Cardiac Magnetic Resonance Research Articles

Cardiac Magnetic Resonance Imaging in the Evaluation of Functional Impairments in the Right Heart.

Cardiac magnetic resonance (cMRI) imaging has recently become essential in cardiology. cMRI is widely recognized as the most reliable imaging technique for assessing the size and performance of the right ventricle. It allows for objective and functional cardiac tissue evaluations. Early in disease progression, cardiac structure and activity decrease subclinically. Late-phase clinically visible signs have been associated with less favourable outcomes. Subclinical alterations ought to be recognized for rapid evaluations and accurate treatment. An increasing amount of evidence supports cMRI deformation parameter quantification. Strain imaging enables cardiologists to assess heart function beyond traditional measurements. Prognostic information for cardiovascular disease patients is obtained through the right ventricle (RV) strain, including information primarily about the left ventricle (LV). Right atrial (RA) function evaluations using RA strain have been promising in recent studies. Therefore, this narrative review aims to present an overview of the data that are currently available for assessing right myocardial strain and biomechanics using cMRI.

Cardiovascular Magnetic Resonance Reveals Cardiac Inflammation and Fibrosis in Symptomatic Patients with Post-COVID-19 Syndrome: Findings from the INSPIRE-CMR Multicenter Study.

Introduction. Post-coronavirus disease-2019 (COVID-19) patients may develop cardiac symptoms. We hypothesized that cardiovascular magnetic resonance (CMR) can assess the background of post-COVID-19 cardiac symptoms using multi-parametric evaluation. We aimed to conduct an investigation of symptomatic patients with post-COVID-19 syndrome using CMR (INSPIRE-CMR). Methods. INSIPRE-CMR is a retrospective multicenter study including 174 patients from five centers referred for CMR due to cardiac symptoms. CMR was performed using 3.0 T/1.5 T system (24%/76%, respectively). Myocardial inflammation was determined by the updated Lake Louise criteria. Results. Further, 174 patients with median age of 40 years (IQR: 26-54), 72 (41%) were women, and 17 (9.7%) had a history of autoimmune disease, muscular dystrophy, or cancer. In total, 149 (86%) patients were late gadolinium enhanced (LGE)-positive with a non-ischemic pattern, and of those evaluated with the updated Lake Louise criteria, 141/145 (97%) had ≥1 pathologic T1 index. Based on the T2-criterion, 62/173 (36%) patients had ≥1 pathologic T2 index. Collectively, 48/145 (33%) patients had both positive T1- and T2-criterion. A positive T2-criterion or a combination of a positive T1- and T2-criterion were significantly more common amongst patients with severe COVID-19 [45 (31%) vs. 17 (65%), p = 0.001 and 32 (27%) vs. 16 (64%), p < 0.001, respectively]. During the one-year evaluation, available for 65/174 patients, shortness of breath, chest pain, and arrhythmia were identified in 7 (4%), 15 (8.6%), and 43 (24.7%), respectively. CMR evaluation, available in a minority of them, showed mildly reduced LVEF, while nat T1 mapping and EVC remained at levels higher than the normal values of the local MRI units. Conclusions. The majority of post-COVID-19 patients with cardiac symptoms presented non-ischemic LGE and abnormalities in T1 and T2-based indices. Multi-parametric CMR reveals important information on post-COVID-19 patients, supporting its role in short/long-term evaluation.

Estimating Coronary Sinus Oxygen Saturation from Pulmonary Artery Oxygen Saturation.

Background and Objectives: Coronary sinus oxygen saturation is a useful indicator of health and disease states. However, it is not routinely used in clinical practice. Cardiovascular magnetic resonance imaging (CMR) oximetry can accurately estimate oxygen saturation in the pulmonary artery. This research aimed to provide a method for calculating coronary sinus oxygen saturation (ScsO2) from pulmonary artery oxygen saturation (SpaO2) that could be applied to CMR. Materials and Methods: A systematic literature review was conducted to identify prior work that included invasive measures of ScsO2 and either SpaO2 or right ventricular oxygen saturation. This revealed one study with appropriate data (ScsO2 and SpaO2 measurements, n = 18). We then carried out agreement and correlation analyses. Results: Regression analysis demonstrated a statistically significant, positive relationship between ScsO2 and SpaO2, giving a regression equation of ScsO2 = -31.198 + 1.062 × SpaO2 (r = 0.76, p < 0.001). A multivariable regression analysis of all reported variables, excluding SpaO2, independently identified superior vena cava oxygen saturation (SsvcO2) and arterial oxygen saturation (SaO2) as predictors of ScsO2 (r = 0.78, p < 0.001), deriving the equation ScsO2 = -452.8345 + 4.3579 × SaO2 + 0.8537 × SsvcO2. Conclusions: In this study, we demonstrated a correlation between coronary sinus oxygen saturation and pulmonary artery oxygen saturation, allowing the estimation of ScsO2 from SpaO2. This association enables the estimation of ScsO2 from purely CMR-derived data. We have also described a second model using arterial and superior vena cava saturation measurements, providing an alternative method. Future validation in larger, independent cohorts is needed.

Late-gestation maternal undernutrition induces circulatory redistribution while preserving uteroplacental function independent of fetal glycaemic state.

Programming effects of maternal undernutrition on fetal metabolic and cardiovascular systems are well elucidated, yet a detailed characterization of maternal haemodynamics is not available. This study used comprehensive cardiovascular magnetic resonance (CMR) imaging to quantify maternal haemodynamics after 29days (111-140 days) of late-gestation undernutrition (LGUN) in pregnant sheep. Control ewes received 100% of metabolizable energy requirements (MERs, n=15), whereas LGUN ewes were globally nutrient restricted to 50% MER (n=18), with a subset of fetuses undergoing continuous glucose infusion (LGUN+G, n=6/18). Ewes underwent CMR (138-140 days' gestation), and placental tissue was collected the next day. Ewes in both LGUN groups had reduced body weight and mean blood glucose concentration across gestation. Ventricular dimensions were lower in both LGUN groups. Uterine artery blood flow (QUtA) was elevated in the LGUN group compared with controls, whereas peripheral blood flow was reduced and further diminished in LGUN+G. Maternal weight change correlated with all haemodynamic parameters across all groups. Uteroplacental oxygen and glucose delivery were increased in LGUN compared to control ewes, whereas uteroplacental oxygen consumption was preserved. LGUN did not impact placental or fetal weight, and markers of brain-sparing physiology were absent. Placental expression of insulin-like growth factors (IGF-1 and IGF-2) and their receptors, glucose, fatty acid (FA) or amino acid transporters and markers of angiogenesis was not impacted. FA transporter expression was positively correlated with QUtA, and FA binding protein correlated negatively with maternal weight change. Maternal cardiovascular adaptations in response to LGUN manifest as preservation of placental growth and function, thereby preserving fetal growth. KEY POINTS: Maternal undernutrition during pregnancy alters fetal metabolic and cardiovascular physiology, but little is known about alterations in maternal haemodynamics. Late-gestation undernutrition (LGUN) and LGUN+G redirected maternal blood flow from the periphery to the uteroplacental unit, concomitantly increasing the delivery of glucose and oxygen to the uteroplacental unit. Substrate transporter expression and uteroplacental oxygen consumption were preserved in LGUN and LGUN+G, suggesting prioritization of the placenta. This study is the first to report detailed maternal haemodynamics in the setting of maternal undernutrition, where placental growth and function were maintained, ultimately preserving fetal oxygen metabolism and growth.

Myocardial involvement in end-stage renal disease patients with anemia as assessed by cardiovascular magnetic resonance native T1 mapping: An observational study.

Cardiovascular disease has become to the main cause of death in the patients with end-stage renal disease (ESRD), and anemia is associated with increased cardiovascular morbidity and mortality in these patients. This study aimed to explore the impact of anemia on myocardial fibrosis using T1 mapping technique in patients with ESRD. A total of 128 subjects including 98 ESRD patients (65 with anemia, 33 without anemia) and 30 normal controls were enrolled. All subjects were underwent cardiovascular magnetic resonance to obtain cardiac cine and T1 mapping images. As potential markers of fibrosis, native T1 values and global longitudinal strain derived by feature-tracking technique were compared. Differences between 3 groups were analyzed using one-way analysis of variance. Associations between variables were assessed by Pearson and Spearman correlation coefficient appropriately. An independent association was identified by the multiple stepwise linear regression analysis. Intraclass correlation was applied to assess observer variability. In all ESRD patients, native T1 values were significantly longer than those of normal controls (global T1, 1357 ± 42 ms vs 1275 ± 48 ms, P < .001). Global T1 value in ESRD patients with anemia was significantly higher (1375 ± 36 ms) compared to that in ESRD patients without anemia (1322 ± 25 ms) and normal controls (1275 ± 48 ms), respectively (all P < .001). Global T1 correlated with hemoglobin negatively (R= -0.499, P < .001). Multiple stepwise linear regression analysis presented the anemia is independently associated with global T1 (R = 0.607, P < .001). Global longitudinal strain was remarkably reduced in ESRD patients with anemia in comparison to those without anemia (P < .001). Diffuse myocardial fibrosis could be detected by native T1 mapping in ESRD patients with long-term anemia. Anemia is an important factor in myocardial fibrosis in ESRD patients, and the evaluation of myocardial involvement is worth considering for clinical management.

ALPK3 heterozygous truncating variants cause late-onset hypertrophic cardiomyopathy with frequent apical involvement and apical aneurysm.

Hypertrophic cardiomyopathy (HCM) is a genetically heterogeneous disorder with several established genotype-phenotype relationships. While biallelic truncating variants in the ALPK3 gene cause severe congenital HCM, recent studies have associated heterozygous truncating variants (ALPK3tv) with milder adult-onset HCM. Here we describe a multicenter cohort of 21 individuals with heterozygous ALPK3tv from 10 institutions in the United States, highlighting distinctive clinical characteristics compared to a control group of 132 patients with HCM caused by deleterious variants in sarcomeric genes. As compared to other HCM genotypes, ALPK3tv patients present at an older age (mean 57.25 years) with significantly lower left ventricular wall thickness (14.09 vs 19.78 mm with echocardiogram and 16.13 vs 21.13 mm with cardiac MRI), a lower prevalence of obstructive HCM (15% of ALPK3tv vs 45% of controls), and a strikingly higher incidence of apical aneurysm (22.22% vs. 2.40% in the control group). These results suggest a milder degree of hypertrophy in heterozygous ALPK3-related HCM as compared to other Mendelian causes of HCM, although the increased occurrence of apical aneurysms could have implications for ventricular arrhythmia risk. Our study underscores the importance of recognizing heterozygous ALPK3tv as a cause of adult-onset HCM and provides a comprehensive characterization of its clinical phenotype.

Magnetic resonance imaging of pulmonary hypertension.

Pulmonary hypertension is a rare but serious disease in children with potentially poor prognosis in the long term. Direct measurement of increased pressure in the pulmonary circulation requires right-heart catheterisation. Echocardiography is the imaging modality commonly used for suggesting the presence of pulmonary hypertension and estimating its severity. Recognition of structural and haemodynamic signs of increased pulmonary arterial pressure and pressure overload of the right ventricle at magnetic resonance (MR) imaging may contribute to the diagnosis of pulmonary hypertension and management of these patients. In this article, the structural, functional, and haemodynamic cardiovascular MR findings of paediatric pulmonary hypertension are reviewed. Typical diagnostic MR scenarios in children with suspected pulmonary hypertension or in children with disease associated with pulmonary hypertension are presented and discussed.

High wall shear stress is related to complicated AHA lesion type VI plaques in mild to moderate internal carotid artery stenosis - a 3D cardiovascular MRI study.

Complicated American Heart Association (AHA) lesion type VI plaques (cCAPs), characterized by the presence of intraplaque hemorrhage, surface defect or thrombus, are strongly associated with ischemic stroke and stroke recurrence. Hemodynamics seem to play a relevant role for their development. Thus, we investigated the association of 4D flow-MRI derived local wall shear stress (WSS) and oscillatory shear stress (OSI) with the presence of cCAPs in patients with mild to moderate internal carotid artery (ICA) stenosis. From a prospective and consecutive cross-sectional study with 121 patients with high cardiovascular risk, 39 patients (49 carotid arteries) demonstrated a 10-50% ICA-stenosis and were included in this analysis. Plaque composition was determined according to the modified AHA classification of lesions by high-resolution multi-contrast 3T-MRI. We determined WSS (minimum, mean and maximum) and OSI in vivo by 4D flow-MRI at different locations within the stenosis (upstream, stenosis center and downstream). We studied the association of each hemodynamic parameter with the presence cCAPs by logistic regression analysis adjusted for age, sex and plaque thickness. 11 (22.4%) of the 49 ICA-stenosis in our cohort showed cCAP. WSS and OSI at the beginning of the stenosis did not differ between complicated and stable plaques. By contrast, WSS was significantly higher in the stenosis center and poststenotic region in cCAPs. OSI was significantly higher in the stenosis center of stable plaques. Logistic regression analysis revealed a significant association for WSSmean (OR per SD increase 1.97, 95%-CI 1.14-3.39, p=0.015) and for WSSmax (OR per SD increase 1.84; 95%-CI 1.10-3.08; p=0.020), but not for WSSmin and OSI with the presence of cCAPs. Higher wall shear stress in ICA stenosis was significantly associated with the presence of cCAPs underlining the potential role of hemodynamics in their development. cCAP, complicated carotid artery plaque; WSS, wall shear stress; OSI, oscillatory shear index.

Prognostic value of β1 adrenergic receptor autoantibodies for microvascular obstruction in patients with STEMI with Post-PCI: A prospective cohort study

BackgroundsCoronary microvascular obstruction (MVO) frequently occurs in patients with ST-segment elevation myocardial infarction (STEMI) following percutaneous coronary intervention (PCI), leading to poor prognosis. β1 adrenergic receptor autoantibodies (β1-AA) are present in various cardiovascular diseases and correlate with cardiac damage and dysfunction. However, whether β1-AA is associated with the occurrence of MVO in patients with STEMI after PCI remains unclear. AimsTo investigate the prognostic relationship between β1-AA and the occurrence of MVO in patients with STEMI with post-PCI. MethodsThis prospective study included 403 patients with STEMI who underwent primary PCI. The patients were divided into MVO+ and MVO- groups. Serum β1-AA levels were measured prior to primary PCI. The primary outcome was MVO, assessed through cardiac magnetic resonance imaging at 5–7 days after PCI. ResultsA total of 127 MVO+ and 276 MVO– patients were identified. Patients with MVO + exhibited higher β1-AA optical density (OD) compared to MVO- patients. β1-AA OD, pNT-proBNP, pCK-MB and pTNI were positively associated with MVO following PCI. Notably, the assocition between β1-AA levels and MVO risk strengthened with increasing pNT-proBNP levels. The combination of β1-AA, pNT-proBNP and pTNI yielded the most efficient MVO prediction with an area under the ROC curve of 0.87 (95 % CI: 0.83–0.90). Conclusionsβ1-AA is significantly associated with the occurrence of MVO in STEMI patients following primary PCI. The combination of β1-AA with pNT-proBNP and pTNI improves predictive accuracy, providing a more robust and effective strategy for assessing MVO risk.

Cardiac amyloidosis.

Cardiac amyloidosis is a disease characterised by the accumulation of amyloid protein in the heart tissue. There are several types of amyloidosis, but the most common types affecting the heart are ATTR amyloidosis (caused by transthyretin protein) and AL amyloidosis (caused by abnormal immunoglobulin light chains). Cardiac amyloidosis causes typical signs and symptoms of heart failure. Diagnosis involves a combination of imaging tests such as echocardiography and cardiac magnetic resonance imaging, as well as nuclear imaging scans and tissue biopsies to confirm the presence of amyloid deposits in the heart. Treatment of cardiac amyloidosis depends on the type and severity of the disease and includes medications to manage symptoms as well as treatments targeting the underlying cause of amyloidosis. Importantly, cardiac amyloidosis is a serious condition requiring specialised care from a multidisciplinary team including cardiologists and haematologists as well as other specialists familiar with the management of this rare disease. This is crucial, as early diagnosis and treatment are important for improving outcomes.

Pericardial Tamponade Two Years after Central Venous Catheter Implantation in a Patient with Breast Cancer: A Case Report

We report a rare and diagnostically challenging case of pericardial tamponade in a breast cancer patient, treated two years earlier. Echocardiogram and an enhanced computed tomography (CT) scan revealed a large mass in the right pericardium with indistinct borders. A positron emission tomography-computed tomography (PET-CT) scan showed no uptake of fluorine-18 fluorodeoxyglucose (18F-GDP) by the mass. Cardiac magnetic resonance imaging (MRI) with late gadolinium enhancement confirmed no signal enhancement within the mass and a clear border, decisively ruling out malignancy. This case highlights the importance of late gadolinium enhancement in this diagnostically challenging case and explores the pericardial tamponade development mechanism.

Multimodal Approach (MRI and Ultrasonography) to the Diagnosis of Fetal Congenital Heart Diseases

Introduction: As the rate of congenital heart diseases (CHD) remains high, medical imaging specialists face a task of early diagnosis of CHD with minimal cost and burden to pregnant women and fetuses and need to verify the prenatal diagnosis in order to develop a strategy for managing pregnant women carrying a fetus with CHD.Objective: To optimize diagnostic measures in fetuses with CHD by comparing fetal echocardiography and cardiac magnetic resonance imaging (MRI).Materials and methods: We retrospectively evaluated findings from 35 fetal standard ultrasonography reports, 29 echocardiography reports, and 35 fetal autopsy reports (termination for medical reasons). We assessed 18 cases of CHD diagnosed by ultrasonography findings on the second screening; in 34% of the cases patients also underwent MRI at that time and a repeated procedure 30 weeks later.Results: When standard ultrasonography and an extended protocol with echocardiography were used together, diagnostic errors were 14.3%. In 85.7% of the fetuses, the findings of different imaging techniques fully coincided with the autopsy findings.Conclusions: In this cohort of pregnant women, the second screening should include more examinations to verify the diagnosis of CHD. Based on the first screening findings (increased nuchal translucency thickness and ductus venosus pulsatility index) patients should be referred to an expert for the second screening. If necessary, to verify the diagnosis of CHD ultrasonography and MRI can be combined during the third screening (34-36 weeks) in order to plan postnatal management of the newborn. The proposed algorithm for fetal CHD diagnosis enables to minimize the likelihood of error and maintain continuity of care between obstetricians-gynecologists, ultrasonographers, radiologists, neonatologists, and cardiologists.

Emerging Imaging Techniques for Atherosclerosis in Systemic Immune-Mediated Inflammatory Conditions.

Atherosclerosis affects patients with systemic immune-mediated inflammatory diseases at an increased rate compared with the general population. In recent years, our understanding of the pathophysiology of atherosclerosis has advanced considerably. Nevertheless, cardiovascular imaging modalities that can adequately assess the biological background of atherosclerosis have not reached widespread clinical adoption. Novel developments in cardiac imaging have the potential to enhance the diagnostic yield of these modalities further while providing essential insights into the anatomy, composition, and biology of atherosclerotic lesions. In this review, we highlight some of the latest developments in the field for the evaluation of atherosclerosis using advances in echocardiography, computed tomography, positron emission tomography, and cardiovascular magnetic resonance. Additionally, we discuss evidence specifically in patients with immune-mediated inflammatory diseases and outline unmet research needs for future development.

Prognostic Value of Left Ventricular Myocardial Strain Parameters Derived from Cardiac Magnetic Resonance Feature Tracking Technique in Light-Chain Cardiac Amyloidosis Patients: A Pilot Study.

Previous research on the prognostic implications of left ventricular myocardial strain using cardiac magnetic resonance feature tracking (CMR-FT) in light-chain cardiac amyloidosis (AL-CA) has shown promising potential. This study aimed to evaluate the prognostic significance of global and segmental left ventricular myocardial strain in AL-CA patients, specifically analyzing the American Heart Association's 16 segments. A total of 75 consecutive patients (50 men, mean age: 55.6 ± 10.0 years) who underwent CMR examination with histologically confirmed systemic AL-CA were retrospectively enrolled between January 2014 and November 2022. Both global and segmental myocardial strain and the American Heart Association's 16 segments were quantified using CMR-FT on the steady-state free precession (SSFP) cine sequence. A comparative analysis was conducted between survivors and non-survivors based on the defined endpoint. Student t-test or Mann-Whitney U, receiver operating characteristic curve, Kaplan-Meier event-free survival curve, and Cox proportional hazards regression were used. Significance was set at p < 0.05. Following a median follow-up of 34 months, 16 out of 75 patients experienced mortality events. B-type natriuretic peptides (BNP) (p < 0.001), global radial strain (RSglobal) (p = 0.033), and RS in the basal inferior segment (RSbas-inferior) (p = 0.025) remained significant as independent predictors of all-cause mortality. The cut-off values were identified as 24.97% for RSglobal, and 20.97% for RSbas-inferior. Kaplan-Meier survival curves revealed significantly reduced event-free survival for individuals in the lower cut-off groups for RSglobal and RSbas-inferior (p = 0.013, p < 0.001, respectively). Radial strain for the global and the basal inferior segment may prove valuable for risk stratification in patients with AL-CA.

Association of prior tuberculosis with cardiovascular status in perinatally HIV-1-infected adolescents

BackgroundWhether, and how, co-occurring HIV-1 infection (HIV) and tuberculosis (TB) impact cardiovascular status, especially in adolescents with perinatally acquired HIV (APHIV), have not been examined. We hypothesised that APHIV with...

A real-life clinical application of cardiac magnetic resonance imaging in patients with acute myocarditis - one-center observational retrospective study.

The diagnosis of acute myocarditis is complex, with cardiac magnetic resonance (CMR) being a recommended diagnostic method. This study aimed to evaluate the real-life use of CMR in the diagnosis of acute myocarditis and to correlate CMR results with the degree of myocardial damage. This is a retrospective, observational tertiary single-center study of 90 consecutive patients (F/M:18/72, mean age:39 ± 14 years) hospitalized between 2015-2022 with a clinical diagnosis of acute myocarditis. The study population was divided into two groups: patients who underwent CMR+ and those who did not undergo CMR - In the CMR+ group, various sequences, including T1/T2-weighted imaging, late gadolinium enhancement (LGE), and mapping techniques, were used to assess myocardial inflammation and damage. CMR was performed in 39 patients (43.3%, F/M:10/29, mean age:41 ± 16 years). In this group, myocardial edema (increased T2 signal intensity) was detected in 29 patients, and LGE (signal intensity 2 standard deviations cabove normal on T1 images) was found in 39 patients. Diagnosis based on Lake Louise Criteria was possible in 29 cases. Edema negatively correlated with TnT levels (r = -0.412, p < 0.05) and positively with the number of LGE segments (r = 0.372, p < 0.05). Significant correlations were found between LVEF and LGE mass (r = -0.360, p < 0.05), and maximal TnT levels (r = -0.38, p < 0.05). CMR+ patients had lower myocardial damage markers and CRP concentrations compared to CMR- patients. CMR is underused in diagnosing acute myocarditis. Myocardial damage markers correlate with CMR-detected edema and volumetric measures, but not LGE extent. More research is needed to enhance risk assessment and treatment.

RADIOMICS APPLICATIONS IN NON-CONTRAST CINE CARDIAC MAGNETIC RESONANCE IMAGING IN THE DETECTION OF LEFT VENTRICULAR POSTINFARCTION CARDIOSCLEROSIS

BACKGROUND: Size and localization, as well as clear differentiation between intact tissue and infarcted area, are important for clinical diagnosis and precision medicine. This work is based on the study of radiomics features capable of differentiating areas of infarcted and distant tissue from the infarct area using data from non-contrast cine cardiac MRI imaging. AIM: Evaluation of the possibilities and informativeness of radiomics analysis in detection of postinfarction areas of the left ventricular myocardium in patients with ischemic cardiomyopathy by contrast-free cine cardiac MRI images. MATHERIALS AND METHODS: The results of contrast enhancement cardiac MRI with of 33 patients undergoing surgical treatment for ischemic cardiomyopathy were analyzed. Texture analysis was performed on 66 sections of cine cardiac MRI images, and 105 texture characteristics were determined for each of them. Cardiac MRI was performed according to the standard technique on a Vantage Titan (Toshiba) 1.5 T. Texture analysis was performed using 3D slicer-version 5.2.2 software, SlicerRadiomics RESULTS: Collinearity diagrams of the features were constructed. We also identified the features with zero importance and established the importance of the features using the gradient boosting algorithm. In addition, the cumulative importance of the features as a function of their total number was estimated. Using the method of identifying features with low importance, we identified the parameters with the lowest importance that do not affect the indicated total level. Using the method of identifying features with a single value, we did not find features with a single unique value. In addition, ROC curve for Lasso logistic regression (Se =57.14% Sp=71.43%, AUC=0.76) was generated based on the results of the analysis. The main result of this study is the identification of radiomics features able to characterize the areas corresponding to postinfarction cardiosclerosis and intact LV wall on the basis of cine cardiac MRI images. CONCLUSION: This study has shown that the use of radiomics analysis on contrast-free cine cardiac MRI images is a promising approach to identify areas corresponding to myocardial infarction and intact wall and could potentially be used as to identify areas of postinfarction cardiosclerosis in patients with ischemic cardiomyopathy without the use of contrast agents.

Correction to: Routine application of cardiac magnetic resonance imaging in patients with suspected myocarditis from immune checkpoint inhibitor therapy.

Correction to: Routine application of cardiac magnetic resonance imaging in patients with suspected myocarditis from immune checkpoint inhibitor therapy.

Abstract 4119187: Association of CMR derived Global Longitudinal Strain with adverse Outcomes in Arrhythmogenic Cardiomyopathy.

Background: Arrhythmogenic cardiomyopathy (ACM) is associated with high risk of ventricular arrhythmias (VA) and heart failure (HF). Different predictive models and diagnostic criteria include parameters related to myocardial structural abnormalities and right ventricular (RV) ejection fraction (EF). Nevertheless, the value of global longitudinal strain (GLS) ascertained from cardiac magnetic resonance (CMR) for risk-stratification in the context of ACM is unknown. Aim: We aim to study the association of low CMR-derived GLS with adverse outcomes in ACM patients. Methods: This was a retrospective cohort study of ACM patients seen at a single quaternary center. ACM diagnosis followed the modified 2010 ARVC modified task force criteria. Primary outcome was a composite of life-threatening VAs, heart transplant or HF hospitalization during follow up. We excluded patients who suffered events prior to diagnosis, and those with missing or inadequate CMR protocol. Imaging parameters were acquired by CMR including EF, GLS, and late gadolinium enhancement (LGE). Results: A total of 82 patients with suspected ACM were included, with a median age of 40 years, and 43 (52.4%) were females. Most common reason of initial visit was family history of genetic cardiomyopathy in 46 (56%), while 16 (20%) patients visited our clinic due to history of syncope. Out of 60 patients who had genetic testing, 21 (35%) had mutations of DSP gene. Left ventricular involvement (non-ischemic LV-LGE by CMR) was present in 42 (56.8%) out of 74 patients who had CMR with gadolinium. Median LVEF was 62% (56, 66), and RVEF of 53% (48, 59), both by CMR. Median LVGLS was -17.01% (-14.71, -18.43), while median RVGLS was -20.5% (-18.3, -24.4). A total of 15 (18%) patients suffered the composite endpoint during an average follow up period of 8 years. Patients who suffered the composite endpoint had significantly lower mean LVGLS (-15.04% vs -16.70%, p= 0.048), and lower average RVGLS (-18.45% vs -21.33%, p=0.035) compared to patients free from the adverse outcome. Meanwhile there was no significant difference in LVEF (60.13% vs 61.18%, p=0.67), nor in RVEF (49.13% vs 54.01%, p=0.065) between the two groups. Conclusion: Lower GLS was significantly associated with VAs and HF hospitalizations in our patient population. CMR derived GLS can be used as an important prognostic parameter of adverse outcomes in patients with suspected ACM. Especially in those with LV involvement and high genetic predisposition as our cohort.

Abstract 4124675: Deep Learning Screening of Cardiac MRIs Uncovers Undiagnosed Hypertrophic Cardiomyopathy in the UK BioBank

Introduction: The prevalence of hypertrophic cardiomyopathy (HCM) in the UK Biobank based on ICD-10 codes (.07%) is lower than global estimates of disease prevalence (0.2 - 0.5%). Prior studies using this data have remarked on the limitations of findings given likely underdiagnosis. The availability of cardiac MRI scans on a fraction of the participants offers an opportunity to identify missed diagnoses. Aims: This study seeks to utilize a generalizable deep learning model to detect likely cases of undiagnosed hypertrophic cardiomyopathy from cardiac MRIs in the UK Biobank. Methods: The foundational model was trained on a multi-institutional dataset of 14,073 cardiac MRIs via a self-supervised contrastive learning approach that sought to minimize the divergence between scans and their associated radiology reports. The pre-trained model was fine-tuned to diagnose hypertrophic cardiomyopathy on a distinct cohort of 4,870 MRIs with 368 cases of HCM, achieving an AUC of 0.94. The fine-tuned model was applied to the UK Biobank cardiac MRI dataset to ascertain predicted probabilities of HCM. Cases exceeding a threshold of 95% – correlating to the top 0.5% of cases (expected specificity of 97% and sensitivity of 60%) – were screened in for manual reading. In a blinded fashion, a board-certified radiologist was tasked with diagnosing HCM on a sample of cases composed of high and low predicted probabilities. Results: Of the 43,017 patients with cardiac MRIs, only 9 (.02%) had an ICD diagnosis of HCM. 266 cardiac MRIs were manually reviewed: 216 had greater than 95% predicted probability of HCM; 50 negative controls were randomly selected amongst cases with predicted probability less than 10%. The radiologist concurred with an HCM diagnosis for 115 cases (sensitivity 53%, specificity 98%), 112 of which were previously undiagnosed. The prevalence of hypertension and aortic stenosis did not significantly differ between the cohort of true positives (69.2%) and false positives (76.6%). The corrected prevalence of HCM in the UK BioBank MRI cohort is estimated at 0.28%. Conclusions: The findings of this study illustrate the remarkable ability of a generalizable deep learning model to detect undiagnosed cases of a rare disease process from cardiac MRIs. This is an important milestone that may allow for widespread screening of hypertrophic cardiomyopathy while minimizing demand for radiologist labor, and thereby allow patients to reap the substantial benefits of earlier treatment.