Simone Rumac¹, Anna Giulia Pavon², Jesse Hamilton³, David Rodrigues¹, Nicole Seiberlich³, Juerg Schwitter², and Ruud B. van Heeswijk^1
1Department of Radiology, Lausanne University Hospital (CHUV), Lausanne, Switzerland, ²Cardiology Service, Lausanne University Hospital (CHUV), Lausanne, Switzerland, ³Department of Radiology, University of Michigan, Ann Arbor, MI, United States

Cardiac magnetic resonance fingerprinting (cMRF) can be used to simultaneously acquire myocardial T₁ and T₂ maps in a single breath-hold. However, the common 250 ms acquisition window of cMRF might leave it vulnerable to motion artefacts. The goal of this study was therefore to compare the performance of cMRF with a short acquisition window (150ms) and low-rank reconstruction to that of routine cardiac parametric mapping techniques. In 7 healthy volunteers, and 62 cardiac patients, cMRF resulted in similar native relaxation times, but slightly different post-contrast T₁ and ECV values compared to routine techniques.

Daming Shen^1,2, Kyungpyo Hong³, Bradley D Allen², Daniel C Lee⁴, and Daniel Kim^1,2
1Biomedical Engineering, Northwestern University, Evanston, IL, United States, ²Radiology, Northwestern University Feinberg School of Medicine, Chicago, IL, United States, ³Biomedical Engineering and Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States, ⁴Division of Cardiology, Internal Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, United States

Late gadolinium enhanced (LGE) CMR is the gold standard test for assessment of myocardial scarring. There is unmet need for high resolution, free-breathing LGE CMR for patients with arrhythmia and/or dyspnea. The purpose of this study was to develop and clinically evaluate a high resolution, free-breathing LGE CMR sequence combined with radial k-space sampling and compressed sensing (CS), which enables image contrast optimization without a TI scout.  

Johanna Stimm¹, Stefano Buoso¹, Martin Genet^2,3,4, Sebastian Kozerke¹, and Christian T Stoeck^1
1Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland, ²Laboratoire de Mécanique des Solides, École Polytechnique, Paris, France, ³C.N.R.S./Université Paris-Saclay, Palaiseau, France, ⁴M3DISIM team, Inria / Université Paris-Saclay, Palaiseau, France

We propose a parametric low-rank representation of major characteristics of cardiomyocyte orientation in a shape-adapted coordinate system from 3D high-resolution ex-vivo cDTI data by exploiting structural similarity across hearts. We compare two dimensionality reduction methods, namely Proper Orthogonal Decomposition and Proper Generalized Decomposition. These low-order descriptions can be fit to sparse, noisy or low-resolution target data. Transferring high-resolution microstructural information with this parametric representation shows potential for in-vivo denoising and 3D extrapolation.

Kellie Phipps¹, Robert Eder¹, Sam Allen Michelhaugh², Aferdita Spahillari², Maaike van den Boomen^1,3,4, Joan Kim¹, Shestruma Parajuli¹, Timothy G Reese^3,5, Choukri Mekkaoui^3,5, David Sosnovik^1,3,6, Denise Gee^7,8, Ravi Shah^1,6, and Christopher Nguyen^1,3,6
1Cardiovascular Research Center, Massachusetts General Hospital, Charlestown, MA, United States, ²Cardiology Division, Massachusetts General Hospital, Charlestown, MA, United States, ³Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, United States, ⁴Department of Radiology, University Medical Center Groningen, Groningen, Netherlands, ⁵Department of Radiology, Harvard Medical School, Boston, MA, United States, ⁶Department of Medicine, Harvard Medical School, Boston, MA, United States, ⁷Weight Center, Massachusetts General Hospital, Boston, MA, United States, ⁸Department of Surgery, Harvard Medical School, Boston, MA, United States

In vivo cardiac DT-MRI allows for imaging of the underlying myocardial fiber orientations but is hindered by clinically infeasible scan times. We developed and tested a residual deep learning denoising algorithm, DnCNN-54, on cardiac DT-MRI scans with fewer averages (4, 2, and 1) than the conventional 8-average 30 minute scan. We demonstrated a 2-fold acceleration can be achieved after DnCNN-54 is applied to 4 average dataset compared with the reference 8-average scan that preserves signal to noise ratio and cardiac DT-MRI parameter quantification. This 2-fold acceleration via DnCNN-54 denoising also maintained cardiac DT-MRI mean differences between obese and lean subjects.

Ruixi Zhou¹, Daniel S. Weller², Yang Yang³, Junyu Wang¹, John P. Mugler⁴, and Michael Salerno^5
1Biomedical Engineering, University of Virginia, Charlottesville, VA, United States, ²Electrical and Computer Engineering, University of Virginia, Charlottesville, VA, United States, ³Biomedical Engineering and Imaging Institute and Department of Radiology, Icahn School of Medicine at Mount Sinai, New York, NY, United States, ⁴Radiology, Biomedical Engineering, University of Virginia, Charlottesville, VA, United States, ⁵Cardiology, Radiology, Biomedical Engineering, University of Virginia, Charlottesville, VA, United States

We propose a technique to obtain cine images and accurate B1-corrected T1 maps in a single free-breathing continuous Look-Locker inversion-recovery acquisition modified to use two excitation flip angles. Data are acquired using a single spiral interleaf, rotated by the golden-angle in time, with an inversion RF pulse applied every four seconds. Cine images are reconstructed from the steady state portion of the signal, while T1 mapping fits the model using  maps with two flip angles. This strategy provides cine images and T1 maps, as well as a flip angle scale factor map, in a single free-breathing continuous acquisition.

Haikun Qi¹, Aurelien Bustin¹, Thomas Kuestner¹, Reza Hajhosseiny¹, Gastao Cruz¹, Karl Kunze^1,2, Radhouene Neji^1,2, René Botnar¹, and Claudia Prieto^1
1School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom, ²MR Research Collaborations, Siemens Healthcare Limited, Frimley, United Kingdom

Cardiac T1ρ mapping has shown promising results for detecting ischemic cardiomyopathy without the need of exogenous contrast agents. Current 2D myocardial T1ρ mapping requires multiple breath-holds and provides limited coverage of the heart. In this study, we proposed a free-breathing 3D T1ρ mapping technique featuring whole heart coverage, near-isotropic spatial resolution (1.7×1.7×2mm³) and 100% respiratory acquisition efficiency. With the proposed technique, five T1ρ weightings were acquired in a clinically feasible scan time (~6 min), based on which 3D T1ρ maps were estimated. The accuracy and feasibility of the 3D technique was investigated in phantoms, healthy subjects and patient.

Aurelien Bustin¹, Alina Hua¹, Giorgia Milotta¹, Olivier Jaubert¹, Reza Hajhosseiny¹, Tevfik Ismail¹, René Botnar¹, and Claudia Prieto^1
1Biomedical Engineering Department, School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom

Myocardial T2 mapping has emerged as a promising tool for edema characterization and detection of myocardial inflammation. T2 mapping is conventionally performed under breath-hold by acquiring multiple T2-prepared images using 2D bSSFP. However, 2D imaging and breath-holding impedes high spatial resolution, limits whole-heart coverage and can be challenging in some patients. We developed a free-breathing 3D whole-heart T2 mapping framework that achieves high isotropic resolution in a clinically feasible scan time in healthy subjects. Here we sought to quantify the reproducibility and repeatability of this technique and assess its performance to detect myocardial inflammation in a clinical setting.

Andrew D Scott^1,2, Peter D Gatehouse^1,2, and David N Firmin^1,2
1CMR Unit, The Royal Brompton Hospital, London, United Kingdom, ²National Heart and Lung Institute, Imperial College London, London, United Kingdom

MR based measures of myocardial extra cellular volume fraction (ECV) obtained from pre and post-contrast T1 mapping are frequently used in research studies. However, typically ECV calculations rely on rapid exchange of water molecules between the intra and extracellular space.  We assess the validity of the shutter speed approximation of the full two-compartment model and use this model to assess the effect of limited water exchange rate between the cardiomyocytes and interstitial fluid. For typical conditions used in measuring ECV, we demonstrate an underestimation of ECV on a similar magnitude to the changes attributed to disease in some studies.

Kevin Godines¹, Wissam AlGhuraibawi¹, Bonnie Lam¹, and Moriel Vandsburger^1
1Bioengineering, University of California Berkeley, Berkeley, CA, United States

CEST-MRI is emerging as a powerful modality for molecular imaging of cardiac metabolites and fibrosis. In order to derive all contrasts (amide proton transfer: APT, creatine, and magnetization transfer: MT) a substantial number of differently CEST-weighted images must be acquired. Application of compressed sensing for cardiac CEST enables a 5x acceleration of acquisition with preserved accuracy.

Brianna F. Moon¹, Srikant Kamesh Iyer², Eileen Hwuang¹, Nicholas J. Josselyn², James J. Pilla², Joseph H. Gorman III³, Robert C. Gorman³, Cory Tschabrunn⁴, Samuel J. Keeney³, Estibaliz Castillero⁵, Giovanni Ferrari⁵, Steffen Jockusch⁶, Haochang Shou⁷, Elizabeth M. Higbee-Dempsey⁸, Andrew Tsourkas¹, Victor A. Ferrari⁴, Yuchi Han⁴, Harold I. Litt², and Walter R. Witschey^2
1Bioengineering, University of Pennsylvania, Philadelphia, PA, United States, ²Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States, ³Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States, ⁴Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States, ⁵Surgery, Columbia University Irving Medical Center, New York City, NY, United States, ⁶Chemistry, Columbia University, New York City, NY, United States, ⁷Biostatistics, Epidemiology and Informatics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States, ⁸Biochemistry and Molecular Biophysics Graduate Group, Perelman School of medicine, University of Pennsylvania, Philadelphia, PA, United States

There are multiple forms of iron including protein bound and labile iron found in reperfusion injury of acute myocardial infarction (MI). This study investigated iron accumulation, molecular form of iron, and cellular response to reperfusion injury with respect to the duration of wound-healing, in a large animal model. We demonstrate with magnetic susceptibility and R2* imaging biomarkers, there is a significant increase in infarct iron content in acute reperfusion injury that dissipates by 8-week post-MI and validate these findings with histology, iron concentration, and mRNA expression.