Myocardial T1 Mapping Research Articles

Myocardial tissue phenotyping by radiomic features of native T1 maps and machine learning enhances disease detection and classification

Abstract Background Myocardial T1 mapping by cardiac magnetic resonance (CMR) is a useful technique to detect diffuse myocardial fibrosis, but a major limitation of T1 mapping is the significant overlap in native T1 values between health and disease. Purpose We explored whether radiomic features from T1 maps could enhance the diagnostic value of T1 mapping in distinguishing health from disease and classifying cardiac disease phenotypes. Methods In a total of 149 patients (n=30 with no evidence of heart disease, n=30 with LVH of various etiologies, n=61 with hypertrophic cardiomyopathy (HCM) and n=28 with cardiac amyloidosis) undergoing a CMR scan for various indications were included in this study. In addition to measuring native myocardial T1 values from T1 maps, we extracted a total of 843 radiomic features of myocardial texture and explored their value in disease classification. Results We first demonstrated that T1 mapping images are a rich source of extractable, quantifiable data. The first three principal components of the T1 radiomics were significantly and distinctively correlated with cardiac disease type. Unsupervised hierarchical clustering of the population by myocardial T1 radiomics was significantly associated with myocardial disease type (chi2=55.98, p<0.0001). After machine learning for feature selection, training with internal validation and external testing, a model of T1 radiomics had good diagnostic performance (AUC 0.753) for multinomial classification of disease phenotype (normal vs. LVH vs. HCM vs. amyloid). A subset of seven radiomic features outperformed mean native T1 values for classification between myocardial health vs. disease and HCM phenocopies (for normal: T1 AUC 0.549 vs. radiomics AUC 0.888, for LVH: T1 AUC 0.645 vs. radiomics AUC 0.790, for HCM T1 AUC 0.541 vs. radiomics AUC 0.638 and for amyloid T1 AUC 0.769 vs. radiomics AUC 0.840). Conclusions We have shown that specific imaging patterns in myocardial native T1 maps are linked to features of cardiac disease and we have provided for the first-time evidence that radiomic phenotyping can be used to enhance the diagnostic yield of native T1 mapping for myocardial disease detection and classification. Funding Acknowledgement Type of funding sources: None.

Amyloid Deposits and Fibrosis on Left Ventricular Endomyocardial Biopsy Correlate With Extracellular Volume in Cardiac Amyloidosis.

BackgroundThe relative contribution of amyloid and fibrosis to extracellular volume expansion in cardiac amyloidosis (CA) has never been defined.Methods and ResultsWe included all patients diagnosed with amyloid light‐chain (AL) or transthyretin cardiac amyloidosis at a tertiary referral center between 2014 to 2020 and undergoing a left ventricular endomyocardial biopsy. Patients (n=37) were more often men (92%), with a median age of 72 years (interquartile range, 68–81). Lambda‐positive AL was found in 14 of 19 AL cases (38%) and kappa‐positive AL in 5 of 19 (14%), while transthyretin was detected in the other 18 cases (48%). Amyloid deposits accounted for 15% of tissue sample area (10%–30%), without significant differences between AL and transthyretin amyloidosis. All patients displayed myocardial fibrosis, with a median extent of 15% of tissue samples (10%–23%; range, 5%–60%), in the absence of spatial overlap with amyloid deposits. Interstitial fibrosis was often associated with mild and focal subendocardial fibrosis. The extent of fibrosis or the combination of amyloidosis and fibrosis did not differ significantly between transthyretin amyloidosis and AL subgroups. In 20 patients with myocardial T1 mapping at cardiac magnetic resonance, the combined amyloid and fibrosis extent displayed a modest correlation with extracellular volume (r=0.661, P=0.001). The combined amyloid and fibrosis extent correlated with high‐sensitivity troponin T (P=0.035) and N‐terminal pro‐B‐type natriuretic peptide (P=0.002) serum levels.ConclusionsExtracellular spaces in cardiac amyloidosis are enlarged to a similar extent by amyloid deposits and fibrotic tissue. Their combination can better explain the increased extracellular volume at cardiac magnetic resonance and circulating biomarkers than amyloid extent alone.

Guidelines for the monitoring and management of iron overload in patients with haemoglobinopathies and rare anaemias.

Guidelines for the monitoring and management of iron overload in patients with haemoglobinopathies and rare anaemias.

A NOVEL LIVER T1 MAPPING SEQUENCE (PROFIT1): TOWARDS EARLY DETECTION OF FONTAN ASSOCIATED LIVER DISEASE

<h3>BACKGROUND</h3> The Fontan procedure is the final surgical stage for congenital heart disease (CHD) patients with single ventricles. Systemic venous return is routed directly to the lungs while the ventricle pumps arterial blood to the body. One long-term complication is known as Fontan-associated liver disease (FALD). Liver damage is due to a combination of chronic congestion from increased venous pressures and ischemic damage during the multiple surgeries a single ventricle patient undergoes. Fibrotic myocardial remodeling may further increase backup and contribute to liver pathology. Liver biopsy is the gold standard for diagnosis of FALD but is invasive and may not detect heterogenous disease. MRI T1 mapping (longitudinal relaxation time) of the liver provides quantitative assessment of fluid overload and diffuse fibrosis that may overcome these limitations. Our hypothesis is that liver T1 will be elevated in Fontan patients compared to corrected biventricular CHD and normal controls. <h3>METHODS AND RESULTS</h3> Cross-sectional cohort study of 33 patients within three cohorts: 11 Fontans, 12 biventricular CHD, and 10 controls with structurally normal hearts. Liver T1 was measured with a new water-specific T1 mapping method (PROFIT1 – Proton Density Fat Fraction Imaging with Water-Specific T1) from three axial slices at the widest dimension of the liver (free-breathing acquisition). Whole-liver average values were calculated, excluding blood vessels. Ventricular volumes and ejection fraction (EF) were calculated from the systemic ventricle. Myocardial native T1 mapping (MOLLI) at a mid-ventricular short axis were quantified in both the septum and free wall of the systemic or dominant ventricle. Cohort means were compared with Kruskal Wallis test and Dunn's posthoc test and association was determined with Spearman correlation coefficient. The Fontan cohort had higher liver T1 (795±59 ms) compared to control (668±62 ms; p=0.002) and CHD (672±54 ms; p=0.0007); control and CHD did not differ (Figure 1A). Fontans also had a significantly lower mean EF compared to CHD and controls (p=0.001); there were no significant differences in myocardial T1 between the 3 groups (Table 1). Liver T1 did, however, correlate with septal myocardial T1 within the whole dataset (Figure 1B; r=0.810; p=0.02); liver T1 did not correlate with EF. <h3>CONCLUSION</h3> T1 mapping with PROFIT1 appears feasible and discriminates Fontan patients from CHD and control. Furthermore, increased liver T1 also was associated with negative cardiac indicators suggesting an association between liver fibrosis and myocardial fibrosis. PROFIT1 is a fast, patient-friendly approach that may provide an early, non-invasive means to detect FALD.

Comparison of myocardial T1 mapping during breath-holding and free-breathing.

T1 mapping is a recently developed imaging analysis method that allows quantitative assessment of myocardial T1 values obtained using MRI. In children, MRI is performed under free-breathing. Thus, it is important to know the changes in T1 values between free-breathing and breath-holding. This study aimed to compare the myocardial T1 mapping during breath-holding and free-breathing. Thirteen patients and eight healthy volunteers underwent cardiac MRI, and T1 values obtained during breath-holding and free-breathing were examined and compared. Statistical differences were determined using the paired t-test. The mean T1 values during breath-holding were 1211.1±39.0 ms, 1209.7±37.4 ms, and 1228.9±52.5 ms in the basal, mid, and apical regions, respectively, while the mean T1 values during free-breathing were 1165.1±69.0 ms, 1103.7±55.8 ms, and 1112.0±81.5 ms in the basal, mid, and apical regions, respectively. The T1 values were lower during free-breathing than during breath-holding in almost all segments (basal: p = 0.008, mid: p < 0.001, apical: p < 0.001). The mean T1 values in each cross section were 3.1, 7.8, and 7.7% lower during free-breathing than during breath-holding in the basal, mid, and apical regions, respectively. We found that myocardial T1 values during free-breathing were about 3-8% lower in all cross sections than those during breath-holding. In free-breathing, it may be difficult to assess myocardial T1 values, except in the basal region, because of underestimation; thus, the findings should be interpreted with caution, especially in children.

Presence of dysfunction and myocardial remodeling in patients with premature ventricular complex-induced cardiomyopathy - a cardiovascular MR study

Abstract Funding Acknowledgements Type of funding sources: None. Background Premature ventricular complexes (PVCs) in the absence of underlying structural heart disease are considered to be benign. However, cardiac dysfunction has been observed in patients with a high PVC burden. The characterization of a PVC-induced cardiomyopathy with structural remodeling including myocardial fibrosis and the determination of a specific PVC burden leading to subclinical cardiac dysfunction remains to be determined. Objectives We aimed to evaluate cardiac function, remodeling and myocardial fibrosis patterns in patients with PVCs using cardiac magnetic resonance imaging (CMR). Additionally, we aimed to determine a PVC cut-off value leading to subclinical cardiac dysfunction. Methods Patients who underwent CMR and 24-hour, 12-lead ECG monitoring (Holter ECG) within six months were retrospectively studied. Patients with evidence of structural heart disease were excluded. The cohort was subdivided based on the number of PVCs in Holter ECG; Group-1 = 0-100, Group-2 = 100-5000 and Group-3 &amp;gt; 5000 PVCs. CMR parameters were extracted from our local databank. Myocardial strain was measured using feature tracking. For quantification of myocardial fibrosis, T1 mapping and late gadolinium enhancement (LGE) were investigated. Z-scores were calculated in order to combine T1 values from a 1.5 and 3Tesla CMR vendor. Results 443 patients (52 ± 20 years, 45% females) were included in the study. Compared to Group-1, Group-3 revealed a significantly reduced LV-EF, an increased indexed LV-EDV and increased indexed LV-ESV, indicating cardiac dysfunction and LV enlargement. PVCs frequency was inversely correlated with LV-EF (r=-0.23, p &amp;lt; 0.001) and positively correlated with indexed LV-EDV (r = 0.13; p &amp;lt; 0.01). Feature tracking showed significantly higher global circumferential strain (GCS) indicating subclinical dysfunction. Global T1 times were significantly prolonged in Group-3. Elevated global T1 Z-scores were found in Group-2 and Group-3 compared to Group-1. Significantly more intramural LGE was present in Group-2. The PVC cut-off value characterized by reduced GCS was defined by 216 PVCs (AUC = 0.61, p = 0.02). Conclusion CMR revealed cardiac dysfunction, left ventricular enlargement and diffuse myocardial fibrosis in patients with PVC in the absence of structural heart disease. These changes indicate the development of a PVC-induced cardiomyopathy depending on the PVC burden. Interestingly, subclinical myocardial dysfunction was determined at already low PVC frequencies. Further investigations are necessary in order to examine the influence of different origins of PVCs and the development of structural remodeling.

Myocardial T2 values by a segmental approach with healthy ageing and gender

Abstract Funding Acknowledgements Type of funding sources: None. Introduction. No data are available in literature about normal ranges for T2 in human myocardium using GE scanners. Aims. Our aims were to obtain myocardial regional and global T2 values as a reference for normality for the first time using a GE scanner and to assess their association with physiological variables. Methods. A stratified approach was adopted for healthy volunteers recruitment, ensuring the presence of 10 participants for both genders in each age decile: 20–30, 30–40, 40-50, 50-60, 60-70 years. Basal, medium, and apical short-axis slices of the left ventricle were acquired by a multi-echo fast-spin-echo (MEFSE) sequence. Image analysis was performed with a commercially available software package. T2 value was assessed in all 16 myocardial segments and global value was the mean. Results. The global T2 value averaged across all subjects was 52.2 ± 2.5 ms (range: 47.0-59.9 ms). Inter-study, intra-observer, and inter-observer reproducibility was good (coefficient of variation &amp;lt; 5%). The 3.6% of segments was excluded because of artifacts and/or partial-volume effects. Segmental T2 values differed significantly (P &amp;lt; 0.0001), with the lowest value in the basal anterolateral segment (50.0 ± 3.5 ms) and the highest in the apical lateral segment (54.9 ± 5.1 ms). Mean T2 was significantly lower in the basal slice compared to both medium (51.0 ± 2.4 vs 51.8 ± 2.6 ms; P &amp;lt; 0.0001) and apical slices (51.0 ± 2.4 vs 54.2 ± 3.7 ms; P &amp;lt; 0.0001), and in the medium slice than in the apical slice (51.8 ± 2.6 vs 54.2 ± 3.7 ms; P &amp;lt; 0.0001). Aging was associated with increased segmental and global T2 values. Females showed higher T2 values than males. T2 values were not correlated to heart rate. Mean T2 values, standard deviation, and lower and upper limits of normal for all 16 myocardial segments are shown in Figure 1 for males and in Figure 2 for females, considering separately each age group. Conclusion. The optimized MEFSE sequence allows for robust, reliable, and reproducible quantification of segmental T2 values. T2 values differ among myocardial slices and are influenced by age and gender, making mandatory to define gender- and age-specific segmental reference values for distinguishing between healthy and diseased myocardium. The normal ranges defined in this study on a large cohort of healthy subjects could be used as reference by other sites using the same sequence, allowing them to recruit a smaller population and accelerating the spread of myocardial T2 mapping in the clinical arena.

Cardiac and skeletal muscle predictors of impaired cardiorespiratory fitness post-anthracycline chemotherapy for breast cancer

This study aimed to characterize peak exercise cardiac function and thigh muscle fatty infiltration and their relationships with VO2peak among anthracycline-treated breast cancer survivors (BCS). BCS who received anthracycline chemotherapy ~ 1 year earlier (n = 16) and matched controls (matched-CON, n = 16) were enrolled. Resting and peak exercise cardiac function, myocardial T1 mapping (marker of fibrosis), and thigh muscle fat infiltration were assessed by magnetic resonance imaging, and VO2peak by cycle test. Compared to matched-CON, BCS had lower peak SV (64 ± 9 vs 57 ± 10 mL/m2, p = 0.038), GLS (− 30.4 ± 2.2 vs − 28.0 ± 2.5%, p = 0.008), and arteriovenous oxygen difference (16.4 ± 3.6 vs 15.2 ± 3.9 mL/100 mL, p = 0.054). Mediation analysis showed: (1) greater myocardial T1 time (fibrosis) is inversely related to cardiac output and end-systolic volume exercise reserve; (2) greater thigh muscle fatty infiltration is inversely related to arteriovenous oxygen difference; both of which negatively influence VO2peak. Peak SV (R2 = 65%) and thigh muscle fat fraction (R2 = 68%) were similarly strong independent predictors of VO2peak in BCS and matched-CON combined. Post-anthracyclines, myocardial fibrosis is associated with impaired cardiac reserve, and thigh muscle fatty infiltration is associated with impaired oxygen extraction, which both contribute to VO2peak.

Deformação Miocárdica (Strain) e Fibrose Miocárdica na Forma Cardíaca Leve da Doença de Chagas

Background: The early identification of myocardial damage seems important in the management of patients with Chagas disease. However, it is unknown whether speckle tracking echocardiography strain and cardiac magnetic resonance imaging are promising methods for assessing myocardial involvement and fibrosis, respectively. Objective: To evaluate myocardial involvement in the mild chronic cardiac form of Chagas disease using speckle tracking strain and myocardial fibrosis by cardiac magnetic resonance and assess their correlations. Method: This cross-sectional study analyzed patients with the mild chronic cardiac form of Chagas disease (preserved ejection fraction) using speckle tracking echocardiography and cardiac magnetic resonance. Results: The study included 21 participants (women: 62%; age: 54 ± 5 years). The prevalence of myocardial fibrosis was 50% on delayed myocardial enhancement. The median global longitudinal strain was decreased (14.1%; interquartile range, 12.1–16.3%) in 17 patients (81%). The mean T1 mapping value was high in patients with Chagas disease (993 ± 163 ms). The T1 map was significantly correlated with the global longitudinal strain (r = 0.634; p = 0.015). In addition, the mechanical dispersion index obtained by strain was increased (&gt;55 ms) by 84%, with the largest area under the receiver operating characteristic curve (area under the curve, 0.696; 95% confidence interval, 0.412–0.981) for fibrosis discrimination by delayed myocardial enhancement. Conclusion: Myocardial strain and T1 mapping are early markers of myocardial damage in mild chronic Chagas heart disease. The mechanical dispersion index was high and the most closely correlated with delayed myocardial enhancement.

Right Ventricular Function and T1-Mapping in Boys With Duchenne Muscular Dystrophy.

Clinical management of boys with Duchenne muscular dystrophy (DMD) relies on in-depth understanding of cardiac involvement, but right ventricular (RV) structural and functional remodeling remains understudied. To evaluate several analysis methods and identify the most reliable one to measure RV pre- and postcontrast T1 (RV-T1) and to characterize myocardial remodeling in the RV of boys with DMD. Prospective. Boys with DMD (N=27) and age-/sex-matched healthy controls (N=17) from two sites. 3.0 T using balanced steady state free precession, motion-corrected phase sensitive inversion recovery and modified Look-Locker inversion recovery sequences. Biventricular mass (Mi), end-diastolic volume (EDVi) and ejection fraction (EF) assessment, tricuspid annular excursion (TAE), late gadolinium enhancement (LGE), pre- and postcontrast myocardial T1 maps. The RV-T1 reliability was assessed by three observers in four different RV regions of interest (ROI) using intraclass correlation (ICC). The Wilcoxon rank sum test was used to compare RV-T1 differences between DMD boys with negative LGE(-) or positive LGE(+) and healthy controls. Additionally, correlation of precontrast RV-T1 with functional measures was performed. A P-value <0.05 was considered statistically significant. A 1-pixel thick RV circumferential ROI proved most reliable (ICC > 0.91) for assessing RV-T1. Precontrast RV-T1 was significantly higher in boys with DMD compared to controls. Both LGE(-) and LGE(+) boys had significantly elevated precontrast RV-T1 compared to controls (1543 [1489-1597] msec and 1550 [1402-1699] msec vs. 1436 [1399-1473] msec, respectively). Compared to healthy controls, boys with DMD had preserved RVEF (51.8 [9.9]% vs. 54.2 [7.2]%, P=0.31) and significantly reduced RVMi (29.8 [9.7]g vs. 48.0 [15.7]g), RVEDVi (69.8 [29.7]mL/m2 vs. 89.1 [21.9]mL/m2 ), and TAE (22.0 [3.2]cm vs. 26.0 [4.7]cm). Significant correlations were found between precontrast RV-T1 and RVEF (β=-0.48%/msec) and between LV-T1 and LVEF (β=-0.51%/msec). Precontrast RV-T1 is elevated in boys with DMD compared to healthy controls and is negatively correlated with RVEF. 1 TECHNICAL EFFICACY: Stage 2.

Fat-saturated dark-blood cardiac T2 mapping in a single breath-hold

PurposeConventional cardiac T2 mapping suffers from the partial-voluming effect in the endocardium and epicardium due to the co-presence of intra-cavity blood and epicardial fat. The aim of the study is to develop a novel single-breath-hold Fat-Saturated Dark-Blood (FSDB) cardiac T2-mapping technique to mitigate the partial-voluming and improve T2 accuracy. MethodsThe proposed FSDB T2-mapping technique combines T2-prepared bSSFP, a novel use of double inversion-recovery with heart-rate-adaptive TI, and spectrally-selective fat saturation to mitigate partial-voluming from both the blood and fat. FSDB T2 mapping was compared to conventional T2 mapping via simulations, phantom imaging, healthy-subject imaging (n = 8), and patient imaging (n = 7). In the healthy subjects, a high-resolution coplanar anatomical imaging was performed to provide a gold standard for segmentation of endocardium and epicardium. T2 maps were registered to the gold standard image to evaluate any inter-layer T2 difference, which is a surrogate for partial-voluming. ResultsSimulations and phantom imaging showed that FSDB T2 mapping was accurate in a range of heartrates, off-resonance, and T2 values, and blood/fat reasonably nulled in a range of heartrates. In healthy subjects, FSDB T2 mapping showed similar T2 values over different myocardial layers in all 3 short-axis slices (e.g. basal epicardial/mid-wall/endocardial T2 = 42 ± 2 ms/41 ± 1 ms/42 ± 1 ms), whereas conventional T2 mapping showed considerably increased T2 in the endocardium and epicardium (e.g. basal epicardial/mid-wall/endocardial T2 = 48 ± 3 ms/43 ± 1 ms/49 ± 3 ms). The homogeneous T2 in the FSDB T2 mapping increased the apparent LV-wall thickness by 25–41% compared with the conventional method. ConclusionsThe proposed technique improves accuracy of myocardial T2 mapping against partial-voluming associated with both fat and blood, facilitating a multi-layer T2 evaluation of the myocardium. This technique may improve utility of cardiac T2 mapping in diseases affecting the endocardium and epicardium, and in patients with a small heart.

Cardiac MRI in Suspected Acute COVID-19 Myocarditis.

Keywords: COVID-19; coronavirus; myocarditis; cardiac MRI; T1 mapping; T2 mapping

Cardiovascular magnetic resonance-determined left ventricular myocardium impairment is associated with C-reactive protein and ST2 in patients with paroxysmal atrial fibrillation

BackgroundMyocardial strain assessed with cardiovascular magnetic resonance (CMR) feature tracking can detect early left ventricular (LV) myocardial deformation quantitatively in patients with a variety of cardiovascular diseases, but this method has not yet been applied to quantify myocardial strain in patients with atrial fibrillation (AF) and no coexistent cardiovascular disease, i.e., the early stage of AF. This study sought to compare LV myocardial strain and T1 mapping indices in AF patients and healthy subjects, and to investigate the associations of a portfolio of inflammation, cardiac remodeling and fibrosis biomarkers with LV myocardial strain and T1 mapping indices in AF patients with no coexistent cardiovascular disease.MethodsThe study consisted of 80 patients with paroxysmal AF patients and no coexistent cardiovascular disease and 20 age- and sex-matched healthy controls. Left atrial volume (LAV), LV myocardial strain and native T1 were assessed with CMR, and compared between the AF patients and healthy subjects. Biomarkers of C-reactive protein (CRP), transforming growth factor beta-1 (TGF-β1), collagen III N-terminal propeptide (PIIINP), and soluble suppression of tumorigenicity 2 (sST2) were obtained with blood tests, and compared between the AF patients and healthy controls. Associations of these biomarkers with those CMR-measured parameters were analyzed for the AF patients.ResultsFor the CMR-measured parameters, the AF patients showed significantly larger LAV and LV end-systolic volume, and higher native T1 than the healthy controls (max P = 0.027). The absolute values of the LV peak systolic circumferential strain and its rate as well as the LV diastolic circumferential strain rate were all significantly reduced in the AF patients (all P < 0.001). For the biomarkers, the AF patients showed significantly larger CRP (an inflammation biomarker) and sST2 (a myocardium stiffness biomarker) than the controls (max P = 0.007). In the AF patients, the five CMR-measured parameters of LAV, three LV strain indices and native T1 were all significantly associated with these two biomarkers of CRP and sST2 (max P = 0.020).ConclusionsIn patients with paroxysmal AF and no coexistent cardiovascular disease, LAV enlargement and LV myocardium abnormalities were detected by CMR, and these abnormalities were associated with biomarkers that reflect inflammation and myocardial stiffness.

Myocardial T1 and T2 Mapping by Magnetic Resonance in Patients With Immune Checkpoint Inhibitor–Associated Myocarditis

BackgroundMyocarditis is a potentially fatal complication of immune checkpoint inhibitor (ICI) therapy. Data on the utility of cardiovascular magnetic resonance (CMR) T1 and T2 mapping in ICI myocarditis are limited. ObjectivesThis study sought to assess the value of CMR T1 and T2 mapping in patients with ICI myocarditis. MethodsIn this retrospective study from an international registry of patients with ICI myocarditis, clinical and CMR findings (including T1 and T2 maps) were collected. Abnormal T1 and T2 were defined as 2 SD above site (vendor/field strength specific) reference values and a z-score was calculated for each patient. Major adverse cardiovascular events (MACE) were a composite of cardiovascular death, cardiogenic shock, cardiac arrest, and complete heart block. ResultsOf 136 patients with ICI myocarditis with a CMR, 86 (63%) had T1 maps and 79 (58%) also had T2 maps. Among the 86 patients (66.3 ± 13.1 years of age), 36 (41.9%) had a left ventricular ejection fraction <55%. Across all patients, mean z-scores for T1 and T2 values were 2.9 ± 1.9 (p < 0.001) and 2.2 ± 2.1 (p < 0.001), respectively. On Siemens 1.5-T scanner (n = 67), native T1 (1,079.0 ± 55.5 ms vs. 1,000.3 ± 22.1 ms; p < 0.001) and T2 (56.2 ± 4.9 ms vs. 49.8 ± 2.2 ms; p < 0.001) values were elevated compared with reference values. Abnormal T1 and T2 values were seen in 78% and 43% of the patients, respectively. Applying the modified Lake Louise Criteria, 95% met the nonischemic myocardial injury criteria and 53% met the myocardial edema criteria. Native T1 values had excellent discriminatory value for subsequent MACE, with an area under the curve of 0.91 (95% confidence interval: 0.84 to 0.98). Native T1 values (for every 1-unit increase in z-score, hazard ratio: 1.44; 95% confidence interval: 1.12 to 1.84; p = 0.004) but not T2 values were independently associated with subsequent MACE. ConclusionsThe use of T1 mapping and application of the modified Lake Louise Criteria provides important diagnostic value, and T1 mapping provides prognostic value in patients with ICI myocarditis.

Multi-parametric cardiovascular magnetic resonance with regadenoson stress perfusion is safe following pediatric heart transplantation and identifies history of rejection and cardiac allograft vasculopathy

BackgroundThe progressive risk of graft failure in pediatric heart transplantation (PHT) necessitates close surveillance for rejection and coronary allograft vasculopathy (CAV). The current gold standard of surveillance via invasive coronary angiography is costly, imperfect and associated with complications. Our goal was to assess the safety and feasibility of a comprehensive multi-parametric CMR protocol with regadenoson stress perfusion in PHT and evaluate for associations with clinical history of rejection and CAV.MethodsWe performed a retrospective review of 26 PHT recipients who underwent stress CMR with tissue characterization and compared with 18 age-matched healthy controls. CMR protocol included myocardial T2, T1 and extracellular volume (ECV) mapping, late gadolinium enhancement (LGE), qualitative and semi-quantitative stress perfusion (myocardial perfusion reserve index; MPRI) and strain imaging. Clinical, demographics, rejection score and CAV history were recorded and correlated with CMR parameters.ResultsMean age at transplant was 9.3 ± 5.5 years and median duration since transplant was 5.1 years (IQR 7.5 years). One patient had active rejection at the time of CMR, 11/26 (42%) had CAV 1 and 1/26 (4%) had CAV 2. Biventricular volumes were smaller and cardiac output higher in PHT vs. healthy controls. Global T1 (1053 ± 42 ms vs 986 ± 42 ms; p < 0.001) and ECV (26.5 ± 4.0% vs 24.0 ± 2.7%; p = 0.017) were higher in PHT compared to helathy controls. Significant relationships between changes in myocardial tissue structure and function were noted in PHT: increased T2 correlated with reduced LVEF (r = − 0.57, p = 0.005), reduced global circumferential strain (r = − 0.73, p < 0.001) and reduced global longitudinal strain (r = − 0.49, p = 0.03). In addition, significant relationships were noted between higher rejection score and global T1 (r = 0.38, p = 0.05), T2 (r = 0.39, p = 0.058) and ECV (r = 0.68, p < 0.001). The presence of even low-grade CAV was associated with higher global T1, global ECV and maximum segmental T2. No major side effects were noted with stress testing. MPRI was analyzed with good interobserver reliability and was lower in PHT compared to healthy controls (0.69 ± − 0.21 vs 0.94 ± 0.22; p < 0.001).ConclusionIn a PHT population with low incidence of rejection or high-grade CAV, CMR demonstrates important differences in myocardial structure, function and perfusion compared to age-matched healthy controls. Regadenoson stress perfusion CMR could be safely and reliably performed. Increasing T2 values were associated with worsening left ventricular function and increasing T1/ECV values were associated with rejection history and low-grade CAV. These findings warrant larger prospective studies to further define the role of CMR in PHT graft surveillance.

Myocardial native T1 mapping and cardiac outcomes in thalassemia major

Abstract Funding Acknowledgements Type of funding sources: Private company. Main funding source(s): The E-MIOT project receives “no-profit support” from industrial sponsorships (Chiesi Farmaceutici S.p.A. and ApoPharma Inc. and Bayer). Background. The T2* cardiovascular magnetic resonance (CMR) is the gold standard for the non invasive detection of myocardial iron overload (MIO). The native myocardial T1 mapping has been proposed as a complementary tool, thanks to its higher sensitivity in presence of small amounts of iron, but no data are available in literature about its clinical impact. Objective To explore the clinical impact of T1 mapping for detecting cardiac complications in thalassemia major (TM). Methods. We considered 146 TM patients (87 females, 38.7 ± 11.1 years) consecutively enrolled in the Extension-Myocardial Iron Overload in Thalassemia Network. Three parallel short-axis slices of the left ventricle (LV) were acquired with the Modified Look-Locker Inversion recovery (MOLLI) sequence. The native T1 values in all 16 myocardial segments were obtained and the global value was the mean. Results. Twenty-one patients had an history of cardiac complications: 11 heart failure, 8 arrhythmias (7 supraventricular and 1 ventricular), and 2 pulmonary hyperthension. Patients with cardiac complications had significantly lower global heart T1 values (879.3 ± 121.9 ms vs 963.2 ± 98.5 ms; P &amp;lt; 0.0001) (Figure) but comparable T2* values (33.32 ± 11.66 ms vs 37.17 ± 9.15 ms; P = 0.116). Cardiac complications were more frequent in the group of patients with reduced global heart T1 value (&amp;lt;928 ms for males and &amp;lt;989 ms for females) compared to the group with normal global heart T1 value (71.4% vs 39.5%; P = 0.009). Odds ratio (OR) for cardiac complications was 3.8 (95%CI = 1.3-10.9) for patients with reduced global heart T1 value versus patients with normal global heart T1 value. Conclusion We found out a significant association between decreased native global heart T1 values and a history of cardiac complications, suggesting that an early detection of myocardial iron burden by native T1 can support the clinicians in modifing chelation therapy earlier. Abstract Figure.

Myocardial native T1 mapping and correlations with clinical and CMR parameters in patients with systemic sclerosis

Abstract Funding Acknowledgements Type of funding sources: None. Background Systemic sclerosis (SSc) is a connective tissue disease characterized by diffuse vascular lesions and fibrosis, also affecting the heart. Cardiovascular magnetic resonance (CMR) can detect replacement myocardial fibrosis by late gadolinium enhancement (LGE) and interstitial myocardial fibrosis/edema by T1 mapping techniques. Purpose To evaluate the prevalence of cardiac involvement by native T1 mapping and its correlation with clinical and CMR parameters in SSc patients. Methods Fifty-one consecutive SSc patients (mean age 51.8 ± 13.7 years, 42 females) and 51 healthy subjects matched for age and sex underwent clinical, bio-humoral assessment, and CMR at 1.5T (Signa Artist, GE Healthcare ). The imaging protocol included: cine, T1 mapping by MOLLI, T2 mapping by multi-echo fast-spin-echo sequence, LGE, and STIR T2-weighted sequences. Native T1 and T2 values were assessed in all 16 myocardial segments and the global value was the mean. Results. Global native T1 values were significantly higher in SSc patients than in healthy subjects (1076.4 ± 50.7 vs 1033.3 ± 31.9 ms; P &amp;lt; 0.0001). As in healthy subjects, in patients native T1 values were significantly lower in males than in females (1033.4 ± 38.3 vs 1085.6 ± 48.6 ms; P = 0.004) and inversely correlated with age (R=-0415; P = 0.002). Twenty-three (45.1%) patients had an increased global heart T1 value (&amp;gt;1060 ms in males and &amp;gt;1085 ms in females). Of them, 14 patients (60.9 %) showed positive LGE. Frequency of cardiovascular risk factors, indices of disease activity and chronicity, biochemical parameters, and cardio-active therapy were comparable between patients with normal and elevated T1. Compared to patients with normal T1 value, patients with elevated T1 had significantly higher left ventricular (LV) end-diastolic volume index (76.8 ± 13.3 vs 69.2 ± 11.8, P = 0.050), LV stroke volume index (49.7 ± 6.4 vs 44.4 ± 6.9 ml/m2; P = 0.010), LV cardiac output (3.6 ± 0.5 vs 3.0 ± 0.6 l/min /m2; P &amp;lt; 0.0001), and global heart T2 values (60.1 ± 3.6 vs 55.7 ± 3.1 ms; P &amp;lt; 0.0001). Replacement myocardial fibrosis was detected in 24 (47.1%) patients and they showed significantly higher global heart native T1 values (Figure 1A). Positive T2-weighted images for myocardial oedema were found in 5 (9.8%) patients, all with increased global heart native T1 value. Patients with oedema had significantly higher native global heart T1 values (Figure 1B). Conclusion Elevated native T1 values measured by CMR are frequent in SSc patients and they are associated with inflammation, replacement fibrosis, and increased LV dimension. CMR T1 mapping seems to be a sensitive parameter to include in the routine clinical assessment of SSc patients for detecting earlier pejorative cardiac involvement, although prospective data are recommended. Abstract Figure.

Gender difference in extreme cardiac remodelling in endurance olympic athletes assessed by non-contrast CMR

Abstract Funding Acknowledgements Type of funding sources: None. Background Male and female athletes present difference spectrum of cardiac remodelling related to their sport activity. However data in elite female athletes are scarce and mainly limited to echocardiography evaluation. Purpose The aim of the study was to assess gender difference in extreme cardiac remodelling in Olympic athletes engaged in endurance sport assessed by non-contrast Cardiovascular Magnetic Resonance including Mapping. Methods Olympic athletes engaged in endurance sport (rowing, canoeing, mid/long distance swimming) were examined with history, physical examination, 12-lead and exercise electrocardiogram, and echocardiography as part of their evaluation prior the Olympic games (Tokyo 2020). Athletes with unremarkable evaluation were undergone to non-contrast CMR including Mapping. The following parameters were calculated: indexed left ventricle (LV) and right ventricle (RV) end-diastolic (EDVi) and end-systolic volumes (ESVi), stroke volume (SVi), ejection fraction (EF), left and right atria area (LAAi and RAAi), LV Mass (Massi) and maximum wall thickness (MWT), RV/LV EDV ratio, spericity index [SI=(long axis diameter/2)3 * 4,187], myocardial native T1 (nT1) and T2 Mapping. Results 51 caucasian elite athletes (without difference in term of age, years of training and hours of training/week) were enrolled and 59% were male. Male showed greater LV EDVi (123 ± 28 ml vs 103 ± 10, p = 0.003), ESVi (55 ± 14 ml vs 44 ± 7, p = 0.001), SVi (68 ± 15 ml vs 59 ± 7, p = 0.023), Massi (76 ± 19 vs 57 ± 10, p &amp;lt; 0.001), MWT (10 ± 1 mm vs 8 ± 1, p &amp;lt; 0.001) and RV EDVi (129 ± 48 ml vs 104 ± 13, p = 0.026), ESVi (57 ± 10 ml vs 45 ± 9, p &amp;lt; 0.001), SVi (68 ± 15 ml vs 59 ± 7, p = 0.018) compared to female, as expected. LVEF (p = 0.05) and RVEF (p = 0.17) did not show significant difference. Despite greater volumes, SI (43 ± 12% vs 44 ± 8, p = 0.8) and RV/LV EDV ratio (0.99 ± 0.05 vs 1 ± 0.05, p = 0.405) did not differ between male and female athletes, as well as LAAi (13 ± 3 cm2 vs 13 ± 1.5, p = 0.86) and RAAi (13 ± 1.9 vs 13 ± 18, p = 0.56). Native T1 mapping was lower in male compared with female (934 ± 21 ms vs 956 ± 33, p = 0.028) while T2 Map values were slightly higher (53 ± 3.9 ms vs 50 ± 3.8, p = 0.027) . Conclusions Male endurance Olympic athletes presented higher volumes and LV mass compared to their female counterparts, while atria dimension, systolic function and sphericity index did not differ. Ventricles showed balanced dilatation in both gender. Lower T1 value observed in male suggested cellular hypertrophy. Figure 1 showed CMR images in a male (top row) and a female (bottom row) Olympic athletes: 4 chamber end-diastolic and end-systolic frame and end-diastolic basal short axis (SAX) showed balanced dilatation. Graphs showed higher EDVi and Massi in male compared o female, no difference in sphericity index and lower native T1 mapping. Abstract Figure 1

Cardiac magnetic resonance in patients with ARVC and family members: the potential role of native T1 mapping

Left ventricular (LV) involvement in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) is not evaluated in the revised Task Force Criteria, possibly leading to underdiagnosis. This study explored the diagnostic role of myocardial native T1 mapping in patients with ARVC and their first-degree relatives. Thirty ARVC patients (47% males, mean age 45 ± 27 years) and 59 first-degree relatives not meeting diagnostic criteria underwent CMR with native T1 mapping. C MR was abnormal in 26 (87%) patients with ARVC. The right ventricle was affected in isolation in 13 (43%) patients. Prior to T1 mapping assessment, 2 (7%) patients exhibited isolated LV involvement and 11 (36%) patients showed features of biventricular disease. Left ventricular involvement was manifest as detectable LV late gadolinium enhancement (LGE) in 12 out of 13 cases. According to pre-specified inter-ventricular septal (IVS) T1 mapping thresholds, 11 (37%) patients revealed raised native T1 values including 5 out of the 17 patients who would otherwise have been classified as exhibiting a normal LV by conventional imaging parameters. Native septal T1 values were elevated in 22 (37%) of the 59 first-degree relatives included. Biventricular involvement is commonly observed in ARVC; native myocardial T1 values are raised in more than one third of patients, including a significant proportion of cases that would have been otherwise classified as exhibiting a normal LV using conventional CMR techniques. The significance of abnormal T1 values in first-degree relatives at risk will need validation through longitudinal studies.

Evaluation of the homogeneity of native T1 myocardial mapping using the polarity corrected inversion time preparation method in a myocardial phantom and healthy volunteers.

Myocardial T1 mapping is a useful technique for the diagnosis of diffuse fibrosis. Although modified look-locker inversion recovery is a widely used T1 mapping method, variation in T1 values has been reported. Non-uniform T1 maps may hinder differentiation between healthy and diseased myocardial tissue. The purpose of this study was to investigate the uniformity of T1 mapping using polarity corrected inversion time preparation (PC TI prep) in a myocardial phantom and healthy volunteers. The myocardial phantom was scanned between polyvinyl alcohol (PVA) and air. T1 values were measured using inversion recovery fast spin-echo (IR-FSE) and PC TI prep in areas adjacent to PVA and air. For the volunteer study, the short-axis plane was imaged using the PC TI prep to compare T1 values in the myocardium of the septal and lateral walls. The T1 value of the phantom using the IR-FSE was not significantly different in the area between PVA and air, whereas the T1 value using the PC TI prep in the air area was significantly lower than that in the PVA area. T1 mapping of the healthy myocardium exhibited no significant difference between the septal and lateral walls. The T1 value using the PC TI prep in the air area was 6.3% lower than that using IR-FSE. In this study, T1 mapping using the PC TI prep exhibited high uniformity of T1 values.