Cardiac Magnetic Resonance Study Research Articles

Left and Right PVC-Induced Ventricular Dysfunction

BackgroundFrequent premature ventricular complexes (PVCs) can result in a reversible form of cardiomyopathy that usually affects the left ventricle (LV). ObjectivesThe objective of this study was to assess whether frequent PVCs have an impact on right ventricular (RV) function. MethodsSerial cardiac magnetic resonance (CMR) studies were performed in a series of 47 patients before and after ablation of frequent PVCs. ResultsPatients with RV cardiomyopathy (ejection fraction [EF] <0.45) had more frequent PVCs than did patients without decreased RV function (23% ± 11% vs 15% ± 11%, P = 0.03). Likewise, patients with LV cardiomyopathy (EF <0.50) had more frequent PVCs than did patients without decreased LV function (23% ± 10% vs 14% ± 12%, P = 0.003). LV dysfunction was present in 21 patients (45%). In patients with LV dysfunction, 15 patients (32%) had biventricular dysfunction, and 6 patients (13%) had isolated LV dysfunction. A total of 19 patients (40%) had RV dysfunction, and 4 of the patients with RV dysfunction (9%) had isolated RV dysfunction. Cardiac magnetic resonance was repeated 1.9 ± 1.3 years after ablation. In patients with successful ablation, RV function improved, and in patients without successful ablation, RV function did not significantly change (before and after ablation RVEF 0.45 ± 0.09 and 0.52 ± 0.09; P < 0.001 vs. 0.46 ± 0.07 and 0.48 ± 0.04; P = 0.14, respectively). ConclusionsFrequent PVCs can cause RV cardiomyopathy that parallels LV cardiomyopathy and is reversible with successful ablation.

Abstract 12248: Decreased Left Ventricular Hemodynamic Forces As A Novel Biomarker Of Myocardial Dysfunction In Duchenne Muscular Dystrophy

Introduction: Patients with Duchenne muscular dystrophy (DMD) develop progressive cardiomyopathy. Cardiac magnetic resonance (CMR) imaging is used to identify global and regional function, as well as myocardial fibrosis in DMD. Unique left ventricular (LV) biomechanics cannot be assessed through conventional CMR techniques. Thus, we investigated hemodynamic force (HDF) through cine derived wall motion in the LV as a novel biomarker of myocardial dysfunction in DMD patients. Methods: This retrospective study consisted of CMR studies from DMD patients and age-matched controls. Feature-tracking (Qstrain, Medis) was performed on short-axis and long-axis cine imaging to capture LV wall motion. A novel technique based on diffeomorphic mapping was used to calculate three-dimensional LV kinematic models and HDF vectors throughout the cardiac cycle (Figure 1A). The apical-basal, lateral-septal, and anterior-posterior HDF vectors were correlated with global and regional functional parameters. Results: Eleven DMD and 11 controls were enrolled with LV EF 51 ± 6 vs 56 ± 6 (p = 0.09). DMD patients had decreased apical-basal and lateral-septal HDF across multiple points in the cardiac cycle compared to controls (Figure 1B). Six DMD patients with LV EF &lt; 55% were compared to 5 DMD patients with normal EF, demonstrating significant decrease in apical-basal systolic root mean square (RMS) HDF (p = 0.015), lateral-septal systolic RMS HDF (p = 0.009), anterior-posterior diastolic RMS HDF (p = 0.011), and magnitude systolic RMS HDF (p = 0.011) in patients with dysfunction. Absolute magnitude RMS HDF in all axes correlated with LV global longitudinal strain, LV global circumferential strain, and LV EF (r = 0.59 to 0.81, p &lt; 0.05). Conclusions: Cine derived HDF may be a more sensitive measure of LV dysfunction in DMD patients. Apical-basal HDF has potential as a novel biomarker for progression of disease.

Abstract 14062: Longitudinal Rate of Change for Cardiac Magnetic Resonance Biomarkers Associates With Mortality in Duchenne Muscular Dystrophy

Introduction: Cardiomyopathy (CM) is the leading cause of death in Duchenne muscular dystrophy (DMD). Progression is variable. Multiple DMD-specific CM medications are in development, but there are no established outcome measures for therapeutic trials. Our prior work demonstrated an association between cardiac magnetic resonance (CMR) metrics and mortality, including left ventricular ejection fraction (LVEF), ventricular volumes, and native T1 mapping. The objective of this study was to determine whether longitudinal change in these metrics associates with all-cause mortality. Methods: Seventy-eight DMD subjects underwent 211 comprehensive CMR studies, including LVEF, indexed LV end diastolic and systolic volumes (LVESVi and LVEDVi), and native T1 mapping. To explore how the slope of CMR biomarkers affects mortality, multivariable linear regression was used to model age, mortality, and the interaction term of age and mortality on predictors of interest (LVEF, LVEDVi, LVESVi, native T1). Results: At baseline CMR, the median age was 12.5 years (range 7.4-27.5), and the median LVEF was 57%; 32 subjects (41%) had LVEF &lt; 55%. LGE was present in 54 subjects (71%). Fifteen subjects (19%) died over a median follow up of 5 years (IQR 3.1,7). The slope of LVEF decline differentiated between subjects with and without mortality (p&lt;0.001) ( Figure 1 ). A steeper increase in LVEDVi and LVESVi also associated with mortality (p&lt;0.001), while change in native T1 did not. Conclusions: DMD all-cause mortality is associated with the slope of progression of LVEF and ventricular volumes. Aggressive medical therapy to decrease the rate of progression may improve mortality in this patient population. In addition, a decrease in the rate of progression may serve as a valid surrogate outcome measure for therapeutic trials.

A Left ventricle remodeling in patients with bicuspid aortic valve.

We assessed the impact of bicuspid aortic valve (BAV), aortic stenosis (AS), and regurgitation (AR) on the metrics of left ventricular (LV) remodeling, as measured by electrocardiogram (ECG), transthoracic echocardiography (TTE), and cardiac magnetic resonance (CMR). This retrospective CMR study included 11 patients with both AS and AR (BAV-ASR), 30 with AS (BAV-AS), 28 with AR (BAV-AR), 47 with neither AS nor AR (BAV-no_AS/AR), and 40 with trileaflet aortic valve (TAV-no_AS/AR). CMR analysis included the LV end-diastolic volume index (LVEDVi), mass index (LVMi), and extracellular volume fraction (ECV). The Sokolow-Lyon and Cornell products by ECG and TTE-derived E/e' were measured. There were no differences in the ECG, TTE, and CMR parameters between BAV-no_AS/AR and TAV-no_AS/AR. However, the presence of aortic valve dysfunction resulted in an elevated Sokolow-Lyon product for BAV-ASR (p = 0.017) and BAV-AR (p = 0.001), as well as increased Cornell product (p = 0.04) and E/e' (p < 0.001) for BAV-AS compared with BAV-no_AS/AR. LVEDVi and LVMi were elevated in patients with BAV-ASR and BAV-AR compared with those with BAV-no_AS/AR (LVEDVi: 101 ± 29 ml/m2 and 112 ± 32 ml/m2 vs. 74 ± 15 ml/m2, p = 0.005 and p < 0.001, LVMi: 75 ± 7g/m2 and 64 ± 14g/m2 vs. 47 ± 9g/m2, respectively; p < 0.001). There was no difference in ECV between the BAV and TAV-no_AS/AR subgroups. Normally functioning BAV did not result in LV remodeling. However, concomitant AV dysfunction was associated with statistically significant morphological remodeling.

Left Ventricular Function and Iron Loading Status in a Tertiary Center Hemochromatosis Cohort-A Cardiac Magnetic Resonance Study.

Haemochromatosis (HCH), a common genetic disorder with variable penetrance, results in progressive but understudied iron overload. We prospectively evaluated organ iron loading and cardiac function in a tertiary center HCH cohort. 42 HCH patients (47 ± 14 years) and 36 controls underwent laboratory workup and cardiac magnetic resonance (CMR), including T1 and T2* mapping. Myocardial T2* (myoT2*), myocardial T1 (myoT1) and liver T2* (livT2*) were lower in patients compared to controls (33 ± 4 ms vs. 36 ± 3 ms [p = 0.004], 964 ± 33 ms vs. 979 ± 25 ms [p = 0.028] and 21 ± 10 ms vs. 30 ± 5 ms [p &lt; 0.001], respectively). MyoT2* did not reach the threshold of clinically significant iron overload (&lt;20 ms), in any of the patients. In 22 (52.4%) patients, at least one of the tissue parameters was reduced. Reduced myocardial T2* and/or T1 were found in 10 (23.8%) patients, including 4 pts with normal livT2*. LivT2* was reduced in 18 (42.9%) patients. MyoT1 and livT2* inversely correlated with ferritin (rs = -0.351 [p = 0.028] and rs = -0.602 [p &lt; 0.001], respectively). LivT2* by a dedicated sequence and livT2* by cardiac T2* mapping showed good agreement (ICC = 0.876 p &lt; 0.001). In contemporary hemochromatosis, significant myocardial iron overload is rare. Low myocardial T2* and/or T1 values may warrant closer follow-up for accelerated myocardial iron overload even in patients without overt liver overload. Cardiac T2* mapping sequence allows for liver screening at the time of CMR.

Assessment of Adult Patients with Long COVID Manifestations Suspected as Cardiovascular: A Single-Center Experience.

Background: Persistent symptoms affect a subset of coronavirus disease 2019 (COVID-19) survivors. Some of these may be cardiovascular (CV)-related. Objective: To assess the burden of objective CV morbidity among, and to explore the short-term course experienced by, COVID-19 patients with post-infectious symptomatology suspected as CV. Methods: This was a single-center, retrospective analysis of consecutive adult patients with new-onset symptoms believed to be CV following recovery from COVID-19, who had been assessed at a dedicated ‘Cardio’-COVID clinic between June 2020 and June 2021. All participants were followed for 1 year for symptomatic course and the occurrence of new CV diagnoses and major adverse cardiovascular events (MACE). Results: A total of 96 patients (median age 54 (IQR, 44–64) years, 52 (54%) females) were included in the final analysis. Initial visits occurred within a median of 142 days after the diagnosis of acute COVID. Nearly all (99%) patients experienced a symptomatic acute illness, which was graded as severe in 26 (27%) cases according to the National Institutes of Health (NIH) criteria. Long-COVID symptoms included mainly dyspnea and fatigue. While the initial work-up was mostly normal, 45% of the 11 cardiac magnetic resonance studies performed revealed pathologies. New CV diagnoses were made in nine (9%) patients and mainly included myocarditis that later resolved. An abnormal spirometry was the only variable associated with these. No MACE were recorded. Fifty-two (54%) participants felt that their symptoms improved. No association was found between CV morbidity and symptomatic course. Conclusions: In our experience, long-COVID symptoms of presumed CV origin signified actual CV disease in a minority of patients who, irrespective of the final diagnosis, faced a fair 1-year prognosis.

Natural history of myocardial fibrosis in dilated cardiomyopathy

Abstract Background It is commonly accepted that myocardial fibrosis (MF) is implicated in the pathology of dilated cardiomyopathy (DCM). However, MF is not a “fixed” abnormality but evolves over time. It is unknown what the natural history of MF is in optimally treated DCM patients. Methods This is a prospective, single-center, observational study. Between May 2019 and September 2020, 90 DCM (81 male, mean age 47.2±9.8 years, mean EF 34.5±12.2%) patients underwent cardiac magnetic resonance (CMR). All patients were optimally treated with heart failure approved medications (beta-blockers in 100%, ACE-I/ARNI/ARB – 98%, MRA – 95%). Both, replacement via late gadolinium enhancement (LGE) and interstitial via T1 mapping MF were assessed. Replacement MF was expressed as LGE mass and LGE extent, whereas interstitial MF as extracellular volume (ECV). Left ventricular (LV) matrix and cell volumes were calculated based on LV mass and ECV as: LV matrix volume = (LV mass/1.05 g/mL) × ECV and LV cell volume = (LV mass/1.05 g/mL) × (1 − ECV). After 12 months CMR studies with MF assessment were repeated. Results Overall, index LV end-diastolic and end-systolic volumes (LVEDvol, LVESvol) and LV mass significantly decreased, whereas EF increased during follow-up (Table 1). Both, LGE mass (8.7±8.1 vs. 8.6±7.7 g; p=0.6) and LGE extent (4.6±4.2 vs. 4.97±4.6%; p=0.14) were similar between two measurements. There was a trend towards ECV decrease between baseline and follow-up studies but it did not reach statistical significance (28.5±4.9 vs. 27.7±4.1%; p=0.09). LV matrix volume significantly decreased during follow-up (49.1±17.8 vs. 46.1±15.7 ml; p&amp;lt;0.05); however LV cell volume remained unchanged (123.1±35.6 vs. 119.7±39.6 ml; p=0.2). Conclusions Beneficial regression of LV volumes and improvement of systolic function is common in DCM over mid-term period (one year). Replacement fibrosis seems to be a “fixed” pathology without much room for improvement. On the other hand, interstitial fibrosis seems to be a subject for substantial change. Left ventricular cells compartment does not change over time. Two types of MF – replacement and interstitial behaved differently during follow-up. Interstitial MF is amenable for treatment, whereas replacement MF does not respond to currently available therapy. Funding Acknowledgement Type of funding sources: Public grant(s) – National budget only. Main funding source(s): This work was founded through the National Science Centre, Poland (grant number 2018/29/B/NZ5/02588) and the Department of Scientific Research and Structural Funds of Medical College, Jagiellonian University (grant number K/ZDS/007192)

T1 mapping of the right ventricle in heart transplant recipients: how does it correlate with endomyocardial biopsy findings?

Abstract Aim Noninvasive detection of cardiac allograft rejection is highly desirable. We sought to assess how right ventricular (RV) T1 mapping correlates with endomyocardial biopsy findings. Methods All patients underwent right heart catheterization with biopsy and cardiac magnetic resonance (CMR) irrespective of symptoms, as part of the institutional registry protocol dedicated to heart transplant (HTx) recipients. CMR studies were performed using a 1.5 T scanner and analyses by using a commercially available software (CMR42, Circle CVI, Calgary, Canada). Endocardial and epicardial borders were drawn on end-systolic and end-diastolic phases for ventricular function analysis. For T1 measurements, region of interests located at the RV free-wall were drawn manually on midventricular short-axis slices avoiding blood pool and epicardial fat. Extracellular volume (ECV) was calculated as ECV = (1 − hematocrit) × (ΔR1 myocardium/ΔR blood), where R1 = 1/T1. Late gadolinium enhancement (LGE) images were also obtained using a phase-sensitive inversion recovery segmented gradient echo sequence. Hyperenhancement was assessed semi-quantitatively as segmental (2–3 cm) or diffuse (&amp;gt;3 cm). Allograft rejection was determined based on the severity of inflammatory infiltrates and myocyte damage on pathological specimens according to the standardized International Society for Heart and Lung Transplantation (ISHLT) nomenclature. Results In all, 61 paired studies were evaluated. None of the patients had heart failure symptoms. We defined 3 subgroups: Group I; never rejected (n=23), group II; biopsy remarkable for rejection (n=19) and group III; history of past rejection(s) (n=19). RV volumes and ejection fraction (EF) did not differ between the groups. However, rejections were nicely mirrored by T1 time and particularly by ECV. Of note, T1 time and ECV improved but not completely normalized after resolution of rejection. Overall, T1 time (cut off 1060ms) and ECV (cut off 35%) were sensitive (84%, both) and had high negative predictive values (88% and 87%, respectively) but not specific (43% and 52% respectively) for discriminating rejection related subclinical RV damage. Their specificity slightly improved to 52 and 61% respectively, if patients with previous rejection were excluded (Figure 1). LGE did not discriminate rejection. Conclusion RV volumes and EF are insensitive to detect allograft rejection. Native T1 time and ECV of the RV, as a means of extracellular expansion, likely reflect interstitial fibrosis, oedema, and inflammation that are typical for, but not limited to allograft rejection. Hence, these parameters can help to exclude rejection but have limited standalone value for making the nonivasive diagnosis due to their low specificity. These results cannot be extrapolated to the left ventricle. Funding Acknowledgement Type of funding sources: Private hospital(s). Main funding source(s): University of Baskent

Non-contrast cardiac magnetic resonance imaging after SARS-CoV2 infection or vaccination in asymptomatic adolescents: insights from the EnIGMA study

Abstract Background Myocarditis after SARS-CoV2 infection or vaccination is rare, but seems to be relatively more frequent in young population. Cardiac magnetic resonance (CMR) T2 weighted sequences have the potential to detect subclinical myocarditis. However, there is paucity of data on the potential myocardial involvement after SARS-CoV2 infection or vaccination in asymptomatic adolescents. Purpose To evaluate the presence of subclinical myocardial damage in adolescents who were infected with SARS-CoV2 or vaccinated against SARS-CoV2 using non-contrast CMR imaging. Methods Asymptomatic adolescents enrolled in the “Early ImaginG Markers of unhealthy lifestyles in Adolescents” (EnIGMA) project were scanned using a 3-Tesla CMR scanner between March 2021 and October 2021. CMR scans included CINE imaging and myocardial T2-mapping sequences. SARS-CoV2 IgG antibody testing was performed in capillary blood samples, and date of confirmed SARS-CoV2 infection and/or vaccination if any was collected. Participants were assigned to three different groups according to SARS-CoV2 status: Group 1 (non-infected and non-vaccinated), Group 2 (infected and non-vaccinated), and Group 3 (vaccinated, independently of past infection status). CMR images were analyzed by experienced observers blinded to adolescent's SARS-CoV2 status. ANOVA and multiple regression analysis, together with correlation coefficients, were used to study between-group differences and associations among variables of interest. Results A total of 115 adolescents with a mean age of 16.0 years (standard deviation (SD)=0.4), 54% girls, completed the CMR study and SARS-CoV2 data successfully, and were assigned to Group 1 (n=72), Group 2 (n=22), and Group 3 (n=21). Left and right ventricular ejection fraction (LVEF/RVEF) did not significantly differ among groups: mean LVEF was 62.8% (SD=4.1), 63.0% (SD=3.7) and 60.9% (SD=3.9) [p=0.12] and mean RVEF was 56.5% (SD=4.2), 56.5% (SD=5.5) and 54.5% (SD=5.1) [p=0.23] in Groups 1, 2 and 3, respectively. Similarly, there were no between-group significant differences in myocardial T2 relaxation values: mean T2 values were 44.1 ms (SD=2.2), 44.1 ms (SD=1.8) and 44.4 ms (SD=1.9) in Groups 1, 2, and 3, respectively (p=0.63) (Figure 1). No differences were found either after adjusting for age and gender. Median time (interquartile range) from date of infection or vaccination to CMR acquisition was 133 (121) days and 28 (38) days in Group 2 and Group 3, respectively. No correlation between time from infection/vaccination to CMR acquisition and T2 values was detected (Figure 2). Conclusions This observational study did not find evidence of subclinical myocardial involvement after SARS-CoV2 infection or vaccination in asymptomatic adolescents, as assessed with T2-mapping magnetic resonance imaging. Funding Acknowledgement Type of funding sources: Foundation. Main funding source(s): Instituto de Salud Carlos III (ISCIII)-Fondo de Investigaciόn Sanitaria.European Regional Development Fund/European Social Fund (“A way to make Europe”/“Investing in your future”.

Histology-verified myocardial fibrosis and quantification in severe AS patients: correlation with non-invasive LV myocardial tissue assessment

Abstract Background Myocardial fibrosis (MF) is a common finding and a potential adverse prognostic marker in several cardiac diseases, including in severe aortic stenosis (AS). While histological analysis obtained through endomyocardial biopsy remains the gold-standard for MF assessment, non-invasive cardiac imaging may offer surrogate biomarkers for fibrosis. We tried to assess the correlation between MF quantification at histopathology and cardiac magnetic resonance (CMR)-derived tissue characterization data in patients with severe AS. Methodology Single-center prospective cohort enrolling 71 patients with severe symptomatic high-gradient AS undergoing surgical aortic valve replacement (SAVR) (mean age 71±9 years; 49% male, mean valvular transaortic gradient 60±20 mmHg; mean left ventricle [LV] ejection fraction 58±9%). Those with past history of myocardial infarction or cardiomyopathy were excluded. All patients underwent pre-operative CMR study with LV tissue characterization and quantification. Normal T1 mapping value was defined as &amp;gt;1021ms as per center protocol. Myocardial tissue was obtained during SAVR either through myocardial biopsy at basal LV septum or harvested from surgical myectomy specimens. Masson's trichrome stain was used for collagen/fibrosis assessment. Automatic quantification was obtained at QuPathTM digital pathology software after applying a dedicated artificial intelligence algorithm on ultra-high-resolution digital slide scanning images. Results Histology-confirmed MF was observed in all patients (median percentage of fibrotic myocardial tissue 15% [IQR 9–22%]). Median global T1 mapping and extracellular volume (ECV) percentage was 1048ms (IQR 1027–1078) and 24% (IQR 20–30%), respectively. Late gadolinium enhancement (LGE) with a non-ischemic pattern was present in 42 patients (59%) with a median LGE mass of 5.8g [IQR 1.0–10.2]; median percentage of 3.7% [IQR 0.6–10.4]. While neither T1 mapping (global or basal LV septum), ECV nor LGE had any significant correlation with histology-confirmed MF (Figure 1) the vast majority had significantly elevated global and basal LV septum T1 mapping – 81% and 92%, respectively. Conclusion In this single-center prospective study, microscopic MF was present in all patients with severe symptomatic high-gradient AS, was accompanied by elevated T1 mapping values but no correlation was found between myocardial fibrosis at histopathology analysis and CMR-derived LV tissue characterization parameters. This may not only stem from sampling (single point biopsy vs. whole myocardial tissue assessment) but also from distinct evaluation of different types of fibrosis by different methods. Funding Acknowledgement Type of funding sources: None.

Characterisation of metabolic phenotype in aortic stenosis: insights from a multi-parametric cardiac magnetic resonance study

Abstract Introduction Left ventricular hypertrophy develops in Aortic stenosis (AS) as a result of increased afterload and is related to perturbations in cardiac fatty acid metabolism with evidence of steatosis and impaired myocardial energetics in severe AS. However, there is wide individual heterogeneity when it comes to degree of hypertrophy and progression to myocardial fibrosis and heart failure in those with same degree of stenosis. Underlying interplay of metabolism and hypertrophy may explain this variability. Purpose We sought to determine if a gradient of myocardial energetic impairment and steatosis exists across the spectrum of AS and precedes irreversible structural remodelling and subclinical LV dysfunction. We investigated metabolic remodelling in AS, focusing on its relationship with stenosis severity, degree of hypertrophy and fibrosis. Methods 74 AS participants including mild AS (n=18), asymptomatic moderate AS (n=38), asymptomatic severe AS (n=18), and healthy volunteers (n=13) underwent assessment of cardiac function, energetics (myocardial phosphocreatine to adenosine triphosphate ratio, PCr/ATP) and myocardial triglyceride content (MTG) using cardiovascular magnetic resonance (CMR) imaging and spectroscopy. Participants were divided into quartile groups based on their LV wall thickness (LVWT) and peak aortic valve gradient (AVG) to study relationship between cardiac metabolism and hemodynamic markers of LV structure and function. Results Baseline CMR characteristics (Fig. 1B-C) show a stepwise deterioration in LV structure and function across both the LVWT and AVG quartile groups (p values significant) with high LV mass index and relatively dilated LV as disease severity increases. Cardiac energetics (PCr/ATP]) were reduced in mild-moderate AS, Q2 (1.43±0.13 vs normal controls, Q1 1.80±0.14, p=0.05, Fig.2A) with a progressive decline with increasing AS severity (severe AS, Q4 PCr/ATP 1.39±0.14, p=0.02 vs controls). MTG was elevated in mild-moderate AS, Q2 (1.52±0.84 vs normal, Q1 1.25±0.70%, p=0.032, Fig. 2B). Whilst all AS groups had evidence of subclinical LV dysfunction with impaired strain parameters, impaired systolic longitudinal strain was related to the degree of energetic impairment (R 0.219, p 0.03). In addition, PCr/ATP was strongly associated with the presence of myocardial fibrosis (p 0.01) strengthening the hypothesis that metabolic changes may play a causative role in disease progression (Fig. 2C). Conclusion A gradient of myocardial energetic deficit and steatosis exists across the spectrum of hypertrophied AS hearts, notably we show in our study that these metabolic changes precede irreversible LV remodelling and subclinical dysfunction. These findings may have value for defining distinct metabolic phenotypes and identifying those most at risk of decompensation. This also opens another avenue for precision metabolic therapy in AS with a potential to intervene and delay or prevent decompensation. Funding Acknowledgement Type of funding sources: Foundation. Main funding source(s): British Heart Foundation Clinical Research Training Fellowship

Myocardial fibrosis detection using kernel methods: preliminary results from a cardiac magnetic resonance study

Abstract Funding Acknowledgements Type of funding sources: None. Background Asserting the presence of myocardial fibrosis from cardiac magnetic resonance (CMR) images is sometimes a complex task, even for experienced cardiac imagers. The application of artificial intelligence models to the evaluation process can be of help for enhancing diagnostic accuracy. Purpose In this work, we tested two different Machine Learning (ML) algorithms, namely kernel methods with Support Vector Machine (SVM) and Convolutional Neural Network (CNN) to a cohort of consecutive CMR studies. The goal was a binary classification task, aimed to identify myocardial scar (present/absent). Methods Dataset consisted of 642 CMR scans, equally divided into healthy and fibrosis-affected. Raw DICOM files were preprocessed through an automated pipeline, in order to retrieve only short-axis post contrast acquisitions. Heart regions were then individuated using a YOLO network, in order to remove the background and focus only on data of interest. Finally, for each subject 10 slices were extracted through interpolation, and all images resized to 128 by 128 pixels. Dataset was divided into training and test sets, with proportions 80%-20%. Results The first analysis was based on state-of-the-art CNN models, pre-trained on the ImageNet dataset. The training of the models was optimized using "reduce learning rate on the plateau", "early stopping", and standard data augmentation techniques. Experiments showed that CNNs-based models led to poor performances. The second attempt was based on kernel methods and SVM. Before feeding the input to the algorithm, dimensionality reduction was implemented using a Principal Component Analysis retaining 99% of the variance. The resulting 335 features were passed as input to an SVM, testing different kernels (e.g. Linear, Gaussian, Cossim). Models were trained and optimized using a Grid Search with a 5-fold Cross-Validation. The best SVM configuration displayed an accuracy of 68% and a sensitivity of 60%. Improved results could be obtained using state-of-the-art Multiple Kernel Learning algorithms, leading to 71% accuracy and sensitivity of 72% (with a 12% increment with respect to the previous algorithm). Conclusions Our preliminary results of this study showed the possibility for a ML system to learn to identify myocardial fibrosis, directly from raw CMR images. In particular, kernel methods were able to achieve good and significant results, even with small amounts of data, suggesting room for improvement. In future works, we plan to furtherly explore kernel methods to improve the results and to build an end-to-end solution for cardiac imagers.

Institutional transition from invasive to non-invasive imaging in children with univentricular heart defects: safety and cost savings.

Patients with univentricular heart defects require lifelong imaging surveillance. Recent advances in non-invasive imaging have enabled replacing these patients' routine catheterisation. Our objective was to describe the safety and cost savings of transition of a tertiary care children's hospital from routine invasive to routine non-invasive imaging of low-risk patients with univentricular heart defects. This single-centre cohort study consists of 1) a retrospective analysis of the transition from cardiac catheterisation (n = 21) to CT angiography (n = 20) before bidirectional Glenn operation and 2) a prospective study (n = 89) describing cardiac magnetic resonance before and after the total cavopulmonary connection in low-risk patients with univentricular heart defects. Pre-Glenn: The total length of CT angiography was markedly shorter compared to the catheterisation: 30 min (range: 20-60) and 125 min (range: 70-220), respectively (p < 0.001). Catheterisation used more iodine contrast agents than CT angiography, 19 ± 3.9 ml, and 10 ± 2.4 ml, respectively (p < 0.001). Controlled ventilation was used for all catheterised and 3 (15%) CT angiography patients (p < 0.001). No complications occurred during CT angiography, while they emerged in 19% (4/21) catheterisation cases (p < 0.001). CT angiography and catheterisation showed no significant difference in the radiation exposure. Pre-/post-total cavopulmonary connection: All cardiac magnetic resonance studies were successful, and no complications occurred. In 60% of the cardiac magnetic resonance (53/89), no sedation was performed, and peripheral venous pressure was measured in all cases. Cost analysis suggests that moving to non-invasive imaging yielded cost savings of at least €2500-4000 per patient. Transition from routine invasive to routine non-invasive pre-and post-operative imaging is safely achievable with cost savings.

The Variation in the Diastolic Period with Interventricular Septal Displacement and Its Relation to the Right Ventricular Function in Pulmonary Hypertension: A Preliminary Cardiac Magnetic Resonance Study.

Background: Pulmonary hypertension (PH) is known to alter the biventricular shape and temporal phases of the cardiac cycle. The presence of interventricular septal (IVS) displacement has been associated with the severity of PH. There has been limited cardiac magnetic resonance (CMR) data regarding the temporal parameters of the cardiac cycle in PH. This study aimed to quantify the temporal changes in the cardiac cycle derived from CMR in PH patients with and without IVS displacement and sought to understand the mechanism of cardiac dysfunction in the cardiac cycle. Methods: Patients with PH who had CMR and right heart catheterization (RHC) examinations were included retrospectively. Patients were divided into an IVS non-displacement (IVSND) group and an IVS displacement (IVSD) group according to IVS morphology, as observed on short-axis cine CMR images. Additionally, age-matched healthy volunteers were included as the health control (HC). Temporal parameters, IVS displacement, ventricular volume and functional parameters were obtained by CMR, and pulmonary hemodynamics were obtained by RHC. The risk stratification of the PH patients was also graded according to the guidelines. Results: A total of 70 subjects were included, consisting of 33 IVSD patients, 15 IVSND patients, and 22 HC patients. In the IVSND group, only the right ventricle ejection fraction (RVEF) was decreased in the ventricular function, and no temporal change in the cardiac cycle was found. A prolonged isovolumetric relaxation time (IRT) and shortened filling time (FT) in both ventricles, along with biventricular dysfunction, were detected in the IVSD group (p < 0.001). The IRT of the right ventricle (IRTRV) and FT of the right ventricle (FTRV) in the PH patients were associated with pulmonary vascular resistance, right cardiac index, and IVS curvature, and the IRTRV was also associated with the RVEF in a multivariate regression analysis. A total of 90% of the PH patients in the IVSD group were stratified into intermediate- and high-risk categories, and they showed a prolonged IRTRV and a shortened FTRV. The IRTRV was also the predictor of the major cardiovascular events. Conclusions: The temporal changes in the cardiac cycle were related to IVS displacement and mainly impacted the diastolic period of the two ventricles in the PH patients. The IRT and FT changes may provide useful pathophysiological information on the progression of PH.

Preoperative myocardial fibrosis is associated with worse survival after alcohol septal ablation in patients with hypertrophic obstructive cardiomyopathy: A delayed enhanced cardiac magnetic resonance study

BackgroundPrior studies have shown that myocardial fibrosis can be detected by late gadolinium enhancement (LGE) of cardiac magnetic resonance (CMR) and might be associated with higher mortality risk in hypertrophic cardiomyopathy (HCM). The objective of this study was to examine the prognostic utility of CMR in patients with hypertrophic obstructive cardiomyopathy (HOCM) undergoing alcohol septal ablation (ASA).Materials and methodsWe conducted a retrospective study which consisted of 183 consecutive patients with symptomatic drug-refractory HOCM who underwent CMR for assessment of myocardial fibrosis before ASA. The cardiovascular disease related survival was evaluated according to LGE-CMR status.ResultsThe cohort comprised 74 (40.4%) women with a mean age of 51 ± 8 years. Preoperative myocardial fibrosis was detected in 148 (80.9%) patients. After a median of 6 years (range 2–11 years) follow-up, adverse clinical events occurred in 14 (7.7%) patients. Multivariate-adjusted Cox regression analyses revealed that age [hazard ratio (HR) 1.142 (1.059–1.230), p = 0.001] and LGE [HR 1.170 (1.074–1.275), p < 0.001] were independent predictors of cardiovascular mortality during follow-up.ConclusionPreoperative myocardial fibrosis measured by LGE-CMR was an independent predictor of increased adverse clinical outcomes in patients with HOCM undergoing ASA and could be used for the pre-operative evaluation of risk stratification and long-term prognosis after ASA in these patients.

Left ventricular remodeling and systolic function changes in patients with obstructive sleep apnea: a comprehensive contrast-enhanced cardiac magnetic resonance study.

BackgroundA comprehensive assessment of left ventricular (LV) remodeling and systolic function using contrast-enhanced cardiac magnetic resonance (CMR) imaging in patients with obstructive sleep apnea (OSA) has not yet been reported. This retrospective case-control study aimed to explore and assess the myocardial structure, function, and tissue characteristic changes of LV remodeling in patients with OSA using the CMR method.MethodsFifty-one selected participants 32 OSA and 19 non-OSA underwent overnight polysomnography and CMR examination using T1 mapping and feature tracking techniques. Twenty age- and sex-matched healthy controls were also enrolled for comparison between the groups.ResultsPatients were grouped by apnea-hypopnea index (AHI): AHI <5 events/h as non-OSA group (n=19, 40.7±8.0 years), 5–30 events/h as mild-moderate OSA (n=13, 47.8±9.4 years), and >30 events/h as severe OSA (n=19, 39.0±10.0 years). The OSA group had a higher LV mass index (LVMI) to height2.7 than the non-OSA and healthy control groups (21.0±3.8 vs. 16.4±3.1 and 16.3±3.2 mL/m2.7, P<0.001). Compared with healthy controls, OSA patients had lower global circumferential strain values, although the LV ejection fraction was preserved. Late gadolinium enhancement was not detected in all participants, whereas the extracellular volume fraction was lower in patients with OSA than in the non-OSA and healthy control groups (24.4%±1.9% vs. 26.2%±2.5%, P=0.006 and 24.4%±1.9% vs. 26.5%±2.3%, P=0.004, respectively). The indexed cellular volume (iCV) of the myocardium was significantly higher in subjects with mild-to-moderate and severe OSA than in those without OSA (14.2±2.3 and 15.8±3.1 vs. 11.6±2.4 mL/m2.7, P<0.05). On multivariate linear regression analysis of patients with two different models, OSA severity remained significantly associated with increased LVMI (β=0.348, P=0.004 and β=0.233, P=0.048, respectively) and iCV (β=0.337, P=0.004 and β=0.231, P=0.047, respectively) after adjusting for clinical risk factors.ConclusionsLVMI is elevated in OSA with a normal LV ejection fraction, mainly with cellular hypertrophy. Cellular hypertrophy without focal fibrosis in OSA may be our main finding.

Predicting post-contrast information from contrast agent free cardiac MRI using machine learning: Challenges and methods.

ObjectivesCurrently, administering contrast agents is necessary for accurately visualizing and quantifying presence, location, and extent of myocardial infarction (MI) with cardiac magnetic resonance (CMR). In this study, our objective is to investigate and analyze pre- and post-contrast CMR images with the goal of predicting post-contrast information using pre-contrast information only. We propose methods and identify challenges.MethodsThe study population consists of 272 retrospectively selected CMR studies with diagnoses of MI (n = 108) and healthy controls (n = 164). We describe a pipeline for pre-processing this dataset for analysis. After data feature engineering, 722 cine short-axis (SAX) images and segmentation mask pairs were used for experimentation. This constitutes 506, 108, and 108 pairs for the training, validation, and testing sets, respectively. We use deep learning (DL) segmentation (UNet) and classification (ResNet50) models to discover the extent and location of the scar and classify between the ischemic cases and healthy cases (i.e., cases with no regional myocardial scar) from the pre-contrast cine SAX image frames, respectively. We then capture complex data patterns that represent subtle signal and functional changes in the cine SAX images due to MI using optical flow, rate of change of myocardial area, and radiomics data. We apply this dataset to explore two supervised learning methods, namely, the support vector machines (SVM) and the decision tree (DT) methods, to develop predictive models for classifying pre-contrast cine SAX images as being a case of MI or healthy.ResultsOverall, for the UNet segmentation model, the performance based on the mean Dice score for the test set (n = 108) is 0.75 (±0.20) for the endocardium, 0.51 (±0.21) for the epicardium and 0.20 (±0.17) for the scar. For the classification task, the accuracy, F1 and precision scores of 0.68, 0.69, and 0.64, respectively, were achieved with the SVM model, and of 0.62, 0.63, and 0.72, respectively, with the DT model.ConclusionWe have presented some promising approaches involving DL, SVM, and DT methods in an attempt to accurately predict contrast information from non-contrast images. While our initial results are modest for this challenging task, this area of research still poses several open problems.

Extracellular volume fraction improves risk-stratification for ventricular arrhythmias and sudden death in non-ischaemic cardiomyopathy.

To evaluate whether cardiac magnetic resonance (CMR)-based parametric mapping and strain analysis can improve the risk-stratification for ventricular arrhythmias (VA) and sudden death (SD) in non-ischaemic cardiomyopathy (NICM). Secondary analysis of a prospective single-centre-registry (NCT02326324), including 703 consecutive NICM patients, 618 with extracellular volume (ECV) available. The combined primary endpoint included appropriate implantable cardioverter defibrillator therapies, sustained ventricular tachycardia, resuscitated cardiac arrest and SD. During a median follow-up of 21 months, 14 patients (2%) experienced the primary endpoint. Native T1 was not associated with the primary endpoint. Left ventricular global longitudinal strain lost its significant association after adjustment for left ventricular ejection fraction (LVEF). Among patients with ECV available, 11 (2%) reached the primary endpoint. Mean ECV was significantly associated with the primary endpoint and the best cut-off was 30%. ECV ≥ 30% was the strongest independent predictor of the primary endpoint (hazard ratio 14.1, P = 0.01) after adjustment for late gadolinium enhancement (LGE) and LVEF. ECV ≥ 30% discriminated the arrhythmic risk among LGE+ cases and among those with LVEF ≤ 35%. A simple clinical risk-stratification model, based on LGE, LVEF ≤ 35% and ECV ≥ 30%, achieved an excellent predictive ability (Harrell's C 0.82) and reclassified the risk of 32% of the study population as compared to LVEF ≤ 35% alone. Comprehensive CMR evaluation in NICM showed that ECV was the only parameter with an independent and strong predictive value for VA/SD, on top of LGE and LVEF. A risk-stratification model based on LGE, LVEF ≤ 35% and ECV ≥ 30% achieved an excellent predictive ability for VA/SD. UHSM CMR study (NCT02326324) https://clinicaltrials.gov/ct2/show/NCT02326324.

Detection and Classification of Myocardial Infarction Transmurality Using Cardiac MR Image Analysis and Machine Learning Algorithms.

The presence of abnormalities when the left ventricle is deformed is related to the patients' prognosis after a first myocardial infarction. These deformations can be detected by performing a cardiac magnetic resonance (CMR) study. Currently, late gadolinium enhancement (LGE) is considered to be the gold standard when performing CMR imaging. However, CMR with LGE overestimates infarct size and underestimates recovery of dysfunctional segments after myocardial infarction. Based on this statement, the objective is to detect, characterize, and quantify the extent of myocardial infarction in patients with cardiac pathologies, using parameters derived from CMR, in order to obtain greater precision in patients' recovery predictions than when only studying LGE images. For this purpose, we studied the infarct presence and extension from a total of 105 images from 35 patients, and calculated myocardium strain and torsion to characterize and quantify the affected tissue. A total of twenty-one parameters were selected to create predictive models. Moreover, we compared two feature extraction methods, and the performance of five machine learning algorithms. Results show that both temporal and strain parameters are the most relevant to detect and characterize the extent of myocardial infarction. The use of imaging techniques and machine learning algorithms have great potential and show promising results when it comes to detecting the presence and extent of myocardial infarction. The current study proposes a novel approach to detect, quantify, and characterize cardiac infarction by using strain and torsion parameters from different CMR images and different Machine Learning algorithms. This would potentially overcome LGE, the current state of the art technique, in estimating the extension of damaged tissue and enable an objective diagnosis and clinical decision.

Cardiac Remodeling in Female Athletes with Relation to Sport Discipline and Exercise Dose – A Cardiac Magnetic Resonance Study

Abstract Purpose: To compare chronic cardiac adaptations to exercise at various intensities and in different sports categories of female athletes. Methods: This was a retrospective study including 30 elite female athletes (members of the National Team), 14 amateur female athletes training 3-6 h per week for several years, and 20 inactive female controls who underwent cardiac magnetic resonance. Results: Left and right ventricular end-diastolic volumes (LVEDVI and RVEDVI) differed between all studied groups. They rose from controls to elite athletes, with amateur athletes in-between (for LVEDVI 73 ± 9 vs. 83 ± 6 vs. 95 ± 13 ml/m2, P&lt; 0.001, for RVEDVI 74 ± 7 vs. 84 ± 6 vs. 97 ± 14 ml/m2, P&lt; 0.001, respectively). Left and right atrial areas (LAA and RAA) were larger in amateur and elite athletes than in controls (P &lt; 0.001), but there was no difference between the two athlete groups. The interventricular septal diameter was mildly higher only in elite female athletes (9 ± 1 mm vs. 8 ± 1 mm, P&lt; 0.001). No difference in the above parameters was found between power and endurance athletes. Three athletes presented with benign myocardial fibrosis in the lower left ventricular (LV)-right ventricle junction point. Conclusions: The hearts of female athletes differed from inactive controls. Part of the changes was related to exercise intensity (LVEDVI and RVEDVI, mild LV muscle thickening), but other changes were not (LAA and RAA). There was no difference in the heart chamber size and LV muscle thickness between studied athletes engaging in power and endurance disciplines. There were also no significant myocardial tissue changes observed in both elite and amateur female athletes.