Pierre Daudé^1,2, Thomas Troalen³, Adèle L C Mackowiak^4,5, Davide Piccini^4,6, Jerôme Yerly^4,5, Josef Pfeuffer⁷, Frank Kober^1,2, Sylviane Confort Gouny^1,2, Monique Bernard^1,2, Matthias Stuber^4,5, Jessica A M Bastiaansen^4,5,8,9, and Stanislas Rapacchi^1,2
1Aix-Marseille Univ, CNRS, CRMBM, Marseille, France, ²APHM, Hôpital Universitaire Timone, CEMEREM, Marseille, France, ³Siemens Healthcare SAS, Saint-Denis, France, ⁴Department of Diagnostic and Interventional Radiology, Lausanne University Hospital, Lausanne, Switzerland, ⁵Center for Biomedical Imaging, Lausanne, Switzerland, ⁶Advanced Clinical Imaging Technology, Siemens Healthcare, Lausanne, Switzerland, ⁷Siemens Healthcare, MR Application Development, Erlangen, Germany, ⁸Department of Diagnostic, Interventional and Pediatric Radiology, Bern University Hospital (Inselspital), Bern, Switzerland, ⁹Translational Imaging Center, sitem-insel, Bern, Switzerland

Free-running cardiac DIXON-MRI has potential for T2*/PDFF quantification to explore cardiac fat accumulation and alteration in metabolic diseases. DIXON at 3T suffers from rapid fat-water phase accrual and inhomogeneous B0. Consequently, bipolar echoes, as opposed to monopolar, are required to achieve equal/shorter than in-phase/out-of-phase echo spacing. However, distortions occur between even and odd echoes due to gradients imperfections. Thus, the existing framework was extended with a k-space trajectory correction based on gradient impulse response function(GIRF). Both monopolar or bipolar echoes without GIRF correction resulted in fat-water swaps and unreliable quantitative maps, that were resolved using GIRF-corrected bipolar free-running DIXON.

Andrew Tyler^1,2, Moritz Hundertmark¹, Jack J. Miller^1,2,3,4, Oliver J. Rider¹, Damian J. Tyler^1,2, and Ladislav Valkovic^1
1OCMR, University of Oxford, Oxford, United Kingdom, ²Department of Physiology, Anatomy & Genetics, University of Oxford, Oxford, United Kingdom, ³Department of Physics, University of Oxford, Oxford, United Kingdom, ⁴The MR Research Centre, Aarhus University, Aarhus, Denmark

Using the SLAM algorithm to reconstruct non-gated acquisition weighted ³¹P cardiac CSI data-sets improved repeatability by 35% and reduced variation by 23%, compared to a Fourier based reconstruction of the same data-set, without requiring a change to acquisition protocol.

Pascal Bouvain¹, Sebastian Temme¹, Maria Grandoch¹, and Ulrich Flögel^1
1Heinrich Heine University, Düsseldorf, Germany

Intravenous ¹⁹F tracer application for in vivo labelling of neutrophils prior to injury allowed the non-invasive 3D visualization of neutrophils within their different hematopoietic niches over the entire body and the subsequent monitoring of their egress into affected tissues. Stimulated murine/human neutrophils exhibited enhanced labelling which could be exploited as an in vivo readout for their activation state in both sterile and nonsterile cardiovascular inflammation. In summary, the present study demonstrates that both human and murine neutrophils can be specifically targeted to track their dynamic trafficking by non-invasive ¹H/¹⁹F MRI in vivo. 

Sebastian Weingärtner¹, Ömer Burak Demirel², Qian Tao¹, Joao Tourais¹, and Mehmet Akcakaya^2
1Department of Imaging Physics, Delft University of Technology, Delft, Netherlands, ²Department of Electrical and Computer Engineering and Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States

Quantitative imaging of magnetization transfer (MT) may enable non-contrast assessment of myocardial scar and fibrosis. However, its application at 3T has so far been limited. In this work we investigate an inversion recovery based method for joint quantification of T1 and MT maps. A numerical binary spin-bath model is used to account for incomplete bound pool saturation in the presence of limited preparation durations. In vivo images were obtained with high visual map quality for both T1 and MT quantification, and comparable, low CoV across the two parameters (T1: 5.5+-0.6% and MT: 5.8+-0.9%).

Jérôme Yerly^1,2, Christopher W Roy¹, Bastien Milani¹, Davide Piccini^1,3, Aurélien Bustin^1,4,5, Mariana B.L. Falcão¹, Ruud B. van Heeswijk¹, and Matthias Stuber^1,2,4
1Radiology, Lausanne University Hospital (CHUV) and University of Lausanne (UNIL), Lausanne, Switzerland, ²CIBM Center for Biomedical Imaging, Lausanne, Switzerland, ³Advanced Clinical Imaging Technology, Siemens Healthcare, Lausanne, Switzerland, ⁴Electrophysiology and Heart Modeling Institute, IHU LIRYC, Bordeaux, France, ⁵Cardiovascular Imaging, Hôpital Cardiologique du Haut-Lévêque, CHU de Bordeaux, Bordeaux, France

The free-running framework (FRF) was recently proposed to address the limitations of current techniques to assess left ventricular (LV) ejection fraction (LVEF). However, the accuracy of FRF to assess LVEF has yet to be quantitatively examined. This work rigorously quantifies and optimizes the effect of the regularization weights on LVEF and several image quality metrics using a numerical phantom with well-controlled boundary conditions, and validates the results in in-vivo 5D FRF data. The results demonstrated that the combination of regularization weights that are optimal in terms of image quality do not correspond to the optimal weights for LVEF assessment.

Ganesh Adluru^1,2, Jason Mendes¹, Ravi Ranjan³, Eugene Kholmovski^1,4, and Edward V.R. DiBella^1,2
1Radiology & Imaging Sciences, University of Utah, Salt Lake City, UT, United States, ²Biomedical Engineering, University of Utah, Salt Lake City, UT, United States, ³Internal Medicine, University of Utah, Salt Lake City, UT, United States, ⁴Biomedical Engineering, Johns Hopkins University, Baltimore, MD, United States

Left atrial late gadolinium enhancement imaging is a promising tool to identify scar and fibrosis. Existing acquisition and reconstruction methods can suffer from long scan time, poor image quality, and inability to accurately quantify the fibrosis. Here we propose a fixed time isotropic imaging of the left atrium with a resolution of 1.25mm³.  We use retrospective respiratory navigation to remove inconsistent data due to motion and use a constrained reconstruction framework with total variation and 3D block-matching regularizers to remove the data undersampling artifacts. Promising results showing gains from the isotropic acquisitions are presented in canine and human studies.

Joao Tourais¹, Omer Burak Demirel², Qian Tao³, Iain Pierce⁴, George Thornton⁴, Thomas Treibel⁴, Sebastian Weingärtner¹, and Mehmet Akcakaya^2
1Imaging Physics, Delft University of Technology (TU Delft), Delft, Netherlands, ²Department for Electrical and Computer Engineering, and Center for Magnetic Resonance Research, University of Minnesota, Minnesota, MN, United States, ³Delft University of Technology (TU Delft), Delft, Netherlands, ⁴Barts heart centre, Barts Health NHS Trust, London, United Kingdom

Spin-lock dispersion is a promising biomarker for the assessment of myocardial infarction. However, at 3T, the required range of T1⍴ maps acquired at different amplitudes suffers from specific absorption rate (SAR) limitations and off-resonance artifacts. Relaxation Along a Fictitious Field (RAFF) is an alternative to SL preparations with lower SAR requirements while still sampling relaxation in the rotating frame. Thus, a single breath-hold simultaneous TRAFF2 and T2 mapping sequence is proposed for sl dispersion mapping at 3T. High visual quality maps and accurate T2, TRAFF2, and SL dispersion values are achieved with the proposed sequence in phantoms and in vivo.

Peter Speier¹, Yan Tu Huang², Carmel Hayes¹, Randall Kroeker¹, Manuela Rick¹, Michael Schwertfeger³, and Mario Bacher^1
1Siemens Healthcare, Erlangen, Germany, ²Siemens Healthcare, Shenzen, China, ³ASTRUM IT GmbH, Erlangen, Germany

Contactless cardiac triggering using Pilot Tone was initially demonstrated for steady-state triggered cine-type sequences that, per definition, are performed with continuous, uniform RF pulses. Here we describe a method that stabilizes Pilot Tone cardiac triggering in the presence of RF artefacts, thereby allowing for pilot tone triggering of complete cardiac MR examinations with a range of sequence flavors including those applying RF pulses intermittently.  The method uses an additional RF calibration measurement and avoids the RF artefact subspace in a PCA-based multi-channel coil combination calculation. Signal examples at 1.5T demonstrate effective RF suppression.

Dmitrij Kravchenko¹, Alexander Isaak¹, Shuo Zhang², Narine Mesropyan¹, Leon M. Bischoff¹, Thomas Vollbrecht¹, Oliver Weber², Claus Christian Pieper¹, Daniel Kuetting¹, Christopher Hart³, Ulrike Attenberger¹, and Julian Luetkens^1
1Diagnostic and interventional radiology, University Hospital Bonn, Bonn, Germany, ²Philips GmbH DACH, Hamburg, Germany, ³Pediatric Cardiology, University Hospital Bonn, Bonn, Germany

Cardiac MRI is currently the standard imaging modality for patients with congenital heart disease (CHD). However, the requirement for breath holds remains a big challenge in clinical practice and image quality is often significantly degraded by respiratory motion artifacts. We employed respiratory-triggered pseudo-golden-angle bSSFP imaging for free-breathing cine MRI and compared cardiac volumetry, function, and image quality with the standard breath hold technique. The proposed method showed good agreement with comparable diagnostic image quality and advantage in patients with limited breath hold capability. These demonstrated promise for a wider clinical routine application in patients with CHD.

Anna V Naumova¹ and William S Kerwin^1
1Radiology, University of Washington, Seattle, WA, United States

A new straight forward approach for rapid and robust quantification of myocardial circumferential strain has been developed. The key to this method is placement of the linear tags in 60-degree pattern offsets and alignment of the tags with the AHA segments for optimized segmental analysis. The approach has been implemented for the first time for evaluation of the human cardiomyocyte transplantation benefits in the infarcted pig heart. We have shown the temporal changes in circumferential strain and strain rate of the infarcted segments of myocardium and recovery of myocardial strain followed human cardiomyocyte transplantation in comparison with untreated control group.

Jacob P. Goes¹, Vivian S. Nguyen¹, Donovan Gorre², Narutoshi Hibino³, Hui Wang^4,5, Marcella K. Vaicik¹, Amit R. Patel⁶, and Keigo Kawaji^1,6
1Biomedical Engineering, Illinois Institute of Technology, Chicago, IL, United States, ²Radiology, University of Chicago Medical Center, Chicago, IL, United States, ³Surgery, University of Chicago Medical Center, Chicago, IL, United States, ⁴Philips, Gainesville, FL, United States, ⁵Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States, ⁶Medicine - Cardiology, University of Chicago Medical Center, Chicago, IL, United States

Multi-Contrast single breath-hold acquisition for cardiac MRI is highly desirable but is rate-limited by the need for a dedicated pre-scan per each acquisition. We revisit the notion of the necessary conditions for repeated preparation calibration steps, with the intent of loosening or selectively bypassing them in consecutive scan acquisitions. Under matched geometric conditions that account for sensitivities especially to off-resonance, we propose a simple bSSFP-SPGR based dual-acquisition method with a single intensive Cine calibration followed by a truncated SPGR calibration. This approach is demonstrated as Cine-Tag SSFP-SPGR CMR method that allows for one breath-hold functional acquisition of both scan sequences.