Cardiovascular Magnetic Resonance Study Research Articles

Inflammation Links Cardiac Injury and Renal Dysfunction: A Cardiovascular Magnetic Resonance Study

Inflammation Links Cardiac Injury and Renal Dysfunction: A Cardiovascular Magnetic Resonance Study

The effect of hyperlipidemia and body fat distribution on subclinical left ventricular function in obesity: a cardiovascular magnetic resonance study

BackgroundObesity is often associated with multiple comorbidities. However, whether obese subjects with hyperlipidemia in the absence of other complications have worse cardiac indices than metabolically healthy obese subjects is unclear. Therefore, we aimed to determine the effect of hyperlipidemia on subclinical left ventricular (LV) function in obesity and to evaluate the association of cardiac parameters with body fat distribution.Materials and methodsNinety-two adults were recruited and divided into 3 groups: obesity with hyperlipidemia (n = 24, 14 males), obesity without hyperlipidemia (n = 25, 13 males), and c ntrols (n = 43, 25 males). LV strain parameters (peak strain (PS), peak diastolic strain rate (PDSR), peak systolic strain rate) derived from cardiovascular magnetic resonance tissue tracking were measured and compared. Dual-energy X-ray absorptiometer was used to measure body fat distribution. Correlations of hyperlipidemia and body fat distribution with LV strain were assessed by multivariable linear regression.ResultsObese individuals with preserved LV ejection fraction showed lower global LV longitudinal, circumferential, and radial PS and longitudinal and circumferential PDSR than controls (all P < 0.05). Among obese patients, those with hyperlipidemia had lower longitudinal PS and PDSR and circumferential PDSR than those without hyperlipidemia (− 12.8 ± 2.9% vs. − 14.2 ± 2.7%, 0.8 ± 0.1 s−1 vs. 0.9 ± 0.3 s−1, 1.2 ± 0.2 s−1 vs. 1.4 ± 0.2 s−1; all P < 0.05). Multivariable linear regression demonstrated that hyperlipidemia was independently associated with circumferential PDSR (β = − 0.477, P < 0.05) in obesity after controlling for growth differences, other cardiovascular risk factors, and central fat distribution. In addition, android fat had an independently negative relationship with longitudinal and radial PS (β = − 0.486 and β = − 0.408, respectively; all P < 0.05); and visceral fat was negatively associated with longitudinal PDSR (β = − 0.563, P < 0.05). Differently, gynoid fat was positively correlated with circumferential PS and PDSR and radial PDSR (β = 0.490, β = 0.481, and β = 0.413, respectively; all P < 0.05).ConclusionHyperlipidemia is independently associated with subclinical LV diastolic dysfunction in obesity. Central fat distribution (android and visceral fat) has a negative association, while peripheral fat distribution (gynoid fat) has a positive association on subclinical LV function. These results suggest that appropriate management of hyperlipidemia may be beneficial for obese patients, and that the differentiation of fat distribution in different regions may facilitate the precise management of obese patients.Clinical trials registration Effect of lifestyle intervention on metabolism of obese patients based on smart phone software (ChiCTR1900026476).

Enhanced Myocardial Tissue Visualization: A Comparative Cardiovascular Magnetic Resonance Study of Gradient-Spin Echo-STIR and Conventional STIR Imaging.

This study is aimed at evaluating the efficacy of the gradient-spin echo- (GraSE-) based short tau inversion recovery (STIR) sequence (GraSE-STIR) in cardiovascular magnetic resonance (CMR) imaging compared to the conventional turbo spin echo- (TSE-) based STIR sequence, specifically focusing on image quality, specific absorption rate (SAR), and image acquisition time. In a prospective study, we examined forty-four normal volunteers and seventeen patients referred for CMR imaging using conventional STIR and GraSE-STIR techniques. Signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), image quality, T2 signal intensity (SI) ratio, SAR, and image acquisition time were compared between both sequences. GraSE-STIR showed significant improvements in image quality (4.15 ± 0.8 vs. 3.34 ± 0.9, p = 0.024) and cardiac motion artifact reduction (7 vs. 18 out of 53, p = 0.038) compared to conventional STIR. Furthermore, the acquisition time (27.17 ± 3.53 vs. 36.9 ± 4.08 seconds, p = 0.041) and the local torso SAR (<13% vs. <17%, p = 0.047) were significantly lower for GraSE-STIR compared to conventional STIR in short-axis plan. However, no significant differences were shown in T2 SI ratio (p = 0.141), SNR (p = 0.093), CNR (p = 0.068), and SAR (p = 0.071) between these two sequences. GraSE-STIR offers notable advantages over conventional STIR sequence, with improved image quality, reduced motion artifacts, and shorter acquisition times. These findings highlight the potential of GraSE-STIR as a valuable technique for routine clinical CMR imaging.

Comparative prognostic importance of measures of left atrial structure and function in non-ischaemic dilated cardiomyopathy.

To compare the association between measures of left atrial (LA) structure and function, derived from cardiovascular magnetic resonance (CMR), with cardiovascular (CV) death or non-fatal heart failure (HF) events in patients with non-ischaemic dilated cardiomyopathy (DCM). CMR studies of 580 prospectively recruited patients with DCM in sinus rhythm (median age 54 [interquartile range 44-64] years, 61% men, median LVEF 42% [30-51%]) were analysed for measures of LA structure (left atrial maximum volume index [LAVImax], left atrial minimum volume index [LAVImin]) and function (left atrial emptying fraction [LAEF], left atrial reservoir strain [LARS], left atrial conduit strain [LACS] and left atrial booster strain [LABS]). Over median follow-up of 7.4 years, 103 patients (18%) met the primary endpoint. Apart from LACS, each measure of LA structure and function was associated with the primary endpoint after adjusting for other important prognostic variables. The addition of each LA metric to a baseline model containing the same important prognostic covariates improved model discrimination, with LAVImin providing the greatest improvement (C-statistic improvement: 0.702 to 0.738; χ2 test comparing likelihood ratio p < 0.0001; categorical net reclassification index: 0.210 (95% CI 0.023-0.392)). Patients in the highest tercile of LAVImin had similar event rates to those with persistent atrial fibrillation. Measures of LA strain did not enhance model discrimination above LA volumetric measures. Measure of left atrial structure and function offer important prognostic information in patients with DCM and enhance prediction of adverse outcomes. LA strain was not incremental to volumetric analysis for risk prediction.

Left atrial strain in patients with β-thalassemia major: a cross-sectional CMR study.

The aim of this cross-sectional study was to investigate the association of left atrial (LA) strain parameters with demographics, clinical data, cardiovascular magnetic resonance (CMR) findings, and cardiac complications (heart failure and arrhythmias) in a cohort of patients with β-thalassemia major (β-TM). We considered 264 β-TM patients (133 females, 36.79 ± 11.95 years) consecutively enrolled in the Extension-Myocardial Iron Overload in Thalassemia (E-MIOT) project. Moreover, we included 35 sex- and age-matched healthy controls (14 females, mean age 37.36 ± 17.52 years). Reservoir, conduit, and booster LA functions were analysed by CMR feature tracking using dedicated software. Compared to the healthy control group, β-TM patients demonstrated lower LA reservoir strain and booster strains, as well as LA reservoir and booster strain rates. However, no differences were found in LA conduit deformation parameters. In β-TM patients, ageing, sex, and left ventricle (LV) volume indexes were independent determinants of LA strain parameters. The number of segments with late gadolinium enhancement (LGE) significantly correlated with all LA strain parameters, with the exception of the LA conduit rate. Patients with cardiac complications exhibited significantly impaired strain parameters compared to patients without cardiac complications. In patients with β-TM, LA strain parameters were impaired compared to control subjects, and they exhibited a significant correlation with the number of LV segments with LGE. Furthermore, patients with cardiac complications had impaired left atrial strain parameters. Clinical relevance statement In patients with β-thalassemia major, left atrial strain parameters were impaired compared to control subjects and emerged as a sensitive marker of cardiac complications, stronger than cardiac iron levels. • Compared to healthy subjects, β-thalassemia major patients demonstrated significantly lower left atrial reservoir strain and booster strains, as well as left atrial reservoir and booster strain rates. • In β-thalassemia major, ageing, sex, and left ventricular volume indexes were independent determinants of left atrial strain parameters, while left atrial strain parameters were not correlated with myocardial iron overload. • An independent association between reduced left atrial strain parameters and a history of cardiac complications was found in β-thalassemia major patients.

Sex-based Differences in the Phenotypic Expression and Prognosis of Idiopathic Non-ischemic Cardiomyopathy: A Cardiovascular Magnetic Resonance Study.

We sought to characterize sex-related differences in CMR-based cardiovascular phenotypes and prognosis in patients with idiopathic non-ischemic cardiomyopathy (NICM). Patients with NICM enrolled in the Cardiovascular Imaging Registry of Calgary (CIROC) between 2015 and 2021 were identified. Z-score values for chamber volumes and function were calculated as standard deviation from mean values of 157 sex-matched healthy volunteers, ensuring reported differences were independent of known sex-dependencies. Patients were followed for the composite outcome of all-cause mortality, heart failure admission, or ventricular arrhythmia.A total of 747 patients were studied, 531 (71%) males. By Z-score values, females showed significantly higher left ventricular (LV) ejection fraction (EF; median difference 1 SD) and right ventricular (RV) EF (difference 0.6 SD) with greater LV mass (difference 2.1 SD; p-value<0.01 for all) versus males despite similar chamber volumes. Females had a significantly lower prevalence of mid-wall striae (MWS) fibrosis (23% versus 36%; p-value<0.001). Over a median follow-up of 4.7 years, 173 patients (23%) developed the composite outcome, with equal distribution in males and females. LV EF and MWS were significant independent predictors of the outcome (respective HR [95% CI] 0.97 [0.95-0.99] and 1.6 [1.2-2.3]; p-value=0.003 and 0.005). There was no association of sex with the outcome. In a large contemporary cohort, NICM was uniquely expressed in females versus males. Despite similar chamber dilation, females demonstrated greater concentric remodelling, lower reductions in bi-ventricular function, and a lower burden of replacement fibrosis. Overall, their prognosis remained similar to male patients with NICM.

False lumen hemodynamics and partial thrombosis in chronic aortic dissection of the descending aorta.

Partial thrombosis of the false lumen (FL) in patients with chronic aortic dissection (AD) of the descending aorta has been associated with poor outcomes. Meanwhile, the fluid dynamic and biomechanical characteristics associated with partial thrombosis remain to be elucidated. This retrospective, single-center study tested the association between FL fluid dynamics and biomechanics and the presence and extent of FL thrombus. Patients with chronic non-thrombosed or partially thrombosed FLs in the descending aorta after an aortic dissection underwent computed tomography angiography, cardiovascular magnetic resonance (CMR) angiography, and a 4D flow CMR study. A comprehensive quantitative analysis was performed to test the association between FL thrombus presence and extent (percentage of FL with thrombus) and FL anatomy (diameter, entry tear location and size), fluid dynamics (inflow, rotational flow, wall shear stress, kinetic energy, and flow acceleration and stasis), and biomechanics (pulse wave velocity). Sixty-eight patients were included. In multivariate logistic regression FL kinetic energy (p = 0.038) discriminated the 33 patients with partial FL thrombosis from the 35 patients with no thrombosis. Similarly, in separated multivariate linear correlations kinetic energy (p = 0.006) and FL inflow (p = 0.002) were independently related to the extent of the thrombus. FL vortexes, flow acceleration and stasis, wall shear stress, and pulse wave velocity showed limited associations with thrombus presence and extent. In patients with chronic descending aorta dissection, false lumen kinetic energy is related to the presence and extent of false lumen thrombus. In patients with chronic aortic dissection of the descending aorta, false lumen hemodynamic parameters are closely linked with the presence and extent of false lumen thrombosis, and these non-invasive measures might be important in patient management. • Partial false lumen thrombosis has been associated with aortic growth in patients with chronic descending aortic dissection; therefore, the identification of prothrombotic flow conditions is desirable. • The presence of partial false lumen thrombosis as well as its extent was related with false lumen kinetic energy. • The assessment of false lumen hemodynamics may be important in the management of patients with chronic aortic dissection of the descending aorta.

Kiosk 3R-TB-01 - Improved Quantitative Flow Analysis of Main and Branch Pulmonary Arteries Distal to the Vortex in Repaired Tetralogy of Fallot- a Single Center 4D Flow Cardiovascular Magnetic Resonance Study

Kiosk 3R-TB-01 - Improved Quantitative Flow Analysis of Main and Branch Pulmonary Arteries Distal to the Vortex in Repaired Tetralogy of Fallot- a Single Center 4D Flow Cardiovascular Magnetic Resonance Study

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

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

Myocardial Fibrosis Improves in Young Patients with Sickle Cell Disease after Hematopoietic Cell Transplantation

Introduction: Cardiovascular complications are a leading cause of early mortality in patients with sickle cell disease (SCD). Chronic anemia, iron overload and repeated microvascular ischemic insults with reperfusion injury often result in progressive myocardial injury and maladaptive remodeling in SCD patients. Patients with SCD develop diffuse myocardial fibrosis, which can be detected by quantifying the myocardial extracellular volume (ECV) using cardiovascular magnetic resonance (CMR) imaging. Our group and others have previously shown that diffuse myocardial fibrosis is highly prevalent in both children and young adults with SCD, including those who have normal ventricular size and function by echocardiography. Additionally, we have shown that the disease modifying therapies (DMT) such as hydroxyurea or chronic transfusions do not appear to be protective against development of diffuse myocardial fibrosis. In a retrospective study, we found no difference in the myocardial ECV in patients who began DMT early (less than 6 years of age) versus later in life (at least 6 years or after) (Morin CE and Sharma A et al. Blood 2023.). Hematopoietic cell transplantation (HCT) can cure SCD, but myocardial effects of the therapy are unknown. Our goal was to evaluate cardiovascular parameters of function and injury, especially the progression of diffuse myocardial fibrosis, by comparing serial CMR studies performed before and after HCT in patients with SCD. Methods: We performed prospective CMR evaluation of children and young adults with SCD who received a matched sibling donor (MSD) or haploidentical donor (HAPLO) HCT following a reduced toxicity conditioning on a clinical trial (NCT04362293). CMR was performed pre-HCT, and at 1 month, and 12 months post-HCT. CMR-derived ventricular and atrial volumes were calculated. ECV was measured from T1 maps with a modified Look-Locker inversion recovery (MOLLI) sequence in short-axis. T2 and T2* maps were obtained. Regions of interest in the mid-ventricular septum were identified for analysis. We report descriptive statistics for CMR measures along with paired t-tests comparing patient ECV levels at 1-month and 12-months post-HCT to their respective baseline ECV. Results: Our study cohort consisted of 14 patients with SCD who underwent HCT and had serial CMR evaluations available. Thirteen patients had HbSS genotype and one had HbSC genotype. All patients were receiving DMT, either with hydroxyurea or chronic transfusions prior to HCT. Participants were majority male (57%) with median age of 15.2 years (range 6.8-21.3) at the pre-HCT CMR. Six received an MSD HCT and 8 received a HAPLO HCT. Ten patients each had follow up CMR evaluations performed at 1 month, and 12 months post-HCT. At 1 and 12 months post-HCT ejection fraction was preserved while biventricular volume and cardiac index decreased (Table 1). Compared to pre-HCT, ECV decreased from median 29% [range 27-38] to 28% (range 21-35, P= 0.061) at 1 month and 27% (range 24-31, P= 0.043) at 12 months post-HCT. There was no difference in the cardiac chamber sizes or the ECV measurements of those who received a MSD versus HAPLO HCT. Conclusions: We observed an improvement in cardiac chamber sizes with preservation of cardiac function as early as one month after HCT in patients with SCD. We further noted a reduction in ECV indicating a decrease in diffuse myocardial fibrosis in these young patients with SCD. To our knowledge, this is the first study to show that diffuse myocardial fibrosis can improve in patients with SCD after HCT. In addition to further corroborating the organ function protective effects of HCT in patients with SCD, these data further demonstrate the use of CMR as an essential non-invasive tool to assess the effects of therapeutic interventions on SCD-cardiac injury.

Obesity-Related Differences in Pathomechanism and Outcomes in Patients With HFpEF: A CMR Study

BackgroundClinical significance of an integrated evaluation of epicardial adipose tissue (EAT) and the right ventricle (RV) in heart failure with preserved ejection fraction (HFpEF) is unknown. ObjectivesThe authors investigated the potential of EAT and RV quantification for obesity-related pathophysiology and risk stratification in obese HFpEF patients using cardiovascular magnetic resonance (CMR). MethodsA total of 150 patients (obese, body mass index ≥30 kg/m2; n = 73, nonobese, body mass index <30 kg/m2; n = 77) with a clinical diagnosis of HFpEF undergoing CMR were retrospectively identified. EAT volume surrounding both ventricles were quantified with manual delineation on cine images. Total RV volume (TRVV) was calculated as the sum of RV cavity and mass at end-diastole. The endpoint was the composite of all-cause mortality and first HF hospitalization. ResultsDuring a median follow-up of 46 months, 39 nonobese patients (51%) and 32 obese patients (44%) experienced the endpoint. EAT was a prognostic biomarker regardless of obesity and was independently correlated with TRVV. In obese HFpEF, EAT correlated with RV longitudinal strain (r = 0.32, P = 0.006), and increased amount of EAT and TRVV was associated with greater left ventricular end-diastolic eccentric index (r = 0.36, P = 0.002). The integration of RV quantification into EAT provided improved risk stratification with a C-statistic increase from 0.70 to 0.79 in obese HFpEF. Obese patients with EAT<130 ml and TRVV<180 ml had low risk (annual event rate 3.2%), while those with increased EAT ≥130 ml and TRVV ≥180 ml had significantly higher risk (annual event rate 11.8%; P < 0.001). ConclusionsCMR quantification of EAT and RV structure provides additive risk stratification for adverse outcomes in obese HFpEF.

Radiomics of pericardial fat: a new frontier in heart failure discrimination and prediction.

To use pericardial adipose tissue (PAT) radiomics phenotyping to differentiate existing and predict future heart failure (HF) cases in the UK Biobank. PAT segmentations were derived from cardiovascular magnetic resonance (CMR) studies using an automated quality-controlled model to define the region-of-interest for radiomics analysis. Prevalent (present at time of imaging) and incident (first occurrence after imaging) HF were ascertained using health record linkage. We created balanced cohorts of non-HF individuals for comparison. PyRadiomics was utilised to extract 104 radiomics features, of which 28 were chosen after excluding highly correlated ones (0.8). These features, plus sex and age, served as predictors in binary classification models trained separately to detect (1) prevalent and (2) incident HF. We tested seven modeling methods using tenfold nested cross-validation and examined feature importance with explainability methods. We studied 1204 participants in total, 297 participants with prevalent (60 ± 7years, 21% female) and 305 with incident (61 ± 6years, 32% female) HF, and an equal number of non-HF comparators. We achieved good discriminative performance for both prevalent (voting classifier; AUC: 0.76; F1 score: 0.70) and incident (light gradient boosting machine: AUC: 0.74; F1 score: 0.68) HF. Our radiomics models showed marginally better performance compared to PAT area alone. Increased PAT size (maximum 2D diameter in a given column or slice) and texture heterogeneity (sum entropy) were important features for prevalent and incident HF classification models. The amount and character of PAT discriminate individuals with prevalent HF and predict incidence of future HF. This study presents an innovative application of pericardial adipose tissue (PAT) radiomics phenotyping as a predictive tool for heart failure (HF), a major public health concern. By leveraging advanced machine learning methods, the research uncovers that the quantity and characteristics of PAT can be used to identify existing cases of HF and predict future occurrences. The enhanced performance of these radiomics models over PAT area alone supports the potential for better personalised care through earlier detection and prevention of HF. •PAT radiomics applied to CMR was used for the first time to derive binary machine learning classifiers to develop models for discrimination of prevalence and prediction of incident heart failure. •Models using PAT area provided acceptable discrimination between cases of prevalent or incident heart failure and comparator groups. •An increased PAT volume (increased diameter using shape features) and greater texture heterogeneity captured by radiomics texture features (increased sum entropy) can be used as an additional classifier marker for heart failure.

Prognostic value of first pass perfusion transit time beyond the pulmonary circulation

Abstract Background Pulmonary transit time (PTT), defined as the time required for a bolus of contrast agent to pass from the right cavities to the left cavities, is an emerging parameter reflective of cardiopulmonary hemodynamics that can be measured in first-pass perfusion cardiovascular magnetic resonance (CMR). Transit times along the left heart (LHTT) and perfusion times of peripheral organs have not been explored so far. Purpose To assess the prognostic value of LHTT and peripheral organs perfusion time in a cohort of patients with left ventricular (LV) disfunction. Methods 50 consecutive patients with LV disfunction (ejection fraction ≤45%) and 56 normal controls who underwent a CMR at our institution were selected. Transit time was calculated as the peak-to-peak time interval between two different areas of the cardiovascular system. PTT was assessed between right ventricle (RV) and left ventricle. LHTT was assessed between left atrium and ascending aorta. Myocardial perfusion time (MyoPT) was measured between left ventricle and the peak of myocardial perfusion. Peripheral organ perfusion (kidney, KPT; spleen, SPT and liver, LPT) between abdominal aorta and the peak organ perfusion. The primary end point was a composite of cardiovascular death, hospitalization, ventricular arrhythmias and the need of any cardiac invasive intervention within the first year. Results Compared with controls, LV disfunction patients presented higher PTT (7.4 [5.9-8.4] vs 11.9 [9.5-13.9] s, p&amp;lt;0.001), LHTT (1.9 [1.05-2.3] vs 3.3 [1.9-4.8] s, p&amp;lt;0.01), MyoPT (9.9 [7.8-11.5] vs 13.1 [9.7-18.6] s, p&amp;lt;0.01), KPT (9.4[7.8-11.2] vs 11.5[8.3-15.5] s, p = 0.012). SPT showed a non-significant trend (9.4[8.1-11.9] vs 11.5[7.9-13.4]s , p = 0.058) . There were no differences in LPT (28.9[24.4-35] vs 33.3[23.3-41.1] s, p = 0.267). Among the patients with LV disfunction, 16 subjects reached the composite end-point; compared to those who did not, these patients had significant higher values of PTT (10.1 [8.7-13.7] vs 13.4[10-15.7] s, p = 0.04), LHTT (2.3[1.8-4] vs 4.3 [3.3-5.8] s, p = 0.008) and MyoPT (10.5[8.8-17.5] vs 13.3[11.9-20.5] s, p = 0.049). SPT showed a non-significant trend (10.3[6.9-12.6] vs 12.6[10.9-17.1] s, p = 0.078), KPT and LPT showed no significant differences. Patients with worse prognosis also presented lower LV ejection fraction (LV: 34.7± 9.5 vs 25.5±9 %, p&amp;lt;0.001) but no significant differences in RV ejection fraction: 52.9±14 vs 49.3±13.8 %, p = 0.473). Due to the small number of events we did not performed a multivariate analysis. KPT showed a weak but significant positive correlation with the creatinine measured at the time of the CMR study (r = 0.262, p = 0.024) and also at follow-up (r = 0.247, p = 0.042). Conclusions Transit time is a surrogate marker of the heamodynamic status that can be assessed beyond the pulmonary circulation. LHTT and organ perfusion times are markedly altered in patients with LV disfunction and are associated with poor prognosis.

Incremental prognostic value of fully-automatic machine-learning based global circumferential strain during a stress CMR exam

Abstract Background Left ventricular global circumferential strain using cardiovascular magnetic resonance (CMR) is an accurate indicator to predict cardiovascular events. Although several studies have shown the excellent prognostic value of stress CMR, the prognostic value of stress global circumferential strain (sGCS) remains unknown. Purpose To investigate the prognostic value of sGCS for predicting cardiovascular events using a fully automatic machine learning algorithm without human correction in consecutive patients referred for stress CMR. Methods Between 2016 and 2018, all consecutive patients referred for stress CMR were included and followed for the occurrence of major adverse cardiovascular events (MACE), defined by cardiovascular death or nonfatal myocardial infarction (MI). A fully automatic machine learning algorithm was trained and validated on unseen CMR studies (MAGNETOM Aera and Skyra, Siemens Healthcare, Erlangen, Germany) to assess the sGCS from short-axis cine images at stress. The algorithm combines multiple deep learning networks for detection and segmentation with an active contours approach. Cox regressions were performed to determine the prognostic value of sGCS. Results Among 2,906 consecutive patients who underwent stress CMR, the automatic sGCS was successfully computed in 2,859 (98.4%) patients (68% male, mean age 64±12 years). A total of 256 (8.8%) MACEs were observed during a median (IQR) follow-up period of 4.5 (3.7-5.3) years. Using Kaplan-Meier analysis, sGCS and the presence of inducible ischemia were significantly associated with the occurrence of MACE (hazard ratio, HR: 1.12 [95% CI, 1.08-1.17]; and HR: 8.48 [95% CI, 6.05-11.91], both p&amp;lt;0.001; respectively). After adjustment for traditional risk factors, inducible ischemia and late gadolinium enhancement (LGE), sGCS was an independent predictor of a higher incidence of MACE (adjusted HR: 1.12 [95% CI, 1.05-1.20]). Finally, sGCS showed an incremental prognostic value to predict MACE compared to a multivariable model including traditional risk factors, the presence of inducible ischemia and LGE (C-statistic improvement: 0.05, p=0.007; NRI= 0.169; IDI= 0.097; both p&amp;lt;0.001). Conclusions Automatic sGCS has an incremental prognostic value to predict MACE above traditional risk factors, and other stress CMR parameters.Survival curvesIncremental prognostic value

Fully automated assessment of global longitudinal strain by machine learning predicts death in patients undergoing stress CMR

Abstract Background Several studies described the independent prognostic value of left ventricular global longitudinal strain (GLS) using cardiovascular magnetic resonance (CMR) to predict death and cardiovascular events. While routine GLS evaluation is a time consuming and partially operator-dependent process, the potential interest of GLS using a fully automated method has not yet been established. Purpose To assess the feasibility and prognostic value of GLS to predict all-cause death using a fully automated machine-learning algorithm without human correction in consecutive patients referred for stress CMR. Methods Between 2016 and 2018, all consecutive patients referred for stress CMR were included and followed for the occurrence of all-cause death. A fully automated machine learning algorithm was trained and validated on unseen CMR studies (MAGNETOM Aera and Skyra) to assess the GLS from long-axis cine images acquired at rest. The algorithm combines multiple deep learning networks for detection and segmentation with an active contours approach. Cox regressions were performed to determine the prognostic value of GLS. Results In a retrospective study of 9,883 consecutive patients who underwent stress CMR between 2016 and 2018, automated GLS was successfully computed in 9,638 (97.5%) patients (67% male, mean age 66±12 years). A total of 510 (5.3%) deaths were observed during a median follow-up period of 4.5 years (interquartile range: 3.7-5.2). GLS, the presence of inducible ischemia and late gadolinium enhancement (LGE) were significantly associated with the occurrence of death (hazard ratio, HR: 1.22 [95% CI, 1.17-1.26]; HR: 2.23 [95% CI, 1.61-3.10]; and HR: 2.04 [95% CI, 1.41-2.95], respectively, all p&amp;lt;0.001). After adjustment for traditional risk factors, inducible ischemia and LGE, GLS was an independent predictor of a higher incidence of death (adjusted HR: 1.14 [95% CI, 1.08-1.20]). Automated GLS showed an incremental prognostic value to predict death compared to traditional risk factors, inducible ischemia and LGE (C-statistic improvement: 0.05; NRI=0.146; IDI=0.244; all p&amp;lt;0.001). Conclusions Fully automated GLS measured at rest has an incremental prognostic value to predict all-cause death above traditional risk factors, and other stress CMR parameters. This finding suggests that unsupervised GLS measurements are accurate and allow improved risk stratification.

Abstract 15044: The Relationship of Pericardial Fat With Metabolic Change and Myocardial Remodelling Following Bariatric Surgery

Introduction: Pericardial fat is a cardiometabolic risk factor that can be quantified from routine cardiovascular magnetic resonance (CMR) studies. However the extent to which this is modifiable, and its relationship with cardiometabolic markers remains unclear. Aims: Determine the effect of bariatric surgery on pericardial fat and associate with cardiometabolic improvements post-surgery. Methods: Thirty-eight people referred for bariatric surgery were assessed pre-operatively using CMR, blood biomarkers and anthropometry. Six months post-operatively, twenty-seven participants underwent paired follow-up assessments. Pericardial fat was quantified manually from routine short axis cine stacks by a single blinded clinical observer. Linear regression was used to assess the association of pericardial fat volume and cardiometabolic parameters, at baseline and changes pre- vs post-surgery. Results: At baseline, pericardial fat volume was associated with multiple cardiometabolic parameters including weight (r=0.46 p=0.004), fasting insulin (r=-0.46, p=0.007) hepatic fat concentration (Hepafat) (r=0.37 p=0.029) and LV mass (r=0.38, p=0.019). Pericardial fat remained independently associated with waist circumference after adjusting for the above (β=0.68, 95% CI: 1.24,9.23, p=0.012). At 6 months post-bariatric surgery pericardial adipose tissue reduced by an average of 29% (95% CI: -21-36%, p&lt;0.001). This change was associated with improvements in fasting insulin levels even after adjusting for changes in weight, Hepafat and LV mass (β=0.72, 95% CI: 0.15, 0.70, p=0.005). Conclusion: Pericardial fat in obesity associates with multiple adverse cardiometabolic parameters, including waist circumference. Bariatric surgery causes a significant reduction in pericardial fat which associates with reduced insulin resistance, providing a potential modifiable mechanism to reduce cardiovascular risk in patients living with obesity.

Abstract 16140: Utility of Cardiovascular Magnetic Resonance Imaging in Clinical Decision Making for Children and Adolescents With Hypertrophic Cardiomyopathy

Introduction: Cardiovascular magnetic resonance (CMR) imaging is recommended for surveillance and risk stratification in patients with hypertrophic cardiomyopathy (HCM), but the role of CMR findings in clinical decision making has not been described in a pediatric population. Methods: In this single center retrospective study we identified all patients with HCM who underwent CMR. We then determined if there was a clinical management change based on CMR findings. Results: We identified 136 patients with an HCM diagnosis from 2005-2022. Of these, 55 patients (40%) underwent 76 CMR studies. The HCM etiology was genetic or familial in 31 (56%), idiopathic in 21 (38%), and syndromic in 3 (5%); 34% of patients were female; and the median age (and IQR) of included patients at first CMR was 12 (9-15) years old. Ten patients underwent more than one CMR. Both awake and sedated CMRs were included and there were no complications. Management changes included confirmation of HCM diagnosis in 9 patients (16%), change in medical therapy for 3 (5%), myectomy recommendation in 1 (2%), and implantable cardioverter defibrillator (ICD) placement recommendation in 11 (20%). Of those recommended for ICD placement, 8 were a result of new late gadolinium enhancement and 3 had massive septal hypertrophy (median Z-score 30) discovered or confirmed by CMR. To date, no ICDs have discharged any shocks. Altogether, changes in clinical management were made based on CMR findings for 22 patients (40%), representing a change in management as a result of 29% of the total CMRs performed. Conclusion: CMR is an important contributor to clinical decision making in the management of children and adolescents with HCM. Specifically, CMR in this population was especially useful in defining the diagnosis of HCM in the presence of an equivocal echocardiogram and deciding to place an ICD. Fewer CMRs contributed to decision making regarding medical therapy and septal myectomy.

Abstract 16291: Regional Variability in Cardiovascular MRI Access and Utilization in the U.S. Population From 2017 to 2019

Background: Despite clinical guidelines and scientific data supporting the use of cardiovascular magnetic resonance (CMR) imaging in multiple applications, CMR continues to be underutilized in the United States (U.S.). Objective: This study aims to capture geographic variability, access, and CMR practice patterns in the U.S. between 2017 and 2019. Methods: Commissioned reports from the Society of Cardiovascular Magnetic Resonance (SCMR), and data from a nationwide survey of CMR centers were used. Medicare claims for CMR studies from 2019 were compiled by the Moran Company. Surveys designed to collect data on center-specific characteristics were sent to 155 CMR centers identified through SCMR email listserve and Medicare claims data. Survey responses were reviewed to ensure only one response was captured from each center. Results: A total of 592 imaging centers were included in the Moran report and 112 unique centers responded to the survey. Of the centers included in the report, 47% billed for less than 10 of the most frequent study (CMR for morphology w/ dye) in 2019. The total density of CMR centers was 15.6 centers per million U.S. Medicare Part B beneficiaries. CMR centers are more dense in geographic areas of lowest socioeconomic disadvantage (based on the Area Deprivation Index), low poverty, and lowest percent of people lacking health insurance. Sixty-eight percent of survey responders were cardiologists, and 28% were radiologists. Seventy-two percent of centers reported performing 81-100% of their CMR exams in an academic healthcare system. Centers performing &gt;500 scans per year had an average of 19 years of experience, whereas centers performing &lt;50 scans had an average 3.5 years’ experience. The most common response for approximate patient wait time for CMR was 2 weeks to 1 month (45% of responses). Conclusions: Although CMR volume is increasing in the U.S., CMR access continues to demonstrate marked geographic variability. While almost half of centers are performing just a handful of scans annually, the greatest volumes are noted in well-established programs with years of experience. Identification of specific barriers to CMR access will be useful for future advocacy efforts and quality improvement initiatives.

Quantifying 4D flow cardiovascular magnetic resonance vortices in patients with pulmonary hypertension: A pilot study.

In this 4D flow cardiovascular magnetic resonance (CMR) study, vortical blood flow in the main pulmonary artery (MPA) is quantified using circulation (ᴦ), a metric used in fluid dynamics to quantify the rotational components of flow. Circulation (ᴦ) is a 4D flow CMR metric that quantifies the vortical blood flow pattern in the MPA of patients with pulmonary hypertension (PH), distinguishes them from healthy controls, and shows high correlation with invasive markers of PH severity.

Imaging characterization of myocardial function, fibrosis, and perfusion in a nonhuman primate model with heart failure-like features.

The availability of a human-like chronic heart failure (HF) animal model was critical for affiliating development of novel therapeutic drug treatments. With the close physiology relatedness to humans, the non-human primate (NHP) HF model would be valuable to better understand the pathophysiology and pharmacology of HF. The purpose of this work was to present preliminary cardiac image findings using echocardiography and cardiovascular magnetic resonance (CMR) in a HF-like cynomolgus macaque model. The NHP diet-induced model developed cardiac phenotypes that exhibited diastolic dysfunction with reduced left ventricular ejection fraction (LVEF) or preserved LVEF. Twenty cynomolgus monkeys with cardiac dysfunction were selected by echocardiography and subsequently separated into two groups, LVEF < 65% (termed as HFrEF, n = 10) and LVEF ≥ 65% with diastolic dysfunction (termed as HFpEF, n = 10). Another group of ten healthy monkeys was used as the healthy control. All monkeys underwent a CMR study to measure global longitudinal strain (GLS), myocardial extracellular volume (ECV), and late gadolinium enhancement (LGE). In healthy controls and HFpEF group, quantitative perfusion imaging scans at rest and under dobutamine stress were performed and myocardial perfusion reserve (MPR) was subsequently obtained. No LGE was observed in any monkey. Monkeys with HF-like features were significantly older, compared to the healthy control group. There were significant differences among the three groups in ECV (20.79 ± 3.65% in healthy controls; 27.06 ± 3.37% in HFpEF group, and 31.11 ± 4.50% in HFrEFgroup, p < 0.001), as well as for stress perfusion (2.40 ± 0.34 ml/min/g in healthy controls vs. 1.28 ± 0.24 ml/min/g in HFpEF group, p < 0.01) and corresponding MPR (1.83 ± 0.3 vs. 1.35 ± 0.29, p < 0.01). After adjusting for age, ECV (p = 0.01) and MPR (p = 0.048) still showed significant differences among the three groups. Our preliminary imaging findings demonstrated cardiac dysfunction, elevated ECV, and/or reduced MPR in this HF-like NHP model. This pilot study laid the foundation for further mechanistic research and the development of a drug testing platform for distinct HF pathophysiology.