Journal of Cardiovascular Magnetic Resonance最新文献

Introduction: 3D water-fat separated LGE imaging is a cardiac 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). 3D water-fat separated LGE images were acquired at 1.5T (n=122) or 3T (n=16). Image quality was subjectively rated (4-point Likert scale) in six categories (overall image quality, blood-myocardium border sharpness, LGE-remote/healthy myocardium border sharpness, fat suppression, myocardial nulling, anatomical structures), additionally the contrast ratio was calculated. Cardiac function, acquisition conditions, and demographic data were investigated as potential confounders for image quality and contrast ratio.

Results: Fat suppression had the highest quality score (2.54 ± 0.72), followed by anatomical structures (2.11 ± 0.94) and myocardial nulling (2.01 ± 0.78). In total, 18 parameters showed a significant correlation with multiple image quality categories, most of which related to cardiac function, such as the cardiac index, which significantly correlated with overall image quality (Wald Chi-squared=4.35; p<0.05), LGE-remote/healthy myocardium border sharpness (Wald Chi-squared=5.03; p<0.05), and anatomical structures (Wald Chi-square=16.00; p<0.001). Left ventricular mass index to height showed significant correlation with overall image quality (Wald Chi-squared=7.57; p<0.01), blood-myocardium border sharpness (Wald Chi-squared=7.35; p<0.01), and contrast ratio (Wald Chi-squared=5.50; p<0.05). Furthermore, demographic parameters, such as body mass index (BMI), were identified as significant confounders, showing a notable correlation between BMI and the depiction of anatomical structures. (Wald Chi-square=11.14; p<0.01).

Conclusion: In this study, 3D water-fat separated LGE imaging shows satisfying image quality, especially for fat separation. However, image quality may be affected by several surrounding parameters such as patient obesity, high myocardial mass, and cardiac function.

Trial registration: 3000339.

Background: The coronary sinus reducer (CSR) is a novel percutaneous treatment for patients with refractory angina. Increasing evidence supports its clinical efficacy in patients with advanced epicardial coronary artery disease. However, its mechanism of action and its effects on myocardial perfusion remain undefined. Using quantitative stress perfusion cardiac magnetic resonance (CMR), this study assessed changes in myocardial perfusion in patients with refractory angina undergoing CSR implantation.

Methods: This single-centre retrospective observational cohort study included 16 patients. Rest and adenosine stress perfusion CMR was performed before and at median 5 months after CSR implantation. Perfusion images were acquired using a dual-sequence quantitative protocol with automated generation of myocardial blood flow (MBF; mL/min/g). In addition to visual assessment of ischaemic segments, changes in absolute MBF across myocardial segments and between myocardial layers were analysed.

Results: A high proportion of myocardial segments had visually adjudicated ischaemia at baseline (208 out of 254: 81.9%), which significantly reduced after CSR implantation (175 out of 254: 68.9%; P=0.001). There were no changes in global MBF or strain values. Changes in myocardial perfusion reserve (MPR) correlated with baseline MPR with more ischaemic segments at baseline improving to a greater extent at follow-up. Similar patterns were observed in both the left and right coronary artery territories. Changes in endocardial/epicardial MBF ratio at stress were similarly dependent on baseline values.

Conclusion: In patients with refractory angina undergoing CSR implantation, quantitative stress perfusion CMR demonstrated redistribution of myocardial perfusion across segments, from less ischaemic to more ischaemic myocardium, and across myocardial layers with greatest improvements in endocardial perfusion observed in the most ischaemic myocardium. Further studies are needed to validate the different patterns MBF redistribution that may occur after CSR implantation and correlate with clinical outcomes.

Background: Arrhythmogenic cardiomyopathy (ACM) related to Desmoplakin (DSP) mutations is a distinct condition associated with particularly severe outcomes, more frequent left ventricular (LV) involvement including fibrosis, dysfunction and inflammatory episodes. Whether DSP-ACM is associated with specific imaging features remains elusive.

Purpose: To provide a comprehensive description of cardiac magnetic resonance (CMR) findings in patients with DSP-ACM and to compare them to RV-dominant ACM with LV involvement (LV+ right-dominant-ACM).

Methods: Patients with DSP-ACM matched with patients with ACM related toa non-DSP desmosomal mutation and ≥1 feature of LV involvement underwent CMR in two institutions. Biventricular metrics and segmental wall motion abnormalities (WMA) were assessed. LV late gadolinium enhancement (LGE) was assessed both qualitatively and quantitatively after semi-automated segmentation.

Results: Overall, 70 ACM patients were analyzed; 37 with DSP-ACM and 33 in the LV+ right-dominant-ACM group. LVEF was significantly lower in the DSP-ACM group (46±12%) than in the LV+ right-dominant-ACM group (56±10%, P=0.001). Conversely, RVEF was significantly higher in the DSP-ACM group (45±11% vs. 40±12%, P=0.04) and both RV end-diastolic (100±24 vs 130±44mL/m², P=0.002) and end-systolic (56±21 vs 81±45mL/m², P=0.007) indexed volumes were significantly smaller in DSP-ACM as compared to the LV+ right-dominant-ACM group. The LV to RV end-systolic volume ratio (0.96[IQR0.70-1.27] vs. 0.59[IQR0.48-0.69]) was significantly higher in the DSP-ACM group (P<0.0001), and had a good performance in differentiating both groups (area under the ROC curve 0.86, optimal threshold 0.8). Patients in the DSP-ACM group had significantly more LV and less RV WMA than those in the LV+ right-dominant-ACM group. The amount of LGE was significantly higher in the DSP group (14±16 vs. 2±3%, P<0.0001) and present in the majority of LV segments, particularly in the lateral and inferior walls, as compared to LV+ right-dominant-ACM patients. Transmural LGE and the presence of a ring-like pattern corresponding to circumferential subepicardial LGE involving ≥3contiguous LV basal segments were highly suggestive of DSP-ACM.

Conclusions: The presence of LV to RV end-systolic volume ratio>0.8, global LGE>5%, transmural and/or a ring-like LGE pattern are highly suggestive of DSP-ACM and should prompt careful diagnostic assessment considering the severe associated outcomes.

Background: Three-dimensional (3D) tagged magnetic resonance (MR) imaging enables in vivo quantification of cardiac motion. While deep learning methods have been developed to analyze these images, they have been restricted to two-dimensional datasets. We present a deep learning approach specifically designed for displacement analysis of 3D cardiac tagged MR images.

Methods: We developed two neural networks to predict left-ventricular motion throughout the cardiac cycle. Networks were trained using synthetic 3D tagged MR images, generated by combining a biophysical left-ventricular model with an analytical MR signal model. Network performance was initially validated on synthetic data, including assessment of signal-to-noise ratio (SNR) sensitivity. The networks were then retrospectively evaluated on an in vivo external validation human datasets and a in vivo porcine study.

Results: For the external validation dataset, predicted displacements deviated from manual tracking by median(IQR) values of 0.72(1.51), 0.81(1.64) and 1.12(4.17) mm in x, y and z directions, respectively. In the porcine dataset, strain measurements showed median(IQR) differences from manual annotations of 0.01(0.04), 0.01(0.06) and  - 0.01(0.18) for circumferential, longitudinal, and radial components. These strain values are within physiological ranges and demonstrate superior performance of the network approach compared to existing 3D tagged image analysis methods.

Conclusions: The method enables rapid analysis times of approximately 10 seconds per cardiac phase, making it suitable for large cohort investigations.

Background: Myocardial strain is a valuable biomarker for diagnosing and predicting cardiac conditions, offering additional prognostic information to traditional metrics like ejection fraction. While cardiovascular magnetic resonance (CMR) methods, particularly cine displacement encoding with stimulated echoes (DENSE), are the gold standard for strain estimation, evaluation of regional strain estimation requires precise ground truth. This study introduces DENSE-Sim, an open-source simulation pipeline for generating realistic cine DENSE images with high-resolution known ground truth strain, enabling evaluation of accuracy and precision in strain analysis pipelines.

Methods: This pipeline is a modular tool designed for simulating cine DENSE images and evaluating strain estimation performance. It comprises four main modules: 1) anatomy generation, for creating end-diastolic cardiac shapes; 2) motion generation, to produce myocardial deformations over time and Lagrangian strain; 3) DENSE image generation, using Bloch equation simulations with realistic noise, spiral sampling, and phase-cycling; and 4) strain evaluation. To illustrate the pipeline, a synthetic dataset of 180 short-axis slices was created, and analysed using the commonly-used DENSEanalysis tool. The impact of the spatial regularization parameter (k) in DENSEanalysis was evaluated against the ground-truth pixel strain, to particularly assess the resulting bias and variance characteristics.

Results: Simulated strain profiles were generated with a myocardial SNR ranging from 3.9 to 17.7. For end-systolic radial strain, DENSEanalysis average signed error (ASE) in Green strain ranged from 0.04 ± 0.09 (true-calculated, mean ± std) for a typical regularization (k=0.9), to  - 0.01 ± 0.21 at low regularization (k=0.1). Circumferential strain ASE ranged from  - 0.00 ± 0.04 at k=0.9 to  - 0.01 ± 0.10 at k=0.1. This demonstrates that the circumferential strain closely matched the ground truth, while radial strain displayed more significant underestimations, particularly near the endocardium. A lower regularization parameter from 0.3 to 0.6 depending on the myocardial SNR, would be more appropriate to estimate the radial strain, as a compromise between noise compensation and global strain accuracy.

Conclusion: Generating realistic cine DENSE images with high-resolution ground-truth strain and myocardial segmentation enables accurate evaluation of strain analysis tools, while reproducing key in vivo acquisition features, and will facilitate the future development of deep-learning models for myocardial strain analysis, enhancing clinical CMR workflows.

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 MRI techniques present as a potential key to unlocking insights into TAA that could guide disease surveillance and surgical intervention. MRI has the capacity to encapsulate the aorta as a complex biomechanical structure, permitting the determination of aortic volume, morphology, composition, distensibility and fluid dynamics in a time-efficient manner. Nevertheless, current standard-of-care imaging protocols do not harness its full capacity. This state-of-the-art review explores the emerging role of MRI in the assessment of TAA and presents a blueprint for the required paradigm shift away from aortic size as the sole metric for risk stratifying TAA.

Background: Left ventricular (LV) reverse myocardial remodeling occurs following septal myectomy in hypertrophic obstructive cardiomyopathy (HOCM), but it remains unclear whether diffuse fibrosis is reversible during this period. Extracellular volume fraction (ECV) and indexed extracellular volume (iECV) are important surrogate markers of diffuse myocardial fibrosis. This study aimed to investigate whether diffuse myocardial fibrosis in HOCM can regress after myectomy.

Methods: A prospective cohort study was conducted among patients with HOCM. All subjects underwent clinical assessment (clinical history, 6-min walk test, biochemical analysis), echocardiography and cardiovascular magnetic resonance (CMR) preoperatively and 6 months after septal myectomy.

Results: A total of 43 patients (52±14 years, 23 female) were included in the analysis. At 6 months post-myectomy, there were significant within-person decreases in LV mass index (101.0[81.5-121.0] to 85.8[66.7-100.0] g/m²; p < 0.001), indexed cell volume (68.6[53.2-82.6] mL/m² to 54.0[4².6-62.0] mL/m²; p < 0.001) and iECV (26.5[22.4-30.1] mL/m² to 21.2[18.7-26.4] mL/m²; p < 0.001). Conversely, ECV (28.2±3.3% to 30.2±2.8%; p < 0.001) and late gadolinium enhancement mass (4.5[0.2-8.2] g to 8.7[2.1-12.8] g; p < 0.001) increased. These changes were accompanied by improvement of New York Heart Association functional class, 6-min walk test results, N-terminal pro-B-type natriuretic peptide, and high-sensitivity cardiac troponin T.

Conclusions: Six months after septal myectomy, both cellular hypertrophy and diffuse fibrosis are reversible in HOCM, while focal fibrosis does not regress. These are accompanied by improvement of exercise parameters and laboratory biomarkers, unfolding the plastic nature of diffuse fibrosis in HOCM and its potential as a therapeutic target.

Introduction: Cardiovascular magnetic resonance (CMR) is the gold standard for assessing cardiac volumes and function using 2D breath-held cine imaging. This technique, however, requires a reliable ECG signal, repetitive breath-holds, and the time-consuming and proficiency-demanding planning of cardiac views. Recently, a free-running framework has been developed for cardiac and respiratory motion-resolved 5D whole-heart imaging without the need for an ECG signal, repetitive breath-holds, and meticulous plan scanning. In this study, we investigate the impact of acquisition time on cardiac volumetric and functional measurements, when using free-running imaging, compared to reference standard 2D cine imaging.

Methods: Sixteen healthy adult volunteers underwent CMR at 1.5T, including standard 2D breath-held cine imaging and free-running imaging using acquisition durations ranging from 1 to 6min in randomized order. All datasets were anonymized and analysed for left-ventricular end-systolic and end-diastolic volumes, as well as ejection fraction. In a subset of data, intra- and inter-observer agreement was assessed. In addition, image quality and observer confidence were scored using a 4-point Likert scale. Finally, acquisition efficiency was reported for both imaging techniques, which was defined as the time required for data sampling divided by the total scan time.

Results: No significant differences in left-ventricular EDV and ESV were found between free-running imaging for 1, 2, 3, 5, and 6minutes and standard 2D breath-held cine imaging. Biases in EDV ranged from -2.4 to -7.4mL, while biases in ESV ranged from -3.8 to 2.1mL. No significant differences in ejection fraction were found between free-running imaging of any acquisition duration and standard 2D breath-held cine imaging. Biases in ejection fraction ranged from -2.8% to 0.94%. Both image quality and observer confidence in free-running imaging improved when the acquisition duration increased. However, they were always lower than standard 2D breath-held cine imaging. Acquisition efficiency improved from 13% for standard 2D cine imaging to 50% or higher for free-running imaging.

Discussion: Free-running CMR with an acquisition duration as short as one minute can provide left-ventricular cardiac volumes and ejection fraction comparable to standard 2D breath-held cine imaging, albeit at the expense of both image quality and observer confidence.

Background: The effects of endovascular therapeutic hypothermia (ETH) in ST-elevation myocardial infarction (STEMI) regional contractility are unknown, and its impact on segmental contractility has still not been evaluated. We sought to evaluate segmental myocardial strain after ETH adjuvant to percutaneous coronary intervention (PCI) in STEMI.

Methods: We included patients who underwent 1.5 T cardiac magnetic resonance exams 5 and 30 days after acute anterior or inferior STEMI in a previous randomized trial. Left ventricle (LV) strain was evaluated on infarcted, adjacent, and remote myocardium. Segmental circumferential (CS) and radial strains (RS) were measured using feature-tracking imaging. Repeated-measures of ANOVA was used for comparisons within time and treatment.

Results: Forty patients were divided into hypothermia (ETH, n=29) and control (n=11) groups, with 5210 LV segments. In ETH infarcted areas, RS (11.2±16 vs. 14.8±15.2, p=0.001) and CS (-5.4±11.1 vs. -8±11.1, p=0.001) showed recovery from 5 to 30 days compared to controls (11.4±14 vs. 13.1±16.8, p=0.09; -6.5±10.6 vs. -6.4±12.5, p=0.94). In control remote areas, RS (28±18 vs. 31.7±18.5, p=0.001) and CS (-15.5±10.7 vs. -17.1±9, p=0.001) improved from 5 to 30 days compared to ETH (28.6±18.6 vs. 29±20, p=0.44; -15.2±10.4 vs. -15.3±10.6, p=0.82). Transmural infarcted areas in ETH improved RS (11.8±13.2 vs. 8.17±14.7, p=0.001) and CS (-6.1±10.9 vs. -3.1±11.3, p=0.001) compared to controls, with better contractility at 30 days.

Conclusions: In anterior or inferior STEMI patients, ETH adjuvant to PCI is associated with significant improvement in RS and CS of infarcted areas, including transmural segments, but not in the remote area. This might further increase our pathophysiological knowledge on early LV remodeling and ultimately suggest potential clinical value.

Availability of data and materials: The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.