Cardiac Magnetic Resonance Exam Research Articles

Effects of pirfenidone on scar size and ventricular remodeling after myocardial infarction: a preclinical study

Abstract Background An intense fibrotic response after myocardial infarction (MI) may lead to scar expansion and left ventricular (LV) remodeling, increasing the risk for ventricular arrhythmias and heart failure. Pirfenidone is a drug currently approved for the treatment of idiopathic pulmonary fibrosis, and reduces LV fibrosis in patients with heart failure and preserved ejection fraction. We aimed to characterize the different profiles or protein expression in the infarct zone in rats receiving or not receiving pirfenidone on top of standard therapy for MI. Methods Male Wistar rats were randomized to: sham procedure (group 1; n=13), reperfused MI induced by surgical ligation of the left anterior descending artery (LAD) for 45 minutes (group 2; n=17), reperfused MI plus standard therapy (aspirin, angiotensin-converting enzyme inhibitor, beta-blocker, and also mineralocorticoid receptor antagonist [MRA]) (group 3; n=17), reperfused MI plus pirfenidone alone (group 4; n=17), reperfused MI plus standard therapy and pirfenidone (group 5; n=17). Rats surviving LAD ligation and reperfusion underwent cardiac magnetic resonance (CMR) after 72 hours and 30 days from MI, and were sacrificed the day after the second CMR exam. The primary endpoint was the change in late gadolinium enhancement (LGE) mass as a percentage of LV mass. Results Forty-six rats survived until the second CMR. Percent changes in LV end-diastolic and end-systolic volume (p=0.370 and 0.423, respectively), ejection fraction (p=0.236) and mass (p=0.815) did not differ significantly between rats on pirfenidone plus standard therapy compared with those receiving standard therapy alone. The decrease in LGE mass was significantly greater in rats on pirfenidone plus standard therapy vs. those on standard therapy alone: -22.0% (interquartile range, -37.1 to -5.7, range -51.1 to +37.5) vs. +1.9% (-7.7 to +12.5, range -19.8 to +56.5), p=0.029. Conclusions Pirfenidone had additive effects to standard therapy for MI (including an MRA) in reducing LV fibrosis in a rat model of reperfused MI, while it did not further improve LV function, volumes or mass.

CMR imaging to study biventricular pacing effects on the right ventricle in left bundle branch block patients

Abstract Background Cardiac resynchronization therapy (CRT) is an established treatment strategy for selected patients with symptomatic heart failure, left ventricular (LV) systolic dysfunction, and a left bundle branch block conduction abnormality. The effect of CRT on right ventricular (RV) function and possible reverse remodeling however, is less well understood and conflicting data are present. Moreover, the difficulty to accurately measure RV hemodynamics non-invasively may also hamper research on RV function in CRT patients. Recent development of cardiac magnetic resonance (CMR) conditional CRT-devices allows for proper patient follow-up as BIV-pacing can be performed during the CMR exam. Therefore, this study assesses the effects of BIV-pacing on change in RV volumes and function using CMR. Methods Ten patients eligible for CRT-D implantation according to the ESC guidelines were prospectively enrolled in this study. All patients underwent CMR imaging at baseline including cine imaging for volume and function assessment. Six weeks after CRT-D implantation, patients received a follow-up CMR scan which consisted of a two-staged imaging protocol. First, patients were scanned during BIV-pacing and thereafter the CRT was turned off and patients were scanned during intrinsic rhythm. RV end systolic volume (ESV), end diastolic volume (EDV), and ejection fraction (RVEF) were assessed on cine images. RV volumes and function before and after device implantation are compared using paired samples T-tests and results are displayed in the figure. Results RV ESV, EDV, and RVEF were not different at CRT-on as compared to baseline (ESV; 94.0±20.3ml vs. 88.9±21.1ml, p=0.44, EDV; 182.4±29.5ml vs. 175.1±22.8ml, p=0.37, and RVEF; 48.6±6.6% vs. 49.6±8.1%, p=0.75). Also, an acute deterioration in RVEF was observed when switching CRT-off (48.6±6.6% vs. 41.1±5.7%, p=0.02). Moreover, RV function was significantly worse during CRT-off compared to baseline in terms of RVEF (41.1±5.7% vs. 49.6±8.1%, p<0.01) and higher volumes (ESV; 119.0±26.4ml vs. 88.9±21.1ml, p<0.001, EDV; 200.8±34.2ml vs. 175.1±22.8ml, p<0.01). Conclusions This study showed that RV hemodynamics did not benefit from CRT. Moreover, turning off CRT at follow-up had an instantaneous negative effect on RV function as compared to BIV-pacing, leading to even worse RV hemodynamics as compared to baseline measurements.

Automatic view plane prescription for cardiac magnetic resonance imaging via supervision by spatial relationship between views.

View planning for the acquisition of cardiac magnetic resonance (CMR) imaging remains a demanding task in clinical practice. Existing approaches to its automation relied either on an additional volumetric image not typically acquired in clinic routine, or on laborious manual annotations of cardiac structural landmarks. This work presents a clinic-compatible, annotation-free system for automatic CMR viewplanning. The system mines the spatial relationship-more specifically, locates the intersecting lines-between the target planes and source views, and trains U-Net-based deep networks to regress heatmaps defined by distances from the intersecting lines. On the one hand, the intersection lines are the prescription lines prescribed by the technologists at the time of image acquisition using cardiac landmarks, and retrospectively identified from the spatial relationship. On the other hand, as the spatial relationship is self-contained in properly stored data, for example, in the DICOM format, the need for additional manual annotation is eliminated. In addition, the interplay of the multiple target planes predicted in a source view is utilized in a stacked hourglass architecture consisting of repeated U-Net-style building blocks to gradually improve the regression. Then, a multiview planning strategy is proposed to aggregate information from the predicted heatmaps for all the source views of a target plane, for a globally optimal prescription, mimicking the similar strategy practiced by skilled human prescribers. For performance evaluation, the retrospectively identified planes prescribed by the technologists are used as the ground truth, and the plane angle differences and localization distances between the planes prescribed by our system and the ground truth arecompared. The retrospective experiments include 181 clinical CMR exams, which are randomly split into training, validation, and test sets in the ratio of 64:16:20. Our system yields the mean angular difference and point-to-plane distance of 5.68 and 3.12 mm, respectively, on the held-out test set. It not only achieves superior accuracy to existing approaches including conventional atlas-based and newer deep-learning-based in prescribing the four standard CMR planes but also demonstrates prescription of the first cardiac-anatomy-oriented plane(s) from the body-orientedscout. The proposed system demonstrates accurate automatic CMR view plane prescription based on deep learning on properly archived data, without the need for further manual annotation. This work opens a new direction for automatic view planning of anatomy-oriented medical imaging beyondCMR.

Evaluation of left ventricular and left atrial volumetric function from native MR multislice 4D flow magnitude data

ObjectivesTo assess the feasibility, precision, and accuracy of left ventricular (LV) and left atrial (LA) volumetric function evaluation from native magnetic resonance (MR) multislice 4D flow magnitude images.Materials & MethodsIn this prospective study, 60 subjects without signs or symptoms of heart failure underwent 3T native cardiac MR multislice 4D flow and bSSFP-cine realtime imaging. LV and LA volumetric function parameters were evaluated from 4D flow magnitude (4D flow-cine) and bSSFP-cine data using standard software to obtain end-diastolic volume (EDV), end-systolic volume (ESV), ejection-fraction (EF), stroke-volume (SV), LV muscle mass (LVM), LA maximum volume, LA minimum volume, and LA total ejection fraction (LATEF). Stroke volumes derived from both imaging methods were further compared to 4D pulmonary artery flow-derived net forward volumes (NFV). Methods were compared by correlation and Bland-Altman analysis.ResultsVolumetric function parameters from 4D flow-cine and bSSFP-cine showed high to very high correlations (r = 0.83-0.98). SV, LA volumes and LATEF did not differ between methods. LV end-diastolic and end-systolic volumes were slightly underestimated (EDV: –2.9 ± 5.8 mL; ESV: -2.3 ± 3.8 mL), EF was slightly overestimated (EF: 0.9 ± 2.6%), and LV mass was considerably overestimated (LVM: 39.0 ± 11.4 g) by 4D flow-cine imaging. SVs from both methods correlated very highly with NFV (r = 0.91 in both cases) and did not differ from NFV.ConclusionNative multislice 4D flow magnitude data allows precise evaluation of LV and LA volumetric parameters; however, apart from SV, LV volumetric parameters demonstrate bias and need to be referred to their respective normal values.Clinical relevance statementVolumetric function assessment from native multislice 4D flow magnitude images can be performed with routinely used clinical software, facilitating the application of 4D flow as a one-stop-shop functional cardiac MR exam, providing consistent, simultaneously acquired, volume and flow data.Key points• Native multislice 4D flow imaging allows evaluation of volumetric left ventricular and atrial function parameters.• Left ventricular and left atrial function parameters derived from native multislice 4D flow data correlate highly with corresponding standard cine-derived parameters.• Multislice 4D flow-derived volumetric stroke volume and net forward volume do not differ.

The pattern of late gadolinium enhancement by cardiac MRI in fulminant myocarditis and its prognostic implication: a two-year follow-up study.

Myocardial fibrosis, as quantified by late gadolinium enhancement (LGE) in cardiac magnetic resonance (CMR), provides valuable prognostic information for patients with myocarditis. However, due to the low incidence rate of fulminant myocarditis (FM) and accordingly small sample size, the knowledge about the role of LGE to patients with FM is limited. A total of 44 adults with viral-FM receiving the Chinese treating regimen were included in this retrospective study. They were divided into the low LGE group and the high LGE group according to the ratio of LGE to left ventricular mass (LGE mass%). CMR exams and LGE were performed after hemodynamic assistance at discharge in all patients with FM. Routine echocardiography parameters and global longitudinal strain (GLS) at discharge and at 2-year follow-up were obtained and then compared. Both left ventricular ejection fraction (LVEF) and GLS showed no significant difference in both groups at discharge, whereas significant differences were observed at 2-year follow-up between two groups. Moreover, there were significant improvements of LVEF and GLS in the low LGE group, but not in the high LGE group during the 2-year period. Furthermore, LGE mass% was negatively correlated with GLS and LVEF. There were two distinct forms of LGE presentation in patients with FM. Moreover, the cardiac function of patients with low LGE was significantly better than those with high LGE at 2-year follow-up. LGE mass% at discharge provided significant prognosis information about cardiac function of patients with FM.

Comparison of free-running whole-heart 5D and 4D flow imaging to standard 2D phase contrast in patients with right-sided congenital heart disease

Abstract Funding Acknowledgements Type of funding sources: None. Background Flow measurements by cardiac magnetic resonance (CMR) are part of a routine assessment in patients with congenital heart disease (CHD). Standard 2D phase contrast (2DPC) sequences, however, require precise prescription of image planes leading to long scan times which could be overcome by 3D-acquisitons covering the entire cardiac anatomy in a single acquisition. Thus, recently introduced accelerated free-breathing 3D whole heart flow sequences promise to simplify CMR exams allowing an easier acquisition and retrospective flow measurements in virtually all vessels. Purpose Comparison of standard 2DPC to an accelerated 4D flow sequence with prospective respiratory navigation (1), and a free-running radial fully self-gated respiratory and cardiac motion-resolved 5D flow sequence (5D flow) (2,3). Methods Patients with right-sided CHD and no intra- or extracardiac shunt underwent a CMR on a 1.5T scanner. 2DPC flow sequences and a 4D flow data set were obtained (1). In addition, a whole-heart free-running 3D radial PC CMR sequence was acquired (2). Using a compressed-sensing-based image reconstruction framework (2,3), 5D flow images were obtained, and the end-expiratory phase was used for analysis. 3D vessel segmentation was based on retrospectively computed phase-contrast angiography images for each 4D and 5D flow datasets. Flow measured in the ascending, descending aorta (AA, DA), main, right and left pulmonary artery (MPA, RPA, LPA) and superior vena cava (SVC) as well as the internal consistency for determination of systemic and pulmonary output were compared between all three sequences by Bland-Altman analyses. Results Twenty CHD patients (age 31±11y, 7 women, tetralogy of Fallot N=7, Ross operation N=10; pulmonary regurgitation, atrial switch and Ebstein’s disease each N=1) were included. Mean peak velocity of MPA/ right ventricle to pulmonary artery conduit was 1.9 (range 0.9; 3.5) m/s. Compared to 2DPC, both 4D and 5D flow moderately underestimated absolute flow with significant lower values for the RPA for 4D flow (Table 1). The bias (i.e. the mean absolute difference) of MPA flow between 2DPC and 4D flow was related to the MPA peak velocity (r2=0.3, p = 0.03) with a similar trend for the comparison of 2DPC vs. 5D flow (r2=0.142, p = 0.141). The comparison of the internal consistency for determination of systemic and pulmonary output showed similar results for 2DPC and 5D flow and a slightly lower agreement for the 4D flow sequence (Table 2). Conclusions In this preliminary study, 4D and 5D flow provide results comparable to 2DPC, however, both sequences showed a trend towards lower absolute flow values. Complex flow patterns due to the right-sided pathologies appear to have an impact on the difference observed between sequences as shown for the MPA. The internal consistency of flow quantification was similar for the 2DPC and 5D flow sequences. The presented observations are currently being evaluated in a larger study.

How different triggers affect CMR parameters in takotsubo syndrome

Abstract Funding Acknowledgements Type of funding sources: Public hospital(s). Main funding source(s): Ospedale Sant'Orsola (Bologna) Background Takotsubo syndrome (TTS) is an acute and transient heart failure syndrome characterized by a temporary wall motion abnormality of the left ventricle. Cardiac magnetic resonance (CMR) has a crucial role to assess ventricles function, regional wall motion abnormalities (RWMA), myocardial edema, late gadolinium enhancement (LGE) and complications. To date, there is a lack of how trigger events impact CMR parameters. Purpose To evaluate the clinical presentation, triggers of TTS and CMR parameters in patients hospitalized for Takotsubo Syndrome (TTS). Methods In our study we evaluated 128 patients hospitalized with TTS between January 2016 and December 2021 in Italy. Diagnosis of Takotsubo syndrome was based on the international Takotsubo diagnostic criteria (InterTAK Diagnostic Criteria). Results The mean age of the study population was 68.7 ± 11.1 years, and 81 % were females. Concerning the event trigger of TTS, 44% of patients experimented with an emotional event and 56% with physical stress. CMR was available in 66 patients, performed 7.5 ± 3.7 days after admission during hospitalization. CMR confirmed that most patients had typical TTS with apical ballooning (87%) while only 4.5% had a midventricular pattern. Left ventricular ejection fraction (LV-EF) mean was 55.3 ± 10.9 %. Mean LV-EF did not significant differ between emotional and physical trigger populations (51±12.5 vs 56.3±7.7; p = 0.12). Myocardial edema was present in 64.2% of patients and the mean number of segments involved was 6.2. ± 5.9. No statistical correlation between TTS trigger and the presence of edema at T2-weighted imaging was noticed. Spotty LGE was observed in 23.1 % of CMR exams, most evidenced in lateral (11.9 %) and inferior segments (10.4 %). LGE was evidenced more frequently in TTS triggered by physical events (38.1% vs 13%; p value=0.04) unlike pericardial effusion (0% vs 14%; p value= 0.04). Moreover, Hs-troponin I peak value was higher in the TTS physical triggered population than TTS with emotional trigger (3413 ± 4457 ng/l vs 2018 ± 2064 ng/l; p value= 0.04). Conclusions Early execution of CMR is essential in suspected TTS because several parameters are relatively time-dependent and derived from dynamic alterations that might resolve over time (such as myocardial edema). In our study patients with a physical trigger had a higher Hs-Troponin I max peak value and, more frequently spotty LGE on CMR. This could be the manifestation of more consistent myocardial damage compared to emotional triggers. However, the physiopathological and prognostic role of LGE in TTS remains unclear.

Deep learning-based left ventricular segmentation demonstrates improved performance on respiratory motion-resolved whole-heart reconstructions.

Deep learning (DL)-based segmentation has gained popularity for routine cardiac magnetic resonance (CMR) image analysis and in particular, delineation of left ventricular (LV) borders for LV volume determination. Free-breathing, self-navigated, whole-heart CMR exams provide high-resolution, isotropic coverage of the heart for assessment of cardiac anatomy including LV volume. The combination of whole-heart free-breathing CMR and DL-based LV segmentation has the potential to streamline the acquisition and analysis of clinical CMR exams. The purpose of this study was to compare the performance of a DL-based automatic LV segmentation network trained primarily on computed tomography (CT) images in two whole-heart CMR reconstruction methods: (1) an in-line respiratory motion-corrected (Mcorr) reconstruction and (2) an off-line, compressed sensing-based, multi-volume respiratory motion-resolved (Mres) reconstruction. Given that Mres images were shown to have greater image quality in previous studies than Mcorr images, we hypothesized that the LV volumes segmented from Mres images are closer to the manual expert-traced left ventricular endocardial border than the Mcorr images. This retrospective study used 15 patients who underwent clinically indicated 1.5 T CMR exams with a prototype ECG-gated 3D radial phyllotaxis balanced steady state free precession (bSSFP) sequence. For each reconstruction method, the absolute volume difference (AVD) of the automatically and manually segmented LV volumes was used as the primary quantity to investigate whether 3D DL-based LV segmentation generalized better on Mcorr or Mres 3D whole-heart images. Additionally, we assessed the 3D Dice similarity coefficient between the manual and automatic LV masks of each reconstructed 3D whole-heart image and the sharpness of the LV myocardium-blood pool interface. A two-tail paired Student's t-test (alpha = 0.05) was used to test the significance in this study. The AVD in the respiratory Mres reconstruction was lower than the AVD in the respiratory Mcorr reconstruction: 7.73 ± 6.54 ml vs. 20.0 ± 22.4 ml, respectively (n = 15, p-value = 0.03). The 3D Dice coefficient between the DL-segmented masks and the manually segmented masks was higher for Mres images than for Mcorr images: 0.90 ± 0.02 vs. 0.87 ± 0.03 respectively, with a p-value = 0.02. Sharpness on Mres images was higher than on Mcorr images: 0.15 ± 0.05 vs. 0.12 ± 0.04, respectively, with a p-value of 0.014 (n = 15). We conclude that the DL-based 3D automatic LV segmentation network trained on CT images and fine-tuned on MR images generalized better on Mres images than on Mcorr images for quantifying LV volumes.

P251 EFFECTS OF PIRFENIDONE ON SCAR SIZE AND VENTRICULAR REMODELING AFTER MYOCARDIAL INFARCTION: A PRECLINICAL STUDY

Abstract Background An intense fibrotic response after myocardial infarction (MI) may lead to scar expansion and left ventricular (LV) remodeling, increasing the risk for ventricular arrhythmias and heart failure. Pirfenidone is a drug currently approved for the treatment of idiopathic pulmonary fibrosis, and reduces LV fibrosis in patients with heart failure and preserved ejection fraction. We aimed to characterize the different profiles or protein expression in the infarct zone in rats receiving or not receiving pirfenidone on top of standard therapy for MI. Methods Male Wistar rats were randomized to: sham procedure (group 1; n=13), reperfused MI induced by surgical ligation of the left anterior descending artery (LAD) for 45 minutes (group 2; n=17), reperfused MI plus standard therapy (aspirin, angiotensin–converting enzyme inhibitor, beta–blocker, and also mineralocorticoid receptor antagonist [MRA]) (group 3; n=17), reperfused MI plus pirfenidone alone (group 4; n=17), reperfused MI plus standard therapy and pirfenidone (group 5; n=17). Rats surviving LAD ligation and reperfusion underwent cardiac magnetic resonance (CMR) after 72 hours and 30 days from MI, and were sacrificed the day after the second CMR exam. The primary endpoint was the change in late gadolinium enhancement (LGE) mass as a percentage of LV mass. Results Forty–six rats survived until the second CMR. Percent changes in LV end–diastolic and end–systolic volume (p=0.370 and 0.423, respectively), ejection fraction (p=0.236) and mass (p=0.815) did not differ significantly between rats on pirfenidone plus standard therapy compared with those receiving standard therapy alone. The decrease in LGE mass was significantly greater in rats on pirfenidone plus standard therapy vs. those on standard therapy alone: –22.0% (interquartile range, –37.1 to –5.7, range –51.1 to +37.5) vs. +1.9% (–7.7 to +12.5, range –19.8 to +56.5), p=0.029. Conclusions Pirfenidone had additive effects to standard therapy for MI (including an MRA) in reducing LV fibrosis in a rat model of reperfused MI, while it did not further improve LV function, volumes or mass.

Characteristics and Prognosis of a Contemporary Cohort with Myocardial Infarction with Non-Obstructed Coronary Arteries (MINOCA) Presenting Different Patterns of Late Gadolinium Enhancements in Cardiac Magnetic Resonance Imaging.

To analyze the characteristics and prognosis of a contemporary cohort of patients with myocardial infarction with non-obstructed coronaries (MINOCA) were referred for cardiac magnetic resonance (CMR) imaging, focusing on late gadolinium enhancement (LGE) patterns. We retrospectively examined and prospectively followed up with 135 patients (49 ± 21 years old, 48% female) undergoing CMR imaging due to a MINOCA diagnosis from 2014 to 2016. We grouped and analyzed the sample according to ischemic (focal or transmural) and non-ischemic LGE patterns. The primary outcome was cardiac-related death; the secondary outcome was a composite of cardiac-related rehospitalizations, the new occurrence of acute myocardial infarction (AMI), heart failure (HF), or arrhythmias. CMR exams were performed after a median of 28 days from the acute event. One-third of the ischemic MINOCA were first managed as myocarditis, while CMR helped to adopt a different therapy regimen in 22% of patients (30/135). After a median follow-up of 2.3 years, more cardiac-related deaths occurred in the ischemic than non-ischemic group (2 vs. 1, p = 0.36), but it was not statistically significant. The ischemic group also experienced more cardiac-related-rehospitalizations (42%, p < 0.001). In a multivariable Cox regression model, dyslipidemia, reduced left ventricular ejection fraction, ST-elevation at the hospitalization, and the LGE transmural pattern were the independent predictors of cardiac-related rehospitalizations. In a contemporary cohort of MINOCA patients who underwent CMR, ischemic and non-ischemic patterns had distinct features and outcomes. Among the MINOCA patients, CMR can identify patients at higher risk who require more aggressive therapeutic approached and strict follow-up.

Change in minimum indexed left atrial volume predicts incident heart failure: the multi-ethnic study of atherosclerosis

Abstract Funding Acknowledgements Type of funding sources: None. Background and Purpose Longitudinal change in the left atrium prior to the onset of heart failure has not been as well studied as left atrial (LA) dysfunction in pre-existing heart failure. This study used cardiac magnetic resonance (CMR) imaging to investigate the relationship between longitudinal change in LA volume and function and incident heart failure (HF), in a multi-ethnic population free of known cardiovascular disease at baseline. Methods and Results In the Multi-Ethnic Study of Atherosclerosis (MESA), 2470 participants (60±9 years, 47% males), free at baseline of clinically recognized cardiovascular disease, had LA volume, emptying fractions and peak longitudinal strain assessed with Multimodality Tissue Tracking (MTT; version 6.0 Toshiba, Japan) on CMR imaging at baseline (2000-02) and at follow-up 9.4±0.6 years later. Seventy three (3%) participants subsequently developed incident HF 7.1±2.1 years after the follow-up CMR exam. In cox regression models, an annualized change in all LA parameters were significantly associated with an increased risk of incident HF. An annual increase of 1ml/m2 in minimum indexed LA volumes (∆LAVimin) was most strongly associated with the risk of incident HF (Hazard Ratio(HR)=1.85, 95% confidence interval(CI) [1.49-2.29], P&amp;lt;0.001) and improved model reclassification and discrimination in predicting incident HF (c-statistic=0.80, 95%CI [0.75-0.86]; NRI=0.13, P=0.04; IDI=0.04, P=0.01; x2=6.52, P=0.69) adjusting for known risk factors (age, gender, systolic blood pressure, anti-hypertensive medication use, smoking status, diabetes mellitus, total cholesterol, previous atrial fibrillation) and baseline LA parameters. Conclusion In this multi-ethnic population free of clinical cardiovascular disease at baseline, ∆LAVimin was most strongly associated with, and incrementally predictive of incident HF, after adjusting for known risk factors and baseline LA measures.

A Cardiac Magnetic Resonance Study: Comparison of Biventricular Longitudinal Function in Hypertrophic Cardiomyopathy Patients and Normal Individuals.

Hypertrophic cardiomyopathy (HCM) is a genetic disease with an incidence of0.2%-0.5%. It has a wide range of clinical presentations varying from coincidental diagnoses to heart failure, ventricular arrhythmias and sudden cardiac death.Mitral annular plane systolic excursion (MAPSE) and tricuspid annular plane systolic excursion (TAPSE) are M-mode-derivedpractical and reproduciblemeasurements of systolic longitudinal displacement of the annular plane. These two measuresmay be used as markers of the left ventricular and right ventricular longitudinal functions. Currently, there are only a fewstudies on cardiac magnetic resonance (CMR)-derived TAPSE and MAPSE measurement comparison between the HCM group andnormal control group. The aim of our study is to show the differences in CMR-derived TAPSE and MAPSE valuesbetween the HCM and normal population. We evaluatedCMR exams of patients diagnosed with HCM andof normal individuals scanned between 2020 and 2021 retrospectively. The patients were from our own institution's and other hospitals'in- and out-patient departments. Data was collected on36 HCMpatients and 34 adults with no known history ofcardiac and non-cardiac diseases. All CMR exams were performed on a 1.5 T (Magnetom Avanto, Siemens Healthcare, Erlangen, Germany) scanner.CMR-derived MAPSE and TAPSE were measured on standard four-chamber steady-state free precession (SSFP) cine images and given in millimeters. From February 2020to December 2021, a total of 150 patients were diagnosed with hypertrophic cardiomyopathy. After exclusion, 36 patients with HCM were included in the study and the normal control group comprised 34 individuals. The mean age of the HCM groupwas 43.2+ 13.5 years, while it was 37.5 + 11.3 in the control group. The female ratio of the HCM group was found to be 36%, while it was56% in the healthy control group.MAPSEvalues were significantly higher in the normal control group when compared to the HCM patient group (MAPSE: 14.5 ± 2.9 mm vs. 11.7 ± 3.2 mm; p<0.001), while TAPSE values did not depict a significant difference between the two groups (p=0.627). This study suggests that MAPSE values are significantly lower in the HCM patient group in comparison with the normal control group on CMRscans. Although not statistically significant, TAPSE values are also lower in the HCMgroup.

Defining Biventricular Abnormalities by Cardiac Magnetic Resonance in Pre-Dialysis Patients with Chronic Kidney Disease.

The aim of the study was to investigate biventricular structural and functional abnormalities in pre-dialysis patients across stages of chronic kidney disease (CKD) by cardiac magnetic resonance (CMR). Fifty-one CKD patients with CMR exams were retrospectively analyzed. Patients were divided into three groups according to estimated glomerular filtration rate (eGFR): CKD 1 group (patients with normal eGFR≥90 mL/min/1.73 m2, n = 20), CKD 2-3 group (patients with eGFR< 90 to ≥30 mL/min/1.73 m2, n = 14), and CKD 4-5 group (patients with eGFR<30 mL/min/1.73 m2, n = 17). Twenty-one age- and sex-matched healthy controls (HC) were recruited. CMR-derived left ventricular (LV) and right ventricular (RV) structural and functional measures were compared. Association between CMR parameters and clinical measures was assessed. There was an increasing trend in RV mass index (RVMi) and LV mass index (LVMi) with the occurrence and development of CKD from HC group to CKD 4-5 group although no significant difference was observed between CKD 1 group and HC group. LV global radial strain and LV global circumferential strain dropped and native T1 value elevated significantly in CKD 4-5 group compared with the other three groups (all p < 0.05), while RV strain measures, RV ejection fraction, and LV ejection fraction showed no significant difference among 4 groups (all p > 0.05). Elevated LV end-diastolic volume index (β = 0.356, p = 0.016) and RV end-systolic volume index (β = 0.488, p = 0.001) were independently associated with RVMi. Increased systolic blood pressure (β = 0.309, p = 0.004), LV end-systolic volume index (β = 0.633, p < 0.001), and uric acid (β = 0.261, p = 0.013) were independently associated with LVMi. Meanwhile, serum phosphorus (β = 0.519, p = 0.001) was independently associated with native T1 value. In pre-dialysis CKD patients, left and right ventricular remolding has occurred. RVMi and LVMi were the first changed CMR indexes in the development of CKD when eGFR began to drop. Because fluid volume overload was the independent risk factor for RVMi and LVMi increase, reasonable controlling fluid volume overload may slow down the progression of biventricular remolding and may reduce related cardiovascular disease risk.

267 EFFECTS OF PIRFENIDONE ON SCAR SIZE AND VENTRICULAR REMODELING AFTER MYOCARDIAL INFARCTION: A PRECLINICAL STUDY

Abstract Background An intense fibrotic response after myocardial infarction (MI) may lead to scar expansion and left ventricular (LV) remodeling, increasing the risk for ventricular arrhythmias and heart failure. Pirfenidone is a drug currently approved for the treatment of idiopathic pulmonary fibrosis, and reduces LV fibrosis in patients with heart failure and preserved ejection fraction. We aimed to characterize the different profiles or protein expression in the infarct zone in rats receiving or not receiving pirfenidone on top of standard therapy for MI. Methods Male Wistar rats were randomized to: sham procedure (group 1; n=13), reperfused MI induced by surgical ligation of the left anterior descending artery (LAD) for 45 minutes (group 2; n=17), reperfused MI plus standard therapy (aspirin, angiotensin-converting enzyme inhibitor, beta-blocker, and also mineralocorticoid receptor antagonist [MRA]) (group 3; n=17), reperfused MI plus pirfenidone alone (group 4; n=17), reperfused MI plus standard therapy and pirfenidone (group 5; n=17). Rats surviving LAD ligation and reperfusion underwent cardiac magnetic resonance (CMR) after 72 hours and 30 days from MI, and were sacrificed the day after the second CMR exam. The primary endpoint was the change in late gadolinium enhancement (LGE) mass as a percentage of LV mass. Results Forty-six rats survived until the second CMR. Percent changes in LV end-diastolic and end-systolic volume (p=0.370 and 0.423, respectively), ejection fraction (p=0.236) and mass (p=0.815) did not differ significantly between rats on pirfenidone plus standard therapy compared with those receiving standard therapy alone. The decrease in LGE mass was significantly greater in rats on pirfenidone plus standard therapy vs. those on standard therapy alone: -22.0% (interquartile range, -37.1 to -5.7, range -51.1 to +37.5) vs. +1.9% (-7.7 to +12.5, range -19.8 to +56.5), p=0.029. Conclusions Pirfenidone had additive effects to standard therapy for MI (including an MRA) in reducing LV fibrosis in a rat model of reperfused MI, while it did not further improve LV function, volumes or mass.

Epicardial adipose tissue, infarct size, microvascular obstruction and ventricular remodelling after ST-segment elevation myocardial infarction

Abstract Background Epicardial adipose tissue (EAT) is a biologically active fat deposit contained beneath the pericardium promoting coronary atherosclerosis. EAT can be accurately measured through cardiac magnetic resonance (CMR), which also enables an accurate quantification of infarct size, microvascular obstruction (MVO), left ventricular (LV) ejection fraction (EF) and volumes in patients with ST-elevation myocardial infarction (STEMI). Purpose We performed a systematic assessment of the correlates of EAT volume at baseline and after 6 months in a homogeneous cohort of patients with STEMI. Methods We prospectively enrolled patients with a first anterior STEMI reperfused within 12 hours from symptom onset. These patients underwent a first CMR exam after 1 week from the MI and after 6 months. Results Patients (n=138) were more often men (81%), with a median age of 58 years (interquartile range 48–66). EAT volume was 30 mL/m2 (23–41). Patients with EAT &amp;gt;30 mL/m2 (n=69) were older (60±12 vs. 55±11 years, p=0.02), more often diabetic (26% vs. 12%, p=0.03), and showed a worse baseline risk profile (Thrombolysis in Myocardial Infarction risk score 3 [2–5] vs. 2 [1–4], p=0.05). Patients with EAT &amp;gt;30 mL/m2 also displayed a larger IS (33±15 vs. 23±16% of LV mass, p=0.001) and MVO (1.5 [0–6.8] vs. 0% [0–2.2], p=0.008). Again in patients with EAT &amp;gt;30 mL/m2, EAT volume independently predicted infarct size (standardized beta coefficient=0.30, p&amp;lt;0.001) and MVO area (standardized beta coefficient=0.36, p&amp;lt;0.001) after adjusting for age, sex and infarct characteristics at 1 week (Figure 1). Despite these correlations with infarct size and MVO, patients with EAT &amp;gt;30 mL/m2 did not display more depressed LVEF or larger LV volumes than those with EAT ≤30 mL/m2, either at 1 week or at 6-month CMR (p&amp;gt;0.1 for all comparisons). Conclusions In a cohort of patients with first anterior STEMI undergoing timely reperfusion, those with a greater EAT volume have a larger infarct size and a larger area of MVO. Despite these correlates of EAT volume size, patients with larger EAT do not have a higher risk of adverse LV remodelling. Funding Acknowledgement Type of funding sources: None.

Accuracy of new transthoracic 3D echocardiographic automated algorithm for right ventricle quantification in children with congenital heart disease

Management of many congenital heart diseases (CHD) depends on right ventricle (RV) assessment for which cardiac magnetic resonance (CMR) remains the gold standard. The objective of this study was to assess feasibility and reproducibility of a new semi-automated algorithm to quantify RV (4D auto RVQ) from 3D transthoracic echocardiography (3D TTE) in a pediatric population, and to compare measurements with those obtained from CMR. In all, 90 infants were prospectively included (age 7.5 years, 3–18). Fifteen healthy infants and 75 patients with CHD (30 repaired TOF, 25 ASD, 8 dilated pulmonary valve stenosis, 7 tricuspid regurgitation, 3 APVR, and 2 repaired TAC). All patients underwent 2D and 3D TTE (Vivid E95, GE Healthcare). RV end-diastolic volume (RVEDV), RV end-systolic volume (RVESV), RV ejection volume (RVEV) and RV ejection fraction (RVEF) were analyzed by 4D auto RVQ and compared with measurements from 18 patients who underwent CMR exams for the follow up of their cardiopathy. 4D auto RVQ was feasible in 87 infants (96.7%). In 3 patients 4D auto RVQ was unable to detect RV contouring due to inadequate image quality. Manual contour adjustment was necessary in 81 cases (80%). Mean time of analysis including the time of manual adjustment was 62 seconds. RV was enlarged in 65 of 75 patients with CHD (mean 95 ml/m 2 , 62–165 ml/m 2 ). Good correlation for RVEDV, RVESV, RVEV and RVEF was found between 4D auto RVQ and CMR (r = 0.89–0.99, all P < 0.0001). 4D auto RVQ underestimated RVEDV/BSA of 8 ml/m 2 and RVEF by 6%, and overestimated RVESV/BSA of 9 ml/m 2 . Intraobserver and interobserver variability were low (4.7% and 8.9% respectively) ( Fig. 1 ). 4D auto RVQ is a promising tool for assessment of RV volume and function in children. Such simple and non-invasive exam could reduce the practice of CMR imaging during the follow up of children with CHD.

Time-dependent cardiac structural and functional changes after kidney transplantation: a multi-parametric cardiac magnetic resonance study.

To map time-dependent cardiac structural and functional change patterns after renal transplantation (KT) using cardiac magnetic resonance (CMR). Fifty-three patients with pre-KT and post-KT CMR exams were retrospectively analyzed. Patients were divided into three groups according to the time of post-KT CMR: group 1 (3 months post-KT, n = 16), group 2 (6 months post-KT, n = 21), and group 3 (over 9 months post-KT, n = 16). Twenty-one age- and sex-matched healthy controls (HC) were recruited for the study. CMR-derived left ventricular (LV) volumes, LV mass index (LVMi), LV ejection fraction (LVEF), global radial strain (GRS), global circumferential strain (GCS), global longitudinal strain (GLS), and native T1 value were compared. The association between the changes of CMR parameters was assessed. LVMi post-KT decreased in groups 2 (p < 0.001) and 3 (p = 0.004) but both groups had higher LVMi values compared to HC (both p < 0.001). GLS post-KT was decreased in group 1 (p = 0.021), but slightly increased in group 2 (p = 0.728) and group 3 (p = 0.100) without significant difference. GLS post-KT in group 3 was not different from HC (p = 0.104). LVEF, GRS, and GCS post-KT in groups 2 and 3 significantly increased and showed no significant difference from HC. The post-KT native T1 value in all three groups significantly decreased; however, no group showed any significant difference from HC. The change of LVEF was associated with the change of GCS, GRS, and GLS. Although GRS, GCS, GLS, and native T1 values reversed to normal level, LVMi remained impaired in median 14 months after KT. • Kidney transplantation has favorable effects on cardiac structure and function. • In a median 14 months of follow-up after KT, left ventricle strain and native T1 value reversed to normal level while LV mass index (LVMi) did not. Left ventricular hypertrophy may help to explain why KT recipients are still at increased cardiovascular risk. • The reason for the decrease of native T1 value after KT may be more than myocardial fibrosis and needs to be further studied.

Regional Left Ventricular Myocardial Injury and Function Characterisation by Cardiac Magnetic Resonance Imaging in a Sheep Model of Myocardial Infarction

Left ventricular (LV) remodelling following a myocardial infarction(MI) elicits different responses in infarct and remote LV, with prior studies reporting increased contractility in the latter. We explored the relationship between myocardial injury and its functional consequences using a combination of 3D late gadolinium enhancement (LGE), feature tracking (FT) cardiac magnetic resonance (CMR) and autopsy findings in a sheep model of MI. MI was induced in sheep (n=11) by coronary artery ligation under general anaesthesia. Baseline (pre-MI) and follow-up (15d post-MI) CMR exams were performed for cine imaging. LGE imaging was performed using a 3D inversion recovery fast low angle shot (IR-FLASH) sequence in the follow-up examination. MI size was confirmed at post-mortem. Regions of MI identified by imaging were compared with post-mortem findings using AHA LV segmentation. The sensitivity and specificity of the LGE imaging was calculated and compared to post-mortem using McNemar’s test. FT was applied to the cine imaging to quantify regional circumferential strain (CS). The percentage change in regional CS was calculated for each segment (Data: mean±SD; *p<0.05). LGE detected MI with a sensitivity of 90.6% and specificity of 96.4% (p=0.7). LV ejection fraction (EF) was 55.7±5.6% post-MI. Percentage changes in regional CS were -34.3±13.8% and -17.4±30.7% in AHA segments 13 and 16, respectively, while other segments exhibited increased CS (range=+0.1% to +28.7%). Our novel application of 3D IR-FLASH and FT provided comprehensive visualisation of LV injury and function in the setting of MI. Our data reproduces prior descriptions of compensatory increases in myocardial contractility in remote regions in STEMI patients with ≥50% EF [[1]Leung S.W. Ratajczak T.M. Abo-Aly M. Shokri E. Abdel-Latif A. Wenk J.F. Regional end-systolic circumferential strain demonstrates compensatory segmental contractile function in patients with ST-segment elevation myocardial infarction.J Biomech. 2021; 129 (110794)Crossref PubMed Scopus (1) Google Scholar] and a canine model of MI [[2]Lew W.Y. Chen Z.Y. Guth B. Covell J.W. Mechanisms of augmented segment shortening in nonischemic areas during acute ischemia of the canine left ventricle.Circ Res. 1985; 56: 351-358Crossref PubMed Scopus (112) Google Scholar].

Abstract 12691: Comparison of Deep Learning and Radiomic Features to Differentiate Non-Ischemic and Ischemic Cardiomyopathy Using Cardiac MRI Cine Imaging

Introduction: Cardiac magnetic resonance (CMR) is frequently utilized to characterize etiology of cardiomyopathy (CM), but there is need for improved disease classification, standardization in the interpretation of findings, and throughput in analysis. Radiomics has been shown to classify disease in a semi-automated manner. Alternatively, deep learning (DL) provides the ability to identify unknown features in image data. Therefore, we sought to compare DL and radiomic approaches to differentiate ischemic vs non-ischemic cardiomyopathy (ICM vs NICM), using cardiac magnetic resonance (CMR) short axis cine images. Methods: We selected 291 patients with cardiomyopathy (CM) who underwent a CMR exam at Cleveland Clinic between 2008 and 2018, of which 249 had NICM (positive label) based on expert review of the CMR exam and electronic medical record documentation. We compared a radiomic and end-to-end DL approach to identify CM etiology from short axis cine images. Automatically generated radiomic features describing myocardial shape, texture, thickness, and motion in the cine images were used to train several machine learning classifiers. In the DL approach, we directly used the cine images to train several DL classifiers, without extracting radiomic features. We evaluated the classifiers through 5-fold cross validation using the area under the curve (AUC), F1-score, and accuracy metrics. Statistical significance was evaluated using paired 2-tailed t-test at 0.05 level. Results: Support vector machine (SVM) and DenseNet121 achieved the best metrics for radiomic and DL approaches respectively. The radiomic and DL approach achieved similar AUCs of 0.852 and 0.858 respectively, but DL approach achieved statistically significant higher F1-score of 0.758 vs 0.585 of the radiomic approach. Conclusions: An end-to-end DL approach more accurately identified NICM vs ICM compared to a radiomics approach, using only cine CMR images.

Abstract 11063: Non-Ischemic Fibrosis on Cardiac Magnetic Resonance Impacts Adverse Left Ventricular Remodeling and Mortality Among Patients with Functional Mitral Regurgitation

Introduction: Functional mitral regurgitation (FMR) alters left ventricular (LV) remodeling, providing a nidus for non-ischemic fibrosis (NIF). Cardiac magnetic resonance (CMR) can measure FMR and LV tissue properties. Prevalence, remodeling manifestations, and prognostic implications of NIF in patients with FMR are unknown. Hypothesis: Among post-myocardial infarction (MI) patients with FMR, NIF associates with advanced LV remodeling and predicts adverse prognosis. Methods: The population comprised post-MI patients with FMR undergoing CMR. CMR exams were retrieved from a single-center registry, reviewed for MR etiology (degenerative excluded) and analyzed for FMR severity, LV structure/function, and late gadolinium enhancement (LGE) including ischemic pattern MI and NIF, which was defined via established criteria (mid-myocardial or epicardial LGE). Follow-up was performed for all-cause mortality. Results: 467 consecutive FMR patients (74% male, 63±16 years old) were studied, of whom 14% had NIF. Prevalence of NIF increased stepwise with FMR severity (12% mild, 16% moderate, 21% severe; p=0.33). Patients with NIF had higher LV end-diastolic (241±72ml vs 194±64ml) and end-systolic volumes (174±70ml vs 120±63ml), paralleled by lower EF (31±13% vs 41±15%) and stroke volumes (67±20ml vs 74±24ml); all p&lt;0.001. LV infarct size was similar between patients with and without NIF (13±8.6 vs 15±10, p=0.17). During follow-up (mean 3.0±2.5 years), overall mortality was 14% and was increased in patients with advanced (≥ moderate) FMR (HR 1.65 [CI 1.13-2.42], p=0.01) and NIF (HR 2.35 [CI 1.32-4.19], p=0.004: Figure). In multivariate analysis, NIF conferred over a 2-fold increase in risk for death (HR 2.15 [CI 1.20-3.85], p=0.01) independent of age and FMR severity. Conclusions: Among post-MI patients with FMR, NIF identifies an aggressive phenotype as evidenced by associations with adverse LV remodeling on CMR and increased mortality.