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Background: Left atrial (LA) myopathy is thought to be associated with silent brain infarctions (SBI) through changes in blood flow hemodynamics leading to thrombogenesis. 4D‐flow MRI enables in‐vivo hemodynamic quantification in the left atrium (LA) and LA appendage (LAA). Purpose: To determine whether LA and LAA hemodynamic and volumetric parameters are associated with SBI. Study Type: Prospective observational study. Population: A single‐site cohort of 125 Participants of the multiethnic study of atherosclerosis (MESA), mean age: 72.3 ± 7.2 years, 56 men. Field Strength/Sequence: 1.5T. Cardiac MRI: Cine balanced steady state free precession (bSSFP) and 4D‐flow sequences. Brain MRI: T1‐ and T2‐weighted SE and FLAIR. Assessment: Presence of SBI was determined from brain MRI by neuroradiologists according to routine diagnostic criteria in all participants without a history of stroke based on the MESA database. Minimum and maximum LA volumes and ejection fraction were calculated from bSSFP data. Blood stasis (% of voxels <10 cm/sec) and peak velocity (cm/sec) in the LA and LAA were assessed by a radiologist using an established 4D‐flow workflow. Statistical Tests: Student's t test, Mann–Whitney U test, one‐way ANOVA, chi‐square test. Multivariable stepwise logistic regression with automatic forward and backward selection. Significance level P < 0.05. Results: 26 (20.8%) had at least one SBI. After Bonferroni correction, participants with SBI were significantly older and had significantly lower peak velocities in the LAA. In multivariable analyses, age (per 10‐years) (odds ratio (OR) = 1.99 (95% confidence interval (CI): 1.30–3.04)) and LAA peak velocity (per cm/sec) (OR = 0.87 (95% CI: 0.81–0.93)) were significantly associated with SBI. Conclusion: Older age and lower LAA peak velocity were associated with SBI in multivariable analyses whereas volumetric‐based measures from cardiac MRI or cardiovascular risk factors were not. Cardiac 4D‐flow MRI showed potential to serve as a novel imaging marker for SBI. Level of Evidence: 3 Technical Efficacy: Stage 2 [ABSTRACT FROM AUTHOR]

Purpose: An automatic method is presented for estimating 4D flow MRI velocity measurement uncertainty in each voxel. The velocity distance (VD) metric, a statistical distance between the measured velocity and local error distribution, is introduced as a novel measure of 4D flow MRI velocity measurement quality. Methods: The method uses mass conservation to assess the local velocity error variance and the standardized difference of means (SDM) velocity to estimate the velocity error correlations. VD is evaluated as the Mahalanobis distance between the local velocity measurement and the local error distribution. The uncertainty model is validated synthetically and tested in vitro under different flow resolutions and noise levels. The VD's application is demonstrated on two in vivo thoracic vasculature 4D flow datasets. Results: Synthetic results show the proposed uncertainty quantification method is sensitive to aliased regions across various velocity‐to‐noise ratios and assesses velocity error correlations in four‐ and six‐point acquisitions with correlation errors at or under 3.2%. In vitro results demonstrate the method's sensitivity to spatial resolution, venc settings, partial volume effects, and phase wrapping error sources. Applying VD to assess in vivo 4D flow MRI in the aorta demonstrates the expected increase in measured velocity quality with contrast administration and systolic flow. Conclusion: The proposed 4D flow MRI uncertainty quantification method assesses velocity measurement error owing to sources including noise, intravoxel phase dispersion, and velocity aliasing. This method enables rigorous comparison of 4D flow MRI datasets obtained in longitudinal studies, across patient populations, and with different MRI systems. [ABSTRACT FROM AUTHOR]

Orthotopic heart transplant (OHT) is a well-established therapy for end-stage heart failure that leads to improved long-term survival rates, with careful allograft surveillance essential for optimizing clinical outcomes after OHT. Unfortunately, complications can arise after OHT that can compromise the success of the OHT. Cardiac MRI is continually evolving, with a range of advanced techniques that can be applied to evaluate allograft structure and function. Understanding the unique features of cardiac MRI in OHT recipients, identifying findings suggestive of acute or chronic complications, and recognizing the limitations of this imaging modality are essential for accurate interpretation of cardiac MRI findings and subsequent clinical reporting. The authors address the anticipated postsurgical anatomy and functionality of the OHT. Emphasis is placed on the advanced functional and tissue characterization features that can be seen in the stable OHT recipient, including global longitudinal strain, late gadolinium enhancement, native T1 and T2 mapping, and extracellular volume fraction. Subsequently, the evidence for detection of acute cardiac allograft rejection with cardiac MRI comprehensive tissue characterization techniques and the role of quantitative myocardial perfusion for cardiac allograft vasculopathy screening are discussed, with reference to their comparative standard of reference screening tests, including endomyocardial biopsy, invasive coronary angiography, and myocardial rest and stress perfusion PET/CT. Cardiac MRI has been included in contemporary OHT management guidelines and therefore can be considered a complementary tool for allograft evaluation. The authors demonstrate the complementary role cardiac MRI can play in cardiac allograft surveillance, with clinical examples. © RSNA, 2025 Supplemental material is available for this article. See the invited commentary by Agarwal in this issue.

Delivery of health care, including medical imaging, generates substantial global greenhouse gas emissions. The cardiovascular magnetic resonance (CMR) community has an opportunity to decrease our carbon footprint, mitigate the effects of the climate crisis, and develop resiliency to current and future impacts of climate change. The goal of this document is to review and recommend actions and strategies to allow for CMR operation with improved sustainability, including efficient CMR protocols and CMR imaging workflow strategies for reducing greenhouse gas emissions, energy, and waste, and to decrease reliance on finite resources, including helium and waterbody contamination by gadolinium-based contrast agents. The article also highlights the potential of artificial intelligence and new hardware concepts, such as low-helium and low-field CMR, in achieving these aims. Specific actions include powering down magnetic resonance imaging scanners overnight and when not in use, reducing low-value CMR, and implementing efficient, non-contrast, and abbreviated CMR protocols when feasible. Data on estimated energy and greenhouse gas savings are provided where it is available, and areas of future research are highlighted., Competing Interests: Declaration of competing interests MM: Grant support by Siemens, Circle Cardiovascular Imaging; Co-founder Third Coast Dynamics; CBD is the CEO (part-time) of the Society for Cardiovascular Magnetic Resonance; speakers fees from Siemens Healthineers, GE HealthCare, Philips and Bayer; consultancy fees from Bayer; ACW is the Principal Investigator on a US Government Cooperative Research and Development Agreement (CRADA) with Siemens Healthcare which includes research on 0.55T CMR; RO: Consulting fees from Bayer, Philips and Prenuvo; honoraria and travel support for presenting Grand Rounds at multiple academic institutions; founder and CEO, Greenwell Project, a 501(c)(3) nonprofit, MYN has received educational grants from Circle Cardiovascular Imaging, Bayer, GE, TeraRecon, Arterys and Lode, as well as speakers fees from GE Healthcare, Boerhinger Ingelheim, Bayer and Circle Cardiovascular Imaging; QZ acknowledges support from British Heart Foundation (FS/IBSRF/23/25190)., (Copyright © 2025 The Authors. Published by Elsevier Inc. All rights reserved.)