yong Zhang², and Minming Zhang^1
1Radiology, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China, People's Republic of, ²MR Research China, GE Healthcare, Beijing, China, People's Republic of

This preliminary study found 25 carotid plaques in eighteen patients with 40-99% stenosis degree. Both readers gave their scores of enhanced QIR T1 weighted images (p>0.05). SNRs were evaluated as 109±21 and 113±18 (p>0.05) before and after the contrast enhancement. And CNRs were 98±19 and 82±22 (p>0.05) for the same comparison. Gd-enhanced QIR for carotid plaque imaging can achieve high quality due to good inhibition of blood flow.

Yutaka Natsuaki¹, Robert Grimm², Xiaoming Bi¹, David Grodzki², Peter Schmitt², and Gerhard Laub^1
1Siemens Healthcare, Los Angeles, CA, United States, ²Siemens Healthcare, Erlangen, Germany

Previously, Ultra-Short TE sequences and their subtraction-based non-contrast MR angiography (e.g. PETRA qMRA) have shown promising results in intracranial applications, in particular with tortuous carotid arteries that has been problematic for the current clinical gold standard 3D Time Of Flight (TOF).  As with any subtraction based MRA techniques, PETRA qMRA is also sensitive to motion occurred in subsequent acquisitions.  The current work demonstrates that the proposed 3D elastic cross-registration can solve this limitation for the PETRA qMRA, and it takes to the next level in motion robustness and in the highest attainable isotropic resolution.  

Hiroshi Kawada¹, Satoshi Goshima¹, Kota Sakurai², Yoshifumi Noda¹, Kimihiro Kajita³, Nobuyuki Kawai¹, Hiromi Ohno¹, and Masayuki Matsuo^1
1Radiology, Gifu university hospital, Gifu, Japan, ²Radiology, China Kosei Hospital, Seki, Japan, ³Radiology Service, Gifu university hospital, Gifu, Japan

We found that standard measurements showed strong correlation between CTA and MRA (r = 0.92- 0.99) and perfect agreement between two observers (ICC = 0.97 - 0.99). We also demonstrated four MRA features which are feasible for the detection of endoleaks. The “mottled high intensity” and “creeping high intensity with low band rim” were significant positive findings (P < 0.001), and “no signal black spot” and “layered high intensity area” were also significant negative findings (P < 0.031). The observation of these findings showed feasible diagnostic performance for detecting endoleaks which also showed reliable reproducibility among blinded observers.

Gang Wu¹, Tianjing Zhang², Peter Schmitt³, and Xiaoming Li^4
1Tongji Hospital, Huazhong university of science and technology, Wuhan, China, People's Republic of, ²Shanghai, China, People's Republic of, ³Erlangen, Germany, ⁴Wuhan, China, People's Republic of

The Diagnostic Value of QISS MRA in Lower-Extremity Arteriosclerosis: A Comparison with CT Angiography

one abstract

four figures

Shuiqing Yang¹, Lee Jiang², Yingjie Mei³, Queenie Chan⁴, Allan Jin², Feng Huang², and Guihua Jiang^1
1Medical Image Center, Guangdong NO.2 Provincial People's Hospital, Guangzhou, China, People's Republic of, ²Philips Healthcare (Suzhou), Suzhou, China, People's Republic of, ³Philips Healthcare, Guangzhou, China, People's Republic of, ⁴Philips Healthcare, HongKong, China, People's Republic of

Arterial stenosis of the lower extremities is the most common cause of amputation in diabetic patients. Contrast-enhanced MR angiographyis images suffer from venous contamination and is reported potential renal toxicity. Our NCE-MRA showed a high percentage of stenosis segments and provides higher image quality than the CE-MRA. The NCE-MRA technique is capable of clear depiction and accurate detection of the whole lower extremity arterial tree in patients with diabetes.

Yuki Ohmoto-Sekine¹, Junji Takahashi², Takashi Yoshida², Makiko Ishihara³, Hiroshi Tsuji¹, Yasuji Arase¹, and Mitsue Miyazaki^4
1Health Management Center, Toranomon Hospital, Tokyo, Japan, ²Toranomon Hospital, Tokyo, Japan, ³Imaging Cenetr, Toranomon Hospital, Tokyo, Japan, ⁴Toshiba Medical Resarch Institute, Chicago, IL, United States

Noncontrast renal 3D MRA using time-spatial labeling inversion pulse (Time-SLIP) with respiratory triggering (Time-SLIP renal MRA) is proven to be valuable for non-invasive assessment of renal arteries. However, to our knowledge, there are no studies demonstrating the reproducibility of Time-SLIP renal MRA. Thus, we examined the reproducibility of Time-SLIP renal MRA and the result showed acceptable inter-scan agreement between the original and repeated scans.

Yuki Furukawa¹, Takashige Yoshida¹, Kouhei Yuda¹, Takumi Koyano¹, Masami Yoneyama², Nobuo Kawauchi¹, Tetsurou Shirai³, and Atushi Senoo^4
1Radiology, Tokyo Metropolitan Police Hospital, Nakano-ku, Japan, ²Phlips Electronics Japan, Minato-ku, Japan, ³Cardiovascular Medicine, Tokyo Metropolitan Police Hospital, Nakano-ku, Japan, ⁴Division of Radiological Sciences, Tokyo Metropolitan University, Arakawa-ku, Japan

We applied a 3D isotropic radial (koosh ball) trajectory WHC-MRA as zoom imaging.  Navigation was not conducted; however, imaging was completed using high resolution. Zoom-KB WHC-MRA demonstrated good delineation of both the myocardial wall and coronary arteries. This was obtained without using a phrenic motion correction algorithm. When Zoom-KB WHC-MRA was compared with the reference standard, there was no significant difference (P > 0.05). The Zoom-KB enabled high isotropic spatial resolution with a short scan time. Motion artifact was controlled by equalizing noise. This was a simple, very efficient robust sequence.

Lirong Yan¹, Songlin Yu¹, Samantha Ma¹, Yeang Chng², Salamon Noriko², Nader Pouratian², and Danny JJ Wang^1
1Neurology, University of California Los Angeles, Los Angeles, CA, United States, ²Radiology, University of California Los Angeles, Los Angeles, CA, United States

A non-contrast 4-D MRA using stack-of-star golden angle acquisition (Radial-TrueSTAR) has been recently introduced, which can accelerate the imaging speed up to 3 fold, compared to conventional Cartesian acquisition. Here we evaluated the clinical utility of Cartesian- and Radial-TrueSTAR in cerebral arteriovenous malformation patients by comparison with time-of-flight and DSA. Our preliminary data demonstrates that Radial-TrueSTAR provides shorter scan time while preserving similar image qualities compared to Cartesian-TrueSTAR. Compared to TOF, the heterogeneity within the nidus can be observed using both Cartesian- and Radial-TrueSTAR. Radial-TrueSTAR may become a promising approach with reduced scan time and patient comfort in clinical applications.

Robert R. Edelman^1,2, Marcos Paulo Botelho¹, Amit Pursnani¹, Shivraman Giri³, and Ioannis Koktzoglou^1,4
1Radiology, NorthShore University HealthSystem, Evanston, IL, United States, ²Radiology, Feinberg School of Medicine, Northwestern Univesity, Chicago, IL, United States, ³Siemens Healthcare, Chicago, IL, United States, ⁴Radiology, University of Chicago Pritzker School of Medicine, Chicago, IL, United States

Radial quiescent-interval slice-selective (QISS) is flow-dependent due to the application of an in-plane FOCI inversion pulse, whereas radial 2D T2-prepared bSSFP is essentially flow-independent.  Both techniques show promise as efficient breath-hold alternatives to standard-of-care free-breathing 3D techniques for coronary MR angiography.  Comparison of radial QISS with T2-prepared radial bSSFP was performed in healthy subjects and patients with coronary artery disease (CAD).  Although the appearance of the coronary arteries in healthy subjects was similar using flow-dependent QISS and flow-independent T2-prepared 2D bSSFP, aside from increased pericardial fluid signal and streak artifact with the latter technique, the appearance diverged in severe CAD. 

AKIYOSHI YAMAMOTO¹, KATSUMI NAKAMURA^1,2, HIROKI MATOBA¹, YUJI SHINTANI¹, DAIJI UCHIYAMA¹, SEIGO YOSHIDA¹, and MITSUE MIYAZAKI^3
1Radiolgy, Tobata Kyoritsu Hospital, Kitakyushu, Japan, ²Nexus Image Lab, Japan, Kitakyushu, Japan, ³Toshiba Medical Research Institute USA, Vernon Hills, IL, United States

A non-gated single 20-sec breath-hold non-contrast-enhanced 3D-MRA technique using bSSFP was developed and the feasibility of the proposed method for the visualization of renal artery was compared using respiratory gated non-contrast-enhanced time-SLIP 3D-MRA with several minutes of scan time. The single breath-hold bSSFP-MRA technique was optimized in flip angle and the number of segmentations to obtain excellent renal blood signal with maintaining about 20 sec breath-holding. The proposed bSSFP-MRA technique gave equal to time-SLIP MRA in the visualization of renal artery.

Xiangzhi Zhou¹ and Mitsue Miyazaki^1
1Toshiba Medical Research Institute USA, Vernon Hills, IL, United States

Fresh Blood Imaging (FBI) scan time can be greatly reduced using variable TR (vTR) technique for imaging the peripheral artery without contrast. To reduce the SAR in FSE acquisition so that the shortest TR can be enabled for the slice encodings at the kz edge, variable refocusing flip angle (vFA) is proposed in addition to vFA for FBI in this study. The optimized FBI sequence with vTR and vFA was applied on volunteers to achieve a 7-minutes 3 station run-off scan to cover from iliac to calf.

Michael Langham¹, Benoit Desjardins¹, Erin Englund¹, Emile R Mohler, III², Thomas Floyd³, Jamal J Derakshan¹, and Felix W Wehrli^1
1Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States, ²Department of Medicine, University of Pennsylvania, Philadelphia, PA, United States, ³Department of Anesthesiology, SUNY Stony Brook, Stony Brook, NY, United States

An alternative unenhanced structural and functional evaluation (SaFE-MRI) MRI is proposed and described for assessing peripheral artery disease (PAD). The SaFE-MRI protocol interleaves 3D double-echo steady-state (DESS) acquisition and velocity mapping at each station. In SaFE-MRI velocity maps in all major conduit arteries (from abdominal aorta to runoff arteries) serve as a “road map” for locating hemodynamically significant stenoses and gray- and black-blood images are used to grade stenoses and detect vascular calcium. Initial results in patients with PAD agree with the finding from CTA and CE-MRA examinations as well as pressure volume recordings. 

Yan Wang¹, Liang Ge², Hsin-Wei Shen³, Evan Kao³, Chengcheng Zhu¹, David Saloner⁴, and Jing Liu^1
1Radiology, UCSF, San Francisco, CA, United States, ²Surgery, UCSF, San Francisco, CA, United States, ³Radiology and Biomedical Imaging, UCSF, San Francisco, CA, United States, ⁴Radiology and Biomedical Imaging, UCSF/VA, San Francisco, CA, United States

3D aortic CINE imaging provides precise functional measurements compared to the 2D imaging techniques. We proposed a highly accelerated free-breathing self-gated 3D MRI method to image the aorta through the entire cardiac cycle. Automatic segmentation based on Level-Set Methods was developed to efficiently segment the aorta lumen with the acquired 3D aortic CINE data. The calculated aortic measurements have potentials for many applications such as aortic aneurysm evaluation and aortic stiffness measurement.

Lyu Li¹, Zechen Zhou¹, Bida Zhang², Bin Xie², Feng Huang³, Chun Yuan⁴, and Hua Guo^1
1Center for Biomedical Imaging Research, Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing, China, People's Republic of, ²Healthcare Department, Philips Research China, Shanghai, China, People's Republic of, ³Philips Healthcare (Suzhou) Co., Ltd., Suzhou, China, People's Republic of, ⁴Department of Radiology, University of Washington, Seattle, WA, United States

Occlusion of lenticulostriate arteries (LSAs) were reported to lead to lacunar infarction. Currently, the major technique to image LSAs is digital subtraction angiography (DSA) for its high resolution and good definition of small vessels. For MRI, qualified images of LSAs can only be acquired from 7T scanners in recent studies. In this abstract, we optimized a technique independent of in-flow effect called flow-sensitive black-blood (FSBB). With this optimized method, qualified images of LSAs can be achieved on a 3T scanner, which makes it more practical for imaging LSAs using MRI in clinical applications.

Sidy Fall¹, Gwenael Page², Jean-Marc Constans³, and Olivier Baledent^1,4
1BioFlowImage, University of Picardy Jules Verne, AMIENS, France, ²BioFlowImage, University of Picardy Jules Verne, Amiens, France, ³Radiology Department, University Hospital of Picardy, Amiens, France, ⁴Image Processing Department, University Hospital of Picardy, Amiens, France

The venous drainage system may be influenced by the blood outflow resistance. Precise quantitative measurements of intracranial venous resistance are few. Phase-contrast (PC) MR angiography was used to quantify vascular resistance (VR) of the global cerebral venous system and to explore the correlations between the estimated resistances and the venous outflows measured by cine phase contrast (PC) MRI. Twenty six healthy volunteers participated in this study. The sum of resistances of the transverse sinus, sigmoid sinus and jugular vein correlated with the blood flows measured at C2C3 level: left R² =0.39 and right R² = 0.40 .

Sören Johst¹, Karsten H Wrede^1,2, Harald H Quick^1,3, and Mark E Ladd^1,4
1Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany, ²Department of Neurosurgery, University Hospital Essen, Essen, Germany, ³High Field and Hybrid MR Imaging, University Hospital Essen, Essen, Germany, ⁴Medical Physics in Radiology, German Cancer Research Center (dkfz), Heidelberg, Germany

Imaging of intracranial plaques and thrombi is important, as they play a role e.g. in rupture risk of cerebral aneurysms. 7T provides the potential to increase spatial resolution due to increased SNR. A time-of-flight MR angiography (TOF MRA) sequence was extended to a hybrid of opposite-contrast MRA sequence providing two contrasts, bright and black blood. Inverting and subtracting both contrasts makes thrombi/plaques visible. Sufficient flow dephasing moments for black-blood contrast were determined for three resolutions, image post-processing was implemented, and contrast evaluated. This approach potentially enables patient studies with higher resolution than previously achievable while maintaining reasonable acquisition times.

Thomas Lindner¹, Naomi Larsen¹, Olav Jansen¹, and Michael Helle^2
1Clinic for Radiology and Neuroradiology, University Hospital Schleswig-Holstein, Kiel, Germany, ²Philips GmbH Innovative Technologies, Research Laboratories, Hamburg, Germany

In this study, different approaches for obtaining selective Arterial Spin Labeling (ASL) angiograms are presented. Conventionally, the label image of each artery has to be matched with a separate control image. In this study, the number of control acquisitions is reduced, thus, making it possible to reduce acquisition times considerably. In one approach, a shared control condition is used for three selectively labeled arteries to obtain the final images (“cycled super-selective ASL”). This means that only one control image is used for subsequent data processing with three images of different arteries. In the second approach, no control image is required at all and the angiography information can be obtained from the label images only (“self-control ASL”). Image quality appeared similar in all approaches. Compared to super-selective ASL, image acquisition times are reduced in the presented approaches.

Julio Garcia¹, Alex J. Barker¹, Susanne Schnell¹, Jeremy D. Collins¹, James C. Carr¹, and Michael Markl^1,2
1Radiology, Northwestern University, Chicago, IL, United States, ²Biomedical Engineering, Northwestern University, Evanston, IL, United States

The processing of time-resolved 3D phase-contrast MRI with three-directional velocity encoding (4D flow MRI) cases can be highly time consuming given the large multi-dimensional datasets (3D+time of the cardiac cycle+3-directional blood flow velocities). However, the fully automated processing of cases in large databases is still challenging. The purpose of this study was to introduce an automated workflow allowing the unattended retrospective processing of aortic 4D flow MRI data from a large database of subjects.

Cristian Montalba¹, Jesus Urbina^1,2, Julio Sotelo^1,3, Marcelo Andia^1,4, Cristian Tejos^1,3, Pablo Irrarazaval^1,3, Israel Valverde^5,6, and Sergio Uribe^1,4
1Biomedical Imaging Center, Pontificia Universidad Católica de Chile, Santiago, Chile, ²School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile, ³Electrical Engineering, Pontificia Universidad Católica de Chile, Santiago, Chile, ⁴Radiology Department, Pontificia Universidad Católica de Chile, Santiago, Chile, ⁵Institute of Biomedicine of Seville, Universidad De Sevilla, Seville, Spain, ⁶Cardiology Unit, Hospital Virgen del Rocio, Universidad de Sevilla, Seville, Spain

4D flow is a MRI technique characterized by long scanning times. Because of that, it is difficult to study the variability of flow parameters when subjected to changes of the MR parameters. The purpose of this work is to study the variability of different flow parameters due to changes of spatial and temporal resolutions in 4D flow acquisitions through controlled experiments using a realistic normal adult thoracic aortic phantom. We conclude that changing the spatial and temporal resolutions in the 4D flow imaging greatly affects different flow parameters with induced errors of up to 23.9%.

Rizwan Ahmad¹, Ning Jin², and Orlando P Simonetti^3
1Electrical and Computer Engineering, The Ohio State University, Columbus, OH, United States, ²Siemens Healthcare, Columbus, OH, United States, ³Radiology and Internal Medicine, The Ohio State University, Columbus, OH, United States

Virtually every phase-contrast MRI (PC-MRI) measurement is contaminated with background phase (BP) from eddy currents and concomitant gradient terms. A widely reported method to correct BP relies on a polynomial fitting of the static pixels within regions of static tissue. This method requires sufficient static tissue in close proximity to the region of interest—a requirement that cannot be met for imaging of the heart or great vessels. In this work, we propose a BP correction method that leverages information from multiple slices collected under identical conditions but with different table positions.

Jan Paul¹, Stefan Wundrak¹, Peter Bernhardt¹, Wolfgang Rottbauer¹, and Volker Rasche^1
1Internal Medicine II, University Hospital of Ulm, Ulm, Germany

Cartesian Tissue Phase Mapping (TPM) usually necessitates respiratory navigators or other means of motion selection/correction to avoid ghosting artifacts. In radial MRI, however, motion artifacts result in image blurring rather than ghosting, which might allow using all respiratory states for reconstruction. The aim of this study is to investigate the influence of respiratory motion on velocities obtained from radial Tissue Phase Mapping MRI. Only small biases towards reduced velocity peaks were found in ungated compared to motion-compensated reconstructions. Overall velocity agreement of ungated data was very high compared to gated reconstructions.

Satoshi Yatsushiro¹, Saeko Sunohara², Naokazu Hayashi³, Akihiro Hirayama³, Mitsunori Matsumae³, Afnizanfaizal Bin Abdullah⁴, and Kagayaki Kuroda^2
1Course of Science and Technology, School of Science and Technology, Tokai University, Hiratsuka, Kanagawa, Japan, ²Course of Electrical and Electronic Engineering, Graduate School of Engineering, Tokai University, Hiratsuka, Kanagawa, Japan, ³Department of Neurosurgery, Tokai University School of Medicine, Isehara, Kanagawa, Japan, ⁴Department of Software Engineering, Faculty of Computing, Universiti Teknologi Malaysia, Johor Bahru, Malaysia

                Correlation mapping technique composed of delay time and correlation coefficient mapping to characterize propagation properties of cerebrospinal fluid (CSF) motion was applied to young, elderly healthy and idiopathic normal pressure hydrocephalus (iNPH) patient groups for classification. Brightness of the color of maximum correlation map was adjusted according to the amplitude of the CSF velocity waveform for assisting clinicians to understand the propagation properties intuitively. The groups were classified by quantifying the standard deviation of the correlation distributing in the intracranial CSF space. The technique was expected to classify diseases related to CSF dynamics such as iNPH.

Michael Loecher¹, Peng Hu¹, and Daniel B Ennis^1,2
1Department of Radiological Sciences, University of California, Los Angeles, CA, United States, ²Biomedical Physics, University of California, Los Angeles, CA, United States

4D Flow phase contrast MRI acquisitions inherently require a measure of background phase to remove phase contributions from non-velocity based components.  The temporal dynamics of this background phase are not well understood.  Consequently, the background phase may be measured too infrequently or too often for accurate and/or time efficient measurements. The purpose of this work was: 1) to measure the temporal dynamics of the background phase with high temporal resolution; and 2) to demonstrate methods of selecting time optimal background phase sampling strategies that improve the measurement efficiency of 4D Flow acquisitions.

Himanshu Gupta^1,2, Ankur Gupta¹, and Thomas S Denney^3,4
1Department of Medicine, Division of Cardiovascular Disease, University of Alabama at Birmingham, Birmingham, AL, United States, ²VA Medical Center, Birmingham, AL, United States, ³Auburn University MRI Research Center, Auburn University, Auburn, AL, United States, ⁴Electrical and Computer Engineering, Auburn University, Auburn, AL, United States

Pulmonary arterial (PA) impedance accounts for pulsatile blood flow through elastic pulmonary arteries as compared to static pulmonary vascular resistance. Increased PA impedance is an early physiological manifestation of PA remodeling. Currently, PA impedance can only be detected invasively, is expensive and cumbersome to calculate and not done in routine clinical practice. Non-invasive assessment of PA impedance can provide insights in evaluation of patients with normal PA pressures or mild pulmonary hypertension such as in patients with chronic obstructive lung disease. We propose a novel non-invasive parameter, the velocity transfer function (VTF), which is related to PA stiffness and impedance.

Julio Sotelo^1,2,3, Jesús Urbina^1,4, Bram Ruijsink⁵, David Nordsletten⁵, Israel Valverde^6,7, Cristian Tejos^1,2,8, Pablo Irarrazaval^1,2,8, Marcelo Andia^1,4,8, Daniel E Hurtado^3,8, and Sergio Uribe^1,4,8
1Biomedical Imaging Center, Pontificia Universidad Catolica de Chile, Santiago, Chile, ²Electrical Engineering Department, Pontificia Universidad Catolica de Chile, Santiago, Chile, ³Structural and Geotechnical Engineering Departement, Pontificia Universidad Catolica de Chile, Santiago, Chile, ⁴Radiology Department, School of Medicine, Pontificia Universidad Catolica de Chile, Santiago, Chile, ⁵Biomedical Engineering Department, King's College London, London, United Kingdom, ⁶Pediatric Cardiology Unit, Hospital Virgen del Rocio, Seville, Spain, ⁷Cardiovascular Pathology Unit, Institute of Biomedicine of Seville (IBIS), Hospital Virgen del Rocio, Seville, Spain, ⁸Biological and Medical Engineering Institute, Schools of Engineering, Medicine and Biological Sciences, Pontificia Universidad Catolica de Chile, Santiago, Chile

A quantitative characterization of vortex flow as turbulence and energy may offer a novel index of left ventricle (LV) dysfunction not available in conventional indexes. In this work we propose a novel method based on finite element interpolations to obtain a 3D quantitative maps of vorticity, helicity density, kinetic energy, and energy loss derived from 4D-flow data sets of the LV.? This new method may offer a novel index of LV dysfunction, permitting identify the vortex ring and the magnitude of turbulence values not available in conventional indexes. In future work we pretend validate clinically our method with patient data. 

Meng-Chu Chang¹, Ming-Ting Wu², Marius Menza³, Mao-Yuan Su⁴, Hung-Chieh Huang², and Hsu-Hsia Peng^1
1Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu, Taiwan, ²Department of Radiology, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan, ³Medical Physics, Department of Radiology, University Hospital Freiburg, Freiburg, Germany, ⁴Department of Medical Imaging, National Taiwan University Hospital, Taipei, Taiwan

The association between right ventricle (RV) volume or pressure overloading pathology and intraventricular flow of repaired tetralogy of Fallot (rTOF) patient is still unclear. Therefore, we evaluated RV input- and output kinetic energy and intraventricular flow patterns for rTOF patients to speculate the energy propagation by using phase-contrast MRI. During systole, rTOF patients presented higher RV output KE. Moreover, in rTOF patients, the blood flow filled into RV with a high velocity, accompanying several local vortices. In conclusion, higher output KE and the visualization of intraventricular vectors helped to comprehend the energy propagation in RV.

Alejandro Roldán-Alzate^1,2, Eric Schrauben^3,4, Oliver Wieben^2,3, and Christopher J Francois^2
1Mechanical Engineering, University of Wisconsin - Madison, Madison, WI, United States, ²Radiology, University of Wisconsin - Madison, Madison, WI, United States, ³Medical Physics, University of Wisconsin - Madison, Madison, WI, United States, ⁴Centre for Advanced MRI, Auckland, New Zealand

The purpose of this study was to evaluate changes in blood flow and kinetic energy distribution between inspiration and expiration in TCPC patients for assessing efficiency of the system using 4D flow MRI. Six TCPC patients were imaged using a PC-VIPR scheme that allows for double gating to the ECG and respiratory cycles providing flow data for separate respiratory phases. Results exhibit greater respiratory-induced flow changes within a single subject than previous work has shown in the same analysis performed on healthy controls, suggesting that respiration plays a larger role in regulating flow in these patients.

Giordanno B. F. Borges¹, Ivan R. Siqueira², Joao L. A. Carvalho³, Jon-Fredrik Nielsen⁴, and Vinicius C. Rispoli^5
1Department of Mathematics, University of Brasilia, Brasilia, Brazil, ²Department of Mechanical Engineering, Pontifical Catholic University of Rio de Janeiro, Rio de Janeiro, Brazil, ³Department of Electrical Engineering, University of Brasilia, Brasilia, Brazil, ⁴Biomedical Engineering, University of Michigan, Ann Arbor, MI, United States, ⁵UnB Gama College, University of Brasilia, Brasilia, Brazil

Julio Sotelo^1,2,3, Jesús Urbina^1,4, Cristian Montalba¹, Israel Valverde^5,6, Cristian Tejos^1,2,7, Pablo Irarrazaval^1,2,7, Marcelo Andia^1,4,7, Daniel E Hurtado^3,7, and Sergio Uribe^1,4,7
1Biomedical Imaging Center, Pontificia Universidad Catolica de Chile, Santiago, Chile, ²Electrical Engineering Department, Pontificia Universidad Catolica de Chile, Santiago, Chile, ³Structural and Geotechnical Engineering Departement, Pontificia Universidad Catolica de Chile, Santiago, Chile, ⁴Radiology Department, School of Medicine, Pontificia Universidad Catolica de Chile, Santiago, Chile, ⁵Pediatric Cardiology Unit, Hospital Virgen del Rocio, Seville, Spain, ⁶Cardiovascular Pathology Unit, Institute of Biomedicine of Seville (IBIS), Hospital Virgen del Rocio, Seville, Spain, ⁷Biological and Medical Engineering Institute, Schools of Engineering, Medicine and Biological Sciences, Pontificia Universidad Catolica de Chile, Santiago, Chile

Aortic coarctation (CoA) cause an irreversible pressure loss post-CoA given by the energy dissipation, increasing the ventricular workload. Turbulent flows through CoA generate an irreversible damage in the surrounding tissue for mechanical stresses. We implement a finite elements method to obtain 3D maps of energy loss, kinetic energy, vorticity and helicity from 4D flow data. We performed an in-vitro study that related the pressure gradient, pulse wave velocity and elastic modulus with the energy loss and vorticity and helicity parameters. Concluding that our method may allow assessing the severity of the CoA and the identification of the regions affected.

Danilo Babin¹, Daniel Devos², and Patrick Segers^3
1TELIN, Ghent University, Ghent, Belgium, ²Ghent University Hospital, Ghent, Belgium, ³ibiTech-bioMMeda, Ghent University, Ghent, Belgium

The purpose is to validate our cardiovascular image analysis toolbox "WaVelocity" for measuring pulse wave velocity (PWV) from cardiac magnetic resonance images against PWV measurements of in-place pressure catheter. The validation was performed using two phantoms: a straight latex tube and an aortic phantom with two different water flow rates. Phase-Contrast para-sagittal image sequences in multiple planes were processed with our image analysis software. Ground truth PWV values were calculated from pressure curves measured by pullback of the catheter. The results show sufficiently high correspondence between calculated MR and catheter PWV to plan for clinical use.

Da Wang^1,2, Jiaxin Shao¹, Daniel B Ennis^1,2, and Peng Hu^1,2
1Radiology, University of California, Los Angeles, Los Angeles, CA, United States, ²Biomedical Physics, University of California, Los Angeles, Los Angeles, CA, United States

In conventional 4D-flow phase-contrast MRI, each cardiac phase acquires the flow-compensated and three-directional flow-encoded echoes, which often limits the achievable temporal-resolution and temporal-footprint. This can result in under-estimation of maximum peak velocity. Herein, we propose a fast 4D-flow strategy that eliminates the flow-compensated acquisition using hybrid one- and two-sided flow encoding only (HOTFEO). The flow-compensated background phase is derived from three-directional flow-encoded data based on a velocity direction constraint that assumes the velocity direction, not the magnitude, changes very little between two cardiac phases. HOTFEO provides accurate blood flow and velocity measurements compared with conventional 4D-flow technique.

Jérémie Bettoni¹, Gwenaël Pagé², Stéphanie Dakpé¹, Jean-Marc Constans³, Sylvie Testelin¹, Bernard Devauchelle¹, and Olivier Balédent^2,4
1Maxillo-Faciale surgery, Amiens Hospital, Amiens, France, ²BioFlow Image, University of Picardie Jules Verne, Amiens, France, ³Diagnostic Radiology, Amiens Hospital, Amiens, France, ⁴Department of Image Processing, Amiens Hospital, Amiens, France

The aim of this study is to create the first physiological database of the blood flow quantification in the external carotid tree in order to help the surgeon in facial reconstruction by free flap. An original protocol association with 32 head coils channel and microscopic coil is created and 2D PC-MRI are performed on arteries from head and neck area. Blood flow average for each artery is 17 mL/min in superior thyroid artery, 6.5 mL/min in lingual artery, 30.5 mL/min in facial artery, 23.5 mL/min in internal maxillary artery, 21.5 mL/min in superficial temporal artery.

Michael Rose¹, Emilie Bollache², Kelly Jarvis^2,3, Alex Barker², Susanne Schnell², Bradley Allen², Joshua Robinson^4,5, Michael Markl^2,3, and Cynthia Rigsby^1,2
1Medical Imaging, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL, United States, ²Radiology, Northwestern University, Chicago, IL, United States, ³Biomedical Engineering, Northwestern University, Chicago, IL, United States, ⁴Pediatrics, Northwestern University, Chicago, IL, United States, ⁵Pediatric Cardiology, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL, United States

Over the course of two 4D flow MRI studies (mean duration between studies: 19 months), 12 pediatric BAV patients were evaluated for any changes in aortic hemodynamics. Hemodynamics were characterized via visual grading of flow patterns, peak systolic velocity and regional mean wall shear stress. There were no significant changes in visual grading scores, peak systolic velocities or mean wall shear stress values between baseline and follow up studies suggesting little BAV disease progression during this time.

Emilie Bollache¹, Paul W.M. Fedak^2,3, Pim van Ooij¹, David Guzzardi², S. Chris Malaisrie³, Alex Hong¹, Patrick M. McCarthy³, James Carr¹, Jeremy Collins¹, Michael Markl^1,4, and Alex J. Barker^1
1Department of Radiology, Northwestern University, Chicago, IL, United States, ²Department of Cardiac Sciences, University of Calgary, Calgary, AB, Canada, ³Division of Surgery-Cardiac Surgery, Northwestern University, Chicago, IL, United States, ⁴Department of Biomedical Engineering, Northwestern University, Chicago, IL, United States

The effect of the type of aortic surgery in patients with aortopathy is not well known. We studied 23 patients who underwent 4D flow MRI both before and after aortic valve (AVR) and/or ascending aortic (AAR) replacement, from which we estimated the pre- and post-surgical area of aortic ‘at-risk’ tissue, with an elevated wall shear stress. After surgery, in most AVR patients, at-risk tissue area was decreased while in most AAR patients, it was increased. This pilot study suggests the usefulness of 4D flow MRI to provide longitudinal aortic hemodynamic follow-up after surgery, which should be confirmed in larger populations.

Jesús Urbina^1,2, Julio Sotelo^1,3, Cristian Montalba¹, Tomás Fernández¹, Felipe Valenzuela^1,3, Cristián Tejos^1,3, Pablo Irarrázaval^1,3, Marcelo Andia^1,4, Israel Valverde^5,6, and Sergio Uribe^1,4
1Biomedical Imaging Center, Pontificia Universidad Católica de Chile, Santiago, Chile, ²School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile, ³Electrical Engineering Department, Pontificia Universidad Católica de Chile, Santiago, Chile, ⁴Radiology Department, Pontificia Universidad Católica de Chile, Santiago, Chile, ⁵Pediatric Cardiology Unit, Hospital Virgen del Rocio, Seville, Spain, ⁶Institute of Biomedicine of Seville, Universidad de Sevilla, Seville, Spain

The aim of this work was to generate a one to one replica of the aorta of a patient with a kinking and to compare the hemodynamic parameters with the ones obtained from patient's PC-MRI and cardiac catheterization. A silicone model was built from CE-MRA data and connected to a MRI compatible pulsatile pump setup. PC-MRI and catheterization data were obtained in the phantom. Most hemodynamic parameters were similar between the patient and the phantom.

Magnus Ziegler^1,2, Jonas Lantz^1,2, Tino Ebbers^1,2, and Petter Dyverfeldt^1,2
1Division of Cardiovascular Medicine, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden, ²Centre for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden

Chaotic velocity fluctuations caused by turbulent blood flow create fluctuations in the shear stress acting on the vascular wall. This turbulent wall shear stress can cause vascular remodeling and increased endothelial cell turnover. This work explores the use of MR-estimated turbulent kinetic energy (TKE) for mapping the turbulent wall shear stress. Time-resolved velocity data for non-pulsatile flow was obtained using computational fluid dynamics in two patient-derived geometries and used to simulate PC-MRI measurements. Near-wall TKE was estimated using a novel sampling method and was found to correlate strongly to turbulent wall shear stress, opening new avenues for analysis.

Teodora Chitiboi^1,2, Mathias Neugebauer¹, Susanne Schnell³, Michael Markl³, Lars Linsen², and Anja Hennemuth^1
1Fraunhofer MEVIS, Bremen, Germany, ²Jacobs University, Bremen, Germany, ³Department of Radiology, Northwestern University, Chicago, IL, United States

Various cardiac diseases can be diagnosed by analyzing myocardial motion. The local myocardial velocity can be efficiently computed using tissue phase mapping MRI. While radial, longitudinal, and rotational myocardial velocities are relevant biomarkers, it is challenging to find a single 3D representation that gives a global overview of these three motion directions for the entire cardiac muscle. We designed a visual encoding that maps the three velocities to glyph shapes according to a barycentric space formed by 3D superquadric glyphs. The glyphs show the aggregated myocardial motion information for each AHA segment and are displayed in a 3D layout.

Lena Václavu¹, Bart J Biemond², John C Wood³, Henk Mutsaerts⁴, Charles BLM Majoie¹, Ed van Bavel⁵, Aart J Nederveen¹, and Pim van Ooij^1
1Radiology, Academic Medical Center, Amsterdam, Netherlands, ²Internal Medicine, Academic Medical Center, Amsterdam, Netherlands, ³Cardiology, Children's Hospital Los Angeles, Los Angeles, CA, United States,⁴Sunnybrook Research Institute, Toronto, ON, Canada, ⁵Biomedical Engineering and Physics, Academic Medical Center, Amsterdam, Netherlands

We employed 4D Flow MRI in patients with Sickle Cell Disease. 4D Flow MRI is a non-invasive technique allowing blood flow velocity measurements and estimation of WSS. We investigated dynamic changes in velocity, WSS and vessel diameter in the anterior circulation of the Circle of Willis (CoW) in response to a vasodilator (acetazolamide [ACZ]).  We found that velocity and WSS  increased in the CoW after administration of the vasodilator ACZ, as measured with 4D flow MRI. The change in velocity after administration of ACZ was larger in controls than in patients.

Stephen Gaeta¹, Petter Dyverfeldt^2,3, Jonatan Eriksson^2,3, Carl-Johan Carlhäll^2,3, Tino Ebbers^2,3, and Ann F Bolger^4
1Department of Medicine, Duke University, Durham, NC, United States, ²Department of Medical and Health Sciences, Linköping University, Linköping, Sweden, ³Center for Medical Image Science and Visualisation (CMIV), Linköping University, Linköping, Sweden, ⁴Department of Cardiology, University of California San Francisco, San Francisco, CA, United States

The aim of this study was to develop a novel fixed-volume approach for particle tracing and employ this to develop quantitative analysis of 4D blood flow characteristics in the left atrium (LA). The proposed fixed volume approach for emission of particle traces permits sampling of LA blood volumes and intuitive visualizations where each trace represents the same volume. Using fixed-volume particle traces, LA flow can be separated into different components based on the transit of blood through the LA. Quantitative analysis of functionally distinct subsets of LA flow may provide new perspectives on LA function in health and disease. 

Hassan Haji-Valizadeh¹, Elwin Bassett², Genesh Adluru³, Edward VR DiBella ³, and Daniel Kim^3
1Bioengineering, University of Utah, Salt Lake City, UT, United States, ²Physics, University of Utah, Salt Lake City, UT, United States, ³Radiology,UCAIR, University of Utah, Salt Lake City, UT, United States

Phase contrast (PC) MRI is a useful tool for assessing hemodynamic, but suffers from low data acquisition efficiency. In this study we compared real-time PC MRI between Cartesian and Radial undersampling trajectories. Our results show that both real-time MRI pulse sequences yield velocity measurements that agree well with those produced by reference breath-hold PC MRI pulse sequence. Compared with real-time MRI with Cartesian sampling, Radial sampling produced images with fewer artifacts.  This study demonstrates feasibility of real-time PC MRI using radial k-space sampling and constrained reconstruction. 

Waltraud B. Buchenberg¹, Florian Wassermann², Sven Grundmann³, Jürgen Hennig¹, and Bernd Jung^4
1Radiology - Medical Physics, University Medical Center Freiburg, Freiburg, Germany, ²Center of Smart Interfaces, Technische Universität Darmstadt, Darmstadt, Germany, ³Institute of Fluid Mechanics, University of Rostock, Rostock, Germany, ⁴Interventional and Pediatric Radiology, University Hospital, Institute of Diagnostic, Bern, Switzerland

Since MR thermometry and MR velocimetry allow non-invasive measurements of temperature fields and velocity fields, they are widely applied to address medical questions; however, they are also suited to investigate 3D fluid flow and heat transfer phenomena in technical devices. This work investigates velocity fields and temperature distributions in a countercurrent double pipe heat exchanger. 3D velocity and temperature measurements were performed consecutively. A combination of forced convection (external pump providing laminar flow) and free convection (heating) using MRI can add valuable new insights into heat transfer processes.

Yoon-Chul Kim¹, Sung Mok Kim¹, Sung-Ji Park¹, and Yeon Hyeon Choe^1
1Samsung Medical Center, Sungkyunkwan Univ. School of Medicine, Seoul, Korea, Republic of

Recently there have been several studies of estimation of extracellular volume (ECV) fraction from dynamic contrast enhanced (DCE) myocardial perfusion images using a distributed parameter (DP) model. We apply the DP model to DCE perfusion images acquired from a standard stress perfusion protocol, and demonstrate ECV measurements in aortic stenosis (AS) patients (n=13) and hypertrophic cardiomyopathy (HCM) patients (n=11).  Preliminary results from sector-wise analysis indicate 1) higher mean ECV values in HCM patients than normal volunteers and AS patients and 2) lower mean blood flow values in AS and HCM patients than those in normal volunteers. 

Tobias Wech¹, Michael Braun^1,2, Daniel Stäb³, Peter Speier⁴, Henning Neubauer¹, Walter Kullmann², Thorsten A. Bley¹, and Herbert Köstler^1
1Department of Diagnostical and Interventional Radiology, University of Würzburg, Würzburg, Germany, ²Institute of Medical Engineering, University of Applied Sciences Würzburg-Schweinfurt, Schweinfurt, Germany,³The Centre for Advanced Imaging, The University of Queensland, Brisbane, Australia, ⁴Siemens Healthcare, Erlangen, Germany

The benefit of using radial instead of Cartesian readouts for MS-CAIPIRINHA accelerated myocardial perfusion measurements was explored. Conjugate gradient SENSE was used to determine fully sampled data for the two slices acquired simultaneously. A phantom study was performed first, which revealed lower g-factors for radial MS-CAIPIRINHA in comparison to a corresponding Cartesian acquisition. Finally, saturation-recovery-prepared and ECG-triggered radial MS-CAIPIRINHA was applied for perfusion investigations of the myocardium in a healthy volunteer.

Wang Jing¹, Yudong Zhang², Yang Fan³, HaiBin Shi², and Xiaoyan Liu^1
1Center for Medical Device Evaluation, CFDA, Beijing, China, People's Republic of, ²Department of Radiology, the First Affiliated Hospital with Nanjing Medical University Nanjing, Nanjing, China, People's Republic of,³GE Healthcare, MR Research China, Beijing, China, People's Republic of

This study compares three methods for quantitatively analyzing dynamic contrast-enhanced MRI datasets for the extraction of myocardial perfusion, permeability, and other hemodynamic parameters. The two-compartment exchange model and the adiabatic approximation to the tissue homogeneity models are compared with reference to model-free deconvolution. The goal was to determine if these three models could reliably estimate hemodynamic parameters and be able to distinguish between normal patients and those with hypertrophic cardiomyopathy. Results demonstrate that all three methods yield consistent estimates for perfusion, blood volume, and mean transit times, and that these parameters were significantly different for the hypertrophic heart.

Karl P Kunze¹, Christoph Rischpler¹, Markus Schwaiger¹, and Stephan G Nekolla^1
1Department of Nuclear Medicine, Klinikum rechts der Isar der TU München, Munich, Germany

This abstract proposes a new B-spline based approach for model-independent deconvolution of myocardial DCE-MRI perfusion data and the reconstruction of the vascular transit time distribution function. It allows the model-independent quantification of vascular mean transit time and vascular transit time heterogeneity, whose relationship is of importance in understanding the implications of different ischemic microvascular disease patterns. The presented algorithm was tested in simulations and showed stability for the range of perfusion parameters expected under stress conditions. 12 DCE-MRI patient datasets from adenosine stress examinations were analyzed, showing a steady increase of heterogeneity with mean transit time.

Madeline Schwid¹, Hannah Recht¹, Kai Lin¹, Jeremy Collins¹, Michael Markl¹, Dan Lee¹, and James Carr^1
1Northwestern University, Chicago, IL, United States

This study evaluated semiquantitative measures of ischemia using noninvasive stress perfusion CMR for the detection and quantification of CAV using invasive coronary angiography as the standard reference on a cohort of chronic heart transplant patients. Based on angiogram results, patients were divided into groups by disease severity. The upslope and myocardial perfusion reserve was measured per segment for each patient based on the AHA 16 segment model. These values were then correlated to the angiogram results and averaged by segment to create bullseye plots for each group. As disease severity increases, both myocardial perfusion reserve and stress upslope decrease. 

Travis DeSa¹, Jeremy D Collins¹, James C Carr¹, Kai Lin¹, and Michael Markl^1
1Radiology, Northwestern University Feinberg School of Medicine, Chicago, IL, United States

Myocardial perfusion using MRI has become a promising non-invasive method to evaluate myocardial ischemia in CVDs. However, assessment of CMR's effectiveness in differentiating regional myocardial perfusion in patients with CVD and comparison of regional myocardial perfusion indices to cardiac global functional parameters has not been thoroughly studied. We evaluated 12 volunteers and 9 cardiac transplant patients and found significant differences in segmental and average CMR perfusion, but little correlation between perfusion and global functional parameters. This weak correlation indicates that myocardial perfusion may be more sensitive to detect early changes in LV dysfunction before the onset of global functional impairment.

Aslan Turer¹, Thomas Gillette¹, Shawn Burgess², Craig Malloy², and Matthew Merritt^3
1Cardiology, UT Southwestern Medical Center, Dallas, TX, United States, ²AIRC, UT Southwestern Medical Center, Dallas, TX, United States, ³Biochemistry and Molecular Biology, University of Florida, Gainesville, FL, United States

Heart failure (HF) was studied using a murine model of aortic constriction. Hearts were perfused to steady state using [1,6-¹³C₂]glucose, [1,3-¹³C₂]acetoacetate, and [U-¹³C]fatty acids. Substrate selection for acetyl-CoA production was measured using isotopomer analysis by carbon-13 NMR. A standard model which includes oxidative flux as well as pyruvate anaplerosis (Y_PC) via pyruvate carboxylase or the malic enzyme was evaluated. Inconsistencies in the fits led to proposal of a more complicated model that also includes anaplerosis through the succinyl-CoA pathway (Y_s), leading to significantly better fits. We hypothesize that induction of the Y_s anaplerotic pathway is phenotypic of HF.  

Jens Wetzl^1,2, Lea Schroeder¹, Christoph Forman³, Felix Lugauer¹, Robert Rehner⁴, Matthias Fenchel³, Andreas Maier^1,2, Joachim Hornegger^1,2, and Peter Speier^3
1Pattern Recognition Lab, Department of Computer Science, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany, ²Erlangen Graduate School in Advanced Optical Technologies, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany, ³Magnetic Resonance, Product Definition and Innovation, Siemens Healthcare GmbH, Erlangen, Germany, ⁴Magnetic Resonance, Research and Development, Hardware, Siemens Healthcare GmbH, Erlangen, Germany

Respiratory monitoring during continuous, free-breathing acquisitions is challenging. Using self-navigation, a respiratory signal can be derived from the imaging data, but  requires frequent sampling of the k-space center. Pilot Tone navigation promises continuous respiratory monitoring independent of the imaging sequence. In this feasibility study, we compared both strategies for free-breathing 3-D CINE imaging. We found good agreement between both respiratory signals, and an excellent match in both reconstructed images and computed ventricular function parameters. Pilot Tone navigation can thus be considered an alternative to self-navigation, with the benefit of working with arbitrary imaging sequences.

Amir Ali Rahsepar¹, Mohammadali Habibi², Cheeling Chan³, Nadine kawel², Kiang Liu³, Joao Lima², and James Carr^1
1Radiology, Northwestern University, Chicago, IL, United States, ²Cardiology, Johns Hopkins University, Baltimore, MD, United States, ³Preventive medicine, Northwestern University, Chicago, IL, United States

In this large cross-sectional study, we found that higher levels of Pro-B-Type Natriuretic Peptide is associated with regional left ventricular function and dyssynchrony measured by MRI in asymptomatic patients participated in The Multi-Ethnic Study of Atherosclerosis (MESA) study.

Bauke Kogelman¹, Margriet Hulsker², Christa Tanganyika-de Winter², Ralf Werring², Annemieke Aartsma-Rus², Maaike van Putten², and Louise van der Weerd^1,2
1Department of Radiology, Leiden University Medical Center, Leiden, Netherlands, ²Department of Human Genetics, Leiden University Medical Center, Leiden, Netherlands

Duchenne muscular dystrophy is affecting skeletal and cardiac muscle tissue, due to non-functional dystrophin protein. Potential therapies restore dystrophin expression in skeletal muscle, while cardiac muscle is more difficult to target. To elucidate whether exercise is beneficial or disadvantageous for (cardio)myopathy, we subjected several mouse models, mdx (0% dystrophin), mdx-Xist?hs (varying dystrophin levels), Bl10-WT and Xist-WT wild type mice (100% dystrophin) to low intensity or no exercise. Results showed that low dystrophin levels improve skeletal muscle and cardiac function and suggest that low intensity exercise is beneficial for skeletal and cardiac muscle function in both dystrophic and wild type mice. 

Amir Ali Rahsepar¹, Haris Saybasili ², Ahmadreza Ghasemiesfe ¹, Bruce Spottiswoode ², Ann Ragin¹, Jeremy Collins ¹, and James Carr^1
1Radiology, Northwestern University, Chicago, IL, United States, ²Siemens Medical Solutions, Siemens Healthcare, Chicago, IL, United States

In this study, we presented a novel technique to extract cine cardiac cycle without respiratory motion from real-time free-breathing images with unsupervised motion correction.

Yi Wang^1
1St. Francis Hospital, Albertson, NY, United States

We tried to develop and validate an early detection technique of chemo therapy cardiotoxicity in the cancer treatment using cardiovascular magnetic resonance imaging. We hypothesized myocardial blood flow (MBF), more sensitive technique than EF or DHE, provides information on the altered physiology and function conditions of the heart. Chemo treatment induces changes in myocardial perfusion at rest enough to be detected with model based quantitation, with sequential imaging on the same subject. It provides an earlier indication of cardiotoxicity.

Anja Hennemuth¹, Christian Schumann¹, Mathias Neugebauer¹, Hanieh Mirzaee¹, Sarah Nordmeyer², Marcus Kelm², Leonid Goubergrits², and Titus Kühne^2
1Fraunhofer MEVIS, Bremen, Germany, ²Department of Congenital Heart Disease / Pediatric Cardiology, German Heart Center Berlin, Berlin, Germany

The induced pressure gradient due to the vessel narrowing associated with coarctation of the aorta is a crucial parameter for treatment planning. Previous studies have shown that pressure differences derived from 4D PC MRI correlate well with conventional pressure catheter measurements. The purpose of the presented work was to investigate how MRI-based pressure maps can be employed in treatment planning of coarctation of the aorta. To this end, a combined 3D maximum value projection, which highlights relative value changes with respect to a reference point, and a curve diagram showing the pressure course along the centerline are provided for interactive exploration. Two cardiologists retrospectively explored 5 datasets of patients with treated coarctation of the aorta. The pressure gradient derived from the 4D PC MRI measurement corresponded well with the interventional measurements. Furthermore, additional relevant information could be derived regarding the location of the critical vessel sections. These findings show the potential of 4D PC MRI pressure mapping as a useful non-invasive tool for treatment planning of coarctation of the aorta.

Arna van Engelen¹, Markus Henningsson¹, and Rene Botnar^1
1Department of Biomedical Engineering, Division of Imaging Sciences and Biomedical Engineering, King's College London, London, United Kingdom

The aim of this study was to perform automatic coronary artery centerline tracking on coronary MRI data, in a clinically relevant population. Our method consisted of computation of a vesselness filter followed by fast marching. Parameters were optimized on three subjects, and performance was evaluated on 27 other subjects. Centrelines were traced between a start and end point, and when needed with one additional point in between. Tracking was successful in 92% (RCA), 88% (LAD) and 65% (LCX), with a median distance from manual annotation of 1.0mm. These results show that automatic centerline tracking on coronary MRI data is possible.

Rizwan Ahmad¹, Samuel Schroeder², Richard D White³, and Arunark Kolipaka^3
1Electrical and Computer Engineering, The Ohio State University, Columbus, OH, United States, ²Mechanical Engineering, The Ohio State University, Columbus, OH, United States, ³Radiology, The Ohio State University, Columbus, OH, United States

Alterations in myocardial stiffness have been linked to wide-ranging cardiovascular conditions. Magnetic resonance elastography (MRE) is a noninvasive, quantitative technique to estimate stiffness of soft tissue.1 Long scan times, however, limit the clinical utility of MRE, especially for cardiac imaging. We propose a data processing technique that not only exploits sparsity in the MRE images but also imposes a constant magnitude constraint to achieve accurate stiffness values from highly undersampled data. The method is validated using a physical phantom of known stiffness value and is then applied to a healthy volunteer to assess myocardial stiffness. 

KEI FUKUZAWA¹, Rieko Ishimura², Takashi Yoshida¹, Chiharu Yoshihara¹, Junji Takahashi¹, and Masakatsu Tano^1
1Radiology, Toranomon Hospital, Tokyo, Japan, ²Cardiovascular center, Toranomon Hospital, Tokyo, Japan

The lower R/T ratio inside a bore are obtained in patients with bathycardia, a condition in which the heart axis is close to the body axis. In addition, the short distance between the apex of the heart and the apex electrode and closeness of lead II and the heart axis are factors of a worse R/T ratio. These two points should be improved to obtain waveforms with a high R/T ratio.

Long Li Ling¹, peng peng¹, and Huang Zhong Kui^1
1The First Affiliated Hospital of Guangxi Medical University, Nanning, China, People's Republic of

To demonstrate that assessment of cardiac iron burden by T2* imaging is feasible, reproducible, and reliable at 3T. With 3T MRI scanners increasingly used in clinical settings, this study may lay a foundation for further MRI development of quantitative markers for noninvasive cardiac iron overloaded assessment at higher fields. Though cardiac T2* measurement at 3T seemed not to offer any greater advantages than 1.5T at present, it is more useful for some hospitals having only 3T scanner.

Jinho Park¹, Panki Kim², Young Joong Yang¹, Jong-Hyun Yoon¹, Byoung Wook Choi², and Chang-Beom Ahn^1
1Kwangwoon University, Seoul, Korea, Republic of, ²Yonsei University, Seoul, Korea, Republic of

For patients with impaired breath-hold capacity, highly accelerated cardiac cine MRI may be useful. The purpose of this study is to perform functional MR imaging of the whole heart in a single breath-hold using an under-sampled data acquisition in combination with compressed sensing with parallel imaging.  The proposed technique is applied for in-vivo functional cardiac imaging of the whole heart in a single breath-hold.  Applied compression factors are 4 of ITSC and 2 of SENSE. The whole heart coverage in a single breath-hold using ITSCxSENSE can be used to achieve adequate spatial resolution (1.8 mm × 1.8 mm) and relatively high temporal resolution (31 ms), with good image quality and functional movement.  It takes 23s for the reconstruction of single slice CINE images (22 cardiac phases). The ITSCxSENSE may be useful for patients with reduced breath-hold capacity.

Kei Fukuzawa¹, Rieko Ishimura², Takashi Yoshida¹, Junji Takahashi¹, Chiharu Yoshihara¹, and Masakatsu Tano^1
1Radiology, Toranomon Hospital, Tokyo, Japan, ²Cardiovascular center, Toranomon Hospital, Tokyo, Japan

To obtain the highest R/T ratio, for good ECG synchronization, The R/T ratio increased as the angle of lead II axis became further away from the body axis and as the apex electrode and the apex of the heart became a little further apart than the basic placement position. The basic placement position was the lowest in the order of R/T ratios among the five kinds of electrode positions (p < 0.01).

Shan Gao¹, Ronald van't Klooster¹, Anne Brandts², Stijntje D. Roes², Reza Alizadeh Dehnavi³, Albert de Roos², Jos J.M. Westenberg¹, and Rob J. van der Geest^1
1Division of Image Processing, Department of Radiology, Leiden University Medical Center, Leiden, Netherlands, ²Department of Radiology, Leiden University Medical Center, Leiden, Netherlands, ³Department of Cardiology, Leiden University Medical Center, Leiden, Netherlands

Atherosclerosis is characterized by thickening of the arterial wall. To monitor disease progression and regression, vessel wall segmentation is required for wall thickness assessment.  In this study, we developed a fully automatic method to detect the vessel wall boundaries and quantify the wall thickness for both the common carotid artery and the descending aorta in MR images. The results demonstrated that our method has good agreement with manual segmentation, excellent scan-rescan reproducibility and capability of detecting vessel wall thickening in hypertensive patients. Therefore, the presented method is promising for application in future cohort studies.

Yan Wang¹, Florent Seguro¹, Farshid Faraji¹, Chengcheng Zhu¹, Henrik Haraldsson¹, Michael Hope¹, Jing Liu¹, and David Saloner^2
1Radiology, UCSF, San Francisco, CA, United States, ²Radiology, UCSF/VA, San Francisco, CA, United States

An abdominal aortic aneurysm (AAA) may rupture if left untreated. Automatic segmentation methods allow quick and reproducible AAA morphology quantification, which is favorable for the diagnosis of AAA disease. This study developed a novel registration based geometric active contour model to segment vessel wall of AAA from 3D black blood MRI. This method was initially tested on six patients. The proposed method agreed well with manual segmentation with an average Dice value of 91.22%, demonstrating good segmentation accuracy.  These methods can be potentially used for AAA evaluation in clinical setting.

Arna van Engelen¹, Torben Schneider², Hubrecht de Bliek³, Miguel Silva Vieira⁴, Isma Rafiq⁴, Tarique Hussain⁴, Rene Botnar¹, and Jordi Alastruey^1
1Department of Biomedical Engineering, Division of Imaging Sciences and Biomedical Engineering, King's College London, London, United Kingdom, ²Philips Healthcare, Guidford, United Kingdom, ³Philips Healthcare, HSDP Clinical Platforms, Best, Netherlands, ⁴Department of Cardiovascular Imaging, Division of Imaging Sciences and Biomedical Engineering, King's College London, London, United Kingdom

Accurate 3D length measurements through the aorta are required for Pulse Wave Velocity (PWV) measurements. We evaluate automatic centreline tracking, requiring only a start and end point, on three different types of MR data (balanced-SSFP, contrast-enhanced and black-blood MRI), in 12 elderly subjects and 10 patients post-coarctation repair. Our algorithm uses vesselness filtering, fast marching and centreline refinement. Length differences between manual and automatic centrelines are generally below 1cm, with corresponding PWV differences well below 0.5m/s. This shows that with minimal user interaction, accurate PWV measurements can be performed using automatic centreline tracking, on commonly used types of MR data.

Jose A. Rosado-Toro¹, Ryan Avery², Maria I. Altbach³, Aiden Abidov⁴, and Jeffrey J. Rodriguez^1
1Electrical and Computer Engineering, University of Arizona, Tucson, AZ, United States, ²Radiology, University of Arizona, Tucson, AZ, United States, ³Medical Imaging, University of Arizona, Tucson, AZ, United States,⁴Medicine, University of Arizona, Tucson, AZ, United States

We present a semi-automated algorithm for right ventricle segmentation in 4-chamber cardiac MR images.  The algorithm takes post-processor landmarks in the end-diastolic and end-systolic frames and generates a segmentation of the right ventricle throughout the cardiac cycle.  For the 175 images we analyzed (i.e., 7 patients with 25 frames per patient), the Dice metric was within human variability.

Yuhua Chen^1,2, Jianing Pang², David Neiman^2,3, Yibin Xie², Christopher T. Nguyen², Zhengwei Zhou², and Debiao Li^2
1Computer and Information Science, University of Pennsylvania, Philadelphia, PA, United States, ²Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States, ³Electrical Engineering, University of Wisconsin, Madison, WI, United States

Measuring left ventricle (LV) function using MRI currently involves a highly user-dependent and labor-intensive workflow, which includes manual segmentation of 2D cine images acquired during patient breath-hold at multiple short axis locations. In this work, we propose a fully automated LV segmentation method based on a recently developed free-breathing, self-gated 4D whole-heart imaging technique and multi-atlas label fusion, which enables streamlined, “push-button” LV function assessment. We performed cross validation study on five healthy subjects where the proposed method was shown to offer consistent results with manual labelling.

Yolanda Georgia Koutraki^1,2, Rachael O. Forsythe², Chengjia Wang^1,3, Olivia Mcbride², Jennifer Robson², Tom J. MacGillivray¹, Calum D. Gray¹, David E. Newby^1,2, and Scott I. Semple^1,2
1Clinical Research Imaging Centre, University of Edinburgh, Edinburgh, United Kingdom, ²Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, United Kingdom, ³Toshiba Medical Visualization System-Europe, Edinburgh, United Kingdom

The measurement of the diameter of abdominal aortic aneurysms (AAA) as a criterion for repair has been proved to be imperfect, thus new methods are required.  Uptake of Ultrasmall Superparamagnetic Particles of Iron Oxide (USPIO) in AAA has been shown to correlate with aneurysm growth-rate. We previously suggested the use of an automatic AAA classification technique in order to replace manual processing. We have now improved our algorithm to include 3D data analysis and visualisation, multivariate analysis of metrics, batch processing and a Graphical User Interface. We are improving growth prediction with full reproducibility, 40 times faster than before.

Markus Huellebrand¹, Mathias Neugebauer¹, Michael Steinmetz², Jens Frahm³, and Anja Hennemuth^1
1Fraunhofer MEVIS, Bremen, Germany, ²Universitätsmedizin Göttingen, Göttingen, Germany, ³Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für Biophysikalische Chemie, Göttingen, Germany

New real-time MRI imaging techniques enable the acquisition of serial images with a temporal resolution of up to 20 ms. These new imaging sequences provide cardiac parameters such as cardiac function and blood flow over multiple heart cycles and their variation over time. To quantify these parameters new analysis methods are required. Our proposed solution combines automatic image processing with interactive exploration techniques in a web application setup. The solution has been successfully tested with data from arrhythmic patients as well as volunteers performing Valsalva maneuver and physical exercise tests.

Shahriar Shalikar¹, Elham Mohammadi¹, and Abbas Nasiraei Moghaddam^1
1Biomedical Engineering, Amirkabir University of Technology (Tehran Polytechnic), Tehran, Iran

The correlation between left ventricle (LV) rotation and cardiovascular diseases, encourages the studying of regional parameters such as regional rotation in cardiac evaluation. Radial Tagged MRI (tMRI) is a promising technique for rotational motion assessment. However, a robust and reproducible method is required to quantify displacement from tMRI. Monogenic signal method and its performance on radial tMRI is investigated in this study for the first time. The proposed method, due to possibility of dense displacement vector estimation, provides an opportunity to accurately analyze the LV twist and its effect on the cardiac function. Results  showed a very robust pattern for transmural changes of the rotation across the wall, calculated as -0.033 degrees per millimeter. 

Hossam El-Rewaidy¹, El-Sayed H. Ibrahim², and Ahmed Fahmy^1
1Nile University, Cairo, Egypt, ²University of Michigan, Ann Arbor, MI, United States

Active-shape modeling (ASM) has potential for segmenting the right ventricle (RV) from MRI images. Nevertheless, the complexity of the RV shape does not allow for concisely capturing all possible shape variations. In this work, we propose a new ASM framework in which the RV contour is split into two simpler segments, septal and free-wall, whose shape variations are independently modeled using two ASM models. Further, the RV contours are aligned using the Bookstein coordinate-transformation. The results from a dataset of 10 patients show that the proposed framework can efficiently model complex RV shape variation with high accuracy in few iterations.

R Reeve Ingle¹, Kangrong Zhu², N Okai Addy¹, Ken O Johnson¹, Michelle M Nystrom¹, William R Overall¹, Galen D Reed¹, Bob S Hu^1,3, and Juan M Santos^1
1HeartVista, Inc., Menlo Park, CA, United States, ²Electrical Engineering, Stanford University, Stanford, CA, United States, ³Cardiology, Palo Alto Medical Foundation, Palo Alto, CA, United States

A 3D heart localization algorithm is proposed to automatically determine the placement and orientation of a 3D ellipsoidal ROI for optimal heart coverage. A fast, multi-slice scout scan is used to acquire a time series of cardiac-triggered images covering the heart. These images are used by the algorithm to automatically compute a cardiac motion map for the proposed ellipsoid fitting optimization. In eight subject scans, the algorithm is shown to yield good ellipsoidal placement and orientation that is in good conformance with the shape and position of the heart.