Clinical Cardiac Magnetic Resonance Research Articles

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

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

Assessment of myocardial lipomatous metaplasia using an optimized out-of-phase cine steady-state free-precession sequence: Validation and clinical implementation.

Myocardial lipomatous metaplasia, which can serve as substrate for ventricular arrhythmias, is usually composed of regions in which there is an admixture of fat and nonfat tissue. Although dedicated sequences for the detection of fat are available, it would be time-consuming and burdensome to routinely use these techniques to image the entire heart of all patients as part of a typical cardiac MRI exam. Conventional steady-state free-precession (SSFP) cine imaging is insensitive to detecting myocardial regions with partial fatty infiltration. We developed an optimization process for SSFP imaging to set fat signal consistently "out-of-phase" with water throughout the heart, so that intramyocardial regions with partial volume fat would be detected as paradoxically dark regions. The optimized SSFP sequence was evaluated using a fat phantom, through simulations, and in 50 consecutive patients undergoing clinical cardiac MRI. Findings were validated using standard Dixon gradient-recalled-echo (GRE) imaging as the reference. Phantom studies of test tubes with diverse fat concentrations demonstrated good agreement between measured signal intensity and simulated values calculated using Bloch equations. In patients, a line of signal cancellation at the interface between myocardium and epicardial fat was noted in all cases, confirming that SSFP images were consistently out-of-phase throughout the entire heart. Intramyocardial dark regions identified on out-of-phase SSFP images were entirely dark throughout in 33 patients (66%) and displayed an India-ink pattern in 17 (34%). In all cases, dark intramyocardial regions were also seen in the same locations on out-of-phase GRE and were absent on in-phase GRE, confirming that these regions represent areas with partial fat. In conclusion, if appropriately optimized, SSFP cine imaging allows for consistent detection of myocardial fatty metaplasia in patients undergoing routine clinical cardiac MRI without the need for additional image acquisitions using dedicated fat-specific sequences.

Machine-Learning Score Using Stress CMR for Death Prediction in Patients With Suspected or Known CAD

BackgroundIn patients with suspected or known coronary artery disease, traditional prognostic risk assessment is based on a limited selection of clinical and imaging findings. Machine learning (ML) methods can take into account a greater number and complexity of variables. ObjectivesThis study sought to investigate the feasibility and accuracy of ML using stress cardiac magnetic resonance (CMR) and clinical data to predict 10-year all-cause mortality in patients with suspected or known coronary artery disease, and compared its performance with existing clinical or CMR scores. MethodsBetween 2008 and 2018, a retrospective cohort study with a median follow-up of 6.0 (IQR: 5.0-8.0) years included all consecutive patients referred for stress CMR. Twenty-three clinical and 11 stress CMR parameters were evaluated. ML involved automated feature selection by random survival forest, model building with a multiple fractional polynomial algorithm, and 5 repetitions of 10-fold stratified cross-validation. The primary outcome was all-cause death based on the electronic National Death Registry. The external validation cohort of the ML score was performed in another center. ResultsOf 31,752 consecutive patients (mean age: 63.7 ± 12.1 years, and 65.7% male), 2,679 (8.4%) died with 206,453 patient-years of follow-up. The ML score (ranging from 0 to 10 points) exhibited a higher area under the curve compared with Clinical and Stress Cardiac Magnetic Resonance score, European Systematic Coronary Risk Estimation score, QRISK3 score, Framingham Risk Score, and stress CMR data alone for prediction of 10-year all-cause mortality (ML score: 0.76 vs Clinical and Stress Cardiac Magnetic Resonance score: 0.68, European Systematic Coronary Risk Estimation score: 0.66, QRISK3 score: 0.64, Framingham Risk Score: 0.63, extent of inducible ischemia: 0.66, extent of late gadolinium enhancement: 0.65; all P < 0.001). The ML score also exhibited a good area under the curve in the external cohort (0.75). ConclusionsThe ML score including clinical and stress CMR data exhibited a higher prognostic value to predict 10-year death compared with all traditional clinical or CMR scores.

Automated Torso Contour Extraction from Clinical Cardiac MR Slices for 3D Torso Reconstruction.

Whilst the electrocardiogram (ECG) is an essential tool for diagnosing cardiac electrical abnormalities, its characteristics are dependent on anatomical variability. Specifically variation in torso geometry affects relative positions of the leads with respect to the heart. We propose a novel pipeline that uses standard cardiac magnetic resonance images to reconstruct the torso and heart, and recreate the ECG considering torso and cardiac anatomy. This requires automated extraction of the torso contours. Our method combines an initial u-net segmenter with a second network that refines contours and removes spurious segments. The networks were evaluated on a cross validation study dataset and an independent test set. The use of two-channel input, including both original image and initial segmentation, in the refinement network significantly improved performance on the independent test set, reducing the Hausdorff distance from 9.1 pixels to 4.3 pixels and increasing Dice coefficient from 0.75 to 0.93. Clinical Relevance- This method can be utilized to allow ECG simulations with personalized torso geometry which has previously been demonstrated to significantly effect QRS parameters. A clinical tool can be developed using this method that accounts for torso geometry in ECG interpretation.

Clinical Impact of Cardiac MRI T1 and T2 Parametric Mapping in Patients with Suspected Cardiomyopathy.

Background There are limited data on the incremental value of parametric mapping compared with core cardiac MRI protocols for suspected cardiomyopathy in routine clinical practice. Purpose To evaluate the impact of cardiac MRI T1 and T2 mapping in routine clinical practice with respect to diagnostic accuracy, reader diagnostic confidence, and downstream cardiac imaging utilization. Materials and Methods In this retrospective single-center study, consecutive clinical cardiac MRI scans obtained with and without T1 and T2 mapping for evaluation of suspected cardiomyopathy between January 2017 and October 2019 were evaluated. Diagnostic accuracy and reader diagnostic confidence were evaluated in a random subset. Downstream cardiac imaging utilization was analyzed in patients with a minimum of 1 year of clinical follow-up ending before January 2020. Results A total of 1876 patients (mean age, 51 years ± 17 [SD]; 1113 men) were evaluated. Of these, 751 (40%) underwent cardiac MRI with the core protocol and 1125 (60%) with the core protocol plus T1 and T2 mapping. In the mapping group, T1 and T2 were high in 280 (25%) and 47 patients (4%), respectively. In the subset evaluated for diagnostic utility (n = 450), the addition of T1 and T2 maps to the core protocol resulted in an improvement in reader diagnostic confidence in 174 patients (39%). Diagnostic sensitivity was higher with the core protocol plus mapping compared with the core protocol alone for myocarditis (89% [31 of 35 patients] vs 69% [24 of 35]; P = .008), Fabry disease (93% [13 of 14 patients] vs 50% [seven of 14]; P = .01), and amyloidosis (100% [16 of 16 patients] vs 63% [10 of 16]; P = .01). In the subset evaluated for downstream imaging utilization (n = 903), 47% of patients with mapping had at least one subsequent cardiac imaging test compared with 55% of patients without mapping (P = .01). Conclusion In patients with suspected cardiomyopathy, cardiac MRI with T1 and T2 mapping had high diagnostic utility and was associated with lower downstream cardiac imaging utilization. © RSNA, 2022 Online supplemental material is available for this article. See also the editorial by Jerosch-Herold and Coelho-Filho in this issue.

Cardiac magnetic resonance features and outcomes of patients with non-compaction cardiomyopathy – A retrospective follow-up from Pakistan

BackgroundThe exact prevalence of left ventricle non-compaction cardiomyopathy (LVNC) in south Asians is not known and phenotypic CMR characteristics, clinical features, and outcomes of LVNC remain unknown for the SA population. ObjectiveTo evaluate clinical characteristics, cardiac magnetic resonance imaging features, and outcomes of patients with left ventricle non-compaction. MethodsThis was a retrospective study of 294 patients undergoing cardiac MRI (CMR) for evaluation of cardiomyopathy from 2011 to 2020. Patients were stratified based on the presence or absence of left ventricle non-compaction (LVNC). Clinical characteristics, CMR features, and outcomes were evaluated. ResultsOut of 294 patients, 18 patients had LVNC, with a prevalence of 6.1%. The mean age was 32 ± 13 years, and the majority were males (78%). The mean EF by echo was 36 ± 14 and by CMR was 31 ± 16 and the mean LV mass was 151 g. The mean LVEDV was 290 ± 154 and the mean LVESV was 211 ± 126. LGE was present in 33% of patients. The majority had uniform LV non-compaction (56%) followed by predominantly anterolateral and apical involvement (28%). Mitral regurgitation was the most common valvular pathology (33%). On follow-up of 37 months, the majority experienced at least one all-cause MACE (69%), while 14% of patients experienced mortality on follow-up. When compared with dilated cardiomyopathy patients without LVNC, the subjects were younger (p = 0.002) and had higher EF by an echocardiogram (0.001) and a lower arrhythmia hospitalization (p = 0.039). No difference was observed in overall MACE outcomes, mortality, and CMR features. ConclusionThe prevalence of LVNC is low in the studied population. Patients with LVNC have younger age, higher EF by echocardiogram, and lower arrhythmia hospitalization when compared with patients with dilated cardiomyopathy without evidence of LV non-compaction. The presence of LVNC does not confer an increased risk of MACE.

The effect of community-acquired pneumonia on myocardial injury in systemic lupus erythematosus: Insights from cardiac magnetic resonance.

Myocardial injury (MInj) in systemic lupus erythematosus (SLE) has been observed in several studies. However, clinical predictors of MInj remain unclear. We aim to explore the effects of community-acquired pneumonia (CAP) on MInj in SLE patients according to cardiac magnetic resonance (CMR) T1 mapping. SLE patients with or without CAP and healthy controls underwent CMR screening. The CMR protocol included: cines, T1- and T2 mapping, and late gadolinium enhancement (LGE). Clinical characteristics, CMR findings, and T1 mapping measuremments were compared between subgroups. Clinical assessment was performed on the subjects. Thirty-eight SLE patients were screened, including 18 patients with CAP (CAP group) and 20 age- and gender-matched patients without CAP (non-CAP group) as well as 26 healthy controls. The platelet count of CAP group was higher than the non-CAP group (p = 0.015). Compared with the health control group, native T1 was higher in the CAP group (p < 0.001) and the non-CAP group (p = 0.002). ECV was higher in the CAP group (p < 0.001) and the non-CAP group (p = 0.002). The LV ejection fraction (p = 0.049) and RV ejection fraction (p = 0.026) of the CAP group was lower than that of the healthy control group, whereas no significant difference was observed between non-CAP and healthy control groups. This is the first study that assesses the effects of CAP on MInj of SLE patients by CMRI T1 mapping. We highlight SLE patients with CAP who are at increased risk of MInj, manifesting as myocardial inflammation, diffuse myocardial fibrosis, and decreased ventricular function.

Cardiac Magnetic Resonance Imaging-Based Screening for Cardiac Sarcoidosis in Patients With Atrioventricular Block Requiring Temporary Pacing.

BackgroundSome myocardial diseases, such as cardiac sarcoidosis, predispose to complete atrioventricular block. The European Society of Cardiology Guidelines on cardiac pacing in 2021 recommend myocardial disease screening in patients with conduction disorder requiring pacemaker with multimodality imaging, including cardiac magnetic resonance (CMR) imaging. The ability of CMR imaging to detect myocardial disease in patients with a temporary pacing wire is not well documented.Methods and ResultsOur myocardial disease screening protocol is based on using an active fixation pacing lead connected to a reusable extracorporeal pacing generator (temporary permanent pacemaker) as a bridge to a permanent pacemaker. From 2011 to 2019, we identified 17 patients from our CMR database who underwent CMR imaging with a temporary permanent pacemaker for atrioventricular block. We analyzed their clinical presentations, CMR data, and pacemaker therapy. All CMRs were performed without adverse events. Pacing leads induced minor artifacts to the septal myocardial segments. The extent of late gadolinium enhancement in CMR imaging was used to screen patients for the presence of myocardial disease. Patients with evidence of late gadolinium enhancement underwent endomyocardial biopsy. If considered clinically indicated, also 18‐F‐fluorodeoxyglucose positron emission tomography and extracardiac tissue biopsy were performed if sarcoidosis was suspected. Eventually, 8 of 17 patients (47.1%) were diagnosed with histologically confirmed granulomatous inflammatory cardiac disease. Importantly, only 1 had a previously diagnosed extracardiac sarcoidosis at the time of presentation with high‐degree atrioventricular block.ConclusionsCMR imaging with temporary permanent pacemaker protocol is an effective and safe early screening tool for myocardial disease in patients presenting with atrioventricular block requiring immediate, continuous pacing for bradycardia.

Combination of late gadolinium enhancement and genotype improves prediction of prognosis in non‐ischaemic dilated cardiomyopathy

AimsGenotype and left ventricular scar on cardiac magnetic resonance (CMR) are increasingly recognized as risk markers for adverse outcomes in non‐ischaemic dilated cardiomyopathy (DCM). We investigated the combined influence of genotype and late gadolinium enhancement (LGE) in assessing prognosis in a large cohort of patients with DCM.Methods and resultsOutcomes of 600 patients with DCM (53.3 ± 14.1 years, 66% male) who underwent clinical CMR and genetic testing were retrospectively analysed. The primary endpoints were end‐stage heart failure (ESHF) and malignant ventricular arrhythmias (MVA). During a median follow‐up of 2.7 years (interquartile range 1.3–4.9), 24 (4.00%) and 48 (8.00%) patients had ESHF and MVA, respectively. In total, 242 (40.3%) patients had pathogenic/likely pathogenic variants (positive genotype) and 151 (25.2%) had LGE. In survival analysis, positive LGE was associated with MVA and ESHF (both, p < 0.001) while positive genotype was associated with ESHF (p = 0.034) but not with MVA (p = 0.102). Classification of patients according to genotype (G+/G−) and LGE presence (L+/L−) revealed progressively increasing events across L−/G−, L−/G+, L+/G− and L+/G+ groups and resulted in optimized MVA and ESHF prediction (p < 0.001 and p = 0.001, respectively). Hazard ratios for MVA and ESHF in patients with either L+ or G+ compared with those with L−/G− were 4.71 (95% confidence interval: 2.11–10.50, p < 0.001) and 7.92 (95% confidence interval: 1.86–33.78, p < 0.001), respectively.ConclusionClassification of patients with DCM according to genotype and LGE improves MVA and ESHF prediction. Scar assessment with CMR and genotyping should be considered to select patients for primary prevention implantable cardioverter‐defibrillator placement.

Post-RNA (mRNA) Vaccination Myocarditis: CMR Features.

RNA (mRNA) vaccines used to prevent COVID-19 infection may cause myocarditis. We describe a case of acute myocarditis in a 27-year-old male after receiving the second dose of a Pfizer immunization. Three days after receiving the second dose of vaccine, he had acute chest pain. Electrocardiographic examination revealed non-specific ST-T changes in the inferior leads. Troponin levels in his laboratory tests were 733 ng/L. No abnormalities were detected on his echocardiography or coronary angiography. The basal inferoseptal segment was hypokinetic. The LV EF was 50%, whereas the RV EF was 46%. Epicardial and mesocardial LGE were shown in the left ventricle’s basal and mid anterolateral, posterolateral, and inferoseptal segments. The native T1 was 1265 ± 54 ms, and the native T2 was 57 ± 10 ms. Myocardial strain indicated that the baseline values for LV GLS (−14.55), RV GLS (−15.8), and RVCS (−6.88) were considerably lower. The diagnosis of acute myocarditis was determined based on the clinical presentation and cardiac magnetic resonance (CMR) findings.

MRI Phase-Contrast Blood Flow in Fasting Pediatric Patients with Fontan Circulation Correlates with Exercise Capacity.

To assess regional blood flow in fasting pediatric patients with Fontan circulation by using MRI and to explore associations with clinical parameters. In this retrospective study, pediatric patients who had undergone the Fontan procedure (<18 years of age) and had undergone clinical cardiac MRI, performed after at least 4 hours of fasting, between 2018 and 2021 were included. Regional blood flow was compared with published healthy volunteer data (n = 19) and assessed in relation to hemodynamic parameters and clinical status. Data are presented as medians, with first to third quartiles in parentheses. Mann-Whitney U, Kruskal-Wallis, χ2, and Spearman rank correlation tests were used. Fifty-five patients (38 boys) with median age at MRI of 14 years (IQR, 11-16 years) and median time from Fontan procedure to MRI of 10 years (IQR, 8-12 years) were included. Patients after Fontan procedure had lower ascending aortic, inferior vena cava, and total systemic blood flow compared with healthy volunteers (3.00 L/min/m2 [IQR, 2.75-3.30 L/min/m2] vs 3.61 L/min/m2 [IQR, 3.29-4.07 L/min/m2]; 1.73 L/min/m2 [IQR, 1.40-1.94 L/min/m2] vs 2.24 L/min/m2 [IQR, 2.06-2.75 L/min/m2]; 2.78 L/min/m2 [IQR, 2.45-3.10 L/min/m2] vs 3.95 L/min/m2 [IQR, 3.20-4.30 L/min/m2], respectively; P < .001). Portal vein flow was greater than hepatic vein flow in 25% of patients. Fontan blood flow was inversely correlated with pre-Fontan mean pulmonary artery pressure (Spearman rank correlation coefficient [rs ]= -0.42, P = .005) and ventricular end diastolic pressure (rs = -0.33, P = .04) and positively correlated with post-Fontan percent predicted oxygen consumption at peak workload (rs = 0.34, P = .02). Reference ranges are provided for regional systemic blood flow derived by using MRI in fasting pediatric patients with Fontan circulation, who had lower systemic blood flow compared with healthy volunteers. Lower fasting Fontan blood flow correlated with lower exercise capacity.Keywords: Pediatrics, Heart, Congenital, MR Imaging, Hemodynamics/Flow Dynamics, Cardiac Supplemental material is available for this article. © RSNA, 2022.

CMR Imaging 6 Months After Myocarditis Associated with the BNT162b2 mRNA COVID-19 Vaccine.

Temporal association between BNT162b2 mRNA COVID-19 vaccine and myocarditis (PCVM) has been reported. We herein present early and 6-month clinical follow-up and cardiac magnetic resonance imaging (CMR) of patients with PVCM. A retrospective collection of data from 15 patients with PCVM and abnormal CMR was performed. Clinical manifestation, laboratory data, hospitalizations, treatment protocols, and imaging studies were collected early (up to 2 months) and later. In nine patients, an additional CMR evaluation was performed 6 months after diagnosis. PCVM was diagnosed in 15 patients, mean age 17 ± 1 (median 17.2, range 14.9–19 years) years, predominantly in males. Mean time from vaccination to onset of symptoms was 4.4 ± 6.7 (median 3, range 0–28) days. All patients had CMR post diagnosis at 4 ± 3 (median 3, range 1–9) weeks, 4/5 patients had hyper enhancement on the T2 sequences representing edemaQuery, and 12 pathological Late glandolinium enhancement. A repeat scan performed after 5–6 months was positive for scar formation in 7/9 patients. PCVM is a rare complication, affecting predominantly males and appearing usually within the first week after administration of the second dose of the vaccine. It usually is a mild disease, with clinical resolution with anti-inflammatory treatment. Late CMR follow up demonstrated resolution of the edema in all patients, while some had evidence of residual myocardial scarring.

Prospective Longitudinal Characterization of the Relationship between Diabetes and Cardiac Structural and Functional Changes.

Objectives In a cohort of type 2 diabetic (T2D) patients who underwent baseline cardiac magnetic resonance (CMR) and biomarker testing, during a median follow-up of 6 years, we aimed to determine longitudinal changes in the phenotypic expression of heart disease in diabetes, report clinical outcomes, and compare baseline clinical characteristics and CMR findings of patients who experienced major adverse cardiovascular events (MACE) to those remaining MACE free. Background T2D increases the risk of heart failure (HF) and cardiovascular mortality. The long-term impact of T2D on cardiac phenotype in the absence of cardiovascular disease and other clinical events is unknown. Methods Patients with T2D (n = 100) with no history of cardiovascular disease or hypertension were recruited at baseline. Biventricular volumes, function, and myocardial extracellular volume fraction (ECV) were assessed by CMR, and blood biomarkers were taken. Follow-up CMR was repeated in those without interim clinical events after 6 years. Results Follow-up was successful in 83 participants. Of those, 29 experienced cardiovascular/clinical events (36%). Of the remaining 59, 32 patients who experienced no events received follow-up CMR. In this cohort, despite no significant changes in blood pressure, weight, or glycated hemoglobin, significant reductions in biventricular end-diastolic volumes and ejection fractions occurred over time. The mean ECV was unchanged. Baseline plasma high-sensitivity cardiac troponin T (hs-cTnT) was significantly associated with a change in left ventricular (LV) ejection fraction. Patients who experienced MACE had higher LV mass and greater LV concentricity than those who remained event free. Conclusions T2D results in reductions in biventricular size and systolic function over time even in the absence of cardiovascular/clinical events.

Outcome of patients with myocarditis according to clinical risk classification and cardiac magnetic resonance parameters

Abstract Funding Acknowledgements Type of funding sources: None. Background Myocarditis is an inflammatory disease defined by precise histological, immunological and immunohistochemical criteria and characterized by a great heterogeneity of presentation. The early evaluation of the possible outcomes and long-term prognosis of patients with myocarditis remains a challenge for the cardiologists, with repercussions on the most appropriate therapeutic choices for the patient. Purpose The purpose of this study was to analyze the outcomes of patients with acute myocarditis using the multiparametric integration of clinical, echocardiographic and cardiac magnetic resonance imaging data. Methods We retrospectively collected data from 127 patients admitted for acute myocarditis from 2011 to 2021 in 3 Sicilian hospitals. The main anamnestic information, risk factors and clinical manifestations at onset, electrocardiogram, echocardiogram including the global longitudinal strain (GLS) measurement and morphofunctional parameters at cardiac magnetic resonance (CMR), presence of edema and delayed enhancement (DE) and myocardial segments involved were collected. Patients were stratified according to the classification proposed by the group of Trieste group in 2017 in high-risk, intermediate-risk patients and low-risk patients. The occurrence of adverse events during follow up in the 3 groups was evaluated. Results High-risk patients had a higher frequency of total adverse events (66.7%) compared to intermediate (14%) and low (16%) risk (p &amp;lt; 0,0001), while no significant differences were observed regarding relapses. Intermediate-risk patients had a tendency to develop events comparable to low-risk patients. At baseline, FE was 34.02 ± 12.98% for high risk patients vs 59.24 ± 3.82% low risk vs 58.41 ± 5.21% intermediate risk (p &amp;lt; 0,0001). The mean GLS was -16 ± 4.43 for high risk patients vs -19 ± 2.37 low risk vs -18 ± 2.06 intermediate risk (p &amp;lt; 0,0271). 78% high-risk patients, 72% low-risk patients, and 75% intermediate-risk patients had edema at baseline MRI (p &amp;lt; 0,0249). 90% patients with high risk, 85% patients with low risk and 97% patients with intermediate risk had DE at baseline MRI (p &amp;lt; 0,0001). In intermediate-risk patients, an association was observed between the number of segments affected by DE at baseline MRI and the occurrence of events (p &amp;lt;0.013). The number of segments involved by DE that, with the best sensitivity and specificity, identifies the subjects most likely to develop events was 2.5 [AUC 0.5; p-value of 0.24]. The sum of the segments involved by DE at MRI statistically correlated with the detection of a reduced mean GLS (p &amp;lt; 0.009). Conclusions Our study confirms the usefulness of the clinical prognostic classification of the Trieste group. Intermediate-risk patients, who still represent a gray area from a prognostic point of view, have shown to have an overall good prognosis, not significantly different since low-risk patients. The extent of edema and the extent of DE at baseline are the major predictors of events.

Characteristics of COVID-19 Myocarditis With and Without Multisystem Inflammatory Syndrome

Multisystem inflammatory syndrome (MIS) is a severe complication described in a minority of patients with COVID-19. Myocarditis has been reported in patients with COVID-19, including MIS. In this study, we compared the clinical characteristics and cardiac magnetic resonance (CMR) findings of COVID-19 myocarditis in patients with and without MIS. In the 330 patients with COVID-19 who were referred for CMR at our institution between July 24, 2020, to March 31, 2021, 40 patients were identified as having myocarditis, MIS myocarditis (n = 21) and non-MIS myocarditis (n = 19). MIS myocarditis was characterized by global myocardial inflammation/edema with significantly elevated native T1, whereas only regional inflammation, and edema were noted in the non-MIS group. Distinct late gadolinium enhancement (LGE) patterns—inferior myocardial involvement in non-MIS myocarditis and septal involvement in MIS myocarditis—were identified. The LGE burden was comparable between the 2 groups (5.9% vs 6.6%, MIS vs non-MIS group, p = 0.83). Myocarditis was diagnosed more frequently by CMR in the MIS group (70% vs 6.3%, MIS vs non-MIS, p <0.001). In the 20 patients with a sequential CMR study at a median 102-day follow-up, 25% had persistent myocardial edema. The LGE burden improved over time, from a median of 5.0% (interquartile range 3.4% to 7.3%) to 3.2% (interquartile range 2.0% to 3.8%; p <0.001). In conclusion, MIS and non-MIS myocarditis exhibit distinct characteristics by CMR. Persistent LGE and edema were common at follow-up CMR examination in both groups.

Safety of Stress Cardiac Magnetic Resonance in Patients With Moderate to Severe Aortic Valve Stenosis.

Dobutamine and adenosine stress cardiac magnetic resonance (CMR) imaging is relatively contraindicated in patients with moderate to severe aortic valve stenosis (AS). We aimed to determine the safety of dobutamine and adenosine stress CMR in patients with moderate to severe AS. In this retrospective study patients with AS who underwent either dobutamine or adenosine stress CMR for exclusion of obstructive coronary artery disease were enrolled. We recorded clinical data, CMR and echocardiography findings, and complications as well as minor symptoms. Patients with AS were compared to matched individuals without AS. A total of 187 patients with AS were identified and compared to age-, gender- and body mass index-matched 187 patients without AS. No severe complications were reported in the study nor the control group. The reported frequency of non-severe complications and minor symptoms were similar between the study and the control groups. Nineteen patients with AS experienced non-severe complications or minor symptoms during dobutamine stress CMR compared to eighteen patients without AS (p = 0.855). One patient with AS and two patients without AS undergoing adenosine stress CMR experienced minor symptoms (p = 0.562). Four examinations were aborted because of chest pain, paroxysmal atrial fibrillation and third-degree atrioventricular block. Inducible ischaemia, prior coronary artery bypass grafting, prior stroke and age were associated with a higher incidence of complications and minor symptoms. Moderate to severe AS was not associated with complications during CMR stress test. The incidence of non-severe complications and minor symptoms was greater with dobutamine.

Electrocardiogram Characteristics and Prognostic Value in Light-Chain Amyloidosis: A Comparison With Cardiac Magnetic Resonance Imaging.

Background: An electrocardiogram (ECG) is a simple and cheap non-invasive tool that shows various abnormalities and has prognostic value for patients with light-chain amyloidosis (AL). The present study aimed to explore the association between ECG characteristics and cardiac magnetic resonance (CMR)-detected amyloid burden and to investigate the prognostic value of ECG in AL amyloidosis.Methods: We prospectively enrolled 99 patients with AL amyloidosis (56 male patients; median age, 58 y). Detailed clinical information, 12-lead ECG, and CMR data were collected. All patients were followed up longitudinally, and the endpoint was all-cause mortality. ECG characteristics were analyzed and correlated with the degree of late gadolinium enhancement (LGE) and extracellular volume (ECV) by T1 mapping on CMR. The prognostic value of ECG characteristics was analyzed using Kaplan–Meier survival analysis and multivariate Cox regression.Results: During a median follow-up period of 33 months, 69 of the 99 patients died. Fragmented Q wave-R wave-S wave (QRS), pathological Q waves, the Sokolow index, QRS duration, and voltages were significantly associated with the extent of LGE, native T1, and ECV by CMR (p < 0.05). Fragmented QRS and Sokolow index showed independent prognostic value in AL amyloidosis (p = 0.001; p = 0.026, respectively). Fragmented QRS remained independent after adjusting for clinical values (hazard ratio: 2.034; 95% confidence interval: 1.148–3.603; p = 0.015). However, no ECG characteristics were independent predictors for prognosis in AL amyloidosis when LGE and ECV were included in the multivariate analysis.Conclusion: ECG abnormalities showed significant association with CMR indicators of amyloid burden. Fragmented QRS has an independent prognostic value in AL amyloidosis and could be used as an alternative marker when CMR is not available.

Implementation and prospective clinical validation of AI‐based planning and shimming techniques in cardiac MRI

PurposeCardiovascular magnetic resonance (CMR) is a vital diagnostic tool in the management of cardiovascular diseases. The advent of advanced CMR technologies combined with artificial intelligence (AI) has the potential to simplify imaging, reduce image acquisition time without compromising image quality (IQ), and improve magnetic field uniformity. Here, we aim to implement two AI‐based deep learning techniques for automatic slice alignment and cardiac shimming and evaluate their performance in clinical cardiac magnetic resonance imaging (MRI).MethodsTwo deep neural networks were developed, trained, and validated on pre‐acquired cardiac MRI datasets (>500 subjects) to achieve automatic slice planning and shimming (implemented in the scanner) for CMR. To examine the performance of our automated cardiac planning (EasyScan) and AI‐based shim (AI shim), two prospective studies were performed subsequently. For the EasyScan validation, 10 healthy subjects underwent two identical CMR protocols: with manual cardiac planning and with AI‐based EasyScan to assess protocol scan time difference and accuracy of cardiac plane prescriptions on a 1.5 T clinical MRI scanner. For the AI shim validation, a total of 20 subjects were recruited: 10 healthy and 10 cardio‐oncology patients with referrals for a CMR examination. Cine images were obtained with standard cardiac volume shim and with AI shim to assess signal‐to‐noise ratio (SNR), contrast‐to‐noise ratio (CNR), overall IQ (sharpness and MR image degradation), ejection fraction (EF), and absolute wall thickening. A hybrid statistical method using of nonparametric (Wilcoxon) and parametric (t‐test) assessments was employed for statistical analyses.ResultsCMR protocol with AI‐based plane prescriptions, EasyScan, minimized operator dependence and reduced overall scanning time by over 2 min (∼13 % faster, p < 0.001) compared to the protocol with manual cardiac planning. EasyScan plane prescriptions also demonstrated more accurate (less plane angulation errors from planes manually prescribed by a certified cardiac MRI technologist) cardiac planes than previously reported strategies. Additionally, AI shim resulted in improved B0 field homogeneity. Cine images obtained with AI shim revealed a significantly higher SNR (12.49%; p = 0.002) than those obtained with volume shim (volume shim: 32.90 ± 7.42 vs. AI shim: 37.01 ± 8.87) for the left ventricle (LV) myocardium. LV myocardium CNR was 12.48% higher for cine imaging with AI shim (149.02 ± 39.15) than volume shim (132.49 ± 33.94). Images obtained with AI shim resulted in sharper images than those obtained with volume shim (p = 0.012). The LVEF and absolute wall thickening also showed that differences exist between the two shimming methods. The LVEF by AI shim was shown to be slightly larger than LVEF by volume shim in two groups: 2.87% higher with AI shim for the healthy group and 1.70% higher with AI shim for the patient group. The LV absolute wall thickening (in mm) also showed that differences exist between shimming methods for each group with larger changes observed in the patient group (healthy: 3.31%, p = 0.234 and patient group: 7.29%, p = 0.059).ConclusionsCMR exams using EasyScan for cardiac planning demonstrated accelerated cardiac exam compared to the CMR protocol with manual cardiac planning. Improved and more uniform B0 magnetic field homogeneity also achieved using AI shim technique compared to volume shimming.

Abstract 12147: Prognostic Impact of Cardiac MRI Derived Left Atrial Volumetric and Functional Parameters in Patients With Advanced Ischemic Cardiomyopathy

Background: Left atrial (LA) size has been shown to be predictive of adverse outcomes in patients with various cardiac conditions. However, the significance of left atrial function (LAF) is not clearly defined in patients with advanced ischemic cardiomyopathy (ICM). We assess the effect of cardiac magnetic resonance imaging (CMR) based LA ejection fraction (LAEF), LA volume index (LAVi) and total LA strain(Las) on outcomes in patients with ICM. Methods: Patients with ICM, who underwent cardiac magnetic resonance (CMR) between January 2002 and January 2017, were included in our study. Clinical characteristics and CMR parameters were collected and analyzed. Maximum and minimum left atrial volume (LAV) and LAEF were calculated using the biplane area-length method. Multi-variable Cox proportional hazards models were then built to test whether LAEF, LAs, and LAVi predict all-cause mortality or time to transplant. The proportionality assumption test and supremum test for functional form were used to verify the model. Results: LA functional data on 656 patients were analyzed. Patients were followed for a median of 1900 days (5.2 years). There were 336 deaths and 17 transplants. LAEF and Las were significant predictors of outcome: HR=0.98, 95% CI [0.97, 0.99], p&lt;0.001 , HR=0.94, 95% CI [0.91, 0.96], p&lt;0.001) respectively. LAVi was not an independent predictor of survival after adjusting for the medical risk score (p=0.749). Multivariable Cox proportional analysis and ROC analysis for the prediction of death or transplant of the model within two years is shown in Figure 1. Conclusion: Left atrial function is a more powerful predictor of adverse outcome than left atrial size and ischemic mitral regurgitation. Further studies are needed to assess impact of treatment on LA function.

Abstract 10622: Z Scores in Pediatric Cardiac Magnetic Resonance: Reclassification of Smaller, Younger Hearts with Novel Calculator

Introduction: The use of z scores to describe growth of normal structures is necessary in the management of pediatric cardiac disorders, particularly in babies and toddlers. Z score calculators for cardiac magnetic resonance (CMR) have traditionally relied on a convenience sample given complexity of the test. A recently published, novel z score calculator from prospectively-imaged, awake, healthy children ages 0-12 years may add value to assessments of ventricular size compared to traditional calculators. Hypothesis: A novel z score calculator (“Olivieri et al”) with robust prediction in younger, smaller children may reclassify right and left ventricular end diastolic volumes and mass (RVEDV, LVEDV, LVM) compared to the traditional calculator (“Buechel et al”). Methods: A retrospective cohort of subjects less than 12 years of age who underwent clinical CMR imaging on a 1.5T scanner (n=96; median age 5.5 years (IQR 3.7-7.6 years); 42% female) was studied. Z scores were calculated using both novel and traditional models for RVEDV, LVEDV and LVM. Subjects were categorized into the agreement group (both calculators agree) or disagreement groups, where novel calculator reclassified to normal (z&lt; ± 2) or abnormal (z&gt; ±2). Reclassified subject characteristics were compared with ANOVA and t-test. Results: Novel and traditional z scores agreed for 77%, 58% and 62% of cases for RVEDV, LVEDV and LVM, respectively. Amongst disagreements, subjects reclassified from abnormal to normal by the novel calculator had significantly lower age, BSA and RV size (Table 1). Reclassified subjects showed no association with specific diagnoses. Conclusion: The novel z score calculator reclassifies younger, smaller children away from severe z scores into more normal z scores. Ventricular volume assessment is highly relevant to critical decision-making in the first years of life in borderline lesions.