Late Gadolinium Enhancement Research Articles

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.

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.

Abstract 4135873: Time Course of Late Gadolinium Enhancement Intensity in Ventricular Myocardium after Proton Beam Irradiation in Swine

Background: Proton beam irradiation to the ventricular myocardium may enable non-invasive targeting of ventricular tachycardia. Previous work has demonstrated the feasibility of imaging ablation lesion with late gadolinium enhanced (LGE) cardiac magnetic resonance imaging (MRI). Hypothesis: We hypothesize that proton beam irradiation will lead to progressively increasing density of LGE corresponding to lesion formation during follow-up after treatment delivery. Aim: The aim of the current study was to determine the time course of LGE intensity in ventricular myocardium following proton beam therapy. Methods: Eleven swine were irradiated with 40 Gy proton beam in the anterior or lateral left ventricular (LV) followed by LGE cardiac MRI every 4 weeks for up to 24 weeks. After manual contouring of the endocardial and epicardial myocardium, a region of interest (ROI) in the area irradiated with 0-5 Gy was contoured (remote ROI). The mean and standard deviation (SD) of the signal intensity (SI) of the remote ROI were calculated. Light LGE was defined as voxels with SI &gt; mean+2SD but &lt; mean+3SD of the remote ROI, while voxels with SI &gt; mean+3SD of the remote ROI were classified as having dense LGE. Voxels identified as bright due to image artifacts or noise were manually removed. The analysis was conducted in a fashion blinded to swine ID and time point after irradiation. Results: A total of 33 time points were analyzed (3.1 ± 1.4 MRI studies per swine). Figure 1A shows a representative time course of LGE in the same swine, progressing from diffuse light LGE at 8 weeks to dense LGE at 16-24 weeks. Figure 1B demonstrates the proportion of light versus dense LGE across timepoints in irradiated myocardial regions. At 8 weeks, light and dense LGE areas were evenly distributed. At 12 to 24 weeks, dense LGE increased to approximately 75%. The proportion of dense versus light LGE was significantly higher at 12, 16, and 24 weeks, as compared to 8 weeks. Conclusion: In ventricular myocardium, diffuse light LGE evident at 8 weeks progresses to denser LGE at 12-24 weeks following proton beam irradiation corresponding with lesion formation.

Abstract 4134729: Quantitative, time-efficient viability cardiac magnetic resonance with delayed-phase dynamic contrast enhancement model: a pilot study in dogs with myocardial infarction

Introduction: Late gadolinium enhancement (LGE) is the gold standard for myocardial viability imaging, recommended by all major cardiology societies. In this study, we aimed to develop a time-efficient viability imaging technique utilizing a dynamic contrast enhancement(dDCE) model to shorten the LGE wait time, provide quantitative measures of the contrast washout procedure, and potentially enable a fast and quantitative mean for scar imaging. Methods: A canine study(n=10) was conducted on reperfused myocardial infarction(MI). A dDCE model using dynamic post-contrast T1 maps was adopted to depict the contrast washout process. dDCE maps were reconstructed using the whole dataset(dDCE 30min ) and a 5-minute subset of the T1 maps(dDCE 5min ). To test the dDCE models for shortening the LGE wait time, LGE dDCE images were synthesized using the dDCE 5min maps and compared to the clinical LGE images. Remote and MI dDCE parameters on dDCE 30min and dDCE 5min maps were compared to test the model's ability to extract physiological features. Results: dDCE 30min and dDCE 5min map showed a good visuospatial difference between remote and MI(Fig. 1A) and no quantitative difference (Fig.1B). v e and PS showed a significant elevation in MI than in remote (61.12±13.65% vs 13.43±5.00%, P =0.018; 44.62±21.40mL/g/min vs 0.42±0.55mL/g/min, P =0.018, respectively). v p and F p were significantly decreased in MI than in remote (4.17±2.06% vs 10.85±3.77%, P =0.02; 1.11±0.32mL/g/min vs 1.51±0.42mL/g/min, P =0.04, respectively). Representative LGE and LGE dDCE images showed high agreement in the presence of MI (Fig. 2A). Bland-Altman analysis showed good agreement between LGE and LGE dDCE images for the measurement of infarct area (bias, -1.74 ± 6.60 %, Fig. 2B) and transmuraltiy (bias, 1.86 ± 2.73 %, Fig. 2C). The simple liner regression showed strong correlations between LGE and LGE dDCE images for the infarct area (R 2 , 0.95; slope, 0.93, P &lt;0.01; Fig. 2D) and transmurality (R 2 , 0.97; slope, 0.93, P &lt;0.01; Fig. 2E). ROC analysis showed that the AUC was 0.97 (95% CI: 0.94 to 1.00) (Fig. 2F). Increased lesion-blood pool contrast by 10 folds on dDCE images improved subendocardial MI detection (Fig.3). Conclusions: The developed dDCE model provides comparable viability assessment ability to the standard LGE images without the prolonged wait time and reflects MI pathophysiological changes. It shows the potential for a rapid and quantitative myocardial viability imaging protocol using cardiac magnetic resonance.

Abstract 4137534: Troponin Can Predict Late Gadolinium Enhancement on Cardiac MRI in COVID-19 Vaccine-Associated Myocarditis

Background/Aim: We previously reported that late gadolinium enhancement (LGE) on cardiac MRI (CMR) was as high as 82% in pediatric patients with COVID-19 vaccine-associated myocarditis (C-VAM) despite mild clinical symptoms and normal left ventricular function. As LGE can be a harbinger for future adverse events including arrhythmias, heart failure or sudden cardiac death, we sought to identify predictors for LGE in C-VAM, specifically assessing troponin as a screening marker for C-VAM patients at risk for myocardial scarring who could then be referred for a confirmatory CMR with LGE. Methods: In this longitudinal multicenter retrospective observational study across 38 U.S. member institutions of the M yocarditis A fter C OVID V accination (MACiV) study network, 333 patients with C-VAM based on CDC criteria were included from April 2021 to November 2022. Data collected included demographics, laboratory values, clinical and cardiac imaging characteristics and outcomes. Using logistic regression, troponin levels at presentation were assessed as a log transformed continuous variable and categorized into tertiles. Results: The C-VAM patients were predominantly white (67%) adolescent males (91%, 15.7± 2.8 years). There were 216/333 (65%) patients who had both a reported troponin value and had a CMR. On univariate analysis, elevated troponin increased the probability of having LGE (OR=1.29, 95% CI: 1.06, 1.58, p=0.012). Even after controlling for age, race, sex, number of vaccine doses and left ventricular ejection fraction (OR=1.32, 95% CI: 1.06, 1.65, p=0.013). Patients &gt;15 years compared to those ≤15 years of age were 2.94 (95% CI: 1.28, 6.75, p=0.011) times more likely to have LGE at presentation. Patients with troponin levels in the highest tertile compared to lowest tertile were 2.66 times (95% CI: 1.04, 6.83, p=0.042) more likely to have LGE along with a greater involvement &gt; 4 AHA myocardial segments with LGE (p=0.004) Conclusions: Higher troponin values are associated with presence of late gadolinium enhancement on cardiac MRI in patients with COVID-19 vaccine-associated myocarditis. Troponin levels at presentation may facilitate risk stratification and function as a screening tool to identify those C-VAM patients with the greatest likelihood of myocardial scarring, who may benefit from undergoing CMR for tissue characterization.

Abstract 4141448: Evaluation of cardiac amyloidosis with cardiac MRI and association with endomyocardial biopsy findings

Introduction: Late gadolinium enhancement (LGE) observed on cardiac magnetic resonance imaging (CMR) has emerged as a potential indicator of myocardial involvement in cardiac amyloidosis (CA). However, discerning which LGE patterns in amyloidosis distinguish it from other cardiomyopathies remains unclear. This study aims to compare LGE characteristics in a predominantly African American cohort who underwent endomyocardial biopsies. Despite advancements in cardiac imaging techniques, the endomyocardial biopsy remains the gold standard for amyloidosis diagnosis. Insights garnered from this analysis could enhance diagnostic precision and facilitate earlier detection. Methods: In this retrospective study at MedStar Union Memorial Hospital in Baltimore, MD, patients who underwent both endomyocardial biopsy and CMR were included. The study compared individuals with biopsy-proven amyloidosis (both AL and ATTR) to those with negative biopsy results. LGE patterns were selected based on their frequent use in CMR interpretation. Statistical analysis employed Pearson chi-square and t-tests. Results: The cohort comprised 42 patients who underwent biopsy, with 13 patients (31%) with positive biopsy results. Among them, 24 were men (57%), and 81% identified as African American. Demographic, anthropomorphic, and objective clinical findings are detailed in Table 1. The average age of the cohort was 68 years, with those with biopsy-proven amyloidosis significantly older (75 vs. 61 years, p = 0.002). Although the biopsy-positive group exhibited a lower absolute NT-pro-BNP, the difference was not statistically significant. The most prevalent LGE patterns among the biopsy-positive group were diffuse (62%) and basal (31%). Notably, 69% of biopsy-positive patients exhibited an LGE pattern described as infiltrative. However, 38% of the biopsy-negative group also manifested infiltrative patterns on LGE, a difference not statistically significant compared to the biopsy-positive group. The positive predictive value of an infiltrative LGE pattern was low (45%). Conclusion: This study compares CMR LGE patterns in biopsy proven CA. Despite findings of an infiltrative LGE pattern on CMR, when using endomyocardial biopsy as the gold standard, the positive predictive value of LGE in differentiating CA patients was low. Further research and larger studies are warranted to explore additional imaging modalities or biomarkers that may complement or refine the diagnostic algorithm for CA.

The capabilities of cardiac MRI in the differential diagnosis of AL- and ATTR-amyloid cardiomyopathy.

BACKGROUND. Cardiac amyloidosis is a serious progressive disease with a high mortality rate. Differentiation between AL and ATTR types of amyloidosis is critically important for choosing the optimal treatment. AIM. This study aims to evaluate the capabilities of cardiac MRI in the differential diagnosis of AL and ATTR amyloidosis. METHODS. A retrospective analysis of medical data from 25 patients with confirmed cardiac amyloidosis (12 with AL and 13 with ATTR) was conducted. These patients underwent contrast-enhanced cardiac MRI, and their structural parameters (particularly wall thickness and myocardial mass), ventricular function, and late gadolinium enhancement (LGE) patterns were assessed. Standard statistical methods were used, with p-values 0.05 considered significant. RESULTS. Patients with ATTR amyloidosis exhibited more pronounced myocardial wall thickening (LV septal wall 17.8±2.3 mm vs 13.8±2.4 mm, p0.01; LV posterior wall 14.2±2.4 mm vs 10.8±2.0 mm, p0.01) and greater LV myocardial mass (110±30 vs 83±17 g/m², p0.01) compared to those with AL amyloidosis. In ATTR amyloidosis, transmural LGE was more frequently observed in the basal and mid inferior-lateral segments of the left ventricle, while subendocardial LGE was more common in the mid anterior and inferior-lateral segments (p0.05). A distinguishing feature of ATTR was the simultaneous contrast uptake in subendocardial layers of both the LV and RV in the area of the interventricular septum (100% vs 50%, p0.01). RV LGE was more common in ATTR (100% vs 58%, p0.05), particularly in the interventricular septum and the inferior wall of the RV (p0.05). Quantitative assessment of LGE using the QALE scale showed more extensive enhancement in ATTR (13 [12;14] vs 10.5 [1.75;12], p0.01). A score of more than 13 allowed differentiation between the types of amyloidosis with a sensitivity of 69% and specificity of 83%. CONCLUSION. Cardiac MRI can identify characteristic differences between AL and ATTR amyloidosis, which may assist in their differential diagnosis. Further research is needed to confirm the diagnostic accuracy of the identified MRI features.

Abstract 4137543: Prevalence, Genetic Correlates and Prognostic Significance of an Apical Pseudo-Infarct Late Gadolinium Enhancement Pattern in LMNA -Mediated Cardiac Laminopathy

Background: Disease-causative variants in LMNA -encoded lamin A/C cause a genetic cardiomyopathy characterized by atrioventricular (AV) block, atrial fibrillation (AF) and ventricular arrhythmias (VA). Whether domain/variant-specific late gadolinium enhancement (LGE) patterns exist and carry prognostic significance is unclear. Objective: To determine if specific LGE patterns correlate with LMNA variant type/missense variant localization and clinical outcomes in a large cohort of cardiac laminopathy patients. Methods: Retrospectively, 621 genotype-positive arrhythmogenic/dilated cardiomyopathy patients were analyzed to identify those with a disease-causative variant in LMNA -encoded lamin A/C. After exclusion of patients without cardiac magnetic resonance data, pertinent demographic/clinical data was extracted from the electronic medical record. LGE distribution (subepicardial, midmyocardial, subendocardial, transmural) and location (septal, free wall, apical) patterns were analyzed by variant type (missense vs truncating) and missense variant localization (central rod domain vs tail domain) and correlated with advanced heart failure (AHF), MVA, AV block, AF and thromboembolic (TE) events. Results: 70 out of 116 (60%) LMNA variant-positive (mean age 39±12, 43% male and 94% Caucasian) were included. Missense variants localizing to the C-terminal tail region showed a higher prevalence of transmural and apical LGE (Table). Amongst the 5 (7%) patients with this distinct apical pseudo-infarct LGE pattern, p.Arg471His-LMNA was identified in all cases. Among the 48/70 (69%) of patients with clinically manifest disease, p.Arg471His-LMNA-positive patients (n=6) were noted to have an increased prevalence of TE events [3 (50%) vs 5 (12%), 0=0.050] despite a reduced prevalence of AF [2 (33%) vs 32 (76%), p= 0.031]. No difference in AHF or MVA were observed, but AV block was less prevalent [1 (20%) vs 29 (74%), p= 0.029]. Conclusion: p.Arg471His-LMNA causes a distinct apical pseudo-infarct LGE pattern associated with an increased risk of TE events and a decreased prevalence of AV block and AF. Future studies are needed to better refine the role of domain/variant-specific risk-stratification/anticoagulation in cardiac laminopathy.

Abstract 4136971: Prognostic Value of Late Gadolinium Enhancement to Predict Non-Sustained Ventricular Tachycardia in Patients with Hypertrophic Cardiomyopathy: A Systematic Review and Meta-Analysis

Background: Non-sustained ventricular tachycardia (NSVT) has been shown to be independently associated with sudden cardiac death (SCD) among patients with hypertrophic cardiomyopathy (HCM). There is limited evidence regarding the efficacy of late gadolinium enhancement (LGE) on cardiac magnetic resonance imaging to predict the incidence of NSVT. Aims: To address this gap in knowledge, our meta-analysis aims to comprehensively evaluate the prognostic value of LGE on cardiac magnetic resonance in predicting the incidence of NSVT in HCM. Methods: PubMed, Embase and Cochrane CENTRAL databses were queried from inception until May 2024 for all studies assessing the prognostic value of LGE on CMR in patients with HCM and reported the incidence of NSVT. Data were combined using a random-effects model meta-analysis to determine the pooled sensitivity, specificity and accuracy of LGE in predicting NSVT in patients with HCM. The association between the LGE extent on CMR and NSVT incidence was also assessed, and weighted mean differences (WMDs) were reported with 95% condidence intervals (CIs). Heterogeneity across the studies was evaluated using the Higgins I 2 statistic. Results: A total of twenty studies were included in our analysis. The pooled senstivity, specificity, and accuracy of LGE in predicting the incidence of NSVT among HCM patients was 91.33%, 37.45%, and 52.86%, respectively. Moreover, we saw a significantly greater extent of LGE (5.95%, CI: 3.08-8.81, P&lt;0.0001) in patients who had NSVT, as compared to patients without NSVT ( Figure 1). Conclusion: Our meta-analysis underscores the significant prognostic value of LGE as a risk stratification tool on CMR imaging in predicting the incidence of NSVT in patients with HCM, by demonstrating a high sensitivity, and a notable association between the LGE extent and NSVT incidence. Nevertheless, the low to moderate Ispecificity and accuracy underscores the need for additional imaging biomarkers for risk stratification.

Abstract 4136412: Quantitative Cardiac Magnetic Resonance Standardized Signal Intensity Comparison in Dilated Cardiomyopathy versus Cardiac Sarcoidosis

Introduction/Background: Dilated cardiomyopathy (DCM) and cardiac sarcoidosis (CS) manifest unique late gadolinium enhancement (LGE) patterns on cardiac magnetic resonance (CMR), indicative of differing distributions of myocardial scar tissue. Nevertheless, these LGE patterns lack specificity, leading to significant overlap between the two conditions. Goals/Aims: This study seeks to introduce a novel quantitative method employing z-score analysis of LGE-CMR signal intensity to objectively evaluate and compare the spatial distribution of LGE intensity between DCM and CS. Methods/Approach: The retrospective cohort included 22 NICM patients (13 DCM, 9 CS) that underwent pre-procedural CMR prior to ventricular tachycardia (VT) ablation between November 2018 to May 2023. LGE images were delineated into sub-endocardial, mid-myocardial, and sub-epicardial layers, categorized into anterior, lateral, inferior, and septal walls based on the AHA 17 segment model for LV myocardial segmentation. CMR signal intensities were standardized as z-scores: z = (x−μ)/σ, where x is the MRI signal intensity for a specific myocardial segment and layer, and μ and σ are the mean and standard deviation across all myocardial segments and layers of the LV, to characterize regional intensity variations. Results/Data: Compared to patients with DCM, those with CS exhibited significantly higher CMR signal intensity z-scores in the septum (β=0.32, p=0.009), particularly in the endocardial third of the right ventricular side (β=0.56, p=0.001). A z-score greater than 0.40 in this area was associated with a CS diagnosis, with an area under the ROC curve of 0.692 in 5-fold cross-validation. Conclusions: Patients with CS exhibit higher affinity for contrast in the septum, particularly on the RV endocardium. Standardized analysis of CMR signal intensities provides a novel, quantitative method for distinguishing CS from DCM, with the former exhibiting higher CMR signal intensity z-scores in the septum.

Abstract 4135080: Relation of focal and diffuse myocardial fibrosis to left bundle branch block in patients with dilated cardiomyopathy and structurally normal heart

The role of fibrosis in etiology of left bundle branch block (LBBB) in still not defined. The aim of this study was to assess the relation of focal and diffuse LV fibrosis to LBBB in patients with dilated cardiomyopathy (DCM) and in patients with structurally normal heart. Materials and methods: 60 DCM with LBBB (DCM-LBBB group, 46.7% male, mean age 57[50;63] years), 50 non-LBBB DCM (78% male, mean age 43[32.3;54] years), 15 patients (53.3% male, mean age 39[28;50] years) with LBBB and no signs of structural heart disease and 10 healthy volunteers (HV) were included in the study. Endomyocardial biopsy (EMB) was performed in 15(24,6%) LBBB-DCM and 16(32%) non-LBBB DCM patients and allowed the quantification of collagen volume fraction (CVF, Fig.1A-D). All patients and HV underwent cardiovascular magnetic resonance (CMR) with late gadolinium enhancement (LGE) analysis. Obtained LGE LV images were post-proceed for core scar (CS) and gray zone (GZ) calculation and 3D reconstruction. Diffuse LV interstitial fibrosis was estimated on all LGE-CMR images with the novel introduced marker - diffuse intensity ratio (DIR). Results: DIR was validated on EMB samples: the percentage of CVF (8.2[4.6;10.8]%) correlated with the DIR value (0.71 ± 0.13) in the same segment (r=0.66, p&lt;0.001, Fig.1E-F). The value of CVF (Fig1A-D) and LGE presence in the septum in both DCM groups (Fig2) was comparable (8.2[4.6; 10.3] versus 7.6[6.1;15.3]%, p=0.82 and 19 (31.7%) versus 17 (34%) patients in non-LBBB DCM group respectively, p=0.8) Moreover, the presence of LGE and midwall fibrosis in septum was not related to the QRS duration (p=0.93 and 0.59). In non-LBBB DCM patients the percentage of CS was significantly higher (4.0[1.55; 11.68]% versus 1.4[0.05;8.5]% in LBBB-DCM patients, p=0.047), whereas percentage of GZ and total fibrosis in both DCM groups was comparable (Fig.3A,B). DIR value was higher in patients with idiopathic LBBB than in HV (0.54±0.09 versus 0.34±0.1, p&lt;0.001) while the percentage of GZ and CS was extremely low and did not differ from its amount in HV (Fig.3C,D). Conclusion: Neither focal (including midwall striae) nor interstitial fibrosis is associated with LBBB in patients with DCM. Diffuse inflammation in LBBB-DCM patients may contribute to the progression of systolic dysfunction but is not the reason for LBBB. The increased value of interstitial fibrosis in patients with LBBB may reflect latent diffuse process in myocardium inexorably leading to DCM development.

Abstract 4120577: Discrimination of Fabry Disease and Cardiac Amyloidosis Using Cardiac MRI and Echocardiography: A Comprehensive Analysis

Background: Discriminating Fabry disease from cardiac amyloidosis based on conventional imaging techniques can be challenging due to overlapping features. We aimed to investigate the discriminatory ability of cardiac MRI (CMR) and echocardiography imaging, to differentiate between these conditions. Methods: Cardiac MRI and echocardiography with SR imaging were performed on patients with suspected Fabry disease (n=39) or cardiac amyloidosis (n=79). Various imaging parameters, including late gadolinium enhancement (LGE) patterns and T1 mapping values derived from CMR, E/e’ and global longitudinal strain (GLS) were analyzed. Discrimination scores were calculated using multivariate analysis, with sensitivity and specificity determined for selected parameters. Results: In Fabry patients, LGE patterns predominantly exhibited a subendocardial distribution (66%), whereas amyloidosis patients showed transmural LGE (93%). LV mass index and T1 mapping values were higher (150±20 vs. 90±15 g/m 2 , 1208±104 vs. 822± 210ms both p p&lt;0.001) in cardiac amyloidosis compared to Fabry disease. Echocardiographic parameters demonstrated significantly reduced GLS (-12±2 vs -18±3%, p&lt;0.001), larger LA size (50 ± 5 mm vs. 40 ± 5 mm, p&lt;0.001) and higher E/e' ratio (15 ± 3 vs. 8 ± 2, p&lt;0.001) in cardiac amyloidosis compared to Fabry disease. Multivariate analysis identified LGE patterns and GLS as significant discriminators, and combining both parameters can discriminate Fabry and Amyloidosis with a sensitivity of 80.0%, specificity of 90.0%, and predictive accuracy of 85.0%. Incorporating LA size, LV mass index and E/e’ further improve the predictive accuracy to 92.0%. Conclusions: Cardiac MRI and echocardiography demonstrate promising discriminatory ability in distinguishing Fabry disease from cardiac amyloidosis. GLS emerges as a valuable parameter, reflecting myocardial function and aiding in accurate diagnosis. Integration of these imaging modalities into clinical practice could enhance diagnostic accuracy and guide appropriate management strategies.

Abstract 4138272: CMR Quantification of Myocardial Oxygenation Extraction Fraction Maps Using a Model-based Self-supervised Learning Network: Initial Experience in Patients with Cardiomyopathies

Background: Measurements of myocardial oxygenation extraction fraction (mOEF) maps with cardiovascular magnetic resonance (CMR) has been recently developed to assess myocardial oxygen metabolism in healthy. Recent studies focus on developing supervised machine learning methods to improve the quantification of mOEF. However, these supervised learning methods may be limited by the lack of ground-truth mOEF maps because MRI cannot directly measure mOEF with the same precision as PET. Hypothesis: Model-based self-supervised learning neural networks maybe feasible to generate mOEF maps accurately. Aims: To develop a physical model-based self-supervised learning neural network to accurately estimate mOEF for the patients with a variety of cardiomyopathies. Methods: An ECG triggered, two-dimensional asymmetric spin-echo (ASE) prepared sequence was employed to scan 71 patients with dilated, hypertrophic, or ischemic cardiomyopathies. At least 3 slices were scanned for each patient and each ASE scan was performed free-breathing with a spatial resolution of 1.7 × 1.7 × 8 mm 3 and scan time of 18 RR-interval. Acquisition of late gadolinium enhancement (LGE) was performed in each patient after the administration of 0.15 mmol/kg gadolinium agent for the visualization of myocardial infarction regions. A fully convolutional neural network with U-Net architecture was optimized with a physical model-based signal loss function (see Figure 1) on the ASE training dataset from 67 patients to generate mOEF maps. To evaluate if the method can accurately quantify abnormal mOEF, four patients with myocardial infarction were selected as the test set. Results: A previous publication reported normal mOEF levels at approximately 0.6-0.7 in healthy subjects. Figure 2 shows our proposed method generated mOEF maps from two representative patients and their LGE images for comparisons. In comparison with the remote region (mOEF = 0.70±0.10), the mOEF of myocardial regions with infarction was significantly lower (mOEF = 0.36±0.12, p &lt; 0.001). The infarction areas predicted by the network overlapped well with the LGE. Conclusion: Quantification of mOEF using the proposed model-based self-supervised U-Net is feasible to detect abnormalities in regional myocardial oxygenation. Current study is ongoing to evaluate the proposed technique in a large cardiac patient dataset.

Abstract 4125497: Diagnostic Discrepancies Revealed by Explant Pathology at the Time of Cardiac Transplant in Patients Clinically Diagnosed with Nonischemic Cardiomyopathy: Role of Cardiac Magnetic Resonance Imaging

Background: Differentiating between causes of non-ischemic cardiomyopathy is important for disease-directed treatment. Cardiac MRI (CMR) and the use of late gadolinium enhancement (LGE) have proven useful for enhancing diagnostic accuracy. Definitive assessment of cardiomyopathy etiology by explant pathology facilitates direct evaluation of CMR utility. Hypothesis: We hypothesized direct comparison between pre-transplant (Tx) CMR and explant pathology will improve the characterization of undifferentiated cardiomyopathy through examination of cases where pre- and post-Tx diagnoses were discordant. Aims: To evaluate discrepant cases to describe imaging patterns in relation to post-Tx diagnosis. Methods: Institutional Tx recipients between 2000 and June 2023 were queried for pre-Tx MRI (n=122). Discrepant cases were identified (n=8). Pre-Tx diagnostic modalities, including CMR, were reviewed, and CMR patterns were evaluated in association with ultimate explant diagnosis. Results: Of the eight patients with discrepant diagnoses, five carried clinical diagnosis of dilated cardiomyopathy, one hypertrophic cardiomyopathy, one peripartum cardiomyopathy, and one congenital heart disease having undergone tricuspid valve and ASD repair. Pathologic evaluation most frequently identified biventricular or left ventricular arrhythmogenic cardiomyopathy (ARVC) (n=6), where CMR disclosed a diffuse pattern of subepicardial LGE and pre-Tx diagnosis of DCM was most common. Two of these pathologic descriptions represented a different disease on genetic evaluation: one patient had Danon disease, another had a LMNA pathogenic variant. The presumed peripartum cardiomyopathy was identified as Fabry’s disease on pathology (however, genetic testing consistent with Danon disease). Both Danon disease patients had primarily subendocardial LGE on CMR. One patient with a DCM phenotype had HCM pathologically. Results summarized in Table 1. Conclusions: Cardiac MRI can be a useful modality for the evaluation of underlying cardiomyopathy and should prompt appropriate genetic testing. Diffuse subepicardial LGE frequently accompanied the diagnosis of ARVC whereas a non-subepicardial pattern reflected alternative etiologies identified only through genetic testing.

Abstract 4125188: Cardiac Specific Biomarkers of Progression in Duchenne Muscular Dystrophy Detected Using Aptamer-Based Proteomics

Background: Duchenne muscular dystrophy (DMD) is an X-linked, progressive neuromuscular disorder characterized by cardiac and skeletal myopathy. The cardiac and skeletal muscle manifestations have different ages of onset and rates of progression, suggesting variability in the pathophysiology of dystrophin loss within the respective muscle groups. Hypothesis: We hypothesized that proteomics with comprehensive clinical phenotyping would identify novel biomarkers that correlate with cardiac but not skeletal disease progression in boys with DMD. Methods: This single-center cohort study of 56 DMD subjects performed cardiac magnetic resonance (CMR), including left ventricular ejection fraction (LVEF), late gadolinium enhancement (LGE), and myocardial circumferential strain (ECC). Fifty-one subjects underwent quantitative muscle testing, and 33 underwent actigraphy (MSK indices). Aptamer-based technology (SomaScan, SomaLogic, Boulder, CO) evaluated 1128 proteins in plasma sampled at the time of CMR. Correlations between serum protein levels and cardiac or MSK indices were tested using Benjamini-Hochberg corrected p-values (q-values). Results: The mean age of DMD subjects was 15.5 years old +/- 4.30. Twenty-six subjects had left ventricular dysfunction (LVEF &lt;55%), 45 subjects had LGE, and 45 were non-ambulatory. Of 1128 proteins analyzed, 208 demonstrated a significant correlation for cardiac but not MSK indices (Figure 1). Figure 2 lists the 20 proteins with the strongest correlations, which included biomarkers of inflammation, calcium regulation in myocytes, and cell adhesion. Conclusion: We detected 208 novel proteins that correlate with cardiac-specific DMD disease progression. These proteins provide a better understanding of the underlying differences of cardiac disease, compared to MSK disease in DMD and provide clues to potential cardiac therapeutic options.

Abstract 4124120: Rare but Deadly - Eosinophilic Myocarditis in a Patient with Eosinophilic Granulomatosis Polyangiitis

Eosinophilic myocarditis (EM) is a rare inflammatory myocarditis characterized by eosinophilic infiltration of myocardial tissue. Despite the high mortality rate, EM is frequently underdiagnosed and is often first identified in postmortem studies. We share a case of EM as an early manifestation of newly diagnosed eosinophilic granulomatosis polyangiitis (EGPA). The patient is a 46-year-old female with a past medical history of ulcerative colitis and adult-onset asthma who presented to the emergency department with a 2–3-week history of worsening positional chest pain radiating to the left upper extremity. Associated symptoms include 3 months of fatigue, headaches, right foot neuropathy, urticaria, and B-symptoms. Prior to admission, the patient was started on empiric prednisone for presumed EGPA. Initial lab work on admission was notable for elevated troponin (602 ng/L), hyper-eosinophilia (19.5%), thrombocytosis (680K/uL), and elevated ESR (42 mm/h) that have improved since initiation of prednisone. Transthoracic echocardiogram revealed a newly reduced LVEF of 40% with basal and mid-septal wall motion abnormalities. Cardiac catheterization showed normal coronaries confirming the diagnosis of non-ischemic cardiomyopathy. Late gadolinium enhancement in cardiac MRI was seen in basal to mid segments with patchy pericardial enhancement, meeting the Lake Louise criteria for myocarditis. An endomyocardial biopsy showed substantial myocardial infiltration with lymphocytes, histiocytes and eosinophils, confirming the diagnosis of EM. After multidisciplinary team discussion with cardiology and rheumatology, the patient was started on guideline-directed medical therapy for her HFrEF and pulse dose steroids with a prolonged taper and cyclophosphamide. She is tolerating her treatment well. This case highlights the importance of early recognition, comprehensive assessment and targeted treatment for EM depending on its underlying etiology. In the case of autoimmune dysfunction, it involves a combination of immunosuppressive and symptomatic therapy. Ongoing research is crucial to enhance our understanding and improve clinical outcomes, like arrhythmias and cardiogenic shock, for this complex condition.

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 4138237: Clinical Utility of T2 Mapping for the Assessment of Myocardial Inflammation in Patients With Cardiac Sarcoidosis

Introduction: 18 F-FDG PET has been used for the evaluation of active inflammatory lesions in cardiac sarcoidosis (CS), but it is burdensome for patients to perform as a routine follow-up. Late gadolinium enhancement (LGE) on cardiac magnetic resonance (CMR) that can detect myocardial fibrosis is limited in its ability to assess active inflammation. T2 mapping has been shown to detect myocardial inflammation in myocardial diseases without radiation exposure and contrast agents (Figure). However, the ability of T2 mapping for discriminating inflammatory myocardium has not been fully clarified in patients with CS. Hypothesis: We assessed the hypothesis that T2 mapping has potential for the discrimination of inflammatory myocardium in patients with CS. Methods: Twenty-seven subjects who underwent CMR at 3T and 18 F-FDG PET to diagnose CS were enrolled. Fourteen subjects were diagnosed as CS due to LGE and myocardial FDG uptake on 18 F-FDG PET (PET-positive group). Thirteen subjects showed no myocardial FDG uptake (PET-negative group). NativeT1, T2, and extracellular volume fraction (ECV) were measured using a 16-segment model. Receiver-operating characteristic (ROC) curve analysis was performed to evaluate T1 and T2 mapping in discriminating between active and inactive inflammatory segments in the PET-positive group. Results: Mean native T1, native T2 and ECV showed no significant differences between the PET-positive and the PET-negative groups. However, maximum T2 values, which were highest ones in the 16 segments, were significantly higher in the PET-positive group than the PET-negative group (51.3 ± 7.7 ms vs 45.7 ± 3.6 ms, p = 0.014). In the PET-positive group, ROC analysis showed AUC of 0.72 in native T2, 0.61 in native T1, and 0.68 in ECV for discriminating inflammatory myocardium. The optimal cutoff value of native T2 was 45.7 ms, and the diagnostic performance had a sensitivity of 44.4 %, specificity of 93.3 % , positive predictive value of 88.1 %, and negative predictive value of 60.1 %. Conclusion: T2 mapping is a promising approach for the discrimination of inflammatory myocardium without radiation exposure and contrast agents in patients with cardiac sarcoidosis.

Abstract 4144526: A Case Presentation of Severe Left Ventricular Dysfunction from Focal Myocarditis due to Immune Checkpoint Inhibitor

Introduction: Immune checkpoint inhibitors (ICI), such as pembrolizumab, are an effective immunotherapy for several malignancies, however, have been associated with adverse events including myocarditis and accelerated atherosclerosis. ICI myocarditis is associated with a mortality rate of up to 33%. This case reports a patient on pembrolizumab with an atypical presentation. Case presentation: A 75-year-old female with a past medical history significant for lung cancer on pembrolizumab and myasthenia gravis presented to the hospital with dyspnea and mild, intermittent exertional chest discomfort. She denied nausea, radiation of pain, diplopia, weakness in extremities, or dysphagia. Workup revealed a leucocyte count of 13,500 cells/uL, pro-brain natriuretic peptide of 13,458 pg/mL, troponin of 26 ng/L, and a normal erythrocyte sedimentation rate and C reactive protein. A chest computed tomography was performed that showed mild bilateral pleural effusion and no pulmonary embolism. A nuclear stress test showed no evidence of ischemia but showed a severely reduced left ventricular ejection fraction (LVEF) at 29%. An echocardiogram confirmed that the ejection fraction was reduced at 23% (baseline LVEF was 60% from 1 year ago). Cardiac MRI revealed a mildly increased regional T2 signal in the anterolateral wall, mildly elevated extracellular volume fraction, and no late gadolinium enhancement. With ongoing clinical suspicion despite equivocal findings on cardiac MRI, an endomyocardial biopsy was done that revealed a single small aggregate of lymphocytes present in 1 of 6 tissue samples. Ultimately, with the single site of aggregated lymphocytes on biopsy, a diagnosis of ICI myocarditis was determined, and the patient was started on high-dose intravenous glucocorticoids as well as bisoprolol, empagliflozin, spironolactone, and Entresto for heart failure management as she was able to tolerate. Discussion: Myocarditis due to pembrolizumab is a rare, but potentially lethal adverse effect. Patients typically have abnormal electrocardiograms and elevated cardiac biomarkers. Cardiac MRIs have sensitivity and specificity of 68% and 91% respectively for diagnosis, and the gold standard is endomyocardial biopsy however, it is limited due to sampling error. Our patient had an unusual presentation, but with both imaging and biopsy, we found a case of focal myocarditis with severe left ventricular dysfunction, which typically is seen with fulminant myocarditis.

Abstract 4136394: Elucidation of a novel genetic substrate responsible for genetically elusive ring-like arrhythmogenic cardiomyopathy

Background: Arrhythmogenic cardiomyopathy (ACM) is a genetic heart disease characterized by fibrofatty replacement of ventricular myocardium. Arrhythmogenic left ventricular (LV) cardiomyopathy (ALVC) is a phenotypic variant of ACM predominantly involving the LV. Mutations in genes encoding for desmosome proteins and filamin C have been implicated in ALVC, especially in the setting of a ring-like late gadolinium enhancement (LGE) imaging pattern. Objective: To identify the underlying genetic substrate responsible for genetically elusive ring-like ALVC in a patient with seemingly sporadic/recessive disease. Methods: A 38-year-old male was referred for genetic investigation to determine the underlying genetic substrate responsible for his ALVC phenotype. The patient fulfilled both electrocardiographic (low voltage in the limb leads and anterolateral T-wave inversions) and imaging (&gt;1 segment of subepicardial LGE) criteria for ALVC. Additionally, the patient experienced unexplained episodes of tachycardia, shakiness, sweating, and nausea prompting concern for an underlying neuromuscular disease. Genome sequencing (GS) was performed on DNA isolated from the affected patient and both of his unaffected parents. Variants were filtered assuming either a sporadic de novo occurrence or an autosomal recessive inheritance pattern. Results: GS identified compound heterozygous GNPTAB variants in the affected patient. A previously reported maternally derived p.Leu257Leu (c.771G&gt;A) variant involving the last nucleotide of exon 7 of the GNPTAB gene and a novel paternally inherited Lys834fs*5 frame-shift variant were identified. The p.Leu257Leu variant has been reported to cause aberrant splicing and exon skipping of the GNPTAB mRNA transcript. Pathogenic variants in the GNPTAB encoded N-acetylglucosamine-1 (GlcNAc)-phosphotransferase subunits alpha/beta cause mucolipidosis type III, a rare recessive lysosomal storage disease characterized by coarse facial features, developmental delay, short stature, skeletal deformities, and cardiac involvement including valvular thickening and cardiomyopathy. Conclusions: Here, using a genome sequencing trio analysis we identified a compound heterozygous GNPTAB pathogenic variants as the underlying genetic substrate in a patient with ring-like ALVC and concomitant neuromuscular disease manifestation. Genome sequencing may identify the genetic etiology responsible for an otherwise undifferentiated diagnosis of cardiomyopathy.