Myocardial T1 Research Articles

Association between objectively-measured sleep duration and early cardiac and hepatic imaging changes in adolescents: insights from the EnIGMA study

Abstract Introduction Inadequate sleep duration (SD) has been associated with adverse cardiovascular (CV) events in adults and adiposity in all life stages. Furthermore, previous cross-sectional studies have shown a possible association between self-reported SD and cardiac structural alterations as detected with echocardiography and cardiovascular magnetic resonance (MR), even in young healthy people. However, there is a lack of longitudinal studies demonstrating an association between objectively-measured SD and structural cardiac alterations. Purpose To assess the association between SD and MR-derived cardiac and hepatic parameters in adolescents. Methods This study used longitudinal data collected as part of the SI! Program for Secondary Schools trial in Spain (2017-2021), which enrolled 1326 participants (mean age: 12.5±0.5 years at baseline). Measurements were taken at three different time-points: baseline, 2-year follow-up and 4-year follow-up. SD and physical activity were assessed by accelerometry for seven consecutive days at each follow-up. The participants were offered to undergo a MR scan in the final follow-up as part of the Early imaging markers of unhealthy lifestyles in adolescents (EnIGMA) study. The imaging protocol included a cine SSFP to provide images for chamber size and function, myocardial tagging acquisitions to assess myocardial strain, T1 and T2 mapping sequences to provide precise myocardial relaxation time properties, and a liver mDixonQuant sequence to obtain liver fat content, using a 3-T scanner. The cumulative effect of the independent variable (SD) and the covariates was assessed using the area under the curve (AUC) method, calculating the integral of the curve parameters during the follow-up period for each subject. To facilitate interpretation, AUC values were divided by the years of follow-up. The participants were included in the analysis if they had available data for SD in at least 2 of the 3 time-points. The association between SD and the MR parameters was assessed by linear regression models. Results 109 participants (61 girls [56.0%]; mean age=16.0±0.5 years) were included in this study. Indexed left ventricular (LV) mass, as well as indexed end-diastolic biventricular volumes were higher in boys than in girls (Figure 1). SD AUC (hours/day) was independently and inversely associated with indexed LV mass and liver fat fraction in the unadjusted and adjusted (age, gender, physical activity, body mass index percentile, and systolic and diastolic blood pressure percentiles AUCs) models (Figure 2). There were no significant associations between the SD AUC and other MR-derived parameters. Conclusion Shorter SD is independently associated with initial stages of cardiac remodeling and liver fat accumulation as assessed with state-of-the-art MR as early as in adolescence. Considering these results, health promotion programs should be implemented early in life emphasizing the importance of good sleep habits.Participant characteristicsAssociation between SD and MR

3D B1+ corrected simultaneous myocardial T1 and T1ρ mapping with subject-specific respiratory motion correction and water-fat separation.

To develop a 3D free-breathing cardiac multi-parametric mapping framework that is robust to confounders of respiratory motion, fat, and B1+ inhomogeneities and validate it for joint myocardial T1 and T1ρ mapping at 3T. An electrocardiogram-triggered sequence with dual-echo Dixon readout was developed, where nine cardiac cycles were repeatedly acquired with inversion recovery and T1ρ preparation pulses for T1 and T1ρ sensitization. A subject-specific respiratory motion model relating the 1D diaphragmatic navigator to the respiration-induced 3D translational motion of the heart was constructed followed by respiratory motion binning and intra-bin 3D translational and inter-bin non-rigid motion correction. Spin history B1+ inhomogeneities were corrected with optimized dual flip angle strategy. After water-fat separation, the water images were matched to the simulated dictionary for T1 and T1ρ quantification. Phantoms and 10 heathy subjects were imaged to validate the proposed technique. The proposed technique achieved strong correlation (T1: R2 = 0.99; T1ρ: R2 = 0.98) with the reference measurements in phantoms. 3D cardiac T1 and T1ρ maps with spatial resolution of 2 × 2 × 4 mm were obtained with scan time of 5.4 ± 0.5 min, demonstrating comparable T1 (1236 ± 59 ms) and T1ρ (50.2 ± 2.4 ms) measurements to 2D separate breath-hold mapping techniques. The estimated B1+ maps showed spatial variations across the left ventricle with the septal and inferior regions being 10%-25% lower than the anterior and septal regions. The proposed technique achieved efficient 3D joint myocardial T1 and T1ρ mapping at 3T with respiratory motion correction, spin history B1+ correction and water-fat separation.

Early Detection of Myocardial Involvement in Thalassemia Intermedia Patients: Multiparametric Mapping by Magnetic Resonance Imaging.

No study has assessed myocardial T1 and T2 values in patients with beta-thalassemia intermedia (β-TI). To assess the prevalence of myocardial involvement in β-TI patients by T2* relaxometry and native T1 and T2 mapping and to determine the correlation of myocardial relaxation times with demographic and clinical parameters. Prospective matched-cohort study. 42 β-TI patients (27 females, 39.65 ± 12.32 years), enrolled in the Extension-Myocardial Iron Overload in Thalassaemia Network, and 42 age- and sex-matched healthy volunteers (27 females, 40.01 ± 11.36 years) and thalassemia major (TM) patients (27 females, 39.27 ± 11.57 years). 1.5 T/multi-echo gradient echo, modified Look-Locker inversion recovery, multi-echo fast-spin-echo, cine balanced steady-state-free precession, and late gadolinium enhancement (LGE) sequences. Hepatic, pancreatic, and left ventricular (LV) T2* values, LV native T1 and T2 values, biventricular ejection fractions and volumes, and presence and extent of replacement myocardial fibrosis. Comparisons between two groups were performed with two-sample t tests, Wilcoxon's signed rank tests, or χ2 testing. Correlation analysis was performed using Pearson's or Spearman's test. P < 0.05 was considered statistically significant. β-TI patients had significantly higher LV T2 values than healthy subjects (56.84 ± 4.03 vs. 52.46 ± 2.50 msec, P < 0.0001) and significantly higher LV T1 values than TM patients (1018.32 ± 48.94 vs. 966.66 ± 66.47 msec, P < 0.0001). In β-TI, female gender was associated with significantly increased LV T1 (P = 0.041) and T2 values (P < 0.0001), while splenectomy and presence of regular transfusions were associated with significantly lower LV T1 values (P = 0.014 and P = 0.001, respectively). In β-TI patients, all LV relaxation times were significantly correlated with each other (T2*-T1: P = 0.003; T2*-T2: P = 0.003; T1-T2: P < 0.0001). Two patients with a reduced LV T2* also had a reduced LV T1, while only one had a reduced LV T2. Three patients had a reduced LV T1 but a normal LV T2*; 66.7% of the patients had an increased LV T2. All LV relaxation times were significantly correlated with pancreas T2* values (T2*: P = 0.033; T1: P < 0.0001; T2: P = 0.014). No LV relaxation time was associated (P > 0.05) with hepatic iron concentration, biventricular function parameters, or LGE presence. The combined use of all three myocardial relaxation times has potential to improve sensitivity in the detection of early/subclinical myocardial involvement in β-Tl patients. 2 TECHNICAL EFFICACY: Stage 2.

Early detection of myocardial iron overload in patients with β-thalassemia major using cardiac magnetic resonance T1 mapping

BackgroundThe T2* technique, used for quantifying myocardial iron content (MIC), has limitations in detecting early myocardial iron overload (MIO). The in vivo mapping of the myocardial T1 relaxation time is a promising alternative for the early detection and management of MIO. Methods32 β-thalassemia major (βTM) patients aged 11.5 ± 4 years and 32 healthy controls were recruited and underwent thorough clinical and laboratory assessments. The mid-level septal iron overload was measured through T1 mapping using a modified Look-Locker inversion recovery sequence with a 3 (3 s) 3 (3 s) 5 scheme. Septum was divided at the mentioned level into 3 zones corresponding to segments 8 and 9 in the cardiac segmentation model. Results21.9 % of βTM had clinical cardiac morbidity. The cut-off of T1 mapping of hepatic and myocardium to differentiate between the patients and control groups was ≤466 and ≥ 923 ms respectively. The T1 technique was able to detect 4 patients with high MIC, two of them were not detected by the T2* technique. There was a statistically significant correlation between the average T1 values of the studied zones in patients with βTM and the liver iron content (LIC), the T1 values within segment 8 of the liver, age of patients, the age at first transfusion, age of splenectomy and serum ferritin value. ConclusionThe addition of the T1 mapping sequence to the conventional T2* technique was able to increase the efficacy of the MIC detection protocol by earlier detection of MIO. This would guide chelation therapy to decrease myocardial morbidity.

Assessment of transfusion-induced iron overload with T2*MRI in survivors of childhood acute lymphoblastic leukemia: A case control study

IntroductionChildhood acute lymphoblastic leukemia survivors receiving multiple packed red blood transfusions may be at risk of vital organ iron deposition causing long-term complications. This study was undertaken to assess the prevalence and severity of iron overload in the liver and heart by magnetic resonance imaging. MethodsA case-control study was conducted on 60 acute lymphoblastic leukemia survivors aged from 6 to 18 years and 60 healthy, age- and sex-matched children as a control group. The hematological profile, and serum ferritin was assessed and the iron content of the liver and heart was measured by T2* magnetic resonance imaging. ResultsTwenty-six (43.3 %) and two (3.3 %) patients had elevated liver and myocardial iron concentrations, respectively. The statistics show a significantly positive correlation between liver T2* magnetic resonance and serum ferritin. The total volume of blood transfused and duration of follow up were associated with elevated liver iron concentrations (p-values = 0.036 and 0.028 respectively). Myocardial T2* magnetic resonance lacked correlation with serum ferritin and transfusion therapy ConclusionLiver iron overload was detected in children and adolescents after acute lymphoblastic leukemia therapy. The risk of iron overload was related mainly to the transfusion burden during therapy. These patients need monitoring after therapy to assess their need for future chelation therapy.

The transition from hypertension to hypertensive heart disease and heart failure with preserved ejection fraction: a retrospective cross-sectional study of myocardial magnetic resonance strain and tissue characteristics.

Due to the variability of symptoms and signs associated with heart failure, along with the lack of specific tests for definitive diagnosis, the noninvasive diagnosis of heart failure with preserved ejection fraction (HFpEF) continues to pose significant clinical challenges. This investigation was designed to elucidate the clinical manifestations of HFpEF and to analyze cardiac magnetic resonance (CMR)-derived myocardial strain metrics and tissue characteristics in a cohort exhibiting HFpEF with hypertension (HFpEF-HTN). This retrospective analysis consisted of 128 patients diagnosed HFpEF-HTN, 78 individuals with hypertensive heart disease (HHD), 89 individuals with hypertension (HTN), and 60 normotensive healthy controls and was conducted from August 2021 to February 2024. All participants were recruited from The First Hospital of Lanzhou Universityand underwent laboratory examinations and 3.0 T CMR. The study compared clinical features and CMR-derived structural and functional parameters across different groups. Logistic regression was employed to determine the association between CMR parameters and HFpEF-HTN. Spearman correlation coefficient analysis was used to clarify the relationship between myocardial strain parameters and left ventricular (LV) ejection fraction and right ventricular (RV) ejection fraction. Additionally, the area under the curve (AUC) from receiver operating characteristic (ROC) analysis was used to compare the diagnostic performance of different CMR parameters for HFpEF-HTN. Patients diagnosed with (HFpEF-HTN) were characterized by an older demographic profile, a higher prevalence of smoking history, elevated systolic and diastolic blood pressure, increased levels of N-terminal pro-brain natriuretic peptide, and more advanced New York Heart Association functional class as compared to other studied groups. In terms of myocardial deformation, individuals with HFpEF-HTN exhibited pronounced impairments in both LV and RV function, as evidenced by significantly reduced longitudinal strain (LS), circumferential strain (CS), and radial strain (RS), relative to HTN, HHD, the control cohorts (all P values <0.001). Patients with HFpEF-HTN showed significantly elevated levels of late gadolinium enhancement, native T1, and extracellular volume fraction (ECV) indicative of myocardial interstitial fibrosis as compared to patients with HHD. Additionally, as compared to ECV, LV GCS emerged as a superior diagnostic indicator, demonstrating greater diagnostic accuracy in differentiating HFpEF-HTN patients from those with HHD (AUC =0.85; P<0.001). Moreover, LVEF showed a mild correlation with CMR-derived LV GLS (R=-0.43; P<0.001), LV GCS (R=-0.42; P<0.001), and LV GRS, (R=0.56; P<0.001) in all patients. Myocardial strain, T1 mapping, and ECV can be used for the quantitative evaluation of LV and RV ventricular remodeling, dysfunction, and tissue characteristics in patients with HFpEF-HTN and thus hold significant potential for the diagnosis of these patients.

Accelerated Cartesian cardiac T2 mapping based on a calibrationless locally low-rank tensor constraint.

Cardiac T2 mapping is a valuable tool for diagnosing myocardial edema, inflammation, and infiltration, yet its spatial resolution is limited by the single-shot balanced steady-state free precession acquisition and duration of the cardiac quiescent period, which may reduce sensitivity in detecting focal lesions in the myocardium. To improve spatial resolution without extending the acquisition window, this study examined a novel accelerated Cartesian cardiac T2 mapping technique. We introduce a novel improved-resolution cardiac T2 mapping approach leveraging a calibrationless space-contrast-coil locally low-rank tensor (SCC-LLRT)-constrained reconstruction algorithm in conjunction with Cartesian undersampling trajectory. The method was validated with phantom imaging and in vivo imaging that involved 13 healthy participants and 20 patients. The SCC-LLRT algorithm was compared with a conventional locally low-rank (LLR)-constrained algorithm and a nonlinear inversion (NLINV) reconstruction algorithm. The improved-resolution T2 mapping (1.4 mm × 1.4 mm) was compared globally and regionally with the regular-resolution T2 mapping (2.3 mm × 1.9 mm) according to the 16-segment model of the American Heart Association. The agreement between the improved-resolution and regular-resolution T2 mappings was evaluated by linear regression and Bland-Altman analyses. Image quality was scored by two experienced reviewers on a five-point scale (1, worst; 5, best). In healthy participants, SCC-LLRT significantly reduced artifacts (4.50±0.39) compared with LLR (2.31±0.60; P<0.001) and NLINV (3.65±0.56; P<0.01), suppressed noise (4.12±0.35) compared with NLINV (2.65±0.50; P<0.001), and improved the overall image quality (4.38±0.40) compared with LLR (2.54±0.41; P<0.001) and NLINV (3.04±0.50; P<0.001). Compared with the regular-resolution T2 mapping, the proposed method significantly improved the sharpness of myocardial boundaries (4.46±0.60 vs. 3.04±0.50; P<0.001) and the conspicuity of papillary muscles and fine structures (4.46±0.63 vs. 2.65±0.30; P<0.001). Myocardial T2 values obtained with the proposed method correlated significantly with those from regular-resolution T2 mapping in both healthy participants (r=0.79; P<0.01) and patients (r=0.94; P<0.001). The proposed SCC-LLRT-constrained reconstruction algorithm in conjunction with Cartesian undersampling pattern achieved improved-resolution cardiac T2 mapping of comparable accuracy, precision, and scan-rescan reproducibility compared with the regular-resolution T2 mapping. The higher resolution improved the sharpness of myocardial borders and the conspicuity of image fine details, which may increase diagnostic confidence in cardiac T2 mapping for detecting small lesions.

The additional value of myocardial T1ρ mapping to T1 and T2 mapping for predicting subsequent cancer therapy-related cardiac dysfunction in breast cancer patients who received anthracyclines with/without trastuzumab

ObjectivesWe aimed to describe changes in parameters derived from myocardial T1ρ, T1, and T2 mapping and assess whether incorporating T1ρ mapping improves the predictive performance of T1 and T2 mapping for subsequent cancer therapy-related cardiac dysfunction (CTRCD) in breast cancer patients treated with anthracyclines with/without trastuzumab. MethodsFrom March 2021 to May 2023, 82 participants with breast cancer treated with anthracyclines with/without trastuzumab were prospectively recruited. Cardiac magnetic resonance was performed at baseline, 3 and 6 months in relation to baseline. T1ρ, T1 and T2 values were measured and compared by repeated measures analyses of variance. Logistic regression and receiver operating characteristic analysis were used to assess the performance in predicting subsequent CTRCD. ResultsNineteen (23.17 %) participants developed CTRCD. T1ρ and T1 values progressively increased over time (all p < 0.001), while T2 values increased at 3 (p < 0.001 and p = 0.002, respectively) and 6 months (all p < 0.001) compared to baseline in both the CTRCD (+) and CTRCD (−) groups. The changes in T1ρ (OR, 3.892, p = 0.003) and T1 (OR, 1.082, p = 0.002) from baseline to 3 months were associated with subsequent CTRCD. The combination of the changes in T1ρ and T1 from baseline to 3 months obtained an improved area under the curve of 0.853. ConclusionT1ρ, T1 and T2 increased after treatment of anthracyclines with/without trastuzumab. Myocardial T1ρ mapping provides additional predictive value to T1 mapping for subsequent CTRCD in breast cancer patients who received anthracyclines with/without trastuzumab. Clinical relevance statementMyocardial T1ρ mapping offers additional predictive value to T1 and T2 mapping for subsequent CTRCD in breast cancer patients who received anthracyclines with/without trastuzumab. This may facilitate accurate prediction of cardiotoxicity and personalized treatment decision making in breast cancer.

Analysis of myocardial T1, T2, and T2* values by age, sex, and cardiac segments in normal population: a prospective study.

This study examines myocardial T1, T2, and T2* values in a sizable cohort of healthy volunteers, analyzing variations by age, sex, and cardiac segments. It offers a novel approach to defining normal parametric mapping boundaries and represents the first comprehensive study of its kind in Turkey. Our prospective study was conducted between August 2021 and August 2022. Healthy volunteers aged 20-80 were grouped, with at least eight females and eight males per decade. Cardiac MRI examination measured T1 and T2 times in 16 left ventricle segments using parametric mapping techniques on a 1.5 Tesla MRI device. T2* mapping was also performed on the mid-section interventricular septum. The data analysis considered the impact of age, sex, and segments. One hundred eighteen cases were included in the study. Female volunteers observed significantly higher T1, T2, and T2* values than male volunteers. For the T2* and T1 times, significantly lower values were detected in women over 50 than those under 50. It was observed that the Midventricular approach (middle section) gave closer results than the Midventricular Septal approach (septal region of middle section) in predicting Global times. We present the normal reference ranges for cardiac T1, T2, and T2* times in a large cohort of healthy volunteers with homogeneous sex and age distribution. Sex was the most influential factor in our study. Therefore, we suggest using separate reference values for males, and females above and below 50 years old, instead of the standard reference intervals that do not account for specified sex in current guidelines.

T2 mapping post acute myocardial infarction: a novel technique in assessing myocardial edema

ObjectiveCardiovascular magnetic resonance (CMR) is considered the gold standard imaging modality for assessing myocardial infarction lesions, offering precise myocardial tissue characterization. Elevated transverse relaxation time (T2) serves as a specific indicator of increased myocardial water content, thus becoming a valuable index for myocardial edema. However, conventional T2-weighted CMR sequence exhibits several limitations, primarily providing qualitative information. In contrast, recently developed quantitative T2 mapping techniques overcome these limitations, enabling a more reliable assessment of myocardial edema. These techniques offer the advantage of diagnosing and monitoring myocardial injury without the necessity of contrast agents. Our study aims to add to a growing literature demonstrating the efficacy of quantitative T2 mapping technique to detect and quantify regions of myocardial edema post-myocardial infarction.ResultNative T1 and T2 mapping accurately identified myocardial edema in all patients enrolled in the study. Notably, native T1 and T2 values exhibited a significant elevation in the infarcted myocardium compared to the remote myocardium (for T1: 1295.50 ± 87.65 vs. 1074.95 ± 92.86 ms, respectively; and for T2: 74.63 ± 6.51 vs. 52.53 ± 6.26 ms, respectively; p < 0.0001 for both). Microvascular obstruction was observed in 12 out of 20 patients, affecting one or more myocardial segments within the infarct areas. Among this subgroup, regions with a microvascular obstruction within the infarct zone displayed lower T1 and T2 values compared to areas of infarction without microvascular obstruction (for T1: 1115.05 ± 64.70 vs. 1295.50 ± 87.65 ms, respectively; and for T2: 53.65 ± 3.56 vs. 74.63 ± 6.51 ms, respectively; p < 0.0001 for both). Additionally, we provided reference values for myocardial T1 and T2 specific to our facility’s 1.5 Tesla CMR system, applicable to both infarct and remote myocardium.ConclusionParametric T1 and T2 mapping techniques can detect and quantify myocardial edema resulting from myocardial infarction. The presence of microvascular obstruction that results from revascularization injury affects both T1 and T2 values. This information can be used and has broad clinical implications for diagnosis and guiding or monitoring the treatment of myocardial infarction.

Evaluation of Right Ventricular Myocardial Properties Using Systolic Myocardial T1 Mapping.

Introduction Myocardial properties can be quantitatively evaluated using myocardial native T1 values (nT1) obtained using cardiac magnetic resonance imaging (CMR). In terms of myocardial wall thickness, the left ventricular nT1 is easy to measure, but the right ventricular nT1 is difficult. Patients with congenital heart disease often develop right ventricular overload. If right ventricular nT1 can be measured consistently, inflammation and fibrosis of the right ventricular myocardium can be quantitatively evaluated. We aimed to determine whether T1 mapping during systole can be used to evaluate right ventricular myocardial properties. Methods T1 mapping was performed at diastole and systole. Systolic T1 mapping was calculated from diastolic T1 mapping and cine images. The myocardial properties of both ventricles were evaluated in 13 healthy volunteers (21-26 years old) and 12 patients with right ventricular overload (12-41 years old) who underwent CMR examination at our hospital. Results From the analysis of left ventricular nT1, we found that nT1 did not change significantly during the cardiac cycle. However, right ventricular nT1 changed between diastole and systole because the right ventricle is affected by blood. Although there was no difference in right ventricular diastolic nT1 between the patients and volunteers (1,346.8 vs. 1,347.6 ms, p = 0.852), the right ventricular systolic nT1 was significantly higher in patients than in volunteers (1,312.7 vs. 1,233.8 ms, p = 0.002). This indicates that right ventricular myocardial damage occurs in patients with right ventricular overload. Conclusion Systolic right ventricular myocardial T1 mapping allows assessment of right ventricular myocardial properties. The right ventricular myocardial systolic nT1 is useful for evaluating myocardial damage due to right ventricular stress and myocardial injury. Measuring right ventricular nT1 may allow consideration of early therapeutic intervention.

Assessing Gene Therapy Efficacy in Infantile-Onset Pompe Disease: Myocardial Native T1 Values of CMR

We report the novel finding of a widespread reduction in myocardial native T1 values and size of abnormal regions following gene therapy in a pediatric patient with infantile-onset Pompe disease. We emphasize the importance of serial cardiac magnetic resonance in assessing the efficacy of gene therapy and monitoring myocardial alterations in Pompe disease.

Quantification of Cardiac Iron Overload at 3 T MRI in a Rabbit Model Utilizing ME-GRE T2* Sequence.

Myocardial iron overload can lead to myocardial dysfunction, muscle cell injury, and end-stage heart failure. The enhanced signal-to-noise ratio and technical advancements have made 3 T magnetic resonance imaging (MRI) more accessible in clinical settings. However, 3 T assessments for early diagnosis of myocardial iron overload are scarce. To evaluate the feasibility of myocardial iron quantification using 3 T MRI in a rabbit model of iron overload. Animal model. Overall, 40 male New Zealand white rabbits were categorized into control (N = 8; no treatment) and experimental (N = 32; weekly 200 mg/kg iron dextran injections) groups. 3 T MRI with multi-echo gradient echo (ME-GRE) T2* sequence. Each week, two experimental rabbits were randomly selected for blood collection to determine serum iron (SI) levels; their tissue was harvested to assess myocardial and hepatic iron deposition. Spearman's rank correlation tests were used to evaluate the correlations among R2*, cardiac iron concentration (CIC), liver iron concentration (LIC), total amount of iron injected, and SI levels. P ≤ 0.05 was considered statistically significant. The myocardial T2* value in the experimental group was significantly lower than that of the control group. An excellent correlation was observed between R2* values and CIC (r = 0.854). CIC moderately correlated with LIC (r = 0.712) and the total amount of iron injected (r = 0.698). A strong correlation was observed between the total amount of iron injected and LIC (r = 0.866). SI levels poorly correlated with the total amount of iron injected (r = 0.205, P = 0.277) and LIC (r = 0.170, P = 0.370) but fairly correlated with CIC (r = 0.415, P = 0.022). A 3 T MRI with an ME-GRE sequence may serve as a noninvasive method for evaluating cardiac iron content. N/A TECHNICAL EFFICACY: Stage 1.

Development and performance evaluation of fully automated deep learning-based models for myocardial segmentation on T1 mapping MRI data

To develop a deep learning-based model capable of segmenting the left ventricular (LV) myocardium on native T1 maps from cardiac MRI in both long-axis and short-axis orientations. Models were trained on native myocardial T1 maps from 50 healthy volunteers and 75 patients using manual segmentation as the reference standard. Based on a U-Net architecture, we systematically optimized the model design using two different training metrics (Sørensen-Dice coefficient = DSC and Intersection-over-Union = IOU), two different activation functions (ReLU and LeakyReLU) and various numbers of training epochs. Training with DSC metric and a ReLU activation function over 35 epochs achieved the highest overall performance (mean error in T1 10.6 ± 17.9 ms, mean DSC 0.88 ± 0.07). Limits of agreement between model results and ground truth were from -35.5 to + 36.1 ms. This was superior to the agreement between two human raters (-34.7 to + 59.1 ms). Segmentation was as accurate for long-axis views (mean error T1: 6.77 ± 8.3 ms, mean DSC: 0.89 ± 0.03) as for short-axis images (mean error ΔT1: 11.6 ± 19.7 ms, mean DSC: 0.88 ± 0.08). Fully automated segmentation and quantitative analysis of native myocardial T1 maps is possible in both long-axis and short-axis orientations with very high accuracy.

Mineralocorticoid Receptor Antagonism Prevents Aortic Plaque Progression and Reduces Left Ventricular Mass and Fibrosis in Patients With Type 2 Diabetes and Chronic Kidney Disease: The MAGMA Trial.

Persistent mineralocorticoid receptor activation is a pathologic response in type 2 diabetes and chronic kidney disease. Whereas mineralocorticoid receptor antagonists are beneficial in reducing cardiovascular complications, direct mechanistic pathways for these effects in humans are lacking. The MAGMA trial (Mineralocorticoid Receptor Antagonism Clinical Evaluation in Atherosclerosis) was a randomized, double-blind, placebo-controlled trial in patients with high-risk type 2 diabetes with chronic kidney disease (not receiving dialysis) on maximum tolerated renin-angiotensin system blockade. The primary end point was change in thoracic aortic wall volume, expressed as absolute or percent value (ΔTWV or ΔPWV), using 3T magnetic resonance imaging at 12 months. Secondary end points were changes in left ventricle (LV) mass; LV fibrosis, measured as a change in myocardial native T1; and 24-hour ambulatory and central aortic blood pressures. Tertiary end points included plasma proteomic changes in 7596 plasma proteins using an aptamer-based assay. A total of 79 patients were randomized to placebo (n=42) or 25 mg of spironolactone daily (n=37). After a modified intent-to-treat, including available baseline data of study end points, patients who completed the trial protocol were included in the final analyses. At the 12-month follow-up, the average change in PWV was 7.1±10.7% in the placebo group and 0.87±10.0% in the spironolactone group (P=0.028), and ΔTWV was 1.2±1.7 cm3 in the placebo group and 0.037±1.9 cm3 in the spironolactone group (P=0.022). Change in LV mass was 3.1±8.4 g in the placebo group and -5.8±8.4 g in the spironolactone group (P=0.001). Changes in LV T1 values were significantly different between the placebo and spironolactone groups (26.0±41.9 ms in the placebo group versus a decrease of -10.1±36.3 ms in the spironolactone group; P=6.33×10-4). Mediation analysis revealed that the spironolactone effect on thoracic aortic wall volume and myocardial mass remained significant after adjustment for ambulatory and central blood pressures. Proteomic analysis revealed a dominant effect of spironolactone on pathways involving oxidative stress, inflammation, and leukocyte activation. Among patients with diabetes with moderate to severe chronic kidney disease at elevated cardiovascular risk, treatment with spironolactone prevented progression of aortic wall volume and resulted in regression of LV mass and favorable alterations in native T1, suggesting amelioration of left-ventricular fibrosis. URL: https://www.clinicaltrials.gov; Unique identifier: NCT02169089.

Global and regional cardiac magnetic resonance feature tracking left ventricular strain analysis in assessing early myocardial disease in β thalassemia major patients

BackgroundCardiac magnetic resonance imaging (CMR) is the modality of choice for quantification of myocardial iron overload in β-thalassemia major patients using the T2* sequence. CMR feature tracking (FT) is a recent magnetic resonance imaging tool that gives an idea about myocardial fibers deformation; thus, it can detect early impairment in myocardial function even before the reduction in ejection fraction.MethodsThis study aims to assess the ability of left ventricular CMR-FT in the early detection of systolic dysfunction in β thalassemia major patients and to correlate it with the degree of myocardial iron overload measured by CMR T2*. This prospective study enrolled 57 β thalassemia major patients who received long-term blood transfusion and 20 healthy controls. CMR was used to evaluate left ventricular volumes, ejection fraction, and the amount of myocardial T2*. A two-dimensional left ventricular FT analysis was performed. Both global and segmental left ventricular strain values were obtained.ResultsThe mean global circumferential strain (GCS) and global radial strain (GRS) values were significantly lower in patients compared to control (P = 0.002 and P = 0.006, respectively). No correlation was found between T2* values and ejection fraction; however, there was a significant correlation between T2* values and GCS and GRS (P = 0.012 and P = 0.025, respectively) in thalassemia patients. Regional strain revealed significantly lower values of GCS and GRS in basal regions compared to apical ones (P = 0.000).ConclusionsOur study revealed that CMR-FT can play a role in the early detection of systolic impairment in thalassemia patients.

Myocardial Fibrosis in Young and Veteran Athletes: Evidence from a Systematic Review of the Current Literature.

Background: Exercise is associated with several cardiac adaptations that can enhance one's cardiac output and allow one to sustain a higher level of oxygen demand for prolonged periods. However, adverse cardiac remodelling, such as myocardial fibrosis, has been identified in athletes engaging in long-term endurance exercise. Cardiac magnetic resonance (CMR) imaging is considered the noninvasive gold standard for its detection and quantification. This review seeks to highlight factors that contribute to the development of myocardial fibrosis in athletes and provide insights into the assessment and interpretation of myocardial fibrosis in athletes. Methods: A literature search was performed using the PubMed/Medline database and Google Scholar for publications that assessed myocardial fibrosis in athletes using CMR. Results: A total of 21 studies involving 1642 endurance athletes were included in the analysis, and myocardial fibrosis was found in 378 of 1595 athletes. A higher prevalence was seen in athletes with cardiac remodelling compared to control subjects (23.7 vs. 3.3%, p < 0.001). Similarly, we found that young endurance athletes had a significantly higher prevalence than veteran athletes (27.7 vs. 19.9%, p < 0.001), while male and female athletes were similar (19.7 vs. 16.4%, p = 0.207). Major myocardial fibrosis (nonischaemic and ischaemic patterns) was predominately observed in veteran athletes, particularly in males and infrequently in young athletes. The right ventricular insertion point was the most common fibrosis location, occurring in the majority of female (96%) and young athletes (84%). Myocardial native T1 values were significantly lower in athletes at 1.5 T (p < 0.001) and 3 T (p = 0.004), although they had similar extracellular volume values to those of control groups. Conclusions: The development of myocardial fibrosis in athletes appears to be a multifactorial process, with genetics, hormones, the exercise dose, and an adverse cardiovascular risk profile playing key roles. Major myocardial fibrosis is not a benign finding and warrants a comprehensive evaluation and follow-up regarding potential cardiac disease.

Myocardial hypertrophy: the differentiation of uremic, hypertensive, and hypertrophic cardiomyopathies by cardiac MRI

ObjectivesTo apply cardiac magnetic resonance imaging (CMR) for detailed myocardial characterization in uremic cardiomyopathy (UC), hypertensive cardiomyopathy (HTN), and hypertrophic cardiomyopathy (HCM) aiming to enrich the understanding of UC’s etiology and further support the development of therapeutic strategies.MethodsA total of 152 patients (age: 49.2 ± 9.9 years; 65.8% male) underwent routine CMR from June 2016 to March 2023. Retrospectively, 53 patients with UC, 39 patients with HTN, 30 patients with HCM, and 30 healthy controls were included. Functional analysis, feature tracking of the left ventricle and left atrium, and myocardial T1, T2, and T2* mapping were performed. Statistical analysis included Pearson correlation and ROC analysis to define correlations and discriminators between groups.ResultsUC patients demonstrated significantly higher native T1 (p < 0.001 for all) and T2 (p < 0.002 for all) values compared with the other three groups. UC patients revealed higher left atrial reservoir strain rate (p < 0.001 for all) and left atrial conduit strain rate (p < 0.001 for all) absolute values as compared with HTN and HCM patients. A significant correlation between T1 and T2 values in UC patients (r = 0.511, p < 0.001) was found. The combination of T1 values and strain parameters was the best discriminator between UC and HTN patients (AUC = 0.872, 95% CI: 0.801–0.943) and between UC and HCM patients (AUC = 0.840, 95% CI: 0.746–0.934).ConclusionUC reveals distinguishing tissue characteristics as evidenced by T1 and T2 mapping, as well as distinguishing functional strain parameters as compared with other hypertrophic phenotypes such as HTN and HCM.Critical relevance statementThe use of CMR imaging in UC patients offers incremental information to elucidate its complex etiology, contributing to ongoing discourse on effective treatment pathways.Key PointsThis study investigated uremic, hypertensive, and hypertrophic cardiomyopathies using cardiac MRI.UC patients have higher T1 and T2 values and better preserved cardiac function.Combined strain and T1 values distinguish UC from other cardiomyopathies.Graphical

Lung water density is increased in patients at risk of heart failure and is largely independent of conventional cardiovascular magnetic resonance measures.

Non-invasive methods to quantify pulmonary congestion are lacking in clinical practice. Cardiovascular magnetic resonance (CMR) lung water density (LWD) mapping is accurate and reproducible and has prognostic value. However, it is not known whether LWD is associated with routinely acquired CMR parameters. This was an observational cohort including healthy controls and patients at risk of heart failure. LWD was measured using CMR with a free-breathing short echo time 3D Cartesian gradient-echo sequence with a respiratory navigator at 1.5 T. Associations were assessed between LWD, lung water volume and cardiac volumes, left ventricular (LV) mass and function, myocardial native T1, and extracellular volume fraction. In patients at risk for heart failure (n = 155), LWD was greater than in healthy controls (n = 15) (30.4 ± 5.0 vs. 27.2 ± 4.3%, P = 0.02). Using receiver operating characteristic analysis, the optimal cut-off for LWD was 27.6% to detect at-risk patients (sensitivity 72%, specificity 73%, positive likelihood ratio 2.7, and inverse negative likelihood ratio 2.6). LWD was univariably associated with body mass index (BMI), hypertension, right atrial area, and LV mass. In multivariable linear regression, only BMI remained associated with LWD (R 2 = 0.32, P < 0.001). LWD is increased in patients at risk for heart failure compared with controls and is only weakly explained by conventional CMR measures. LWD provides diagnostic information that is largely independent of conventional CMR measures.

Test-retest repeatability of myocardial radiomic features from quantitative cardiac magnetic resonance T1 and T2 mapping

Radiomics of cardiac magnetic resonance (MR) imaging has proved to be potentially useful in the study of various myocardial diseases. Therefore, assessing the repeatability degree in radiomic features measurement is of fundamental importance.The aim of this study was to assess test-retest repeatability of myocardial radiomic features extracted from quantitative T1 and T2 maps.A representative group of 24 subjects (mean age 54 ± 18 years) referred for clinical cardiac MR imaging were enrolled in the study. For each subject, T1 and T2 mapping through MOLLI and T2-prepared TrueFISP acquisition sequences, respectively, were performed at 1.5 T. Then, 98 radiomic features of different classes (shape, first-order, second-order) were extracted from a region of interest encompassing the whole left ventricle myocardium in a short axis slice. The repeatability was assessed performing different and complementary analyses: intraclass correlation coefficient (ICC) and limits of agreement (LOA) (i.e., the interval within which 95% of the percentage differences between two repeated measures are expected to lie).Radiomic features were characterized by a relatively wide range of repeatability degree in terms of both ICC and LOA. Overall, 44.9% and 38.8% of radiomic features showed ICC values > 0.75 for T1 and T2 maps, respectively, while 25.5% and 23.4% of radiomic features showed LOA between ±10%. A subset of radiomic features for T1 (Mean, Median, 10Percentile, 90Percentile, RootMeanSquared, Imc2, RunLengthNonUniformityNormalized, RunPercentage and ShortRunEmphasis) and T2 (MaximumDiameter, RunLengthNonUniformityNormalized, RunPercentage, ShortRunEmphasis) maps presented both ICC > 0.75 and LOA between ±5%.Overall, radiomic features extracted from T1 maps showed better repeatability performance than those extracted from T2 maps, with shape features characterized by better repeatability than first-order and textural features. Moreover, only a limited subset of 9 and 4 radiomic features for T1 and T2 maps, respectively, showed high repeatability degree in terms of both ICC and LOA. These results confirm the importance of assessing test-retest repeatability degree in radiomic feature estimation and might be useful for a more effective/reliable use of myocardial T1 and T2 mapping radiomics in clinical or research studies.