Cardiovascular magnetic resonance imaging: Principles and advanced techniques.

Cardiovascular magnetic resonance (CMR) imaging is an established non-invasive tool for the assessment of cardiovascular diseases, which are the leading cause of death globally. CMR provides dynamic and static multi-contrast and multi-parametric images, including cine for functional evaluation, contrast-enhanced imaging and parametric mapping for tissue characterization, and MR angiography for the assessment of the aortic, coronary and pulmonary circulation. However, clinical CMR imaging sequences still have some limitations such as the requirement for multiple breath-holds, incomplete spatial coverage, complex planning and acquisition, low scan efficiency and long scan times.

Motion corrected 3D whole-heart SAVA T mapping at 0.55 T.

Purpose: To propose a novel highly efficient isotropic-resolution 3D whole-heart saturation-recovery and variable-flip-angle (SAVA) T mapping sequence at 0.55 T, incorporating image navigator (iNAV)-based non-rigid motion correction and dictionary matching.

Methods: The proposed iNAV-based isotropic-resolution 3D whole-heart SAVA T mapping sequence at 0.

Accelerated DESPOT1 with variable parameters for 3D T1 brain mapping.

Purpose: Driven equilibrium single pulse observation of T1 (DESPOT1) is a reliable technique for clinical 3D T1 brain mapping. However, its fixed repetition time (TR) and bandwidth (BW) and its linear modeling to estimate T1 conveys to an inefficient imaging protocol. We propose a variable DESPOT1 (vDESPOT1) acquisition and modeling strategy to improve scan efficiency and to accelerate image acquisition.

High-resolution 3D whole-heart bright- and black-blood imaging with co-registered T2 mapping at 0.55 T.

Introduction: Conventional CMR exams for assessment of cardiac anatomy and tissue characterization require multiple sequential 2D acquisitions under breath-hold in different orientations, in addition to being limited to 1.5 T and 3 T.

Methods: In this study, we sought to develop a novel 3D motion-compensated free-breathing sequence for comprehensive high-resolution whole-heart assessment of cardiovascular anatomy via simultaneous bright- and black-blood imaging and co-registered myocardial tissue quantification in a one-click scan at 0.

Simultaneous 3D aortic lumen and vessel wall imaging at 0.55 T at either systole or diastole.

Purpose: To evaluate the feasibility of a novel, non-contrast enhanced, 3D, simultaneous bright-blood, and black-blood sequence (iT2prep-BOOST) for aortic imaging at 0.55 T at either systole or diastole.

Methods: Simultaneous contrast-free 3D aortic lumen and vessel wall imaging at 0.

Automated segmentation of thoracic aortic lumen and vessel wall on three-dimensional bright- and black-blood magnetic resonance imaging using nnU-Net.

Background: Magnetic resonance angiography (MRA) is an important tool for aortic assessment in several cardiovascular diseases. Assessment of MRA images relies on manual segmentation, a time-intensive process that is subject to operator variability. We aimed to optimize and validate two deep-learning models for automatic segmentation of the aortic lumen and vessel wall in high-resolution electrocardiogram-triggered free-breathing respiratory motion-corrected three-dimensional (3D) bright- and black-blood MRA images.

Initial experience of cardiac Tρ mapping at 0.55 T: Continuous wave versus adiabatic spin-lock preparation pulses.

Purpose: To propose and validate a cardiac Tρ mapping sequence at 0.55 T comparing continuous-wave and adiabatic spin-lock (SL) preparation pulses.

Methods: The proposed 2D sequence acquires four single-shot balanced SSFP readout images with differing contrasts in a single breath-hold.

Isotropic, high-resolution, whole-chest inversion recovery contrast-enhanced magnetic resonance angiography in under 4.5 min using image-based navigator fluoro trigger.

Background: Serial assessment of the thoracic aorta with magnetic resonance angiography (MRA) is desirable due to 3D volumetric dataset, high spatial resolution, and lack of ionizing radiation. Electrocardiogram (ECG) gated, contrast-enhanced (CE), inversion recovery gradient echo MRA is efficient and historically provides low artifact burden, but the window for imaging with weak albumin binding extracellular gadolinium based contrast agents is small. Our purpose was to acquire whole-chest gated CE-MRA with 1.

High-resolution automated free-breathing coronary magnetic resonance angiography in comparison with coronary computed tomography angiography.

Aims: Clinical implementation of coronary magnetic resonance angiography (CMRA) is limited due to variability in image quality. A protocol utilizing an image navigator (iNAV) integrated with automated scan planning has been developed to facilitate consistent diagnostic image quality. The aim of this study was to evaluate the agreement of automated iNAV CMRA compared with coronary computed tomography angiography (CCTA) using Coronary Artery Disease-Reporting and Data System (CAD-RADS) to classify coronary artery disease (CAD).

Free-breathing, non-contrast, three-dimensional whole-heart coronary magnetic resonance imaging for the identification of culprit and vulnerable atherosclerotic plaque.

Background: Detection of vulnerable coronary plaque can predict future myocardial infarctions. We have developed a novel, non-contrast cardiovascular magnetic resonance sequence (iT2prep-BOOST), enabling simultaneous, co-registered coronary angiography and plaque detection.

Objectives: To validate iT2prep-BOOST in patients with non-ST-segment elevation myocardial infarction (NSTEMI).

End-to-End Deep Learning-Based Motion Correction and Reconstruction for Accelerated Whole-Heart Joint T/T Mapping.

Purpose: To accelerate 3D whole-heart joint T/T mapping for myocardial tissue characterization using an end-to-end deep learning algorithm for joint motion estimation and model-based motion-corrected reconstruction of multi-contrast undersampled data.

Methods: A free-breathing high-resolution motion-compensated 3D joint T/T water/fat sequence is employed. The sequence consists of the acquisition of four interleaved volumes with 2-echo encoding, resulting in eight volumes with different contrasts.

Highlights of the society for magnetic resonance angiography 2024 conference.

The 36th Annual International Meeting of the Society for Magnetic Resonance Angiography (SMRA), held from November 12-15, 2024, in Santiago de Chile, marked a milestone as the first SMRA conference in Latin America. Themed "The Ever-Changing Landscape of MRA", the event highlighted the rapid advancements in magnetic resonance angiography (MRA), including cutting-edge developments in contrast-enhanced MRA, contrast-free techniques, dynamic, multi-parametric, and multi-contrast MRA, 4D flow, low-field solutions and artificial intelligence (AI)-driven technologies, among others. The program featured 174 attendees from 15 countries, including 43 early-career scientists and 30 industry representatives.

Reconstruction techniques for accelerating dynamic cardiovascular magnetic resonance imaging.

Achieving sufficient spatial and temporal resolution for dynamic applications in cardiovascular magnetic resonance (CMR) imaging is a challenging task due to the inherently slow nature of CMR. In order to accelerate scans and allow improved resolution, much research over the past three decades has been aimed at developing innovative reconstruction methods that can yield high-quality images from reduced amounts of k-space data. In this review, we describe the evolution of these reconstruction techniques, with a particular focus on those advances that have shifted the dynamic reconstruction paradigm as it relates to CMR.

Analysis of confounders of the image quality of a high-resolution isotropic three-dimensional Dixon water-fat late gadolinium enhancement technique.

Background: Three-dimensional (3D) water-fat separated late gadolinium enhancement (LGE) imaging is a cardiovascular magnetic resonance imaging technique allowing simultaneous assessment of and discrimination between cardiac fibrosis and myocardial fatty infiltration. The aim of this study is to systematically analyze the image quality of a 3D water-fat separated LGE research sequence and identify confounders of image quality METHODS: In total, 126 patients and 12 healthy volunteers were included. Patients were included with inflammatory bowel disease (n=35), muscular dystrophy (n=38), hypertrophic cardiomyopathy (n=23) and paroxysmal atrial fibrillation (n=30).

The future of cardiovascular magnetic resonance imaging in thoracic aortopathy: blueprint for the paradigm shift to improve management.

Thoracic aortopathies result in aneurysmal expansion of the aorta that can lead to rapidly fatal aortic dissection or rupture. Despite the availability of abundant non-invasive imaging tools, the greatest contemporary challenge in the management of thoracic aortic aneurysm (TAA) is the lack of reliable metrics for risk stratification, with absolute aortic diameter, growth rate, and syndromic factors remaining the primary determinants by which prophylactic surgical intervention is adjudged. Advanced cardiovascular magnetic resonance (CMR) techniques present a potential key to unlocking insights into TAA that could guide disease surveillance and surgical intervention.

3D joint T/T /T mapping and water-fat imaging for contrast-agent free myocardial tissue characterization at 1.5T.

Purpose: To develop a novel, free-breathing, 3D joint / / mapping sequence with Dixon encoding to provide co-registered 3D , , and maps and water-fat volumes with isotropic spatial resolution in a single min scan for comprehensive contrast-agent-free myocardial tissue characterization and simultaneous evaluation of the whole-heart anatomy.

Methods: An interleaving sequence over 5 heartbeats is proposed to provide , , and encoding, with 3D data acquired with Dixon gradient-echo readout and 2D image navigators to enable respiratory scan efficiency. Images were reconstructed with a non-rigid motion-corrected, low-rank patch-based reconstruction, and maps were generated through dictionary matching.

Unsupervised reconstruction of accelerated cardiac cine MRI using neural fields.

Background: Cardiac cine MRI is the gold standard for cardiac functional assessment, but the inherently slow acquisition process creates the necessity of reconstruction approaches for accelerated undersampled acquisitions. Several regularization approaches that exploit spatial-temporal redundancy have been proposed to reconstruct undersampled cardiac cine MRI. More recently, methods based on supervised deep learning have been also proposed to further accelerate acquisition and reconstruction.

3D B1+ corrected simultaneous myocardial T1 and T1ρ mapping with subject-specific respiratory motion correction and water-fat separation.

Purpose: To develop a 3D free-breathing cardiac multi-parametric mapping framework that is robust to confounders of respiratory motion, fat, and B1+ inhomogeneities and validate it for joint myocardial T1 and T1ρ mapping at 3T.

Methods: An electrocardiogram-triggered sequence with dual-echo Dixon readout was developed, where nine cardiac cycles were repeatedly acquired with inversion recovery and T1ρ preparation pulses for T1 and T1ρ sensitization. A subject-specific respiratory motion model relating the 1D diaphragmatic navigator to the respiration-induced 3D translational motion of the heart was constructed followed by respiratory motion binning and intra-bin 3D translational and inter-bin non-rigid motion correction.

Evaluation of myocarditis with a free-breathing three-dimensional isotropic whole-heart joint T1 and T2 mapping sequence.

Background: The diagnosis of myocarditis by cardiovascular magnetic resonance (CMR) requires the use of T2 and T1 weighted imaging, ideally incorporating parametric mapping. Current two-dimensional (2D) mapping sequences are acquired sequentially and involve multiple breath-holds resulting in prolonged scan times and anisotropic image resolution. We developed an isotropic free-breathing three-dimensional (3D) whole-heart sequence that allows simultaneous T1 and T2 mapping and validated it in patients with suspected myocarditis.

Non-invasive in vivo imaging of changes in Collagen III turnover in myocardial fibrosis.

Heart failure (HF) affects 64 million people globally with enormous societal and healthcare costs. Myocardial fibrosis, characterised by changes in collagen content drives HF. Despite evidence that collagen type III (COL3) content changes during myocardial fibrosis, in vivo imaging of COL3 has not been achieved.

Image navigator-based, automated coronary magnetic resonance angiography for the detection of coronary artery stenosis.

Background: Coronary computed tomography angiography (CCTA) is recommended as the first-line diagnostic imaging modality in low-to-intermediate-risk individuals suspected of stable coronary artery disease (CAD). However, CCTA exposes patients to ionizing radiation and potentially nephrotoxic contrast agents. Invasive coronary angiography is the gold-standard investigation to guide coronary revascularisation strategy; however, invasive procedures incur an inherent risk to the patient.

Elastin-specific MR probe for visualization and evaluation of an interleukin-1β targeted therapy for atherosclerosis.

Atherosclerosis is a chronic inflammatory condition of the arteries and represents the primary cause of various cardiovascular diseases. Despite ongoing progress, finding effective anti-inflammatory therapeutic strategies for atherosclerosis remains a challenge. Here, we assessed the potential of molecular magnetic resonance imaging (MRI) to visualize the effects of 01BSUR, an anti-interleukin-1β monoclonal antibody, for treating atherosclerosis in a murine model.

Cardiovascular magnetic resonance reveals myocardial involvement in patients with active stage of inflammatory bowel disease.

Background: Active inflammatory bowel disease (A-IBD) but not remission (R-IBD) has been associated with an increased risk of cardiovascular death and hospitalization for heart failure.

Objectives: Using cardiovascular magnetic resonance (CMR), this study aims to assess adverse myocardial remodeling in patients with IBD in correlation with disease activity.

Methods: Forty-four IBD patients without cardiovascular disease (24 female, median-age: 39.

Simultaneous 3D , , and fat-signal-fraction mapping with respiratory-motion correction for comprehensive liver tissue characterization at 0.55 T.

Purpose: To develop a framework for simultaneous three-dimensional (3D) mapping of , , and fat signal fraction in the liver at 0.55 T.

Methods: The proposed sequence acquires four interleaved 3D volumes with a two-echo Dixon readout.