Late Gadolinium Enhancement Cardiac Magnetic Resonance Research Articles

Cardiac magnetic resonance to predict appropriate therapies in secondary prevention

Abstract Introduction Implantable cardioverter-defibrillator (ICD) therapy plays a pivotal role in the management of patient’s survivors of life-threatening ventricular arrhythmias (secondary prevention). Risk of recurrence may be related to presence of myocardial scar and its components (including core mass, border zone (BZ) mass, and BZ channels) assessed with late gadolinium enhancement cardiac magnetic resonance (LGE-CMR). Purpose Our study aims to analyze the role of imaging in predicting the risk of recurrent ventricular arrhythmias and improving the risk stratification for appropriate ICD therapy in patients receiving an ICD for secondary prevention. Methods From 2015 to 2020, a total of 111 patients with LGE-CMR before ICD implantation for secondary prevention. Scar tissue including core, BZ and BZ channels were automatically detected by specialized investigational software in patients with LGE-CMR. Patients were followed until a new event was detected. Results The mean age was 65.4 ± 11.4 years; 87% were men; 55% had ischemic cardiomyopathy. The mean left ventricular ejection fraction was 37.8 % ± 14.31%. Patients were followed for a median of 3.26 years (IQR 1.4-4.9). Within the first year of follow-up 22% of patients had received an appropriate therapy, 39% within 3 years and 53% within 6 years. Chronic kidney disease and New York Heart Association (NYHA) class were associated with the primary endpoint [HR 1.94(1.06-3.55), P-value 0.032)] and [HR 1.86 (1.19-2.91), P-value 0.006)], respectively. Regarding CMR characteristics, BZ percentage was also associated with appropriate ICD therapy in the follow up [HR 1.04(1-1.08), P-value 0.048)]. Other CMR parameter, such as BZ mass, BZ core %, BZ core mass and core mass showed a trend to predict ICD therapies during follow-up. ROC curve analysis with Youden’s index defined an optimal BZ percentage cutoff value for recurrence prediction of 9.5% [HR 0.49 (0.28-0.85)]. Conclusion In patients receiving an ICD for secondary prevention, chronic kidney disease, NYHA class and BZ percentage analyzed by LGE-CMR were predictors of recurrent ventricular arrhythmia. A cutoff of BZ of 9.5% could be used to select patients with high risk of recurrence.

Improving functional substrate delineation for ablation of ventricular tachycardia using high-density electroanatomic mapping and double ventricular extra stimuli protocol

Abstract Background A partial delineation of targets for ventricular tachycardia (VT) ablation may contribute to a suboptimal success rate. Abnormal electrograms (EGMs) with low-voltage near-field components might be concealed within high-amplitude far-field signals. Our hypothesis posited that acquiring functional mapping after double ventricular extrastimuli (S3 protocol) could reveal relevant areas of functional substrate overlooked during sinus or S1 mapping. Purpose To assess the benefit and feasibility of functional substrate mapping using a full ventricle S3 protocol and to evaluate its colocalization with conducting channels (CCs) identified in late gadolinium enhancement cardiac magnetic resonance (LGE-CMR). Methods (Figure 1) - An S3 mapping protocol with a drive train of S1 followed by S2 (effective refractory period (ERP) +30ms) and S3 (ERP+50ms) from the RV apex was conducted in 40 consecutive patients undergoing scar-related VT ablation. Deceleration zones (DZs) and areas of late potentials (LPs) were identified for all maps (S1, S2, and S3). Pre-procedural non-invasive substrate assessment was performed with LGE-CMR and post-processing using a commercially available system with automated CC identification. Results The S3 protocol was completed in 34 of the 40 procedures (85.0%). Repeated induction of ventricular arrhythmias prevented the full S3 protocol in 5 patients (15.0%). Functional substrate identified during S3 activation mapping was significantly more extensive than that identified using S2 and S1, including a higher number of DZs (2.94, 2.47, and 1.82, respectively; p<0.01) and a wider area of LPs (44.1cm2, 38.2cm2, and 29.4cm2, respectively; p<0.001). The percentage of CCs unmasked by DZs and LPs using S3 maps was significantly higher than the ones using S2 and S1 maps(78%, 65%, and 48%; p<0.001, and 88%, 81%, and 68%; p<0.01, repectively). After VT ablation based on an S3 protocol, 77.9% of patients have been VT free during a median follow-up of 13.6 months. Conclusions (Graphical abstract -Figure 2) - This novel substrate-based protocol for assessing functional substrate is feasible in most patients, enables better identification of ablation targets, and has the potential to improve patient prognosis post-ablation.Methods - The S3 protocolConclusion - Graphical abstract

Single-beat mapping during programmed ventricular stimulation identifies infarct-related ventricular tachycardia isthmus sites

Abstract Introduction Complete characterization of reentrant ventricular tachycardia (VT) circuits using classical electrophysiological criteria and high-density mapping during VT is complex. Often, VT episodes cannot be fully characterized because of hemodynamic instability during the mapping procedure. This common limitation has motivated the implementation of mapping strategies during sinus rhythm or ventricular pacing aiming to identify scar regions associated with VT isthmuses or potential arrhythmogenicity. However, these strategies still require time-consuming catheter-based mapping. Purpose We aimed to develop and validate a single-beat mapping strategy during programmed ventricular stimulation (PVS) to identify scar regions associated with VT isthmus sites. We hypothesize that protected VT isthmuses within scar regions are characterized by larger activation time dispersion than surrounding scar areas not related to critical isthmus sites. Methods Experimental study including 16 pigs with established myocardial infarction (MI) in the anterior wall. Ten-to-twelve weeks after MI, pigs underwent left ventricular characterization using 3D late-gadolinium enhancement cardiac magnetic resonance imaging, and further invasive electroanatomical mapping to obtain high-density sequential activation maps during ventricular pacing and VT. High-density maps were compared with single-beat maps using a 64-pole basket catheter positioned in the left ventricle. After VT induction, high-density activation maps in well-tolerated VT episodes were used to identify VT isthmus sites. Simultaneous activation data from the 64-pole basket catheter were also obtained during PVS and VT. Off-line analysis was performed to: (i) validate single-beat activation maps during the baseline drive pacing cycle length (S1), and (ii) identify basket-catheter electrodes with the larger local activation time-dispersion score (LAT-DS) during PVS including up to 4 coupled extrastimuli (S2, S3, S4, S5) (Figure 1). LAT-DS was defined as the normalized product of the LAT of each electrode and the activation dispersion among its neighboring electrodes. Results Basket-catheter based single-beat activation maps during S1 pacing showed high correlation values with high-density sequential activation maps (N=16. R²=0.91). In 7 pigs, the VT isthmus site was fully characterized using high-density activation maps. During any of the coupled extrastimuli of the PVS protocol, basket catheter electrodes colocalizing with documented VT isthmus sites on high-density maps showed higher LAT-DS values compared to surrounding electrodes located on scar or healthy regions. Conversely, LAT values alone could not differentiate scar regions relevant for VT maintenance during PVS protocol (Figure 2). Conclusions Sixty-four pole single-beat activation maps during PVS identify left ventricular scar areas with higher than surrounding LAT-DS values that are associated with VT isthmus sites.Figure 1.Experimental modelFigure 2.A-Example. B-C-Full results

Novel systematic processing of cardiac magnetic resonance imaging identifies target regions associated with infarct-related ventricular tachycardia

Abstract Introduction In the clinic, complete characterization of reentrant ventricular tachycardia (VT) circuits using classical electrophysiological criteria and state-of-the-art high density mapping during VT is complex, and often cannot be completed because of hemodynamic instability. This common limitation has motivated the implementation of mapping strategies during sinus rhythm or ventricular pacing aiming to identify scar regions associated with VT isthmuses or potential arrhythmogenicity. Complementary imaging-based strategies including advanced analyses of scar tissue characteristics have been also proposed for procedure planning and identification of potential arrhythmogenic regions. However, the most recent expert consensus report on catheter ablation of ventricular arrhythmia highlights the lack of agreement on the preferable signal intensity (SI) cut-off values for assessment of tissue heterogeneity and scar areas on late gadolinium enhancement cardiac magnetic resonance (LGE-CMR) images. The latter makes LGE-CMR imaging processing highly operator-dependent and potentially sensitive to selection bias. Purpose We aimed at developing and validating a systematic processing approach on LGE-CMR images to identify potential VT corridors that may include protected isthmuses associated with VT maintenance. Methods Translational study including 18 pigs with established myocardial infarction and inducible VT undergoing in vivo characterization of the anatomical and functional myocardial substrate associated with VT maintenance. Clinical validation was conducted in a multicenter series of 33 patients with ischemic cardiomyopathy undergoing VT ablation. Three-dimensional CMR-LGE images were processed using systematic scanning of 15 signal intensity cut-off ranges to obtain surface visualization of all potential VT corridors. Analysis and comparisons of imaging and electrophysiological data were performed in individuals with full electrophysiological characterization of the isthmus sites of at least one VT morphology. Results In both the experimental pig model and patients undergoing VT ablation, all the electrophysiologically-defined isthmus sites (n=11 and n=19, respectively) showed overlapping regions with CMR-based potential VT corridors. Such imaging-based VT corridors were less specific than electrophysiologically-guided ablation lesions at functionally relevant isthmus sites (Figure). However, in patients, decreasing from 15 to 7 the number of signal intensity cut-off ranges for systematic imaging processing significantly reduced the area of imaging-based potential VT corridors, without diminishing the capability to detect functionally relevant VT isthmus sites. Conclusions Systematic processing of 3D LGE-CMR images provides unbiased identification of imaging based potential VT corridors that contain functionally relevant protected isthmus sites.

Clinical validation of a novel digital twin framework for ventricular functional substrate simulation in post-infarction patients

Abstract Background Catheter ablation is a cornerstone treatment for scar related post-infarction ventricular arrhythmias. Functional substrate driven ablation strategies guided by local activation time (LAT) mapping have been proven as efficient and effective approaches, especially when dealing with large scar areas. In-silico electrophysiological modeling is emerging as a potential tool for procedural planning and guidance. Purpose To clinically validate the feasibility, diagnostic performance, and accuracy of a novel late gadolinium enhancement cardiac magnetic resonance (LGE-CMR) based digital twin framework for simulated LAT map generation in post-infarction patients and their integration with CARTO3 EAM suite. Methods Five ischemic subjects who underwent CMR-aided scar-related ventricular tachycardia ablation at our referral center were retrospectively enrolled. Their CMR derived 3D pixel-signal-intensity (PSI) maps generated with ADAS3D were processed with novel in-house software to obtain patient-specific ventricular geometry, tissue characterization, and to generate a model of Purkinje system and myocyte fiber orientation. According to local normalized pixel intensity (NPI) values, myocardial regions were marked as healthy, scar, or border-zone. Electrophysiological properties of border-zone (BZ) were modulated according to local NPI. Continuous and 8-steps isochronal endo-epicardial LAT maps were generated and imported in CARTO3 system, aligned with electroanatomical mapping (EAM), and compared at an ASE 17-segments level, in terms of sensitivity, specificity, predictive values, and accuracy to actual high-density LAT maps obtained with a multipolar catheter. Deceleration Zones (DZ) were defined as previously described (>3 isochrones within 1 cm radius). Results A total of 85 ASE segments (34 epicardial) were analyzed. 24 EAM segments (28%) held DZs, 40 (47%) segments harbored bipolar scar or BZ. Thirty-seven (44%) CMR segments held scar core/BZ. Thirty (35%) digital model segments harbored DZs. Generated LAT maps were successfully imported and aligned with CARTO3 EAM suite for validation. In terms of DZ localization prediction, our LAT model showed 83% sensitivity (95% CI 63%-95%), 90% specificity (95% CI 80%-96%), 77% positive predictive value (PPV) (95% CI 56%-91%), 93% negative predictive value (NPV) (95% CI 83%-98%), 88% accuracy (95% CI 79%-94%). Conclusion Our newly developed framework for LGE-CMR derived functional substrate simulation in post-infarction patients holds high sensitivity, specificity, predictive values, and accuracy for DZ localization. Further validation, with a larger sample size, is required for evaluating potential implications in clinical practice.

Cardiac magnetic resonance - aided ventricular tachycardia substrate ablation

Abstract Objectives To assess feasibility and reliability of Cardiac magnetic resonance (CMR)-derived pixel signal intensity (PSI) maps obtained by Three Dimensional (3D)- Late Gadolinium Enhancement (LGE) images for detecting potential targets for VT substrate ablation procedures. Background Parametric imaging with color-coded PSI maps obtained from pre-ablation 3D LGE -CMR imaging can be used for identification and characterization of arrhythmic abnormal substrate. Recent publications have shown that PSI maps permit visualization of border zone areas inside the scar. Specifically, corridors of viable tissue within the scar connecting healthy myocardium define VT corridors that may be the electrical equivalent of the abnormal conducting channels on the electroanatomical mapping (EAM). Methods 8 patients with scar-dependent monomorphic VTs who underwent 3D-LGE CMR imaging prior to substrate ablation were included in the study. The studies were performed at 1.5T scanner. We obtained two data sets of 3D whole heart LGE imaging with high resolution. Patients underwent two acquisitions: the conventional respiratory navigated, electrocardiographically-gated 3D fast gradient echo (1.3slice thickness, 256x256 matrix acquisition) and the image-navigated isotropic high resolution 3D GE with Dixon water-fat separation. 3D LGE-CMR images were processed with ADAS-VT software to produce a 3-dimensional model of the heart with 10 layers from the endocardium to epicardium and PSI maps color-coded from the LGE data projected to each of the shells (Figure 1). In the LGE-CMR PSI maps, VT corridors were obtained automatically by the ADAS VT software. Subsequently, data were given to the electrophysiologists and merged with the CARTO3 system EAM data obtained for the ablation (Figure2). CMR information was used to facilitate the identification of target ablation sites in the areas identified by CMR as abnormal substrate and radiofrequency was applied in the presence of both a pathological electrogram (EGM) and a VT corridor as identified by CMR. Results There was a 95% agreement between the abnormal conducting channels as detected by abnormal electrograms in the EAM and the VT corridors identified by 3D LGE CMR imaging. In two occasions, there was one VT corridor that did not correlate with abnormal electrograms and was not ablated. The two 3D LGE sequences used for ADAS-VT corridors analysis showed complete agreement in the number and location of VT corridors. Mean acquisition time for 3D LGE imaging was 11±4minutes for the conventional fast gradient echo sequence, and 5±2minutes for the novel 3D self-image navigated LGE sequence. The image quality of 3D LGE was superior with the Dixon fat-water separation. Overall CMR-aided VT ablation reduced the procedural and fluoroscopy time by 40%. Conclusions CMR-aided VT ablation is feasible, reliable and significantly reduces the procedural time.

Incremental value of myocardial global longitudinal strain in predicting major adverse cardiac events among patients with hypertrophic cardiomyopathy.

Endocardial global longitudinal strain (endo-GLS) measured with echocardiography (echo) has been demonstrated to be associated with myocardial fibrosis (MF) and is a prognostic predictor in patients with hypertrophic cardiomyopathy (HCM). Late gadolinium enhancement cardiac magnetic resonance (LGE-CMR) imaging showed that MF is primarily located in the myocardial layer of the extremely hypertrophic septal or ventricular wall. We hypothesized that GLS of the myocardial layer (myo-GLS) is more strongly correlated with the extent of LGE (%LGE) and is a more powerful prognostic factor than endo-GLS. A total of 177 inpatients (54.0 [IQR: 43.0, 64.0] years, female 37.3%) with HCM were retrospectively included from May 2019 to April 2021. Among them, 162 patients underwent echocardiographic examination and contrast-enhanced CMR within 7 days. Myo-GLS and %LGE were blindly assessed in a core laboratory. All the patients were followed after they were discharged. During a mean follow-up of 33.77 [IQR 30.05, 35.40] months, 14 participants (7.91%) experienced major adverse cardiac events (MACE). The MACE (+) group showed lower absolute endo-GLS and myo-GLS than the MACE (-) group. Myo-GLS was more associated with %LGE (r=-.68, P<.001) than endo-GLS (r=-.64, P<.001). Cox multivariable analysis indicated that absolute myo-GLS was independently associated with MACE (adjusted hazard ratio=.75, P<.05). Myo-GLS was better than endo-GLS at detecting MACE (+) patients (-8.64%, AUC.939vs. - 16.375%, AUC.898, P<.05). Myo-GLS is a stronger predictor of MACE than endo-GLS in patients with HCM and is highly correlated with %LGE.

Catheter ablation of parahisian premature ventricular complexes in patients with and without cardiac scar

BackgroundAblation of premature ventricular complexes (PVCs) originating from the parahisian area is challenging. Late gadolinium-enhanced cardiac magnetic resonance (LGE-CMR) scar may influence procedural outcomes; the impact of cardiac scar on parahisian PVCs has not been described. ObjectiveThe objective of this study was to examine the incidence and significance of LGE-CMR scarring in patients undergoing ablation for parahisian PVCs. MethodsConsecutive patients who underwent preprocedure LGE-CMR imaging and ablation of parahisian PVCs were included. Acute and long-term outcomes were examined. ResultsForty-eight patients were included (male, n = 37; age, 66 ± 10 years; ejection fraction, 50% ± 12%; preprocedure PVC burden, 21% ± 12%). Intramural LGE-CMR scar was present in 33 of 48 (69%) patients. Cryoablation was used in 9 patients; ablation in multiple chambers was required in 28 (58%) patients. The PVC site of origin (SOO) was intramural (n = 25 patients), left ventricular (n = 5), and right ventricular (n = 18). Patients with LGE-CMR scar were more likely to have intramural PVCs (64% vs 27%; P < .04) and to require ablation in multiple cardiac chambers (58% vs 13%; P < .02). Patients with intramural scar required longer duration of ablation delivery (31 ± 20 minutes vs 17 ± 8 minutes; P < .02). Acute procedural success was 69%; PVC burden on follow-up was 6% ± 9% and similar for those with and without scar. ConclusionAblation of parahisian PVCs often requires mapping and ablation of multiple cardiac chambers, with an intramural SOO identified in most patients. An intramural scar was associated with an intramural SOO of the PVCs requiring more extensive ablation procedures, with similar long-term outcomes compared with those without scar.

Myocardial Injury by COVID-19 Infection Assessed by Cardiovascular Magnetic Resonance Imaging - A Prospective Multicenter Study.

This prospective multicenter study assessed the prevalence of myocardial injury in patients with COVID-19 using cardiac magnetic resonance imaging (CMR).Methods and Results: We prospectively screened 505 patients with moderate to severe COVID-19 disease from 7 hospitals in Japan. Of these patients, 31 (mean [±SD] age 63.5±10.4 years, 23 [74%] male) suspected of myocardial injury, based on elevated serum troponin or B-type natriuretic peptide concentrations either upon admission or 3 months after discharge, underwent CMR 3 months after discharge. The primary endpoint was the presence of myocardial injury, defined by any of the following: (1) contrast enhancement in the left or right ventricle myocardium on late gadolinium enhancement CMR; (2) left or right ventricular dysfunction (defined as <50% and <45%, respectively); and (3) pericardial thickening on contrast enhancement. The mean (±SD) duration between diagnosis and CMR was 117±16 days. The primary endpoint was observed in 13 of 31 individuals (42%), with 8 (26%) satisfying the modified Lake Louise Criteria for the diagnosis of acute myocarditis. This study revealed a high incidence of myocardial injury identified by CMR in patients with moderate to severe COVID-19 and abnormal findings for cardiac biomarkers.

Scar architecture affects the electrophysiological characteristics of induced ventricular arrhythmias in hypertrophic cardiomyopathy.

Late gadolinium enhancement cardiac magnetic resonance (LGE-CMR) detects myocardial scarring, a risk factor for ventricular arrhythmias (VAs) in hypertrophic cardiomyopathy (HCM). The LGE-CMR distinguishes core, borderzone (BZ) fibrosis, and BZ channels, crucial components of re-entry circuits. We studied how scar architecture affects inducibility and electrophysiological traits of VA in HCM. We correlated scar composition with programmed ventricular stimulation-inducible VA features using LGE intensity maps. Thirty consecutive patients were enrolled. Thirteen (43%) were non-inducible, 6 (20%) had inducible non-sustained, and 11 (37%) had inducible sustained mono (MMVT)- or polymorphic VT/VF (PVT/VF). Of 17 induced VA, 13 (76%) were MMVT that either ended spontaneously, persisted as sustained monomorphic, or degenerated into PVT/VF. Twenty-seven patients (90%) had LGE. Of these, 17 (57%) had non-sustained or sustained inducible VA. Scar mass significantly increased (P = 0.002) from non-inducible to inducible non-sustained and sustained VA patients in both the BZ and core components. Borderzone channels were found in 23%, 67%, and 91% of non-inducible, inducible non-sustained, and inducible sustained VA patients (P = 0.003). All 13 patients induced with MMVT or monomorphic-initiated PVT/VF had LGE. The origin of 10/13 of these VTs matched scar location, with 8/10 of these LGE regions showing BZ channels. During follow-up (20 months, interquartile range: 7-37), one patient with BZ channels and inducible PVT had an ICD shock for VF. Scar architecture determines inducibility and electrophysiological traits of VA in HCM. Larger studies should explore the role of complex LGE patterns in refining risk assessment in HCM patients.

Deep Learning for Automatic Volumetric Segmentation of Left Ventricular Myocardium and Ischemic Scar from Multi-Slice LGE-CMR.

This study details application of deep learning for automatic volumetric segmentation of left ventricular myocardium and scar and automated quantification of myocardial ischemic scar burden from late-gadolinium enhancement cardiovascular magnetic resonance (LGE-CMR). We included 501 images and manual segmentations of short-axis LGE-CMR from over 20 multinational sites, from which 377 studies were used for training and 124 studies from unique participants for internal validation. A third test set of 52 images was used for external evaluation. Three models, U-Net, Cascaded U-Net, and U-Net++, were trained with a novel adaptive weighted categorical cross entropy loss function. Model performance was evaluated using concordance correlation coefficients (CCC) for left ventricular (LV) mass and percent myocardial scar burden. Cascaded U-Net was found to be the best model for quantification of LV mass and scar percentage. The model exhibited a mean difference of -5 ± 23 g for LV mass, -0.4 ± 11.2 g for scar mass, and -0.8 ± 7% for percent scar. CCC were 0.87, 0.77, and 0.78 for LV mass, scar mass, and percent scar burden, respectively, in the internal validation set and 0.75, 0.71, and 0.69, respectively, in the external test set. For segmental scar mass, CCC was 0.74 for apical scar, 0.91 for midventricular scar, and 0.73 for basal scar, demonstrating moderate to strong agreement. We successfully trained a convolutional neural network for volumetric segmentation and analysis of left ventricular scar burden from LGE-CMR images in a large, multinational cohort of participants with ischemic scar.

Unsupervised unpaired multiple fusion adaptation aided with self-attention generative adversarial network for scar tissues segmentation framework

Late gadolinium enhancement (LGE) is a specialized imaging technique used in cardiovascular magnetic resonance (CMR) imaging to detect and characterize areas of scar tissue or fibrosis within the heart muscle. After a heart attack, the affected region of the heart muscle becomes scarred due to insufficient blood supply. LGE CMR enhances the infarcted myocardium to appear with distinctive brightness compared to healthy tissues. It is primarily used to assess various heart conditions and can identify the extent and location of scar tissue, helping in risk stratification and guiding treatment decisions. Automated myocardium segmentation in LGE CMR poses challenges due to intensity heterogeneity caused by the accumulation of contrast agents in infarcted areas. Furthermore, LGE CMR images with gold standard labels are particularly scarce compared to other sequences, making the task even more demanding. Besides, the heart’s motion involves complex non-rigid deformations, including regional wall thickening, circumferential, and longitudinal ventricular shortening, making it challenging to model. This work presents an unsupervised unpaired domain adaptive scar tissue segmentation framework aided with the self-attention generative adversarial network. Besides, we proposed a novel segmentation architecture based on a parallel transformer for scar segmentation and compared the results with and without style transfer GAN and unpaired style self-supervised attention GAN. Besides, to model longitudinal changes in scare, we used eight days’ time points as a source and 1 month and 12 as a target and applied our proposed attention-generative network to transfer style from one-time point to another time. Experiments on four different LGE MICCAI datasets from 2019 to 2023 achieved significantly better performance than state-of-the-art segmentation methods.

Can right ventricular endomyocardial biopsy predict left ventricular fibrosis beforehand in dilated cardiomyopathy?

Myocardial fibrosis of the left ventricle (LV) is a prognostic factor in dilated cardiomyopathy (DCM). This study aims to evaluate whether fibrosis of right ventricular (RV) endomyocardial biopsy (EMB) can predict the degree of LV fibrosis beforehand in DCM. Fibrosis extent in 70 RV-EMB specimens of DCM diagnosis was compared with that in the whole cross-sectional LV of excised hearts in the same patients (52 explanted hearts for transplant and 18 autopsied hearts). The median interval between biopsy and excision was 4.1 (0.13-19.3) years. The fibrosis area ratio of the EMBs and excised hearts were evaluated via image analysis. The distribution of cardiovascular magnetic resonance-late gadolinium enhancement (LGE) in the intraventricular septum was classified into four quartile categories. The fibrosis area ratio in RV-EMB correlated significantly with that in the short-axis cut of the LV of excised hearts (r=0.82, P<0.0001) and with a diffuse pattern of LGE (r=0.71, P=0.003). In a multivariate model, after adjusting for the interval between biopsy performance and heart excision, the fibrosis area ratio in RV-EMB was associated with that in LV-excised heart (regression coefficient, 0.82; 95% confidence interval, 0.68-0.95; P<0.0001). The fibrosis observed in RV-EMB positively correlated with the extent of fibrosis in the LV of excised hearts in patients with DCM. The study findings may help predict LV fibrosis, considered a prognostic factor of DCM through relatively accessible biopsy techniques.

Association between left bundle branch block and ventricular septal mid-wall fibrosis in patients with preserved left ventricular ejection fraction

BackgroundThe left bundle branch block (LBBB) is associated with ventricular septal mid-wall fibrosis (SMF) in patients with dilated cardiomyopathy (DCM). However, whether LBBB is also associated with SMF in patients with preserved left ventricular ejection fraction (LVEF) remains unclear. MethodsWe performed a retrospective study of 210 patients with preserved LVEF (male, n = 116; female, n = 94; mean age, 44 ± 17 years). LBBB was defined as QRS duration ≥140 ms for men or ≥ 130 ms for women, QS or rS in V1-V2, mid-QRS notching or slurring in at least two leads (V1, V2, V5, V6, I, and aVL). SMF determined by late gadolinium-enhancement cardiovascular magnetic resonance was defined as stripe-like or patchy mid-myocardial hyper-enhancement in the interventricular septal segments. ResultsSMF was detected in 24.8% (52/210) of these patients. The proportion of patients with SMF with LBBB was higher than the proportion of patients with SMF without LBBB (58.3% vs. 20.4%; P < 0.001). In the forward multivariate logistic analysis, LBBB (OR, 4.399; 95% CI, 1.774–10.904; P = 0.001) and age (OR, 1.028; 95% CI, 1.006–1.051; P = 0.011) were independently associated with SMF. The presence of LBBB showed a sensitivity of 27%%, specificity of 94%, positive predictive value of 58%%, and negative predictive value of 80% for the detection of SMF. ConclusionLBBB was significantly associated with SMF in hospitalized patients with preserved LVEF. Screening with a resting 12‑lead ECG may help to identify patients who are at a high risk of the presence of SMF.

Unrecognized myocardial scar by late-gadolinium-enhancement cardiovascular magnetic resonance: Insights from the population-based Hamburg City Health Study

The presence of myocardial scar is associated with poor prognosis in several underlying diseases. Late-gadolinium-enhancement (LGE) cardiovascular magnetic resonance (CMR) imaging reveals clinically silent "unrecognized myocardial scar" (UMS), but the etiology of UMS often remains unclear. This population-based CMR study evaluated prevalence, localization, patterns, and risk factors of UMS. The study population consisted of 1064 consecutive Hamburg City Health Study participants without a history of coronary heart disease or myocarditis. UMS was assessed by standard-phase-sensitive-inversion-recovery LGE CMR. Median age was 66 [quartiles 59, 71] years and 37% (388/1064) were females. UMS was detected in 244 (23%) participants. Twenty-five participants (10%) had ischemic, and 217 participants (89%) had non-ischemic scar patterns, predominantly involving the basal inferolateral left-ventricular (LV) myocardium (75%). Two participants (1%) had coincident ischemic and non-ischemic scar. The presence of any UMS was independently associated with LV ejection fraction (odds ratios (OR) per standard deviation (SD) 0.77 (confidence interval (CI) 0.65-0.90), p=0.002) and LV mass (OR per SD 1.54 (CI 1.31-1.82), p<0.001). Ischemic UMS was independently associated with LV ejection fraction (OR per SD 0.58 (CI 0.39-0.86), p=0.007), LV mass (OR per SD 1.74 (CI 1.25-2.45), p=0.001), and diabetes (OR 4.91 (CI 1.66-13.03), p=0.002). Non-ischemic UMS was only independently associated with LV mass (OR per SD 1.44 (CI 1.24-1.69), p<0.001). UMS, in particular with a non-ischemic pattern, is frequent in individuals without known cardiac disease and predominantly involves the basal inferolateral LV myocardium. Presence of UMS is independently associated with a lower LVEF, a higher LV mass, and a history of diabetes.

CMR 3-109 - Automatic Quality Assurance of Late Gadolinium enhancement CMR Images: A Deep Learning Classifier for abnormality-likelihood with Potential to Prompt Real-time Image Optimisation

CMR 3-109 - Automatic Quality Assurance of Late Gadolinium enhancement CMR Images: A Deep Learning Classifier for abnormality-likelihood with Potential to Prompt Real-time Image Optimisation

Tissue characterization of acute lesions during cardiac magnetic resonance-guided ablation of cavo-tricuspid isthmus-dependent atrial flutter: a feasibility study.

To characterize acute lesions during cardiac magnetic resonance (CMR)-guided radiofrequency (RF) ablation of cavo-tricuspid isthmus (CTI)-dependent atrial flutter by combining T2-weighted imaging (T2WI), T1 mapping, first-pass perfusion, and late gadolinium enhancement (LGE) imaging. CMR-guided catheter ablation offers a unique opportunity to investigate acute ablation lesions. Until present, studies only used T2WI and LGE CMR to assess acute lesions. Fifteen patients with CTI-dependent atrial flutter scheduled for CMR-guided RF ablation were prospectively enrolled. Directly after achieving bidirectional block of the CTI line, CMR imaging was performed using: T2WI (n = 15), T1 mapping (n = 10), first-pass perfusion (n = 12), and LGE (n = 12) imaging. In case of acute reconnection, additional RF ablation was performed. In all patients, T2WI demonstrated oedema in the ablation region. Right atrial T1 mapping was feasible and could be analysed with a high inter-observer agreement (r = 0.931, ICC 0.921). The increase in T1 values post-ablation was significantly lower in regions showing acute reconnection compared with regions without reconnection [37 ± 90 ms vs. 115 ± 69 ms (P = 0.014), and 3.9 ± 9.0% vs. 11.1 ± 6.8% (P = 0.022)]. Perfusion defects were present in 12/12 patients. The LGE images demonstrated hyper-enhancement with a central area of hypo-enhancement in 12/12 patients. Tissue characterization of acute lesions during CMR-guided CTI-dependent atrial flutter ablation demonstrates oedema, perfusion defects, and necrosis with a core of microvascular damage. Right atrial T1 mapping is feasible, and may identify regions of acute reconnection that require additional RF ablation.

Novel implementation of cardiac magnetic resonance first-pass perfusion imaging for semi-quantitatively evaluating microvascular dysfunction in paediatric patients with Duchenne muscular dystrophy.

The current study aimed to assess myocardial microcirculation dysfunction via cardiac magnetic resonance (CMR) first-pass perfusion imaging in children with Duchenne muscular dystrophy (DMD). In total, 67 children with DMD and 15 controls who underwent contrast-enhanced CMR first-pass perfusion imaging were enrolled in this study. CMR first-pass perfusion and late gadolinium enhancement (LGE) sequences were acquired. Further, the global, regional, and coronary artery distribution area perfusion indexes (PI), upslope (%BL), maximum signal intensity (MaxSI), time to maximum signal intensity (TTM), and baseline SI were analysed. The perfusion parameters of the LGE positive (+), LGE negative (-), and control groups were compared. Pearson correlation analysis was performed to assess the association between myocardial microcirculation and conventional cardiac function and LGE parameters. The LGE+ group had a significantly lower global and apical-ventricular MaxSI than the control group (all P < .05). The left anterior descending arterial (LAD), left circumflex coronary arterial (LCX), and right coronary arterial (RCA) segments of the LGE+ group had a lower upslope and MaxSI than those of the control group (all P < .05). The LAD segments of the LGE- group had a lower MaxSI than those of the control group (41.10 ± 11.08 vs 46.36 ± 13.04; P < .001). The LCX segments of the LGE- group had a lower PI and upslope than those of the control group (11.05 ± 2.84 vs 12.46 ± 2.82; P = .001; 59.31 ± 26.76 vs 68.57 ± 29.99; P = .002). Based on the correlation analysis, the upslope, MaxSI, and TTM were correlated with conventional cardiac function and LGE extent. Paediatric patients with DMD may present with microvascular dysfunction. This condition may appear before LGE and may be correlated with coronary artery blood supply and LGE extent. First-pass perfusion parameters may reveal the status of myocardial microcirculation and reflect the degree of myocardial injury at an earlier time in DMD patients. Perfusion parameters should be analysed not only via global or base, middle, and apical segments but also according to coronary artery distribution area, which may detect myocardial microvascular dysfunction at an earlier stage, in DMD patients with LGE-.

Myocardial infarct size for predicting improvements in cardiac function in patients with ischemic cardiomyopathy following coronary artery bypass grafting.

This study used late gadolinium enhancement-cardiac magnetic resonance (LGE-CMR) to assess myocardial infarct size, with the data being employed to predict whether patients with ischemic cardiomyopathy (ICM) would experience improvements in left ventricular function at 6 months following coronary artery bypass grafting (CABG). The data of patients with ICM with left ventricular ejection fraction (LVEF) ≤40% who underwent CABG were retrospectively analyzed. All patients underwent preoperative LGE-CMR imaging. Echocardiography results from 6 months post-CABG were used to assess improvements in LVEF, with improvement being defined as ΔLVEF ≥5%. The value of myocardial infarction segments and infarct size as predictors of improved cardiac function following CABG was analyzed. Of the included patients, 66.7% (52/78) exhibited improved cardiac function at 6 months post-CABG. LGE-CMR imaging data revealed that compared to improved group, the improved group had significantly more myocardial infarct segments [improved group: median 1.0, interquartile range (IQR) 0-3; nonimproved group: median 4.0, IQR 3.0-6.0; P<0.001] and significantly greater myocardial infarct size (improved group: 22.4%±8.2%; nonimproved group: 34.7%±5.9%; P<0.001). The area under the receive operating characteristic curve values for myocardial infarct size in predicting cardiac function improvement were significantly higher than those of myocardial infarct segments (0.88 vs. 0.81; P=0.041). The respective sensitivity and specificity values for using a myocardial infarct size cutoff of 26.4% in differentiating between these 2 patient groups were 92.3% and 71.2%, respectively. According to logistic regression analysis, myocardial infarct size was an independent predictor of nonimprovement in cardiac function [odds ratio (OR) =1.244; 95% confidence interval (CI): 1.114-1.389; P<0.001]. A median 1.6-year follow-up interval (range, 0.5-4.1 years) revealed that the incidences of major adverse cerebrovascular events and cardiovascular events were significantly higher in the nonimproved group (5.8% vs. 26.9%; P<0.001), with these individuals having a higher New York Heart Association grading than patients with improved cardiac function (P=0.019). Myocardial infarct size can be measured to reliably predict improvements in cardiac function in patients with ICM following CABG. These results can guide clinicians in their efforts to identify those patients most likely to achieve positive outcomes following CABG.

Aligning Multi-Sequence CMR Towards Fully Automated Myocardial Pathology Segmentation.

Myocardial pathology segmentation (MyoPS) is critical for the risk stratification and treatment planning of myocardial infarction (MI). Multi-sequence cardiac magnetic resonance (MS-CMR) images can provide valuable information. For instance, balanced steady-state free precession cine sequences present clear anatomical boundaries, while late gadolinium enhancement and T2-weighted CMR sequences visualize myocardial scar and edema of MI, respectively. Existing methods usually fuse anatomical and pathological information from different CMR sequences for MyoPS, but assume that these images have been spatially aligned. However, MS-CMR images are usually unaligned due to the respiratory motions in clinical practices, which poses additional challenges for MyoPS. This work presents an automatic MyoPS framework for unaligned MS-CMR images. Specifically, we design a combined computing model for simultaneous image registration and information fusion, which aggregates multi-sequence features into a common space to extract anatomical structures (i.e., myocardium). Consequently, we can highlight the informative regions in the common space via the extracted myocardium to improve MyoPS performance, considering the spatial relationship between myocardial pathologies and myocardium. Experiments on a private MS-CMR dataset and a public dataset from the MYOPS2020 challenge show that our framework could achieve promising performance for fully automatic MyoPS.