Journal of Cardiovascular Magnetic Resonance最新文献

Background: Sodium-glucose cotransporter 2 (SGLT2) inhibitors improve metabolic and cardiovascular outcomes, but the mechanisms remain incompletely understood. We utilized cardiovascular magnetic resonance (CMR) and complementary methods to investigate whether preventive SGLT2 inhibitor administration attenuates the development of metabolic heart disease in a high-fat, high-sucrose diet (HFHSD) mouse model.

Methods: Male wild-type (WT) C57BL/6 J mice were fed an HFHSD for 18 weeks to induce obesity, coronary microvascular disease, and diastolic dysfunction. WT mice treated preventively with an SGLT2 inhibitor, empagliflozin (EMPA), were compared to untreated WT mice, and mice fed either an HFHSD or standard chow diet with myeloid cell-specific knockout of the Nos2 gene (Nos2^LysMCre) were compared to floxed controls (Nos2^fl/fl). CMR assessed epicardial adipose tissue (EAT) volume, fatty acid composition (FAC), proton density fat fraction (PDFF), and T1, and myocardial perfusion, and strain. EAT FAC, PDFF, and T1 were quantified using an inversion-recovery multi-echo gradient-echo sequence and a multi-resonance triglyceride model. EAT volume was quantified using cine images. Myocardial perfusion reserve (MPR) and strain were measured using arterial spin labeling, and displacement encoding with stimulated echoes (DENSE), respectively. Histology and flow cytometry assessed EAT remodeling and macrophage polarization.

Results: EMPA treatment reduced EAT volume (0.36±0.18 µL/g vs 0.61±0.25 µL/g, p<0.01) and saturated fatty acid fraction (38.81 [32.83-47.71]% vs 48.06 [43.82-52.65]%, p<0.05), increased EAT T1 (0.799 [0.764-0.859] s vs 0.755 [0.678-0.772] s, p<0.05), and decreased EAT NOS2⁺ macrophages (34.74 [21.38-42.098^]% vs 46.36 [38.08-61.30]%, p<0.05) compared to controls. EMPA improved diastolic strain rate (2.96 [2.61-3.99] s^-1 vs 1.68 [1.21-2.80] s^-1, p<0.01) and adenosine MPR (2.00±0.54 vs 1.37±0.40, p<0.01) compared to controls. Myeloid cell NOS2 knockout mice fed an HFHSD exhibited improved adenosine MPR (1.90±0.47 vs 1.39±0.38, p<0.01) compared to floxed controls.

Conclusions: In this obesity-related metabolic heart disease model, EMPA treatment prevents cardiometabolic dysfunction by improving EAT quantity and quality, coronary microvascular function, and diastolic function. These benefits are mediated in part through macrophage NOS2.

Background: Heart failure (HF) is a leading cause of morbidity and mortality in the United States and is projected to increase in the next decade. Left ventricular ejection fraction (LVEF) is used to guide optimal medical therapy and is typically quantified using two-dimensional transthoracic echocardiography (TTE) due to ease of accessibility and cost. However, LVEF measurements by cardiovascular magnetic resonance (CMR) are considered the gold standard due to their accuracy and precision. Despite this, CMR is not the first imaging modality selected for LVEF evaluation due to perceptions of long study time, high cost, and inaccessibility. Our study aims to determine the cost of imaging studies (e.g., CMR, TTE) relative to the overall HF-related health care costs and associated outcomes.

Methods: A retrospective single-center cohort study of 420 participants with same-day TTE and CMR from 2009-2019, including participants >18 years of age with good image quality with or at risk for cardiovascular disease. Primary outcome was a composite outcome defined as HF admission, left ventricular assist device, cardiovascular disease-related death, heart transplantation, and implantable cardioverter defibrillator implantation. HF risk groups were determined based on clinically relevant LVEF cutoffs. All costs were calculated and adjusted to 2022 US$.

Results: Participants were 49 ± 17 years old, 52% (219/420) female, 50% (209/420) White, and 41% (174/420) Black. Median follow-up was 4 years. HF was the most common co-morbidity (31%). LVEF measured by CMR predicted HF outcomes better than TTE (p = 0.005). Continuous net reclassification index of CMR LVEF was 0.36 (95% confidence interval: 0.16-0.56); p = 0.001 due to predominant reclassification to lower risk groups. On an individual level, HF health care cost increased from low- to high-risk groups irrespective of modality. High-risk individuals classified by CMR had lower average per-person HF health care costs compared to TTE counterparts. Cost of CMR and TTE was <1% of the total HF health care cost.

Conclusion: The cost of non-invasive imaging studies accounted for <1% of the cost compared to other components of HF care. Downstream cost prediction based on LVEF classification using CMR has the potential to better predict cost burden compared to TTE in patients with HF.

Background: Cardiac functional metrics such as ejection fraction, strain, and valve excursion are important diagnostic and prognostic measures of cardiac disease. However, they ignore a large amount of systolic shape change information available from modern cardiovascular magnetic resonance (CMR) examinations. We aimed to automatically quantify multidimensional shape and motion scores from CMR, investigate covariates, and test their discrimination of disease in the UK Biobank compared against standard functional metrics.

Methods: An automated analysis pipeline was used to obtain quality-controlled three-dimensional left and right ventricular shape models in 38,858 UK Biobank participants, 5149 of whom had one or more diagnoses of cardiovascular or cardiometabolic disease. Principal component analysis was used to obtain a statistical shape atlas and quantify each participant's left and right ventricular shape at both end-diastole and end-systole simultaneously. Systolic strain was obtained from arc length changes computed from the shape model, and mitral/tricuspid annular plane systolic excursion (MAPSE/TAPSE) was computed from the displacement of the valves. Discrimination for prevalent disease was quantified using linear discriminant analysis area under the receiver operating characteristic curve.

Results: The first 25 principal component scores captured >90% of the total shape variance. Significantly stronger discrimination for atrial fibrillation, heart failure, diabetes, ischemic disease, and conduction disorders (p<0.001 for each) was obtained using shape scores compared with volumes, ejection fractions, strains, MAPSE, and TAPSE.

Conclusion: Automatically derived shape and motion z-scores capture more discriminative information on disease effects than standard metrics, including volumes, ejection fraction, strain and valve excursions.

Background: Cardiovascular magnetic resonance (CMR) is a complex imaging modality requiring a broad variety of image processing tasks for comprehensive assessment of the study. Recently, foundation models (FM) have shown promise for automated image analyses in natural images (NI). In this study, a CMR-specific vision FM was developed and then finetuned in a supervised manner for nine different imaging tasks typical to a CMR workflow, including classification, segmentation, landmark localization, and pathology detection.

Methods: A ViT-S/8 model was trained in a self-supervised manner using DINO on 36 million CMR images from 27,524 subjects from three sources (UK Biobank and two clinical centers). The model was then finetuned for nine tasks: classification (sequence, cine view), segmentation (cine SAX, cine LAX, LGE SAX, Mapping SAX), landmark localization, pathology detection (LGE, cardiac disease), on data from various sources (both public and three clinical datasets). The results were compared against metrics from state-of-the-art methods on the same tasks. A comparable baseline model was also trained on the same datasets for direct comparison. Additionally, the effect of pretraining strategy, as well as generalization and few-shot performance (training on few labeled samples) was explored for the pretrained model, compared to the baseline.

Results: The proposed model obtained similar performance or moderate improvements to results reported in the literature in most tasks (except disease detection), without any task-specific optimization of methodology. The proposed model outperformed the baseline in most cases, with an average increase of 6.8% points (pp) for cine view classification, and 0.1 to 1.8 pp for segmentation tasks. The proposed method also obtained generally lower standard deviations in the metrics. Improvements of 3.7 and 6.6 pp for hyperenhancement detection from LGE and 14 pp for disease detection were observed. Ablation studies highlighted the importance of pretraining strategy, architecture, and the impact of domain shifts from pretraining to finetuning. Moreover, CMR-pretrained model achieved better generalization and few-shot performance compared to the baseline.

Conclusions: Vision FM specialized for medical imaging can improve accuracy and robustness over NI-FM. Self-supervised pretraining offers a resource-efficient, unified framework for CMR assessment, with the potential to accelerate the development of deep learning-based solutions for image analysis tasks, even with few annotated data available.

Background: Conventional cardiovascular magnetic resonance (CMR) examinations require patients to repeatedly hold their breath, which can reduce examination efficiency and pose challenges for patients unable to do so. This study aimed to demonstrate the feasibility and effectiveness of a full free-breathing CMR protocol in clinical practice.

Methods: Patients prospectively enrolled in this study underwent a full free-breathing CMR exam on a 3T scanner between June 1 and June 30, 2024. Acquisition time and image quality were assessed. Cine and flow imaging were compared with those acquired with the conventional breath-holding CMR protocol. Other sequences, including T1/T2 mapping and late gadolinium enhancement (LGE), were evaluated quantitatively and qualitatively, respectively. Group comparisons were performed using the Wilcoxon signed-rank test or paired t-test. Consistency was assessed using Kappa statistics, Bland-Altman statistics, intraclass correlation coefficient (ICC), and linear regression.

Results: A total of 211 patients were evaluated (median age: 53 years [IQR: 38-63]; range: 10-82 years; 145 men). The mean acquisition time for full free-breathing CMR was 22.6±3.7 min. The median image quality scores for cine and LGE images acquired with free-breathing CMR were 4 (IQR: 4-4) and 5 (IQR: 4-5), respectively. Compared with conventional breath-holding CMR, the end-diastolic volume (EDV), end-systolic volume (ESV), EDV index, and ESV index measured by free-breathing CMR were slightly higher (all P＜0.05), whereas the left ventricular ejection fraction and left ventricular mass were slightly lower (both P＜0.05). Nonetheless, the two methods demonstrated good agreement and correlation (r values: 0.85-0.99). Native T1 and T2 values in healthy subjects from free-breathing CMR were 1214.9±16.7ms and 38.4±3.2ms, respectively. Among the 211 patients, 147 were LGE positive. Except for five patients with image quality scores below 3, all others had scores of 3 or higher.

Conclusion: Full free-breathing CMR examinations are feasible and effective in clinical practice, significantly reduce scan time while maintaining high image quality.

Background: Electrocardiogram (ECG)-triggered cardiovascular magnetic resonance (CMR) can be challenging in patients with ECG unreliability. Pilot tone (PT)-triggered CMR may offer a reliable alternative.

Purpose: To evaluate the feasibility of PT-triggered CMR and compare its performance with ECG-triggered imaging across various sequences in patients with common cardiovascular diseases.

Methods: This prospective study included 50 participants (26 males, 24 females; mean age 46.0±19.0y), including 15 with normal CMR findings and 35 with various cardiovascular diseases. All participants underwent both PT-triggered and ECG-triggered CMR on a 3T MRI system. Imaging included T2-weighted imaging (T2WI), T1-mapping, T2-mapping, cine, late gadolinium enhancement (LGE), and post-contrast T1-mapping sequences. Image quality and quantitative measurements were evaluated, including T2WI signal intensity, native T1-mapping, T2-mapping, and extracellular volume fraction (ECV) values, and comparative signal-to-noise ratio (compSNR) and comparative contrast-to-noise ratio (compCNR) of cine and LGE images, left/right ventricular function. Inter-reader agreement was evaluated using the intraclass correlation coefficient (ICC). Comparisons between the two methods were performed using paired t-test or the Wilcoxon signed-rank test.

Results: No significant differences were observed in scanning times (p=.253-.864) or image quality (ICC: .589-1.000, p=.057-1.000) between PT- and ECG-triggered scans and images. Quantitative assessments showed good to excellent consistency (ICC=.843-.987). While PT-triggered LGE images showed higher compCNR (14.14±7.68 vs. 13.24±7.52, p=.016), other quantitative parameters showed no significant differences between PT- and ECG-triggered images. Six participants with hypertrophic cardiomyopathy or heart valve disease experienced false R-wave triggering during ECG gating, leading to motion artifacts, which were not visible in PT-triggered images.

Conclusion: PT-triggered cardiac MRI provides comparable image quality and quantitative assessments to ECG-triggered sequences and may offer advantages in minimizing motion artifacts, particularly in patients with conditions affecting ECG reliability, making it a promising alternative for cardiac MRI synchronization.

Background: Timing of pulmonary valve intervention (PVI) for pulmonary regurgitation in patients with repaired tetralogy of Fallot (TOF) is guided by right ventricle (RV) volumetric/function assessment on cardiac magnetic resonance (CMR) indexed to actual body surface area (BSA). However, different RV contouring techniques and BSA formulae exist with significant variability in reported measurements. We aimed to review the protocols reported in CMR studies of PVI in TOF.

Methods: A search of electronic databases (Embase and MEDLINE) was performed to identify studies published between February 28, 2010 and February 28, 2025 which assessed adults with repaired TOF before and after PVI using CMR. RV contouring methods and BSA formulae were reviewed.

Results: After screening 610 references, a total of 27 studies met the criteria and were included. All studies were of only level III or level IV (lowest) levels of evidence. Most studies (81%, 22/27) did not specify the RV contouring technique used and none defined the RV basal slice. Of the five studies describing the RV contouring technique, four excluded trabeculations/papillary muscles from the RV volume and one included these structures. No studies reported the formula used to calculate actual BSA.

Conclusion: RV contouring technique and BSA methodology utilized in CMR studies of PVI in TOF is poorly reported. Given the importance of severity thresholds for RV volumes in triggering intervention in clinical practice, clear reporting and standardization of RV contouring and BSA methodology should be mandatory. Further research into the optimal RV thresholds for PVI based on clear contouring methods is required.

Introduction: Mitral annular disjunction (MAD) is a pathologic fibrous separation of the mitral valve hinge point from the ventricular myocardium. The aims of this study were to describe the range of MAD distance by cardiovascular magnetic resonance (CMR) in children and young adults with connective tissue disorders (CTDs) versus a healthy control sample, and to assess the MAD distance as a predictor of adverse cardiovascular outcomes.

Methods: This was a retrospective, single-center study of healthy subjects and patients with Marfan syndrome, Loeys-Dietz syndrome, Ehlers-Danlos syndrome, or nonspecific CTD who underwent CMR between January 01, 2000 and January 01, 2020. The MAD distance was measured from the 2-chamber, 4-chamber, and left ventricular outflow tract views in systole and diastole and analyzed as absolute values as well as indexed to BSA and height. The primary outcome was a composite defined as the presence of significant ventricular arrhythmias, cardiac arrest, and/or death. Age-adjusted odds ratios with 95% confidence intervals and c-statistic are reported. Classification and Regression Tree analysis was performed to identify the most discriminating binary threshold to predict the occurrence of the composite outcome.

Results: Around 30 healthy control subjects and 254 patients with CTD met inclusion criteria. The mean ± SD age at initial CMR was 17±6years for patients with CTD and 14±3years for controls. The mean MAD distance was larger in patients with CTD compared to the control sample, and the maximum MAD distance in the control sample was 3.6 mm. Median follow-up in the CTD group was 5 years (IQR 3-11years). Thirty-four (15%) patients met the composite outcome. Systolic MAD distance was positively associated with the composite outcome. The optimal binary threshold for height-indexed maximum systolic MAD distance was 0.033 mm/cm with an event rate of 18.6% at/above threshold versus 2.6% below threshold (AUC 0.74). The association was independent of other important clinical predictors.

Conclusion: A small MAD distance can be measured in healthy children and young adults. Children and young adults with CTD have a longer MAD distance than healthy control subjects, and a longer MAD distance is associated with adverse outcomes.

Myocardial perfusion imaging plays a central role in the management of patients with known or suspected coronary artery disease (CAD) and increasingly in patients with suspected ischemia with normal coronary arteries (INOCA) as well as anomalous origins of the coronary arteries and Kawasaki disease. Stress perfusion cardiovascular magnetic resonance (CMR) is recognized by international guidelines, with several Class 1 indications for the detection of abnormal myocardial blood flow in these clinical scenarios and offers excellent diagnostic accuracy and independent prognostic value. While visual interpretation of the perfusion data is the prevailing analysis method in clinical practice, quantitative perfusion CMR is at least as accurate for the detection of significant obstructive CAD and provides a more accurate estimation of the total ischemic burden in patients with CAD. Moreover, quantitative myocardial perfusion analysis provides unique insights into the pathophysiology of myocardial ischemia, including microvascular disease in INOCA. Quantitative perfusion CMR can be fully automated, is user-independent, and may facilitate more widespread use of the modality. The aim of this Society for Cardiovascular Magnetic Resonance (SCMR) expert consensus document is to provide recommendations for the acquisition and analysis of quantitative myocardial perfusion CMR to facilitate standardization of methodology. This paper also discusses research and development goals to address current limitations, to ensure data reliability and validity, to create the basis for future multi-vendor and multicenter research, and to broaden the clinical use of quantitative perfusion CMR.