3D Cardiovascular Magnetic Resonance Research Articles

Echocardiography and Cardiac Magnetic Resonance in the Assessment of Left-Ventricle Remodeling: Differences Implying Clinical Decision.

Introduction: Transthoracic echocardiography (TTE) and cardiovascular magnetic resonance (CMR) are the most important modalities used in clinical practice to assess cardiac chambers. However, different imaging techniques may affect their results and conclusions. The aim of our study was to compare left-ventricle (LV) remodeling assessed using TTE and CMR in the context of various cardiovascular diseases. Methods: A total of 202 consecutive patients sent for an elective cardiovascular diagnosis were scheduled for a 2D TTE and CMR, performed within 2 weeks. The study group was divided and analyzed based on the clinical indications for CMR, including coronary artery disease, heart failure, native aortic valve regurgitation or paravalvular leak after aortic valve replacement, or cardiomyopathies. Results: The mean LV mass index (LVMi) values calculated using TTE were significantly larger (127.1 ± 44.5 g/m²) compared to the LVMi assessed using CMR (77.1 ± 26.2 g/m²; p < 0.001). The LV end-diastolic volumes assessed using TTE were underestimated for all the study patients (78.6 ± 43 mL vs. 100.5 ± 39 mL; p < 0.0001) and subgroups, but a statistical trend was observed in patients with cardiomyopathy. Those differences in single parameters led to differences in LV remodeling and the final treatment decision. CMR and TTE provided similar conclusions on LV systolic dysfunction in 68% of the patients. Conclusions: Our results showed that the greater the degree of LV remodeling and dysfunction, the greater the difference between the modalities. Therefore, CMR should be introduced into routine clinical practice, especially for patients undergoing LV remodeling, which may change clinical decisions in a considerable number of cases.

A Predictive Model for Cardiomyopathy Progression in a Longitudinal Cohort of DMD Patients

Background: Cardiomyopathy (CM) is currently the leading cause of mortality in patients with Duchenne muscular dystrophy (DMD). DMD CM is asymptomatic during the early stages of disease and age of onset and clinical progression vary. We previously showed that 4D kinematic analysis of cardiovascular magnetic resonance (CMR) imaging is a robust method to visualize strain and function changes in DMD patients. Our objective, using 4D CMR image analysis, is to build a predictive model to quantify disease progression, and predict functional decline as measured by left ventricular ejection fraction (LVEF) in a longitudinal cohort of DMD patients. &#x0D; &#x0D; Methods: We obtained 4D CMR images from 40 DMD patients imaged every 12 months for three years. Localized surface area strain (Ea) values were derived from compiled 4D CMR images. Patient demographics, presence or absence (+/-) of late gadolinium enhancement (LGE) and LVEF were obtained by a trained cardiologist. Principal component analysis was used to identify prominent variables contributing most to variability. These variables, along with clinically relevant variables, were selected to build the predictive model. We built a linear mixed effects model using visit, age, basal Ea, and LGE presence. Each patient was considered a random effect to account for variability in initial CM severity. &#x0D; &#x0D; Results: Study patients were grouped into stages of heart failure according to the American Heart Association: Stage A, LVEF&gt;55%, LGE(-); Stage B, LVEF&gt;55%, LGE(+); Stage C, 40%&lt;LVEF&lt;55%, LGE(+); Stage D, LVEF&lt;40%, LGE(+). Linear mixed effects model showed a good prediction of LVEF on year 3 with a root mean squared error of 3.6% and an R2 value of 0.75 (p&lt;0.0001.). &#x0D; &#x0D; Conclusion: Early detection is crucial for appropriate clinical intervention. This novel predictive model was developed to determine if Ea derived from 4D imaging, LVEF, and (+/-) LGE can be used to predict functional outcomes in DMD CM.

Aortic Wall Thickness as a Surrogate for Subclinical Atherosclerosis in Familial and Nonfamilial Hypercholesterolemia: Quantitative 3D Magnetic Resonance Imaging Study and Interrelations with Computed Tomography Calcium Scores, and Carotid Ultrasonography.

We aimed to compare the extent of subclinical atherosclerosis in the ascending and descending aortas by measuring wall area and thickness using 3D cardiovascular magnetic resonance imaging (aAWAI and dAWAI) in patients with asymptomatic familial hypercholesterolemia (FH) and nonfamilial hypercholesterolemia (NFH). We also aimed to establish the interrelations of CMR parameters with other subclinical atherosclerosis measurements, such as calcium scores, obtained using computed tomography in coronary arteries (CCS) and ascending and descending aorta (TCSasc and TCSdsc), as well as the carotid intima-media thicknesses (cIMT) using ultrasonography. A total of 60 patients with FH (29 men and 31 women), with a mean age of 52.3 ± 9.6 years, were analyzed. A subclinical atherosclerosis assessment was also performed on a group consisting of 30 age- and gender-matched patients with NFH, with a mean age of 52.5 ± 7.9 years. We found the ascending and descending aortic wall areas and thicknesses in the FH group to be significantly increased than those of the NFH group. A multivariate logistic regression analysis showed that a positive FH mutation value was a strong predictor of high aAWAI and dAWAI independent of the LDL cholesterol level. Correlations across CMR atherosclerotic parameters, calcium scores, and cIMT in the FH and NFH groups, were significant but low. Most of the atherosclerosis tests with high results belonged to the FH group. We found that patients with documented heterozygous FH had a higher atherosclerosis burden in the aorta compared to patients with severe hypercholesterolemia without FH gene mutation. Atherosclerosis is not severe in asymptomatic patients with FH, but is more pronounced and also more diffuse than in patients with NFH. The etiology of hypercholesterolemia, and not just cholesterol levels, plays a significant role in determining the degree of subclinical atherosclerosis.

Consistency of left ventricular ejection fraction measurements in the early time course of STEMI.

Early after ST-segment elevation myocardial infarction (STEMI), initial LV reshaping and hypokinesia may affect analysis of LV function. Concomitant microvascular dysfunction may affect LV function as well. To perform a comparative evaluation of left ventricular ejection fraction (LVEF) and stroke volume (SV) by different imaging modalities to assess LV function early after STEMI. LVEF and SV were assessed using serial imaging within 24 h and 5 days after STEMI using cineventriculography (CVG), 2-dimensional echocardiography (2DE), 2D/3D cardiovascular magnetic resonance (CMR) (2D/3D) in 82 patients. 2D analyses of LVEF using CVG, 2DE and 2D CMR yielded uniform results within 24 h and 5 days of STEMI. SV assessment between CVG and 2DE was comparable, whereas values for SV were higher using 2D CMR (p < 0.01 all). This was due to higher LVEDV measurements. LVEF by 2D versus 3D CMR was comparable, 3D CMR yielded higher volumetric values. This was not influenced by infarct location or infarct size. 2D analysis of LVEF yielded robust results across all imaging techniques implying that CVG, 2DE, and 2D CMR can be used interchangeably early after STEMI. SV measurements differed substantially between imaging techniques due to higher intermodality-differences of absolute volumetric measurements.

Imaging of Mitral Valve Area by Cardiac Magnetic Resonance in Patients with Rheumatic Mitral Stenosis

Background: Rheumatic heart disease which is a result of rheumatic fever is still a major health problem in developing countries. Rheumatic mitral stenosis (MS) is the commonest delayed valvular affection as a consequence of rheumatic fever. The assessment of MS severity by measuring mitral valve area (MVA) is very essential for patient management. Different imaging modalities are available for MVA assessment including echocardiography and cardiovascular magnetic resonance (CMR). Objectives: The aim of this study is to compare the planimetric MVA between CMR and two dimensional echocardiography in MS patients. Patients and methods: A forty adult patients with symptomatic mitral stenosis were included in the study. Other significant valvular lesions, atrial fibrillation, poor echocardiographic window, contraindications to CMR, and NYHA IV were excluded from the study. All patients were assessed by 2D echocardiography and CMR for MVA measurement. Results: The mean 2D TTE MVA was 1.2±0.26 cm2 , while the mean CMR MVA 1.2±0.28 cm2 . No significant statistical difference was found between both methods (P value 0.842) with a very strong correlation between both methods (r = 0.93 and p-value &lt; 0.0001). The mean difference of MVA between the two methods was 0.012 cm2 . Conclusion: CMR is a non-invasive imaging modality that provides MVA measurement and is a reliable method in the diagnosis of MS patients.

A Novel U-Net Based Deep Learning Method for 3D Cardiovascular MRI Segmentation.

Medical multiobjective image segmentation aims to group pixels to form multiple regions based on the different properties of the medical images. Segmenting the 3D cardiovascular magnetic resonance (CMR) images is still a challenging task owing to several reasons, including individual differences in heart shapes, varying signal intensities, and differences in data signal-to-noise ratios. This paper proposes a novel and efficient U-Net-based 3D sparse convolutional network named SparseVoxNet. In this network, there are direct connections between any two layers with the same feature-map size, and the number of connections is reduced. Therefore, the SparseVoxNet can effectively cope with the optimization problem of gradients vanishing when training a 3D deep neural network model on small sample data by significantly decreasing the network depth, and achieveing better feature representation using a spatial self-attention mechanism finally. The proposed method in this paper has been thoroughly evaluated on the HVSMR 2016 dataset. Compared with other methods, the method achieves better performance.

Prognostic impact of cardiac MRI in acute myocardial injury with non-obstructive coronary arteries: The role of 2D speckle-tracking echocardiography and CMR imaging

Acute myocardial injury with non-obstructive coronary arteries (aMINOCA), broader term than MINOCA, including ischemic and non-ischemic causes, represents a diagnostic dilemma, and the prognostic markers have not been clarified. this study sought to assess the prognostic impact of cardiovascular magnetic resonance (CMR) in patients with aMINOCA. Prospective study including patients presenting aMINOCA, admitted from June 2019 to September 2020, undergoing 2D STE Echocardiography and CMR assessment at admission. A 1.5-T CMR was performed using a comprehensive protocol (cines, T2-STIR and late gadolinium enhancement sequences). CMR (performed at an average of 3.22 days from presentation) was able to identify the cause for the troponin rise in 82% (24/29) of the patients (41% myocarditis, 35% MI, and 7% Takotsubo cardiomyopathy), whereas a normal CMR was identified in 17%. 2D LV Global longitudinal systolic myocardial strain (2D GLS) correlated significantly with the amount of LGE (r 2 = 0.230; P = 0.021). Pick troponin level was significantly higher in groups of patients with LGE (18.6 vs. 1.6; P = 0.012) and with myocardial edema (24.4 vs. 4.1; P = 0.026). At follow-up, we found that both LVEF assessed by CMR and amount of myocardial edema were significantly correlated with the absence of recovery of the GLS at 6 months-follow-up echocardiography (r 2 = 0.243; P = 0.032 and r 2 = 0.410; P = 0.003). In contrast, no significant correlation between echography LVEF, 2D GLS and recovery of the GLS at follow-up was founded (r 2 = 0.07; P = 0.71 and r 2 = 0.185; P = 0.06). In a prospective study including 29 patients with non-obstructive coronary myocardial injury, CMR identified a final diagnosis in 82% of patients. 2D speckle-tracking echocardiography was a useful tool in the diagnostic process and follow-up. Presence of myocardial oedema assessed by CMR at admission is a strong predictive factor of absence of LV systolic function recovery.

Automatic segmentation of the great arteries for computational hemodynamic assessment

BackgroundComputational fluid dynamics (CFD) is increasingly used for the assessment of blood flow conditions in patients with congenital heart disease (CHD). This requires patient-specific anatomy, typically obtained from segmented 3D cardiovascular magnetic resonance (CMR) images. However, segmentation is time-consuming and requires expert input. This study aims to develop and validate a machine learning (ML) method for segmentation of the aorta and pulmonary arteries for CFD studies.Methods90 CHD patients were retrospectively selected for this study. 3D CMR images were manually segmented to obtain ground-truth (GT) background, aorta and pulmonary artery labels. These were used to train and optimize a U-Net model, using a 70-10-10 train-validation-test split. Segmentation performance was primarily evaluated using Dice score. CFD simulations were set up from GT and ML segmentations using a semi-automatic meshing and simulation pipeline. Mean pressure and velocity fields across 99 planes along the vessel centrelines were extracted, and a mean average percentage error (MAPE) was calculated for each vessel pair (ML vs GT). A second observer (SO) segmented the test dataset for assessment of inter-observer variability. Friedman tests were used to compare ML vs GT, SO vs GT and ML vs SO metrics, and pressure/velocity field errors.ResultsThe network’s Dice score (ML vs GT) was 0.945 (interquartile range: 0.929–0.955) for the aorta and 0.885 (0.851–0.899) for the pulmonary arteries. Differences with the inter-observer Dice score (SO vs GT) and ML vs SO Dice scores were not statistically significant for either aorta or pulmonary arteries (p = 0.741, p = 0.061). The ML vs GT MAPEs for pressure and velocity in the aorta were 10.1% (8.5–15.7%) and 4.1% (3.1–6.9%), respectively, and for the pulmonary arteries 14.6% (11.5–23.2%) and 6.3% (4.3–7.9%), respectively. Inter-observer (SO vs GT) and ML vs SO pressure and velocity MAPEs were of a similar magnitude to ML vs GT (p > 0.2).ConclusionsML can successfully segment the great vessels for CFD, with errors similar to inter-observer variability. This fast, automatic method reduces the time and effort needed for CFD analysis, making it more attractive for routine clinical use.

Non-contrast free-breathing 3D cardiovascular magnetic resonance angiography using REACT (relaxation-enhanced angiography without contrast) compared to contrast-enhanced steady-state magnetic resonance angiography in complex pediatric congenital heart disease at 3T

BackgroundTo evaluate the great vessels in young children with complex congenital heart disease (CHD) using non-contrast cardiovascular magnetic resonance angiography (CMRA) based on three-dimensional relaxation-enhanced angiography without contrast (REACT) in comparison to contrast-enhanced steady-state CMRA.MethodsIn this retrospective study from April to July 2021, respiratory- and electrocardiogram-gated native REACT CMRA was compared to contrast-enhanced single-phase steady-state CMRA in children with CHD who underwent CMRA at 3T under deep sedation. Vascular assessment included image quality (1 = non-diagnostic, 5 = excellent), vessel diameter, and diagnostic findings. For statistical analysis, paired t-test, Pearson correlation, Bland–Altman analysis, Wilcoxon test, and intraclass correlation coefficients (ICC) were applied.ResultsThirty-six young children with complex CHD (median 4 years, interquartile range, 2–5; 20 males) were included. Native REACT CMRA was obtained successfully in all patients (mean scan time: 4:22 ± 1:44 min). For all vessels assessed, diameters correlated strongly between both methods (Pearson r = 0.99; bias = 0.04 ± 0.61 mm) with high interobserver reproducibility (ICC: 0.99 for both CMRAs). Native REACT CMRA demonstrated comparable overall image quality to contrast-enhanced CMRA (3.9 ± 1.0 vs. 3.8 ± 0.9, P = 0.018). With REACT CMRA, better image quality was obtained at the ascending aorta (4.8 ± 0.5 vs. 4.3 ± 0.8, P < 0.001), coronary roots (e.g., left: 4.1 ± 1.0 vs. 3.3 ± 1.1, P = 0.001), and inferior vena cava (4.6 ± 0.5 vs. 3.2 ± 0.8, P < 0.001). In all patients, additional vascular findings were assessed equally with native REACT CMRA and the contrast-enhanced reference standard (n = 6).ConclusionIn young children with complex CHD, REACT CMRA can provide gadolinium-free high image quality, accurate vascular measurements, and equivalent diagnostic quality compared to standard contrast-enhanced CMRA.

Cross-modality analysis of left ventricular function and volume in patients with st-segment elevation myocardial infarction: impact of infarct patterns

Abstract Funding Acknowledgements Type of funding sources: Public hospital(s). Main funding source(s): Sonderforschungsbereich 1116, University Düsseldorf Background Left ventricular (LV) function is considered of major importance to estimate prognosis of patients with ST-segment elevation myocardial infarction (STEMI) [1]. Although transthoracic echocardiography (TTE) after STEMI is recommended to assess for LV function and identify patients at high risk for rehospitalisation due to heart failure, Cardiovascular Magnetic Resonance (CMR) is still considered the gold standard for an adequate quantification of volumes, function and infarct size (IS) [2]. In addition, unenhanced TTE has been shown to underestimate LV function [3]. It is complicating that parameters such as IS and area-at risk (AAR) are thought to further deteriorate prognosis [4,5]. Purpose To test the hypothesis that cross-modality 2D/3D analyses using TTE, CMR and cineventriculography are comparable for the determination of LV-function in STEMI and that infarct patterns influence the determination of LV-function and volumes across modalities. Methods In a group of 70 patients after STEMI, estimation of LV function and volumes was performed by biplane cineventriculography during acute catheterization, biplane (2D) CMR 28 ± 16 hours (1 day) as well as 2D/3D-CMR and TTE 114 ± 31 hours (5 days) post STEMI. 3D-TTE after STEMI was only performed in a subset of 36 patients respectively. IS and AAR were assessed by T2-weighted and contrast enhanced CMR (1.5T) as percentage of the LV mass. Results Both, 2D- and 3D-, LV ejection fraction (LVEF) were comparable between the single modalities. Stroke volume (SV) and LV end-diastolic volume (LVEDV) were underestimated when comparing 2D- to 3D-CMR and when comparing TTE/cineventriculography to CMR. Correlating IS to the difference of 2D- and 3D-CMR, higher IS/AAR did not alter previous results, except from a fairly increased difference in SV (R = 0.3). For 2D-TTE versus 2D-CMR, higher IS/AAR increased differences in LVEDV (IS &amp; AAR: p &amp;lt;0.001 both, R = -0.58, R=-0.54). For 3D-TTE and 3D-CMR, IS and AAR increased the difference in LVEF (p = 0.009, R = 0.50; p &amp;lt; 0.001, R = 0.60) and LVEDV (p = 0.021, R=-0.5; p = 0.027, R=-0.46). A general linear model (GLM) for repeated measures including IS as covariate supported this finding by showing a significant interaction effect between the imaging modalities (TTE/CMR) for LVEF estimation and IS. AAR increased the difference in LVEF comparing cineventriculography and 2D-CMR as well (p = 0.001, R = 0.47). This was again supported by a significant interaction effect as detected by the GLM. Conclusions There is good agreement between LVEF analysis across dimensions (2D and 3D) and different modalities (TTE, cineventriculography and CMR) whereas the comparison of SV and LVEDV is hampered. However, with increasing IS or AAR, LVEF differences between modalities increase and 3D-CMR, if available, or alternatively 3D-TTE should be used for the most accurate estimation of LVEF.

VALUE OF DIFFERENT ECHOCARDIOGRAPHIC MODALITIES IN THE ASSESSMENT OF LEFT VENTRICULAR HYPERTROPHY IN HYPERTENSIVE PATIENTS WITH TYPE II DIABETES MELLITUS

Background: Left ventricular hypertrophy (LVH) is the response of myocytes to various stimuli leading to myocytes’ hypertrophy, which occurs as a compensatory response to increased after-load. It is defined as an increase in LV mass assessed by postmortem measurements, electrocardiographic (ECG), echocardiographic and cardiovascular magnetic resonance (CMR) criteria. Objective: To investigate the reproducibility of different echocardiographic modalities in the assessment of LVH in hypertensive patients and patients with type II DM in comparison to the golden standard CMR measurements. Patients and Methods: We prospectively investigated 40 patients with LVH, 20 patients being hypertensive and diabetic, 20 patients being diabetic only and 20 healthy control subjects (normal ventricular function and ECG and no cardiac risk factors). In addition to clinical and conventional echocardiographic parameters, LV mass and volumes were analyzed. Results: The comparison between new echocardiographic techniques and CMR showed that the assessments of LV volumes/LVEF by echocardiography and CMR have good correlations. However, the inter-technique agreement of absolute LV volumes revealed considerable differences, with significant underestimation of volumes and LVEF with respect to CMR. The LV mass was less in patients assessed by different algorithms of 2D echo rather than 3D echo and CMR, correlated positively with EDV and ESV. Conclusion: 3D echocardiography attains more solid results in patients diagnosed having LVH by 2D echocardiography. CMR would be preferable for research and specific clinical conditions requiring higher accuracy and reproducibility.

Accuracy of dynamic three-dimensional magnetic resonance perfusion imaging for the detection of coronary artery disease in patients with reduced ejection fraction

AbstractBackgroundTo assess the accuracy of 3D cardiovascular magnetic resonance (CMR) perfusion imaging for the detection of coronary artery disease (CAD) against fractional flow reserve (FFR) and quantitative coronary angiography (QCA) in patients with reduced ejection fraction (EF).MethodsOut of 447 patients who underwent 3D CMR perfusion imaging (at 1.5 and 3.0 T under adenosine stress and at rest) at 5 European centers, 86 cases with an EF ≤50% were identified (mean age 64 ± 11 yrs, 80% male). Significant CAD was defined as a FFR value &lt;0.8 and a QCA &gt;50%. 86 individuals matched for age, gender and major cardiovascular risk factors, were chosen as the control group.ResultsThe prevalence of CAD defined by FFR (&lt;0.8) was 59% (EF≤50%) vs. 54% (EF&gt;50%), P = 0.4). In relation to FFR, 3D perfusion imaging yielded a sensitivity of 84.5% (95% CI 76.0–90.4) and specificity of 77.3% (95% CI 66.7–85.3). The sensitivity of perfusion imaging was higher in patients with an EF≤50% (90.2 vs. 78.3%, P = 0.1) whereas specificity showed the reverse (62.9 vs. 90.0%, P = 0.005) The diagnostic accuracy was comparable in both subgroups (AUC 79.1 vs. 83.7%, P = 0.25). According to QCA, the prevalence of CAD was 78 vs. 72% (P = 0.4). Perfusion imaging yielded a sensitivity and specificity of 82.1 vs. 62.9%, P = 0.01 and 79.0 vs. 95.8%, P = 0.09 respectively with a high diagnostic accuracy in both subgroups (AUC 82.0 vs. 80.5%).Conclusion3D-CMR perfusion imaging yields a high sensitivity and diagnostic accuracy with regards to the detection of significant CAD irrespective of left ventricular (LV) systolic function.

Myocardial deformation in patients with a single left ventricle using 2D cardiovascular magnetic resonance feature tracking: a case\u2013control study

Ventricular dysfunction is a well-known complication in single ventricle patients in Fontan circulation. As studies exclusively examining patients with a single left ventricle (SLV) are sparse, we assessed left ventricular (LV) function in SLV patients by using 2D-cardiovascular magnetic resonance (CMR) feature tracking (2D-CMR-FT) and 2D-speckle tracking echocardiography (2D-STE). 54 SLV patients (11.4, 3.1–38.1 years) and 35 age-matched controls (12.3, 6.3–25.8 years) were included. LV global longitudinal, circumferential and radial strain (GLS, GCS, GRS) and strain rate (GLSR, GCSR, GRSR) were measured using 2D-CMR-FT. LV volumes, ejection fraction (LVEF) and mass were determined from short axis images. 2D-STE was applied in patients to measure peak systolic GLS and GLSR. In a subgroup analysis, we compared double inlet left ventricle (DILV) with tricuspid atresia (TA) patients. The population consisted of 19 DILV patients, 24 TA patients and 11 patients with diverse diagnoses. 52 patients were in NYHA class I and 2 patients were in class II. Most SLV patients had a normal systolic function but median LVEF in patients was lower compared to controls (55.6% vs. 61.2%, p = 0.0001). 2D-CMR-FT demonstrated reduced GLS, GCS and GCSR values in patients compared to controls. LVEF correlated with GS values in patients (p < 0.05). There was no significant difference between GLS values from 2D-CMR-FT and 2D-STE in the patient group. LVEF, LV volumes, GS and GSR (from 2D-CMR-FT) were not significantly different between DILV and TA patients. Although most SLV patients had a preserved EF derived by CMR, our results suggest that, LV deformation and function may behave differently in SLV patients compared to healthy subjects.

Native contrast visualization and tissue characterization of myocardial radiofrequency ablation and acetic acid chemoablation lesions at 0.55\xa0T

PurposeLow-field (0.55 T) high-performance cardiovascular magnetic resonance (CMR) is an attractive platform for CMR-guided intervention as device heating is reduced around 7.5-fold compared to 1.5 T. This work determines the feasibility of visualizing cardiac radiofrequency (RF) ablation lesions at low field CMR and explores a novel alternative method for targeted tissue destruction: acetic acid chemoablation.MethodsN = 10 swine underwent X-ray fluoroscopy-guided RF ablation (6–7 lesions) and acetic acid chemoablation (2–3 lesions) of the left ventricle. Animals were imaged at 0.55 T with native contrast 3D-navigator gated T1-weighted T1w) CMR for lesion visualization, gated single-shot imaging to determine potential for real-time visualization of lesion formation, and T1 mapping to measure change in T1 in response to ablation. Seven animals were euthanized on ablation day and hearts imaged ex vivo. The remaining animals were imaged again in vivo at 21 days post ablation to observe lesion evolution.ResultsChemoablation lesions could be visualized and displayed much higher contrast than necrotic RF ablation lesions with T1w imaging. On the day of ablation, in vivo myocardial T1 dropped by 19 ± 7% in RF ablation lesion cores, and by 40 ± 7% in chemoablation lesion cores (p < 4e−5). In high resolution ex vivo imaging, with reduced partial volume effects, lesion core T1 dropped by 18 ± 3% and 42 ± 6% for RF and chemoablation, respectively. Mean, median, and peak lesion signal-to-noise ratio (SNR) were all at least 75% higher with chemoablation. Lesion core to myocardium contrast-to-noise (CNR) was 3.8 × higher for chemoablation. Correlation between in vivo and ex vivo CMR and histology indicated that the periphery of RF ablation lesions do not exhibit changes in T1 while the entire extent of chemoablation exhibits T1 changes. Correlation of T1w enhancing lesion volumes indicated in vivo estimates of lesion volume are accurate for chemoablation but underestimate extent of necrosis for RF ablation.ConclusionThe visualization of coagulation necrosis from cardiac ablation is feasible using low-field high-performance CMR. Chemoablation produced a more pronounced change in lesion T1 than RF ablation, increasing SNR and CNR and thereby making it easier to visualize in both 3D navigator-gated and real-time CMR and more suitable for low-field imaging.

Free-breathing non-contrast flow-independent cardiovascular magnetic resonance angiography using cardiac gated, magnetization-prepared 3D Dixon method: assessment of thoracic vasculature in congenital heart disease

BackgroundTo evaluate a non-contrast respiratory- and electrocardiogram-gated 3D cardiovascular magnetic resonance angiography (CMRA) based on magnetization-prepared Dixon method (relaxation-enhanced angiography without contrast and triggering, REACT) for the assessment of the thoracic vasculature in congenital heart disease (CHD) patients.Methods70 patients with CHD (mean 28 years, range: 10–65 years) were retrospectively identified in this single-center study. REACT-CMRA was applied with respiratory- and cardiac-gating. Image quality (IQ) of REACT-CMRA was compared to standard non-gated multi-phase first-pass-CMRA and respiratory- and electrocardiogram-gated steady-state-CMRA. IQ of different vessels of interest (ascending aorta, left pulmonary artery, left superior pulmonary vein, right coronary ostium, coronary sinus) was independently assessed by two readers on a five-point Likert scale. Measurements of vessel diameters were performed in predefined anatomic landmarks (ascending aorta, left pulmonary artery, left superior pulmonary vein). Both readers assessed artifacts and vascular abnormalities. Friedman test, chi-squared test, and Bland-Altman method were used for statistical analysis.ResultsOverall IQ score of REACT-CMRA was higher compared to first-pass-CMRA (3.5 ± 0.4 vs. 2.7 ± 0.4, P < 0.001) and did not differ from steady-state-CMRA (3.5 ± 0.4 vs. 3.5 ± 0.6, P = 0.99). Non-diagnostic IQ of the defined vessels of interest was observed less frequently on REACT-CMRA (1.7 %) compared to steady-state- (4.3 %, P = 0.046) or first-pass-CMRA (20.9 %, P < 0.001). Close agreements in vessel diameter measurements were observed between REACT-CMRA and steady-state-CMRA (e.g. ascending aorta, bias: 0.38 ± 1.0 mm, 95 % limits of agreement (LOA): − 1.62–2.38 mm). REACT-CMRA showed high intra- (bias: 0.04 ± 1.0 mm, 95 % LOA: − 1.9–2.0 mm) and interobserver (bias: 0.20 ± 1.1 mm, 95 % LOA: − 2.0–2.4 mm) agreements regarding vessel diameter measurements. Fat-water separation artifacts were observed in 11/70 (16 %) patients on REACT-CMRA but did not limit diagnostic utility. Six vascular abnormalities were detected on REACT-CMRA that were not seen on standard contrast-enhanced CMRA.ConclusionsNon-contrast-enhanced cardiac-gated REACT-CMRA offers a high diagnostic quality for assessment of the thoracic vasculature in CHD patients.

Left ventricular ejection fraction as an imaging biomarker to guide cardiac resynchronisation therapy in heart failure patients: a multimodal comparison of 2D and 3D echocardiography and CMR

Abstract Funding Acknowledgements Type of funding sources: Public Institution(s). Main funding source(s): The authors acknowledge financial support from the Department of Health through the National Institute for Health Research (NIHR) comprehensive Biomedical Research Centre award to Guy’s &amp; St Thomas’ NHS Foundation Trust in partnership with King’s College London and King’s College Hospital NHS Foundation Trust and by the NIHR MedTech Co-operative for Cardiovascular Disease at Guy’s and St Thomas’ NHS Foundation Trust. This work was supported by the Wellcome/EPSRC Centre for Medical Engineering [WT 203148/Z/16/Z]. MSN was funded by a clinical lectureship awarded by the NIHR. The views expressed are those of the authors and not necessarily those of the NHS, the NIHR, the DoH, EPSRC, MRC or the Wellcome Trust. Introduction – Imaging derived left ventricular ejection fraction (LVEF) has an important role to guide initiation of medical therapy and device insertion in patients with heart failure and reduced ejection fraction (HFrEF). Previous studies have reported the correlation and agreement of LVEF in various patient populations, but sparse evidence exists on patients with heart failure referred for Cardiac Resynchronisation Therapy (CRT) using 2D and 3D echocardiography (2DE &amp; 3DE) and cardiovascular magnetic resonance (CMR). Objectives – To determine the correlation and agreement of LVEF as determined by 2DE, 3DE and CMR in a cohort of HF patients referred for assessment of CRT. Methods – Patients with suspected HFrEF referred for assessment for CRT therapy were included in this single centre study. Patients underwent 2DE, 3DE and CMR to derive LVEF, LVESV and LVEDV. Correlation was determined with Pearson’s correlation, agreement with Bland-Altman analysis and Cohen’s kappa analysis for agreement using a dichotomous cut off of LVEF ≤35% as a threshold for CRT insertion (Ponikowski, 2016). Results - 55 patients (mean age 71 ± 9.2, 76% male) were included. The mean LVEF for 2DE, 3DE, CMR and were 32.4 ± 8.6, 32.1 ± 9.6 and 30.3 ± 9.5 respectively. CMR had a significantly lower LVEF compared to 2DE (p = 0.03). There was good correlation between 3DE &amp; CMR and 2DE &amp; CMR, and excellent correlation between 3DE and 2DE for LVEF (Table 1). There was for trend for CMR to underestimate LVEF compared to 2DE and 3DE, with small biases although wide limits of agreement (Figure 1). There was excellent correlation of LVEDV and LVESV across all 3 techniques. CMR underestimated volumes compared to 2DE and 3DE with large biases and wide LOA. The kappa coefficient agreement at threshold level for CRT insertion (LVEF ≤35%) was fair for 3DE and CMR (0.379, p = 0.004) and 2DE and CMR (0.462, p = 0.001), and moderate for 3DE and 2DE (0.575, p ≤ 0.001). Conclusion – Whilst LVEF is not the only indicator to guide CRT insertion, it remains an important imaging parameter for clinical decision making. We observed large biases in left ventricular volumes between 2D, 3D and CMR. However, whilst the overall bias in LVEF is small, the wide limits of agreement (LOA) observed may represent an area of clinical uncertainty, which may impact on the dichotomous imaging threshold for CRT insertion. Comparison of indices between modalities LVEF Correlation (r) LVEF Bias &amp; LOA (%±SD) EDV Correlation (r) EDV Bias &amp; LOA (mL ± SD) ESV Correlation (r) ESV Bias &amp; LOA (mL ± SD) 3DE vs CMR 0.676 (p &amp;lt; 0.001) +1.75 ± 15.4 0.896 (p &amp;lt; 0.001) -82.16 ± 42.8 0.937 (p &amp;lt; 0.001) -61.3 ± 34.9 3DE vs 2DE 0.872 (p &amp;lt; 0.001) +0.48 ± 4.5 0.909 (p &amp;lt; 0.001) -10.31 ± 28.3 0.936 (p &amp;lt; 0.001) -8.42 ± 20.5 2DE vs CMR 0.675 (p &amp;lt; 0.001) +2.35 ± 14.6 0.876 (p &amp;lt; 0.001) -67.35 ± 36.3 0.898 (p &amp;lt; 0.001) -51.42 ± 30.1 Abstract Figure. Bland-Altman Plot LVEF by 3DE &amp; CMR

Direct measurement of atrioventricular valve regurgitant jets using 4D flow cardiovascular magnetic resonance is accurate and reliable for children with congenital heart disease: a retrospective cohort study

Background3D-time resolved flow (4DF) cardiovascular magnetic resonance (CMR) with retrospective analysis of atrioventricular valve regurgitation (AVVR) allows for internal validation by multiple direct and indirect methods. Limited data exist on direct measurement of AVVR by 4DF CMR in pediatric congenital heart disease (CHD). We aimed to validate direct measurement of the AVVR jet as accurate and reliable compared to the volumetric method (clinical standard by 2D CMR) and as a superior method of internal validation than the annular inflow method.MethodsWe identified 44 consecutive patients with diverse CHD referred for evaluation of AVVR by CMR. 1.5 T or 3 T scanners, intravenous contrast, and a combination of parallel imaging and compressed sensing were used. Four methods of measuring AVVR volume (RVol) were used: volumetric method (VOL; the clinical standard) = stroke volume by 2D balanced steady-state free precession – semilunar valve forward flow (SLFF); annular inflow method (AIM) = atrioventricular valve forward flow [AVFF] – semilunar valve net flow (SLNF); and direct measurement (JET). AVFF was measured using static and retrospective valve tracking planes. SLFF, SLNF, AVFF, and JET were measured by 4DF phase contrast. Regurgitant fraction was calculated as [RVol/(RVol+SLNF)]× 100. Statistical methods included Spearman, Wilcoxon rank sum test/Student paired t-test, Bland Altman analysis, and intra-class coefficient (ICC), where appropriate.ResultsRegurgitant fraction by JET strongly correlated with the indirect methods (VOL and AIM) (ρ = 0.73–0.80, p < 0.001) and was similar to VOL with a median difference (interquartile range) of − 1.5% (− 8.3–7.2%; p = 0.624). VOL had weaker correlations with AIM and JET (ρ = 0.69–0.73, p < 0.001). AIM underestimated RF by 3.6–6.9% compared to VOL and JET, p < 0.03. Intra- and inter- observer reliability were excellent for all methods (ICC 0.94–0.99). The mean (±standard deviation) inter-observer difference for VOL was 2.4% (±5.1%), p < 0.05.ConclusionsIn a diverse cohort of pediatric CHD, measurement of AVVR using JET is accurate and reliable to VOL and is a superior method of internal validation compared to AIM. This study supports use of 4DF CMR for measurement of AVVR, obviating need for expert prospective prescription during image acquisition by 2D CMR.

Co-existing cerebrovascular atherosclerosis predicts subsequent vascular event: a multi-contrast cardiovascular magnetic resonance imaging study

BackgroundIt is still unknown that whether co-existing intracranial stenosis and extracranial carotid vulnerable plaques have higher predictive value for subsequent vascular events. This study aimed to determine the relationship between co-existing extracranial carotid vulnerable plaques and intracranial stenosis and subsequent vascular events utilizing cardiovascular magnetic resonance (CMR) vessel wall imaging.MethodsPatients who had recent cerebrovascular symptoms in anterior circulation (< 2 weeks) were consecutively enrolled and underwent multi-contrast CMR vessel wall imaging for extracranial carotid arteries and 3D time-of flight CMR angiography for intracranial arteries at baseline. After baseline examination, all patients were followed-up for at least 1 year to determined recurrence of vascular events. The co-existing cerebrovascular atherosclerosis was defined as presence of both intracranial artery stenosis and at least one the following measures of extracranial artery atherosclerosis: plaque, calcification, lipid-rich necrotic core (LRNC), or intraplaque hemorrhage. Univariate and multivariate Cox regressions were used to calculate the hazard ratio (HR) and corresponding 95% confidence interval (CI) of co-existing plaques in predicting subsequent vascular events.ResultsIn total, 150 patients (mean age: 61.8 ± 11.9 years; 109 males) were recruited. During the median follow-up time of 12.1 months, 41 (27.3%) patients experienced vascular events. Co-existing intracranial artery stenosis and extracranial carotid plaque (HR, 3.57; 95% CI, 1.63–7.82; P = 0.001) and co-existing intracranial artery stenosis and extracranial carotid LRNC (HR, 4.47; 95% CI, 2.15–9.27; P < 0.001) were significantly associated with subsequent vascular events, respectively. After adjusted for confounding factors and carotid stenosis, these associations remained statistically significant (HR, 5.12; 95% CI, 1.36–19.24; P = 0.016 and HR, 8.12; 95% CI, 2.41–27.31; P = 0.001, respectively).ConclusionsThe co-existing cerebrovascular atherosclerotic diseases, particularly co-existing carotid lipid-rich necrotic core and intracranial stenosis, are independent predictors for subsequent vascular events.

Carotid geometry is an independent predictor of wall thickness \u2013 a 3D cardiovascular magnetic resonance study in patients with high cardiovascular risk

BackgroundThe posterior wall of the proximal internal carotid artery (ICA) is the predilection site for the development of stenosis. To optimally prevent stroke, identification of new risk factors for plaque progression is of high interest. Therefore, we studied the impact of carotid geometry and wall shear stress on cardiovascular magnetic resonance (CMR)-depicted wall thickness in the ICA of patients with high cardiovascular disease risk.MethodsOne hundred twenty-one consecutive patients ≥50 years with hypertension, ≥1 additional cardiovascular risk factor and ICA plaque ≥1.5 mm thickness and < 50% stenosis were prospectively included. High-resolution 3D-multi-contrast (time of flight, T1, T2, proton density) and 4D flow CMR were performed for the assessment of morphological (bifurcation angle, ICA/common carotid artery (CCA) diameter ratio, tortuosity, and wall thickness) and hemodynamic parameters (absolute/systolic wall shear stress (WSS), oscillatory shear index (OSI)) in 242 carotid bifurcations.ResultsWe found lower absolute/systolic WSS, higher OSI and increased wall thickness in the posterior compared to the anterior wall of the ICA bulb (p < 0.001), whereas this correlation disappeared in ≥10% stenosis. Higher carotid tortuosity (regression coefficient = 0.764; p < 0.001) and lower ICA/CCA diameter ratio (regression coefficient = − 0.302; p < 0.001) were independent predictors of increased wall thickness even after adjustment for cardiovascular risk factors. This association was not found for bifurcation angle, WSS or OSI in multivariate regression analysis.ConclusionsHigh carotid tortuosity and low ICA diameter were independent predictors for wall thickness of the ICA bulb in this cross-sectional study, whereas this association was not present for WSS or OSI. Thus, consideration of geometric parameters of the carotid bifurcation could be helpful to identify patients at increased risk of carotid plaque generation. However, this association and the potential benefit of WSS measurement need to be further explored in a longitudinal study.

Post-cardioversion Improvement in LV Function Defined by 4D Flow Patterns and Energetics in Patients With Atrial Fibrillation.

BackgroundAtrial fibrillation (AF) is a prevalent cause of cardiovascular morbidity, including thromboembolism and heart failure. Left ventricular dysfunction (LVD) detected in AF patients may be either precursor or consequence of the arrythmia. Successful cardioversion of chronic AF is often followed by a transient period of left atrial (LA) stunning, where depressed mechanical atrial contraction persists despite reinstitution of sinus rhythm. To determine if AF-associated LVD would improve with resolution of LA dysfunction, AF patients were examined immediately and 4 weeks after cardioversion to sinus rhythm. 4D flow cardiovascular magnetic resonance (CMR) assesses ventricular function according to the volumes and energetics of functional components of the LV volume. Previously, described 4D CMR markers of LVD include decreased volume and end-diastolic kinetic energy (KE) of the Direct flow, which is the portion of LV volume that passes directly from inflow to outflow in a single cycle. We hypothesize that impaired LV flow patterns and energetics will be found immediately after cardioversion during atrial stunning, and that those parameters will improve as atrial function returns.MethodsTen patients with a history of AF underwent CMR 2–3 h (Time-1) and 4 weeks (Time-2), following electrical cardioversion to sinus rhythm. 4D phase-contrast velocity data and morphological images were acquired at a 3T CMR system. Using a previously evaluated method, pathlines were emitted from the LV end diastolic volume (LVEDV) and traced forward and backward in time until end-systole. The LVEDV was automatically separated into four functional flow components whose volume and KE were calculated.ResultsLeft atrial fractional area change increased over the follow-up period (P = 0.001), indicating recovery of LA mechanical function. LVEF increased between Time-1 and Time-2 (P = 0.003); LVEDVI did not change (P = 0.319). Over that interval, the ratios of Direct flow/LVEDV volume and KE increased (P = 0.001 and P = 0.003, respectively), while the ratios of Residual volume/LVEDV volume and KE decreased (P = 0.001 and P = 0.005, respectively).ConclusionPost-cardioversion recovery of LA function was associated with improvements in conventional and 4D CMR markers of LV function. Flow-specific measures demonstrate the negative but potentially reversible impact of LA dysfunction on volume and energetic aspects of LV function.