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Paulina Siuryte¹, Markus Henningsson², Christal van de Steeg-Henzen³, and Sebastian Weingärtner^1
1TU Delft, Delft, Netherlands, ²Department of Health, Medicine and Caring Sciences, Linköping University, Linköping, Sweden, ³Holland PTC, Delft, Netherlands

Keywords: Heart, Artifacts, cardiac B1+ mapping, transmit field imaging

Cardiac MRI at 3T offers gains in SNR, but is strongly affected by field inhomogeneities, including the transmit field B₁⁺. Mapping |B₁⁺| field around the heart is particularly challenging due to the presence of motion, and few techniques exist for robust imaging. Recently, Bloch-Siegert shift mapping was proposed for motion robust cardiac |B₁⁺| mapping, however, it requires long echo times making it more susceptible to artifacts. Here, we introduce a new preparation module for efficient |B₁⁺| mapping. The method shows 0.06% / 0.35% reduced noise variability in phantom and 0.61±0.35% / 0.89±0.63% in-vivo imaging, and visually improved map quality.

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Grzegorz Tomasz Kowalik¹, Radhouene Neji^1,2, Tracy Moon³, Nina Mellor³, Reza Razavi¹, Kuberan Pushparajah¹, and Sébastien Roujol^1
1School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom, ²MR Research Collaborations, Siemens Healthcare Limited, Camberley, United Kingdom, ³Guy's and St Thomas' NHS Foundation Trust, London, United Kingdom

Keywords: Heart, MR-Guided Interventions

An automated catheter tracking approach was developed for real-time continuous catheter visualization during MR-guided cardiac catheterization. 1D projection images are acquired for each slice of a stack providing fast 3D volume screening. These images are first collected in the absence of catheter to create an atlas on background signal across the breathing cycle. During catheter navigation, incoming images are matched to the best images of the atlas, which are then subtracted to suppress background signal. Finally, automated peak detection is applied to extract the catheter balloon location. The technique is successfully demonstrated during in-vitro and in one patient.

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Theresa Reiter¹, Oliver M Weber², Ingo Weiss³, and Wolfgang Rudolf Bauer^1
1Medicine I, University Hospital Wuerzburg, Wuerzburg, Germany, ²Philips GmbH, Hamburg, Germany, ³Biotronik SE Co.KG, Berlin, Germany

Keywords: Myocardium, Visualization

Performing a cardiac MRI in the presence of active cardiac implants remains a challenge due to the extensive artifact burden caused by the implant. Sequence solutions established at 1.5 T have yet to be transferred to a clinical use at 3T. In this work, we use phantom and volunteer measurements in order to establish an adapted 3T protocol for CINE with TFE and wideband LGE-PSIR sequences that sufficiently suppress image artifacts caused by active implants. The first clinical data show the feasibility of this protocol and its ability to detect scar tissue in patients with implanted ICD.

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Rohini Vidya Shankar¹, Li Huang¹, Radhouene Neji^1,2, Grzegorz Kowalik¹, Alexander Paul Neofytou¹, Ronald Mooiweer^1,2, Tracy Moon³, Nina Mellor³, Reza Razavi¹, Kuberan Pushparajah¹, and Sébastien Roujol^1
1Biomedical Engineering, King's College London, London, United Kingdom, ²MR Research Collaborations, Siemens Healthcare Limited, Camberley, United Kingdom, ³Guy's and St Thomas' NHS Foundation Trust, London, United Kingdom

Keywords: Heart, MR-Guided Interventions, Tracking, Real-time

MR-guided cardiac catheterization procedures currently employ passive tracking approaches to follow the gadolinium-filled catheter balloon during catheter navigation. This requires frequent manual tracking and repositioning of the imaging slice, especially when the catheter moves out-of-plane during the procedure. In this study, we developed a novel MRI guidance approach that enables automatic real-time tracking of the catheter balloon and repositioning of the imaging slice for continuous visualization of the balloon during catheter navigation. We first demonstrate the proposed approach in a phantom and subsequently present an initial evaluation in patients.

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Heeseung Lim¹, Benjamin Wilk^1,2, Gerald Moran³, Heather Biernaski¹, Jonathan D. Thiessen^1,2,4, and Frank S. Prato^1,2,5
1Lawson Imaging, Lawson Health Research Institute, London, ON, Canada, ²Medical Biophysics, Western University, London, ON, Canada, ³Siemens Healthcare Limited, Oakville, ON, Canada, ⁴Medical Imaging, Western University, London, ON, Canada, ⁵Physics and Astronomy, Western University, London, ON, Canada

Keywords: Heart, Cardiovascular

Different motion correction methods for cardiac imaging were compared with no motion correction and free-motion images on a hybrid PET/MRI platform. These data were acquired in eight large animals five days after induction of myocardial infarction. PET/MRI images were acquired under different conditions of cardiac and respiratory motion: BodyCompass™, XD-GRASP, ECG gated. Upon completion of in vivo imaging, the animal was immediately euthanized within the scanner, and motion-free images were acquired. Initial quantitative evaluation of the cardiac images showed variation in mean and standard deviation values between the region of interest and different motion correction methods.

Yang Wu¹, Peng Sun², Zhigang Wu², Xiaoxiao Zhang², Jing Zhang², and Jiazheng Wang^2
1Department of Medical Imaging, Wuhan Asia General Hosipital, Wuhan, China, ²Philips Healthcare, Beijing, China

Keywords: Myocardium, Cardiovascular

Diffusion MRI delivers unique information about the heart without the use of external contrast agents, Because of B0 inhomogeneity within the thorax and short transverse relaxation durations, which cause substantial distortion and signal loss, it has proven technically problematic. DWI with Zoom imaging with 2D RF pulse (iZoom) could significantly minimize distortion, but it is still vulnerable to field inhomogeneity when it is big. iZoom with SENSE could reduce distortion and signal loss even further. An in vivo research on volunteers with various SENSE factors revealed that combining iZoom with SENSE considerably improves visual quality.

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Eyal Hanania¹, Lilach Barkat¹, Israel Cohen¹, Haim Azhari¹, and Moti Freiman^1
1The Technion – Israel Institute of Technology, Haifa, Israel

Keywords: Myocardium, Quantitative Imaging, Cardiac, Relaxation

Diffuse myocardial diseases can be diagnosed using T1 mapping technique. The T1 relaxation parameter is computed through the pixel-wise model fitting. Hence, pixel misalignment resulted by cardiac motion leads to an inaccurate T1 mapping. Therefore, registration is needed. However, standard registration methods are computationally expensive. To overcome this challenge, we propose a new deep-learning-based group-wise registration approach that register all the different time points simultaneously. Our approach achieved the best median model-fitting R² compared to baseline methods (0.9846, vs. 0.9651/0.9744/0.9756), and achieve reasonably close T1 value to the expected myocardial T1 value

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Terrence Jao¹, Christopher Sandino², and Shreyas Vasanawala^1
1Department of Radiology, Stanford University, Stanford, CA, United States, ²Department of Electrical Engineering, Stanford University, Stanford, CA, United States

Keywords: Heart, Machine Learning/Artificial Intelligence, Deep Learning, Unrolled, Self Attention, CINE

A deep learning based ESPIRiT (DL-ESPIRiT) was recently proposed to reconstruct dynamic MRI data with higher reconstruction accuracy. However, the method still has difficulty resolving fine anatomic structures. We propose incorporating self-attention to the network using a computationally lightweight squeeze-excitation block (DL-ESPIRiT SE), which uses global information to select more important features while suppressing less important ones. We demonstrate improved reconstruction with DL-ESPIRiT SE, which is most pronounced during faster cardiac motion such as in ventricular ejection.

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Habib Rebbah¹ and Timothé Boutelier^1
1Research & Innovation, Olea Medical, La Ciotat, France

Keywords: Myocardium, Segmentation

Obtaining databases with expert’ manual segmentations to train U-Net is an essential but also a time-consuming operation. We explore here the effect of expanding such a database to other cases with a demon co-registration algorithm. The purpose is to speed up the manual steps but also to allow the development of segmentation algorithms for new cases. We illustrate our approach with MOLLI’ masks expanded to T2 and perfusion data.

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Alexander Paul Neofytou¹, Grzegorz Tomasz Kowalik¹, Radhouene Neji^1,2, Reza Razavi¹, Kuberan Pushparajah¹, and Sébastien Roujol^1
1School of Biomedical Engineering and Imaging Sciences, Faculty of Life Sciences and Medicine, King's College London, London, United Kingdom, ²MR Research Collaborations, Siemens Healthcare Limited, Camberley, United Kingdom

Keywords: Heart, MR-Guided Interventions

A deep neural network trained on images with artificially generated catheter signal was developed and enables accurate detection of catheter signal under real-time conditions. Further investigations, with in-line integration, are now warranted to determine the benefit of this technique for improved catheter navigation.

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Xinqi Li¹, Yuheng Huang², Xingmin Guan², Xinheng Zhang², Ghazal Yoosefian², Xiaoming Bi³, Fei Han³, HsuLei Lee¹, Anthony Christodoulou¹, Debiao Li¹, Rohan Dharmakumar², Hui Han¹, and Hsin-Jung Yang^1
1Biomedical Image Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States, ²Krannert Cardiovascular Research Center, Indiana University School of Medicine, Indianapolis, IN, United States, ³Siemens Healthineers, Malvern, PA, United States

Keywords: Myocardium, Shims

B₀ inhomogeneity is a long-lasting issue for CMR in high-field (3T and above) scanners. B₀ shimming is a standard way to improve the B₀ field. However, motion-induced field inhomogeneity is an unknown factor in routine practice and compromises cardiac B₀ shimming quality. Here, we proposed a motion-resolved cardiac B₀ shimming strategy by acquiring motion-resolved cardiac B₀ field maps and adopting a modified U-net model for precise and automatic shim field derivation. We showed that dynamic shimming could improve field homogeneity through the respiratory cycle and provide a reliable B₀ field for free-breathing CMR at 3T.

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Komlan Payne¹, Yunkun Zhao¹, Leslie L. Ying¹, and Xiaoliang Zhang^1
1Department of Biomedical Engineering, University at Buffalo, Buffalo, NY, United States

Keywords: Vessel Wall, Interventional Devices, Blood vessels

Catheter-based RF coils are preferred over conventional external coils due to the weak detection signal from intermediate field region. One of the major issues using catheter RF coils is the design payload (feeding network, preamplifier, balun) associated with the limited space of the catheter. The technique also lacks efficient way to track the catheter during the procedure. To overcome these challenges, we propose 4-channel standalone and wireless resonators to amplify the local B1 field while a body coil is used as the transceiver. The receive B1 fields with and without the local resonators are obtained for field enhancement analysis.

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Jiameng Diao¹, Yang Liu¹, Wenjian Liu¹, Yiming Tao¹, Jianing Geng¹, Shang Cao¹, Jiayu Zhu², Junpu Hu², Jian Xu³, Zijian Zhou¹, Haikun Qi^1,4, and Peng Hu^1,4
1School of Biomedical Engineering, ShanghaiTech University, Shanghai, China, ²United Imaging Healthcare, Shanghai, China, ³UIH America, Inc., Houston, TX, United States, ⁴Shanghai Clinical Research and Trial Center, Shanghai, China

Keywords: Heart, Motion Correction

Magnetic resonance imaging (MRI) is susceptible to respiratory motion-induced artifacts due to the relatively slow data acquisition. These artifacts remain an impediment to clinical application and are further amplified in cardiovascular MRI. Respiratory motion model is an effectively method to reduce motion artifacts. In this study, we proposed a novel patient-specific respiratory motion correction method with more reliable training data and capability to perform spoke-wise correction. Combined with compressed sensing, parallel imaging, image registration and model fitting, this method greatly reduces respiratory motion artifacts.

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Yun Shang¹, Sebastian Theilenberg¹, Boyu Peng², Michael Hock³, Laura M. Schreiber^3,4, Sachin Jambawalikar^1,2, and Christoph Juchem^1,2
1Department of Biomedical Engineering, Columbia University in the City of New York, New York, NY, United States, ²Department of Radiology, Columbia University in the City of New York, New York, NY, United States, ³Chair of Molecular and Cellular Imaging, Comprehensive Heart Failure Center (CHFC), Würzburg, Germany, ⁴Section of Medical Physics, Department of Radiology, Mainz University Hospital, Mainz, Germany

Keywords: Heart, Shims

Cardiac functional scans adopting bSSFP sequences suffer from dark band artifacts due to B₀ inhomogeneity. The best remedy to mitigate this issue is through cardiac B₀ shimming. A limited understanding of the B₀ conditions in clinical diagnostic orientations impedes the development of an optimal B₀ shim strategy in the human heart. Here we perform a theoretical analysis of spherical harmonic B₀ shim at 3 T using a static global approach and slice-specific dynamic shim updating in the short-axis views of human hearts from 921 subjects as a starting point for the development of optimized cardiac B₀ shim strategies.

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Suvai Gunasekaran¹, KyungPyo Hong¹, Roberta Catania¹, Joshua Robinson², Rod Passman³, Aggelos Katsaggelos⁴, Cynthia Rigsby⁵, Walter Witschey⁶, and Daniel Kim^1
1Radiology, Northwestern University, Feinberg School of Medicine, Chicago, IL, United States, ²Cardiology, Lurie Children’s Hospital, Chicago, IL, United States, ³Cardiology, Northwestern University, Feinberg School of Medicine, Chicago, IL, United States, ⁴Electrical and Computer Engineering, Northwestern University, Evanston, IL, United States, ⁵Radiology, Lurie Children’s Hospital, Chicago, IL, United States, ⁶Radiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States

Keywords: Myocardium, Quantitative Imaging, Fibrosis

T1ρ mapping is an emerging non-contrast pulse sequence for measuring cardiac fibrosis. Unfortunately, current T1ρ techniques suffer from lack of coverage, poor spatial resolution, and long scan time. Thus, we developed an accelerated, free-breathing 3D cardiac T1ρ mapping pulse sequence using XD-GRASP reconstruction including both respiratory and contrast dimensions; additionally, view sharing and KWIC filtering were incorporated to improve spatial resolution. This sequence was tested in 8 patients undergoing clinically indicated cardiac MRI, resulting in robust image quality and T1ρ values that are in agreement with literature.  

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Ayda Arami¹, Christal van de Steeg-Henzen², Hildo J.Lamb³, and Sebastian Weingärtner^1
1TU Delft, Delft, Netherlands, ²HollandPTC, Delft, Netherlands, ³LUMC, Leiden, Netherlands

Keywords: Myocardium, RF Pulse Design & Fields

Black-Blood imaging is an integral part of clinical cardiac MRI, due to it’s clear depiction of the cardiac morphology. Double inversion recovery, is most commonly used for black-blood contrast, by successively applying a non-selective inversion and a slice-selective reinversion. In this work, we investigate dual band adiabatic inversion pulses, as an alternative, to achieve nulling of the blood signal outside of the imaging slice. Thorough blood suppression and comparable noise performance to double inversion recovery were demonstrated in vivo while achieving an 11% reduction in SAR and a 10% reduction in pulse duration.

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David Lohr¹, Wiebke Schlötelburg², Maxim Terekhov¹, and Laura Maria Schreiber^1
1Chair of Molecular and Cellular Imaging, Comprehensive Heart Failure Center (CHFC), University Hospital Würzburg, Würzburg, Germany, ²Department of Nuclear Medicine, University Hospital Würzburg, Würzburg, Germany

Keywords: Myocardium, High-Field MRI

In this study we aim to analyze blood tissue contrast (BTC), SNR, and reproducibility in measurements of cardiac function at 7T. Furthermore, we assess shim quality and its impact on image quality as well as T₂^*. Measurements are performed in n=7 healthy volunteers using a 7T system. Diastolic BTC and SNR in scan1 and scan2 were 2.14±0.24 and 2.22±0.33 as well as 96±35 and 105±29, respectively. Reproducibility assessed via intra class correlation coefficient was found to be excellent for ejection fraction (0.93), myocardial mass (0.99), stroke volume (0.91), end-systolic volume (0.94), and end-diastolic volume (0.93).

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Yasaman Safarkhanlo^1,2, Jerome Yerly^3,4, Mariana Falcao³, Adèle LC Mackowiak^2,3,5, Davide Piccini^3,6, Matthias Stuber^3,4, Bernd Jung^2,5, Christoph Gräni^1,2, and Jessica AM Bastiaansen^2,5
1Department of Cardiology, University Hospital Bern, Inselspital, Bern, Switzerland, ²Translation Imaging Center (TIC), Swiss Institute for Translational and Entrepreneurial Medicine, Bern, Switzerland, ³Department of Diagnostic and Interventional Radiology, Lausanne University Hospital (CHUV), Lausanne, Switzerland, ⁴Center for Biomedical Imaging, Lausanne, Switzerland, ⁵Diagnostic, Interventional and Pediatric Radiology (DIPR), University Hospital Bern, Inselspital, Bern, Switzerland, ⁶Advanced Clinical Imaging Technology, Siemens Healthineers International AG, Lausanne, Switzerland

Keywords: Heart, Fat, data acquisition, data analysis, image reconstruction, low-field MRI

 The presence of fat signals around the heart can affect the diagnostic quality of cardiovascular MR images. There are multiple fat-suppression pulses, such as FISS, and off-resonance water-excitation (WE) pulses, such as BORR, LIBRE, and LIBOR, that have been developed for the free-running balanced Steady-State Free-Precession (bSSFP) sequences at low-field MRI (1.5T). These fat-suppression pulses have never been thoroughly compared to each other, therefore, in this work, we implemented four different fat-suppression pulses and validated their performance on phantoms and healthy volunteers. Our results indicated LIBOR provided better fat suppression compared to BORR and LIBRE, while having fast acquisition time.

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Habib Rebbah¹ and Timothé Boutelier^1
1Research & Innovation, Olea Medical, La Ciotat, France

Keywords: Myocardium, Segmentation

Deducing the orientation main view of an image from the DICOM information could be complicated especially for unconventional image plane as for cardiac MR. We explore here the feasibility of deducing the orientation of the image based on CNN approach.

Xuefang Lu¹, Weiyin Vivian Liu², Yuchen Yan¹, Changsheng Liu¹, Wei Gong¹, Yan Wang¹, Yilin Zhao¹, Guangnan Quan³, and Yunfei Zha^1
1Department of Radiology, Renmin Hospital of Wuhan University, Wuhan, China, ²GE Healthcare, MR Research China, Beijing, China, ³General Electric Medical (China) Co, Beijing, China

Keywords: Myocardium, Image Reconstruction

SNR and CNR are essential for radiologists to precisely assess the signal enhancement in myocardia tissues. High-resolution late gadolinium enhancement cardiac magnetic resonance (LGE-CMR) is important but often possess low SNR and takes long scan time. Compared with original PSMDE (PSMDE_O), ^AIRTM Recon DL-based PSMDE (PSMDE_DL) effectively and significantly improved SNR, CNR and image quality without extra scan time. High-resolution PSMDE_DL images also accelerated diagnossis speed of identifying defected tissues from noisy but normal myocardial tissues and elevated the diagnosis confidence despite no statistically different diagnostic performance between PSMDE_DL and PSMDE_O images.