Late Gadolinium Enhancement Quantification Research Articles

P299 CONDUCTION DISORDERS AS THE FIRST HALLMARK OF ISOLATED CARDIAC SARCOIDOSIS IN A HIGHLY ACTIVE INDIVIDUAL: A CASE REPORT

Abstract A 45–year–old highly active Caucasian individual was admitted to the emergency department complaining of slightly reduced physical performances: he reported a lack of increase of heart rate beyond 80–100 bpm at fitness tracker monitoring during physical activity during the previous week. He used to train 3–4 times/week. He had no previous medical concerns and he didn’t take any medication. Basal electrocardiogram (ECG) showed 2:1 atrioventricular block (AVB) and left axis deviation, with the exception of his 2:1 AVB, the other features on the ECG are common training related changes. Transthoracic echocardiogram was normal. Treadmill exercise test revealed paroxysmal 2:1 AVB and Mobitz I AVB at peak effort, then first degree AVB and isolated and coupled right infundibular premature ventricular complexes (PVC) in the recovery phase: exercise related AV–conduction improvement suggested supra–nodal AVB. Cardiac magnetic resonance (CMR) imaging reported two areas of late gadolinium enhancement (LGE) with midwall/subepicardial distribution: the first one in the basal anterior septal wall extending to basal anterior wall and the second one involving the basal and medium segment of inferior septum and inferior wall. LGE quantification was 6.0 g/m2 (9.5%). Short tau inversion recovery (STIR) acquisitions were negative for oedema (Figure 1). Subsequent FDG–PET imaging confirmed high uptake in the basal anterior septal wall, the anterior wall and in the basal inferior septal area (Figure 2). No other organ involvement was detected. Considering the FDG–PET, LGE and AV–conduction abnormalities, the patient was clinically diagnosed with symptomatic isolated CS. However, a definitive histologic diagnosis was not possible as no myocardial biopsy was performed. High dose corticosteroid therapy was startedand after few days of treatment ECG monitoring revealed an imrovement of cardiac conduction. The treadmill test was repeated and showed conduction improvement during effort, however the test was suspended due to the occurrence of ventricular couples and ventricular bigeminy during effort. For arrhythmic risk assessment, electrophysiological study (EPS) was performed and no arrhythmias were induced. We decided to defer ICD implantation. However, a loop–recorder for continuous arrhythmias monitoring was implanted. At three months, a new CMR was performed and was identical to the previous one, with no significant LGE reduction or increase detected.

FLORA software: semi-automatic LGE-CMR analysis tool for cardiac lesions identification and characterization.

Today there is a growing interest in the quantification of late gadolinium enhancement (LGE) in ischemic and non-ischemic cardiac pathologies. We build an automatic self-made free software FLORA (For Late gadOlinium enhanced aReas clAssification) for the recognition, classification and quantification of LGE areas that allows to improve the observer's performances and that homogenizes the evaluations between different operators. We have retrospectively selected 120 CMR exams: 40-ischemic with evident scar tissue on LGE sequences; 40-non-ischemic cardiomyopathy; 40-any myocardial alteration on CMR, especially on LGE sequences. FLORA's performance was compared to the radiologist's evaluation. FLORA identified both ischemic and non-ischemic myocardial lesions in almost all cases (80/80 and 79/80 for the double-Gaussian fit method and fixed-shift method, respectively, with sensitivity and specificity of 100%/98.8% and 55%/50%, respectively). The best results were obtained from the classification of ischemic myocardial damage, which was correctly identified in 85%-95% of cases. FLORA also increases the agreement between observers and allows a quantitative evaluation of transmurality. FLORA has proven to be an applicable tool that improves and facilitates the classification of LGE areas allowing their quantification.

Looking for appropriate criterias for SCD prevention: prognostic role of MRI in patients with nonischemic ventricular arrhythmias

Abstract Background Currently left ventricular ejection fraction (LVEF) remains the only indicator for identifying candidates for implantable cardioverter-defibrillator (ICD)therapy for the primary prevention of sudden cardiac death (SCD). However the majority of patients suffering SCD have a preserved LVEF and some of them with poor LVEF do not benefit from ICD therapy. Late gadolinium enhancement (LGE) on cardiac-MRI (CMR) has been proposed as an independent predictor of ventricular arrhythmias. Limited data exist on the role and methods of LGE quantification in patients with a nonischemic ventricular arrhythmias. Purpose The goal of this study is to explore whether theextent of LGE would improve risk stratification in patients with a nonischemic ventricular arrhythmias with an indication for implantable cardioverter-defibrillator (ICD) therapy for the primary or secondary prevention of SCD. Methods Fifty six patients with a nonischemic ventricular arrhythmias underwent LGE-CMR prior to ICD implantation for primary and secondary prevention of SCD. LGE extent was quantified using both the full-width half-maximum (FWHM) andthe standard deviation–based (2-SD) method. The primary endpoint was appropriate ICD discharge for sustained ventricular tachyarrhythmia. Results During a median follow-up of 18 [11,5–26,0] months the primary endpoint occurred in 22 patients. The median percentage of LV myocardium fibrosis assessed by the 2-SD method was 9,8 [6,0–18,8]%, while for the FWHM method it was 5,1 [3,0–10,6]% (p<0,001). Intra-observer and inter-observer variability of the FWHM technique was excellent, intraclass correlation coefficients (ICC) 0,97 (95% CI: 0,92–0,99) for intraobserver variability and 0,95 (95% CI: 0,85–0,98) for interobserver variability. The ICC for the 2-SD method were lower: 0,92 (95% CI: 0,76–0,97) and 0,90 (95% CI: 0,69–0,96), for intra- and interobserver variability, respectively. By Cox univariate regression analysis, past syncope, HR: 3,14; (CI: 1,28–7,73), past sustained VT, HR: 8,24; (CI: 2,43–27,96), the presence of LBBB before implantation cardiac resynchronization therapy defibrillator (CRT-D), HR: 0,22; (CI: 0,05–0,96) as well as extent of LGE, HR: 1,067; per 1% increase in the extent of LGE, (CI: 1,029–1,107) demonstrated the strongest association with the appropriate ICD discharge. In multivariate regression analysis, the history of sustained VT, HR: 9,17; (CI: 2,60–32,38; p=0,001) and the value of the extent of LGE, HR: 1,081; per 1% increase in volume of LGE, (CI: 1,034–1,131; p=0,001) demonstrated an independent association with the appropriate ICD discharge. Conclusions FWHM is the optimal semi-automated quantification method in patients with nonischemic ventricular arrhythmias, demonstrating the highest technical consistency. LGE extent is an independent predictor of adverse outcomes in patients with nonischemic ventricular arrhythmia and may have an important role in risk stratification. Funding Acknowledgement Type of funding sources: None. LGE QuantificationEvent-Free Survival

Feasibility of late gadolinium enhancement (LGE) in ischemic cardiomyopathy using 2D-multisegment LGE combined with artificial intelligence reconstruction deep learning noise reduction algorithm

BackgroundDespite the low spatial resolution of 2D-multisegment late gadolinium enhancement (2D-MSLGE) sequences, it may be useful in uncooperative patients instead of standard 2D single segmented inversion recovery gradient echo late gadolinium enhancement sequences (2D-SSLGE). The aim of the study is to assess the feasibility and comparison of 2D-MSLGE reconstructed with artificial intelligence reconstruction deep learning noise reduction (NR) algorithm compared to standard 2D-SSLGE in consecutive patients with ischemic cardiomyopathy (ICM). MethodsFifty-seven patients with known ICM referred for a clinically indicated CMR were enrolled in this study. 2D-MSLGE were reconstructed using a growing level of NR (0%,25%,50%,75%and 100%). Subjective image quality, signal to noise ratio (SNR) and contrast to noise ratio (CNR) were evaluated in each dataset and compared to standard 2D-SSLGE. Moreover, diagnostic accuracy, LGE mass and scan time were compared between 2D-MSLGE with NR and 2D-SSLGE. ResultsThe application of NR reconstruction ≥50% to 2D-MSLGE provided better subjective image quality, CNR and SNR compared to 2D-SSLGE (p < 0.01). The best compromise in terms of subjective and objective image quality was observed for values of 2D-MSLGE 75%, while no differences were found in terms of LGE quantification between 2D-MSLGE versus 2D-SSLGE, regardless the NR applied. The sensitivity, specificity, negative predictive value, positive predictive value and accuracy of 2D-MSLGE NR 75% were 87.77%,96.27%,96.13%,88.16% and 94.22%, respectively.Time of acquisition of 2D-MSLGE was significantly shorter compared to 2D-SSLGE (p < 0.01). ConclusionWhen compared to standard 2D-SSLGE, the application of NR reconstruction to 2D-MSLGE provides superior image quality with similar diagnostic accuracy.

Myocardial fibrosis quantification methods by cardiovascular magnetic resonance imaging with contrast-enhancement in patients with Fabry disease

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – EU funding. Main funding source(s): National Agency for Academic Exchange (NAWA). Background. Presence and extent of late gadolinium enhancement (LGE) in patients with Fabry disease (FD) is a predictor of adverse cardiac events. However there is no gold standard method to quantify the amount of myocardial fibrosis in cardiac magnetic resonance imaging (CMR). Purpose. The aim of this study was to establish the most reliable and reproducible technique for quantifying LGE in patients with FD. Methods. 68 patients with FD (40% male, 40 ± 16 years old) treated in our outpatient clinic, who underwent CMR with administration of 0.2 mmol of gadobutrol per kilogram of body weight between December 2012 and March 2019 were enrolled into the study. Presence of LGE was described in 25 patients (37%). Twenty patients underwent CMR with the same LGE sequence (Philips 1.5 Tesla, two-dimensional multi-breath-hold inversion recovery sequence) and were enrolled into further analysis. LGE quantifications were performed using gray-scale thresholds with 2, 3, 4, 5 and 6 standard deviations (SD) above the mean signal intensity for the remote myocardial tissue, full width at half maximum method (FWHM), visual assessment with threshold (VAT) and fully manual method (MM; Philips IntelliSpace Portal 10). LGE quantifications were done twice by the same observer in different time periods and once by another observer. Intraclass correlation coefficient (ICC), Bland- Altman analysis and coefficient of variation (CV) were used to assess intra- and interobserver reliability and reproducibility. Results. The mean quantity of fibrosis mass (in gram) in all studied patients was: 35.5 ± 18.7 at 2SD, 21.0 ± 12.8 at 3SD, 12.7 ± 8.5 at 4SD, 8.0 ± 5.7 at 5SD, 5.3 ± 4.1 at 6SD, 1.9 ± 1.8 at FWHM, 8.6 ± 7.4 at VAT and 9.1 ± 6.1 at MM. Intra-observer reliability of almost all studied LGE quantification methods was excellent, with a range of ICCs from 0.90 for 6SD to 0.95 for VAT, with one exception for FWHM, which had good intraobserver reliability (ICC 0.84; all P &amp;lt; 0.05). Interobserver reliability was excellent for VAT (ICC 0.94) and good for all other LGE quantifications methods (range of ICCs from 0.76 for MM to 0.87 for 5SD, all P &amp;lt; 0.05). 5SD had the lowest CV (6%) for intraobserver reproducibility and 2SD and VAT for interobserver reproducibility (35% and 38%). FWHM had the highest CV for both intra- and interobserver reproducibility (63% and 94%, accordingly). Conclusions 1. All studied methods of LGE quantification in patients with FD and presence of myocardial fibrosis have good to excellent intra- and interobserver reliability. 2. The total amount of LGE differs in studied LGE quantifications methods. Therefore in clinical practice it is important to report which technique of LGE quantification was used and choose the same for CMR-follow up. 3. FWHM might be avoided for LGE quantification in patients with FD due to the highest intra- and interobserver variability in comparison to other available techniques.

Prognostic assessment following acute myocarditis requires convalescent scanning: neither peak troponin nor index scan T2 signal predicts convalescent late gadolinium enhancement

Abstract Funding Acknowledgements Type of funding sources: None. Background Cardiovascular magnetic resonance (CMR) is a key diagnostic investigation in acute myocarditis (1) and permits quantification of late gadolinium enhancement (LGE) and myocardial oedema. Follow-up CMR imaging is recommended to check for persistence of scar and oedema (2). Persistent late gadolinium enhancement is associated with a worse prognosis (3). It is not known whether all patients require follow-up scanning or whether the initial scan can provide useful information to identify which patients need convalescent assessment. Purpose In this study we considered whether extent of troponin elevation, extent of T2 elevation and initial late gadolinium enhancement burden predicted long-term late gadolinium enhancement at follow-up. Methods Index and follow-up CMR scans of consecutive patients presenting with a diagnosis of acute myocarditis between 2019 and 2020 across three hospitals were included. Inclusion criteria were: follow-up scan within 9 months of the index scan, CMR with LGE imaging and T2 mapping, and acute myocarditis being the primary diagnosis of the index scan. Myocardial T2 values in the area affected by myocarditis and percentage of LV myocardium showing late enhancement (using a threshold-based full height half width or manual region of interest strategy) were extracted. Results 20 patients were included in the study (80% male; mean age 37 years). Mean interval between the index and follow-up scan was 4.1 months. Peak troponin level during the acute illness was not associated with the proportion of LV myocardium affected by LGE in the index scan (R^2 &amp;lt;0.01) (Figure 1A). Myocardial T2 values in the first scan were not associated with the proportional resolution in LGE between the index and follow-up scans (R^2 0.02) (Figure 1B). The mean change in LGE was -61.7% (+/-22.8%) but the initial LGE burden did not predict the proportional degree of improvement in LGE between scans (R^2 &amp;lt;0.01)(Figure 1C). Conclusions The extent of troponin elevation and initial CMR phenotype was not a good predictor of the burden of long-term late gadolinium enhancement. Although most cases showed improvement in LGE scar burden between index and follow-up imaging, neither peak troponin level during the acute episode, nor T2 values at the first CMR scan were predictive of initial or change in scar burden. Serial CMR assessment is required to identify those patients who have residual long-term scarring.

Left atrial morpho-functional changes in hypertrophic cardiomyopathy and Fabry disease: a CMR-feature tracking study

Abstract Funding Acknowledgements Type of funding sources: None. Background Left ventricular (LV) diastolic dysfunction (DD) is a hallmark of hypertrophic cardiomyopathy (HCM) and its phenocopies, such as Fabry disease (FD). Together with left atrial (LA) size, LA function is emerging as a sensitive marker of the adaptive changes to backward transmission of LV cardiac filling pressure, thus implementing DD assessment. Additionally, both HCM and FD are characterized by a primitive atrial myopathy, but LA morpho-functional changes in HCM and FD have never been directly compared. More recently, LA strain by Cardiovascular Magnetic Resonance Feature Tracking (CMR-FT) has been demonstrated to be a feasible and reproducible tool to explore LA function. Purpose To compare LA morpho-functional changes in HCM and FD and to explore their correlation with tissue alterations. Methods 15 HCM and 15 sex-, age- and LV mass index-matched FD patients underwent CMR (Magnetom Aera 1.5T, Siemens) and Doppler Echocardiography for LV diastolic function assessment (E/e’ and DD grading from 0 to 3). LA phasic function was evaluated by CMR-FT strain (Qstrain Medis). The software output included passive (εe, conduit function), active (εa, booster pump function) and total strain (εs, reservoir function), along with LA volumes and ejection fraction (EF). Late gadolinium enhancement (LGE) was quantified as a percentage of LV mass using the standard deviations (SDs) method (≥ 5 SDs). Interstitial fibrosis was assessed by extracellular volume (ECV) quantification in remote myocardium. All patients were in sinus rhythm. Results In the HCM group, the proportion of patients with DD grade 2-3 was only slightly higher than in FD (p 0.26). Accordingly, no significant difference was found in E/e’ value (p 0.78). Compared to FD, HCM patients showed more severe LA morpho-functional changes, including larger LA end-systolic volume (ESV) (113 ± 35 vs 84 ± 23 ml), lower LA EF (37 ± 7 vs 44 ± 9 %) and a greater reduction of εs (-20 ± 5 vs -25 ± 6 %) and εa (-10 ± 4 vs -15 ± 4 %) (all p &amp;lt; 0.05). LV size and function and the burden of fibrosis (LGE quantification and ECV) were comparable between the two groups. Interestingly, in HCM population, unlike in FD, LA morpho-functional measurements significantly correlated with tissue characterization parameters (LA ESV with LGE, r 0.56, p 0.03; εs and εa with ECV, r -0.51, p 0.05 and r -0.59, p 0.02, respectively). Conclusions LA morpho-functional alterations are much more severe in HCM compared to FD with similar degree of LV hypertrophy. A more severe atrial myopathy or different mechanisms of atrial damage in the two cardiomyopathies may explain these findings. LA CMR-FT analysis may represent a sensitive tool to discriminate between HCM and FD, although larger studies are needed to confirm this finding and the possible correlation with the occurrence of atrial arrhythmias and thromboembolic risk.

Patients with acute myocarditis and preserved systolic left ventricular function: comparison of global and regional longitudinal strain imaging by echocardiography with quantification of late gadolinium enhancement by CMR

BackgroundConventional transthoracic echocardiography (TTE) does often not accurately reveal pathologies in patients with acute myocarditis and preserved left ventricular ejection fraction (LVEEF). Therefore, we investigated the diagnostic value of two-dimensional (2D) speckle tracking echocardiography compared to late gadolinium enhancement (LGE) by cardiac magnetic resonance (CMR) imaging in patients with acute myocarditis and normal global LVEF.Methods and results31 patients (group 1) with the diagnosis of acute myocarditis confirmed by CMR according to the Lake Louise criteria and 20 healthy controls (group 2) were analyzed including global longitudinal strain (GLS) and regional longitudinal strain (RLS) derived by the bull’s eye plot. Although preserved LVEF was present in both groups, GLS was significantly lower in patients with acute myocarditis (group 1: GLS − 19.1 ± 1.8% vs. group 2: GLS − 22.1 ± 1.7%, p < 0.001). Compared to controls, lower RLS values were detected predominantly in the lateral, inferolateral, and inferior segments in patients with acute myocarditis. Additionally RLS values were significantly lower in segments without LGE.ConclusionIn patients with acute myocarditis and preserved LVEF, a significant reduction of GLS compared to healthy subjects was detected. Further RLS adds important information to the localization and extent of myocardial injury.Graphic abstract

Simultaneous visualization of left atrial fibrosis and epicardial adipose tissue using 3D Dixon late gadolinium enhancement cardiovascular magnetic resonance

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Swedish Medical Research Council (Grant Number: 2018-02779) Swedish Heart and Lung Foundation (Grant Number: 20170440) Background Cardiovascular magnetic resonance (CMR) is a powerful tool to identify structural changes of the left atrium (LA). LA fibrosis can be quantified using late gadolinium enhancement (LGE) and is a major risk factor for progression of atrial fibrillation (AF). Epicardial adipose tissue (EAT) around the LA can also be assessed using CMR and is associated with incidence and severity of AF. The theory that EAT may induce LA wall inflammation and thus promoting LA fibrosis highlights the need for assessment of the interrelation of the spatial distribution of these two AF risk factors. However, previous CMR studies have used separate pulse sequences to visualize LA fibrosis and EAT. Purpose To develop and evaluate a novel 3D Dixon water-fat separated LGE (Dixon-LGE) pulse sequence for visualization and quantification of LA fibrosis and EAT. Methods 19 subjects were prospectively included and scanned on a 1.5T scanner (mean age 54 ± 20 years; 9 female): 10 patients with a history of AF, and 9 patients without any known cardiovascular disease (NCD). The 3D Dixon-LGE scan was performed 20 minutes after Gd contrast injection. Dixon reconstructed water images were used for LGE quantification while the fat images were used to quantify EAT. Segmentations of the LA myocardium and EAT were performed manually. The image intensity ratio (IIR) method was used for fibrosis quantification, by normalizing the intensity of the LA wall by the mean value of the blood pool intensity and classifying fibrosis as pixels with normalized intensity more than 1.2. For comparison with the automated IIR method, fibrosis was manually segmented in the LGE images as ground truth (GT). Results Example images from an AF and NCD patient are shown in the figure. Heart rate was higher (84 ± 14 vs. 65 ± 14 bpm, P = 0.007), and BMI was higher (28 ± 3 vs. 24 ± 3 kg/m², P = 0.014) in the AF group compared to NCD. AF had also larger LA end-systolic volume index (83 ± 16 vs. 38 ± 9 mL/m², P &amp;lt; 0.001) and larger LA EAT volume index (7.1 ± 4.1 vs. 3.2 ± 2.2 mL/m², P = 0.022) compared to NCD. Further, fibrosis as percentage of LA surface area was larger 14.9 ± 18.4 vs. 3.2 ± 2.5 %, P = 0.028 in AF compared to NCD. The interclass correlation coefficient (ICC) for inter-observer and intra-observer measurements of LA volume were 0.99 (95% CI, 0.97%–0.99%) and 0.99 (95% CI, 0.99%–0.99%), respectively, of LA EAT volume were 0.95 (95% CI, 0.87%–0.98%) and 0.97 (95% CI, 0.89%–0.99%), respectively, and of LA fibrosis, IIR method, were 0.98 (95% CI, 0.94%–0.99%) and 0.99 (95% CI, 0.98%–0.99%), respectively. The IIR method had a very high level of agreement with the GT segmentation, ICC = 0.96 (95% CI, 0.78%-0.99%). Conclusions LA fibrosis and EAT can be visualized simultaneously by using a single 3D LGE-Dixon pulse sequence. This new method has a high level of intra- and inter observer repeatability, can reduce the scan time and allows the analysis of spatial correlation of these AF risk factors. Abstract Figure. Dixon-LGE acquisition and quantification

Gaps in Evidence for Risk Stratification for Sudden Cardiac Death in Hypertrophic Cardiomyopathy.

Gaps in Evidence for Risk Stratification for Sudden Cardiac Death in Hypertrophic Cardiomyopathy.

Late gadolinium enhancement in patients with Tetralogy of Fallot: A systematic review

PurposeThe aim of this study is to review the literature concerning myocardial late gadolinium enhancement (LGE) with cardiac magnetic resonance in patients with Tetralogy of Fallot (ToF), with regards to its prevalence, characteristics and clinical relevance. MethodsWe performed a systematic search, aiming to retrieve original articles that evaluated LGE in ToF, running a search string on MEDLINE and EMBASE in November 2019 and November 2020. Papers were then selected by two independent, blinded readers based on title and abstract, and then on full-text reading, and articles which did not include LGE evaluation were excluded. From each included paper two readers extracted descriptive data concerning technical parameters of LGE acquisition, LGE description and clinical significance. Results18 articles were eventually included in our review. The included studies observed that a higher amount of right ventricular LGE relates with higher right ventricular volumes, lower ejection fraction and a higher pulmonary regurgitant fraction, thus acting as a marker of progressive impairment of myocardial function. Moreover, LGE in ToF patients correlated with the onset of arrhythmias, and with serum biomarkers indicative of myocardial stress and fibrosis. ConclusionsLGE could be used in the follow-up repaired ToF patients as its appraisal can provide information concerning cardiac dysfunction. Moreover, it may be ideal to aim towards a common framework for standardizing assessment and quantification of LGE in ToF patients.

Role of free-breathing motion-corrected late gadolinium enhancement technique for image quality assessment and LGE quantification

ObjectiveTo compare the image quality and late gadolinium enhancement (LGE) quantification between free-breathing motion-corrected and conventional breath-hold LGE method in a variety of cardiovascular diseases. Materials and Methods149 consecutive patients underwent contrast-enhanced cardiac magnetic resonance examination employing both free-breathing motion-corrected LGE and conventional breath-hold LGE method. Scan time, contrast-to-noise ratio, overall image quality score and LGE mass were measured and analyzed statistically. ResultsFree-breathing motion-corrected LGE method had a shorter scan time and higher overall image quality score in comparison with conventional breath-hold LGE method (p < 0.001). Univariate/multivariate logistic regression analysis showed that breath-holding difficulty, high heart rate and arrhythmia could be predictive factors possibly for an inferior image quality score (p < 0.05 for all). The contrast-to-noise ratios of free-breathing motion-corrected LGE images were higher than those of conventional breath-hold LGE images (p < 0.001). In the cases with subepicardial and/or transmural myocardial enhancement, the measured LGE masses were larger on free-breathing motion-corrected LGE images in comparison with those on conventional breath-hold LGE images (p < 0.05). ConclusionFree-breathing motion-corrected LGE could be a better choice for patients who need contrast-enhanced cardiac MRI and have one or more of the risk factors for an inferior image quality score, including breath-holding difficulty, high heart rate and arrhythmia. However, an overestimation of LGE mass on free-breathing motion-corrected LGE image should be taken into consideration when LGE pattern involves subepicardial and/or transmural myocardium.

Prognostic value of late gadolinium enhancement mass index in patients with pulmonary arterial hypertension

PurposeDysfunction of the right ventricle (RV) is an important determinant of survival in patients with pulmonary arterial hypertension (PAH). The presence of late gadolinium enhancement (LGE) in cardiac magnetic resonance (CMR) at RV insertion points (RVIPs) has been found in majority of PAH patients and was associated with parameters of RV dysfunction. We hypothesize, that more detailed quantification of LGE may provide additional prognostic information. Material and methodsTwenty-eight stable PAH patients (mean age 49.9 ​± ​15.9 years) and 12 healthy subjects (control group, 44.8 ​± ​13.5 years) were enrolled into the study. Septal LGE mass was quantified at the RVIPs and subsequently indexed by subject’s body surface area. Mean follow-up time of this study was 16.6 ​± ​7.5 months and the clinical end-point (CEP) was defined as death or clinical deterioration. ResultsMedian LGE mass index (LGEMI) at the RVIPs was 2.75 ​g/m2 [1.41–4.85]. We observed statistically significant correlations between LGEMI and hemodynamic parameters obtained from right heart catheterization – mPAP (r ​= ​0.61, p ​= ​0.001); PVR (r ​= ​0.52, p ​= ​0.007) and from CMR – RVEF (r ​= ​−0.54, p ​= ​0.005); RV global longitudinal strain (r ​= ​0.42, p ​= ​0.03). Patients who had CEP (n ​= ​16) had a significantly higher LGEMI (4.49 [2.75–6.17] vs 1.67 [0.74–2.7], p ​= ​0.01); univariate Cox analysis confirmed prognostic value of LGEMI. Furthermore, PAH patients with LGEMI higher than median had worse prognosis in Kaplan-Meier analysis (log-rank test, p ​= ​0.0006). ConclusionsThe body surface indexed mass of LGE at RV septal insertion points are suggestive of RV hemodynamic dysfunction and could be a useful non-invasive marker of PAH prognosis.

Abstract 16082: Machine Learning to Improve Left Ventricular Scar Quantification in Hypertrophic Cardiomyopathy Patients

Introduction: Accurate and reproducible scar quantification of late gadolinium enhancement (LGE) images from cardiac magnetic resonance imaging (CMR) is important in risk stratifying hypertrophic cardiomyopathy (HCM) patients. Previous machine learning algorithms for CMR LGE quantification deployed three-dimensional convolutional neural network (CNN) architecture, which required image cropping and custom graphic processing units (GPUs) to function, thus limiting their general applicability. We aim to develop a deep two-dimensional (2D) CNN model that contours the left ventricle (LV) endo- and epicardial borders and quantifies LGE. Hypothesis: We hypothesize that a deep 2D CNN model, which uses commercially available GPUs, could be used to efficiently and accurately contour LV endo- and epicardial borders and quantify CMR LGE in HCM patients. Methods: We retrospectively studied 296 HCM patients (2423 images) from the University Health Network (Toronto, Canada) and Tufts Medical Center (Boston, USA). LGE images were manually segmented by an expert reader. Scar was defined as 5 standard deviations higher than the mean of the annotated normal region pixels. A 2D U-net CNN variant was used to train a model on 80% of the datasets. Testing was performed on the remaining 20%. We applied a 5-folds cross validation algorithm for training to improve model robustness. Model performance was assessed using the Dice Similarity Coefficient (DSC). Results: We were able to develop a deep learning model that could successfully perform both LV segmentation and scar quantification using a generally available GPU card. Our algorithm did not require image cropping and processed one image every 60 milliseconds. DSC scores averaged across the 5-folds was excellent at 0.89+0.22 for the endocardium and 0.81+0.17 for the epicardium, and good at 0.57+0.31 for scar. Conclusions: Using novel 2D CNN methods, we have successfully developed an automatic algorithm that rapidly provides LV endo- and epicardial contours and scar quantification on LGE CMR images that is superior to previously published studies. Unlike previous algorithms, our program does not require the use of custom CPUs or image cropping, potentially allowing it to be integrated into routine clinical practice.

High sensitivity troponin I in hypertrophic cardiomyopathy

Abstract Background ESC guidelines recommend measurement of troponin T in patients with hypertrophic cardiomyopathy (HCM) because high concentrations are associated with cardiovascular events, heart failure and death. The cardiac Troponin I subunit is not expressed in skeletal muscle making it a cardio-specific isoform. The use of troponin biomarkers in management of patients HCM is limited because concentrations only weakly correlate with clinical parameters. Most studies are small, and few have examined their relation with genotype and mortality. Purpose To assess the relationship between high-sensitive troponin I (hsTnI) and characteristics of adults with HCM. Methods Patients included were adults with an established diagnosis of HCM referred to a single centre for genetic testing. Demographic, clinical and imaging data were recorded at baseline. Echocardiography and cardiac magnetic resonance (CMR) were performed according to EACVI standards. Quantification of late gadolinium enhancement (LGE) was performed using the 5 SD quantitative threshold. Genotype was evaluated using a 16 gene panel in an accredited UK laboratory. Pathogenic and likely pathogenic variants were considered as a positive genotype. Serum hsTnI was measured by a two-site electrochemiluminescence immunoassay on a Roche E170 analyser. Normal values for the assay 0–34 ng/L for males and 0–16 ng/L for females. Results 313 patients (n=200, 64% male) median age 57 (IQR 47–68) years were included. hsTnI concentration was abnormal in 69 (22%) patients. An abnormal hsTnI was more common in females (n=36, 32%) compared to males (n=33, 17%, c2 9.9, p&amp;lt;0.05). A pathogenic variant in a sarcomere gene was identified in 95 (30%) individuals. An abnormal hsTnI concentration was associated with higher left ventricular (LV) wall thickness (20mm v 18mm, p&amp;lt;0.05) and LV outflow tract (LVOT) gradient (34 v 22 mmHg) on echocardiography (n=313). Of the patients (n=204) who had a CMR, an abnormal hsTnI concentration was associated with higher LV mass (183 v 156g, p&amp;lt;0.05) and greater % LGE (30 v 16%, p&amp;lt;0.01, n=129). There was no difference in hsTnI between those with a positive or negative genotype. During follow-up, 18 patients died. Of the 9 patients that died with a normal hsTnI, two died suddenly. Conclusions In HCM, patients with abnormal hsTnI concentration have higher LV mass and LVOT gradient and more fibrosis. Whilst mortality is higher in those with abnormal hsTnI, sudden cardiac death may occur with a normal hsTnI. It may not be appropriate to extrapolate hsTnI sex-specific thresholds used in the diagnosis of myocardial infarction to HCM. Funding Acknowledgement Type of funding source: None

MACHINE LEARNING FOR LEFT VENTRICULAR SEGMENTATION AND SCAR QUANTIFICATION IN HYPERTROPHIC CARDIOMYOPATHY PATIENTS

Accurate and reproducible quantification of cardiac magnetic resonance imaging (CMR) late gadolinium enhancement (LGE) scar volume is essential in managing patients with hypertrophic cardiomyopathy (HCM) due to the importance of scar burden in predicting clinical outcomes. In current practice, LGE quantification is subjective, time-consuming, and requires extensive training to delineate both the myocardial borders and the hyper-enhanced regions on the LGE images. Machine learning algorithms have the potential to improve scar quantification from CMR LGE images. In HCM patients, we aimed to develop novel machine learning methods that could contour the left ventricle (LV) endo- and epicardial borders and to quantify the LGE within those borders efficiently and accurately.

Effectiveness of alcohol septal ablation for hypertrophic obstructive cardiomyopathy in patients with late gadolinium enhancement on cardiac magnetic resonance

BackgroundAccording to European guidelines, alcohol septal ablation (ASA) for hypertrophic obstructive cardiomyopathy (HOCM) may be less effective in patients with extensive septal scarring on cardiac magnetic resonance (CMR). This study aimed to analyze the impact of late gadolinium enhancement (LGE) on CMR on the effectiveness of ASA. MethodWe conducted an observational retrospective study involving adult patients with symptomatic drug-refractory HOCM who underwent CMR before ASA at two European centres from May 2010 through June 2019. Patients were compared in binary format based on LGE presence. Moreover, a subanalysis focused on patients with septal fibrosis was performed. The effectiveness of ASA was evaluated by echocardiographic, ECG and clinical findings. ResultsOf the 113 study patients, 54 (48%) had LGE on CMR. The LGE quantification performed in 29 patients revealed septal fibrosis in 17. The mean follow-up was 4.4 ± 2.6 years. Baseline parameters were similar between groups except for basal septal thickness that was greater in LGE+ group (21.1 ± 3.9 mm for LGE+ vs. 19.2 ± 3.2 mm for LGE-: p = .005). ASA improved symptoms in all groups and reduced left ventricular outflow tract obstruction (LVOTO) (delta gradient reduction: LGE+: 62 ± 37.3%; septal LGE+: 75.6 ± 20.8%; LGE-: 72.5 ± 21.0%). However, 13% of the LGE+ and 2% of the LGE- group had residual LVOTO above 30 mmHg (p = .027). ConclusionASA was effective in all patients with HOCM, whether they had LGE on CMR or not and whether they had septal fibrosis or not.

Intensity and Distribution of Patchy Late Gadolinium Enhancement in Left Atrium in Patients With Atrial Fibrillation.

Late gadolinium enhancement (LGE) cardiac magnetic resonance imaging (MRI) studies were performed on healthy individuals to establish signal intensity thresholds for reproducible left atrial (LA) patchy LGE detection. Using established criteria, differences in LA patchy LGE between healthy volunteers (HV) and patients with atrial fibrillation (AF) or hypertension were analyzed. Fifty-three patents with AF (mean age 56 years, 60% men), 25 patients with hypertension and no history of AF (mean age 54 years, 40% men), and 28 HV (mean age 50 years, 52% men) were enrolled in an observational, non-interventional, case-control prospective study. LA patchy LGE quantification was performed using LGE MRI (1.5 T scanner, voxel size 1.25x1.25x2.5 mm) and the custom-built software based on estimation of LA voxel image intensity ratio and comparison with threshold value obtained from HV data. Based on analysis of healthy individuals' data, the optimal threshold value for the left atrial patchy LGE quantification was determined at 1.38. Patients with AF had a higher extent of LA patchy LGE (9.1 [1.72; 18.58] %) than patients with hypertension (3.81 [0.57; 9.51] %) and HV (0.78 [0.05; 3.5] %). The predominant location of LA patchy LGE in AF was in the pulmonary vein ostia region, in hypertension - LA posterior wall, and in HV - lower part of LA posterior wall. In AF patients, the extent of LA patchy LGE correlated with LA end-diastolic volume (r=0.37) and LA ejection fraction (r=-0.4), in HV - with age (r=0.66) and LA end-diastolic volume (r=0.4). AF and hypertension are associated with higher extent and different location of LA patchy LGE compared to changes caused by natural aging. The extent of LA patchy enhancement correlates with LA dilatation.

Late Gadolinium Enhancement Predicts Adverse Clinical Events in Heart Transplant Patients

Introduction Late gadolinium enhancement (LGE) on cardiac magnetic resonance imaging (CMR) is a well-studied predictor of adverse clinical outcomes in many cardiac conditions. While the presence of LGE in heart transplant (HTx) patients has been previously demonstrated, these studies were limited by sample size and short follow-up. Therefore, we sought to examine the presence and extent of myocardial LGE at two time points and its association with long-term outcomes following HTx. Hypothesis Myocardial LGE persists over time and portends worse prognosis in HTx patients. Methods This was a single-center, prospective, longitudinal study of HTx patients who underwent CMR imaging at baseline (median of 5.1 years post-HTx; IQR 2.1, 8.0) and follow-up imaging (median of 12 month from baseline scan; IQR 6,22). Quantification of LGE was performed using Circle Cardiovascular Imaging. The primary endpoint was pre-defined as a composite of death, nonfatal myocardial infarction, coronary revascularization and hospitalization. Survival by LGE status (absence/presence) was assessed using Kaplan-Meier-curve. Differences in event-free survival curves between patients with and without LGE were compared using log-rank test. Univariate and multivariate Cox regression analysis was performed to examine the association of myocardial LGE on clinical outcomes adjusted for demographic and clinical characteristics. Results Of the 92 patients enrolled, mean age was 50±16 years, 72% were male, and 80 % had a history of cellular rejection. Median follow-up after the baseline scans was 2.4 years (IQR 1.5, 3.5). LGE was present in 35% (n=32) of patients at baseline and follow-up. Among patients with LGE, the extent of LGE in the baseline and follow-up was 3% (median; IQR 2.3, 6.8) and 3% (median; IQR 2.3, 6.0) of the LV myocardium respectively. All patients with LGE had a non-coronary pattern. No incident or resolution of LGE was observed. Patients with a higher prevalence of baseline LGE were at increased risk of major clinical events (52% vs 25%; p=0.012). Furthermore, the presence of baseline LGE independently predicted adverse clinical events even after adjustment for clinical characteristics in a multivariate model (HR 2.25; 95% CI 1.10, 4.60, p=0.027, FIGURE). Conclusions Presence and extent of myocardial LGE was stable over a median follow-up of 24 months and was independently associated with adverse prognosis in HTx patients.

Comparison of myocardial fibrosis quantification methods by cardiovascular magnetic resonance imaging for risk stratification of patients with suspected myocarditis

BackgroundAlthough the presence of late gadolinium enhancement (LGE) using cardiovascular magnetic resonance imaging (CMR) is a significant discriminator of events in patients with suspected myocarditis, no data are available on the optimal LGE quantification method.MethodsSix hundred seventy consecutive patients (48 ± 16 years, 59% male) with suspected myocarditis were enrolled between 2002 and 2015. We performed LGE quantitation using seven different signal intensity thresholding methods based either on 2, 3, 4, 5, 6, 7 standard deviations (SD) above remote myocardium or full width at half maximum (FWHM). In addition, a LGE visual presence score (LGE-VPS) (LGE present/absent in each segment) was assessed. For each of these methods, the strength of association of LGE results with major adverse cardiac events (MACE) was determined. Inter-and intra-rater variability using intraclass-correlation coefficient (ICC) was performed for all methods.ResultsNinety-eight (15%) patients experienced a MACE at a medium follow-up of 4.7 years. LGE quantification by FWHM, 2- and 3-SD demonstrated univariable association with MACE (hazard ratio [HR] 1.05, 95% confidence interval [CI]:1.02–1.08, p = 0.001; HR 1.02, 95%CI:1.00–1.04; p = 0.001; HR 1.02, 95%CI: 1.00–1.05, p = 0.035, respectively), whereas 4-SD through 7-SD methods did not reach significant association. LGE-VPS also demonstrated association with MACE (HR 1.09, 95%CI: 1.04–1.15, p < 0.001). In the multivariable model, FWHM, 2-SD methods, and LGE-VPS each demonstrated significant association with MACE adjusted to age, sex, BMI and LVEF (adjusted HR of 1.04, 1.02, and 1.07; p = 0.009, p = 0.035; and p = 0.005, respectively). In these, FWHM and LGE-VPS had the highest degrees of inter and intra-rater reproducibility based on their high ICC values.ConclusionsFWHM is the optimal semi-automated quantification method in risk-stratifying patients with suspected myocarditis, demonstrating the strongest association with MACE and the highest technical consistency. Visual LGE scoring is a reliable alternative method and is associated with a comparable association with MACE and reproducibility in these patients.Trial registration numberNCT03470571. Registered 13th March 2018. Retrospectively registered.