Steady-state Free Precession Cine Images Research Articles

Bayesian Uncertainty Estimation by Hamiltonian Monte Carlo: Applications to Cardiac MRI Segmentation

Deep learning (DL)-based methods have achieved state-of-the-art performance for many medical image segmentation tasks. Nevertheless, recent studies show that deep neural net- works (DNNs) can be miscalibrated and overconfident, leading to ”silent failures” that are risky for clinical applications. Bayesian DL provides an intuitive approach to DL failure de- tection, based on posterior probability estimation. However, the posterior is intractable for large medical image segmentation DNNs. To tackle this challenge, we propose a Bayesian learning framework using Hamiltonian Monte Carlo (HMC), tempered by cold posterior (CP) to accommodate medical data augmentation, named HMC-CP. For HMC compu- tation, we further propose a cyclical annealing strategy, capturing both local and global geometries of the posterior distribution, enabling highly efficient Bayesian DNN training with the same computational budget as training a single DNN. The resulting Bayesian DNN outputs an ensemble segmentation along with the segmentation uncertainty. We evaluate the proposed HMC-CP extensively on cardiac magnetic resonance image (MRI) segmentation, using in-domain steady-state free precession (SSFP) cine images as well as out-of-domain datasets of quantitative T1 and T2 mapping. Our results show that the proposed method improves both segmentation accuracy and uncertainty estimation for in- and out-of-domain data, compared with well-established baseline methods such as Monte Carlo Dropout and Deep Ensembles. Additionally, we establish a conceptual link between HMC and the commonly known stochastic gradient descent (SGD) and provide general insight into the uncertainty of DL. This uncertainty is implicitly encoded in the training dynamics but often overlooked. With reliable uncertainty estimation, our method provides a promising direction toward trustworthy DL in clinical applications. We release our code in <a href='https://gitlab.tudelft.nl/yidongzhao/hmc_uncertainty'>https://gitlab.tudelft.nl/yidongzhao/hmc_uncertainty</a>

Fractal Analysis of Left Ventricular Trabeculae in Patients with End-Stage Renal Disease: A Random Survival Tree Analysis.

The complexity of left ventricular (LV) trabeculae is related to the prognosis of several cardiovascular diseases. To evaluate the prognostic value of LV trabecular complexity in patients with end-stage renal disease (ESRD). Prospective outcome study. 207 participants on maintenance dialysis, divided into development (160 patients from 2 centers) and external validation (47 patients from a third center) cohorts, and 72 healthy controls. 3.0T, steady-state free precession (SSFP) and modified Look-Locker imaging sequences. All participants had their trabecular complexity quantified by fractal analysis using cine SSFP images. Patients were followed up every 2 weeks until April 2023, or endpoint events happened. Random Forest (RF) and Cox regression models including age, diabetes, LV mass index, mean basal fractal dimension (FD), and left atrial volume index, were developed to predict major adverse cardiac events (MACE). Patients were divided into low- and high-risk groups based on scores derived from the RF model and survival compared. Receiver operating characteristic curve analysis; Kaplan-Meier survival analysis with log rank tests; Harrel's C-index to assess model performance. A P value <0.05 was considered statistically significant. Fifty-five patients (26.57%) experienced MACE during a median follow-up time of 21.83 months. An increased mean basal FD (≥1.324) was associated with a significantly higher risk of MACE. The RF model (C-index: 0.81) had significantly better discrimination than the Cox regression model (C-index: 0.74). Participants of the external validation dataset classified into the high-risk group had a hazard of experiencing MACE increased by 12.29 times compared to those in the low-risk group. LV basal FD was an independent predictor for MACE in patients with ESRD. Reliable risk stratification models could be generated based on LV basal FD and other MRI variables using RF analysis. 2 TECHNICAL EFFICACY: Stage 2.

Utilizing Artificial Intelligence-Based Deformable Registration for Global and Layer-Specific Cardiac MRI Strain Analysis in Healthy Children and Young Adults

The absence of published reference values for multilayer-specific strain measurement using cardiac magnetic resonance (CMR) in young healthy individuals limits its use. This study aimed to establish normal global and layer-specific strain values in healthy children and young adults using a deformable registration algorithm (DRA). A retrospective study included 131 healthy children and young adults (62 males and 69 females) with a mean age of 16.6±3.9 years. CMR examinations were conducted using 1.5T scanners, and strain analysis was performed using TrufiStrain research prototype software (Siemens Healthineers, Erlangen, Germany). Global and layer-specific strain parameters were extracted from balanced Steady-state free precession cine images. Statistical analyses were conducted to evaluate the impact of demographic variables on strain measurements. The peak global longitudinal strain (LS) was -16.0±3.0%, peak global radial strain (RS) was 29.9±6.3%, and peak global circumferential strain (CS) was -17.0±1.8%. Global LS differed significantly between males and females. Transmural strain analysis showed a consistent pattern of decreasing LS and CS from endocardium to epicardium, while radial strain increased. Basal-to-apical strain distribution exhibited decreasing LS and increasing CS in both global and layer-specific analysis. This study uses DRA to provide reference values for global and layer-specific strain in healthy children and young adults. The study highlights the impact of sex and age on LS and body mass index on RS. These insights are vital for future cardiac assessments in children, particularly for early detection of heart diseases.

Abstract 14427: Subclinical Age- and Sex-Differences in Ventricular Strain in the Community: A Framingham Heart Study Cardiac Magnetic Resonance Study

Introduction: Myocardial strain is a measure of deformation and a marker of cardiovascular disease (CVD). The subclinical age- and sex-associations of left and right ventricular (LV, RV) strain by feature tracking cardiovascular magnetic resonance (FT-CMR) are not well established in the community. Methods: Framingham Heart Study Offspring cohort participants (n=1077) without prevalent CVD, hypertension, diabetes, or use of treatment for these conditions underwent 1.5T CMR. Steady-state free precession cine images spanning the entirety of both ventricles were acquired in the short-axis, 2-chamber, and 4-chamber views. Global longitudinal (GLS), circumferential (GCS), and radial (GRS) strains were measured by FT-CMR (Circle cvi42 v.5.11.1). Comparisons among age groups (&lt;45 years, 45-54 years, 55-65 years, and &gt;65 years) were performed by one-way analysis of variance and between sexes by independent samples t -test. Results: Clinical characteristics, CMR measures, and LV and RV strain by age and sex for the cohort are presented in the Table . Across increasing age groups, we observed more favorable LV GLS, GCS, and GRS (p=0.010, p&lt;0.001, and p&lt;0.001, respectively). Similar trends were present for RV strain for GCS and GRS (both p&lt;0.001) but not GLS (p=0.22). Compared with men, women had greater magnitude (more favorable) LV and RV strain values for GLS, GCS, and GRS (all p≤0.013). Conclusions: In this large community based study of individuals without CVD, LV and RV strains by FT-CMR were greater (more favorable) with increasing age and in women. The associations and long-term implications of these differences in myocardial mechanics between groups require further investigation.

Systolic anterior motion of the anterior mitral valve leaflet begins in subclinical hypertrophic cardiomyopathy.

Anterior mitral valve leaflet (AMVL) elongation is detectable in overt and subclinical hypertrophic cardiomyopathy (HCM). We sought to investigate the dynamic motion of the aorto-mitral apparatus to understand the behaviour of the AMVL and the mechanisms of left ventricular outflow tract obstruction (LVOTO) predisposition in HCM. Cardiovascular magnetic resonance imaging using a 1.5 Tesla scanner was performed on 36 HCM sarcomere gene mutation carriers without left ventricular hypertrophy (G+LVH-), 31 HCM patients with preserved ejection fraction carrying a pathogenic sarcomere gene mutation (G+LVH+), and 53 age-, sex-, and body surface area-matched healthy volunteers. Dynamic excursion of the aorto-mitral apparatus was assessed semi-automatically on breath-held three-chamber cine steady-state free precession images. Four pre-defined regions of interest (ROIs) were tracked: ROIPMVL: hinge point of the posterior mitral valve leaflet; ROITRIG: intertrigonal mitral annulus; ROIAMVL: AMVL tip; and ROIAAO: anterior aortic annulus. Compared with controls, normalized two-dimensional displacement-vs.-time plots in G+LVH- revealed subtle but significant systolic anterior motion (SAM) of the AMVL (P < 0.0001) and reduced longitudinal excursion of ROIAAO (P = 0.014) and ROIPMVL (P = 0.048). In overt and subclinical HCM, excursion of the ROITRIG/AMVL/PMVL was positively associated with the burden of left ventricular fibrosis (P < 0.028). As expected, SAM was observed in G+LVH+ together with reduced longitudinal excursion of ROITRIG (P = 0.049) and ROIAAO (P = 0.008). Dyskinesia of the aorto-mitral apparatus, including SAM of the elongated AMVL, is detectable in subclinical HCM before the development of LVH or left atrial enlargement. These data have the potential to improve our understanding of early phenotype development and LVOTO predisposition in HCM.

#4572 EFFECTS OF EMPAGLIFLOZIN ON KIDNEY AND CARDIAC MRI MEASURES IN PATIENTS WITH CHRONIC KIDNEY DISEASE

Abstract Background and Aims EMPA-KIDNEY demonstrated empagliflozin reduced the risk of kidney disease progression or cardiovascular death in patients with CKD at risk of progression, but the mechanisms of benefit are uncertain. MRI was used to assess whether empagliflozin modified the structure and function of the kidneys and heart at around 18 months after randomization. Method Randomized participants from 8 sites in UK and Germany without a contraindication to MRI scanning, were eligible and invited to participate in this substudy. MRI scans were performed using a standardized protocol. Renal T1 mapping (MOLLI 5[3]3 scheme which measures fibrosis and inflammation) was computed by first segmenting MOLLI data using a U-net and then applying the masks to both kidneys. Cardiac MRI included cine steady-state free precession imaging to assess biventricular volumes, mass and function, and T1 mapping to assess myocardial inflammation and fibrosis. The primary outcome was kidney cortical T1 mapping measured by MOLLI. Secondary outcomes included LV ejection fraction, myocardial T1 MOLLI and LV mass index. Differences in MRI measurements between treatment groups were analysed using linear regression adjusted for baseline age, sex, eGFR, UACR and diabetes status. 172 participants were required to provide 90% power at 2p = 0.05 to detect a 50 ms difference in T1. Results 172 participants had an MRI scan around 18 months after randomization. 93 (54%) were allocated empagliflozin and 79 (46%) placebo. Mean (SD) age was 60 (15) years, 26% were female and 23% had diabetes. Mean eGFR was 37 (13) mL/min/1.73m2 and geometric mean (95% CI) UACR was 242 (182-322) mg/g (Table 1). Adjusted mean (SE) cortical T1 mapping by MOLLI was 1623 (10) ms in those allocated empagliflozin versus 1634 (11) ms in those allocated placebo, difference in means (95% CI) −11 (−41 to 18), P = 0.45 (Table 2). Medullary T1 MOLLI scores were similar. Empagliflozin had no significant effect on cardiac MRI measures: difference (95% CI) in LV ejection fraction 1% (−1 to 4); myocardial T1 MOLLI −3 ms (−16 to 10); LV mass index −3 g/m2 (−5 to 0) (Table 2). Conclusion Empagliflozin had no significant effect on MRI-based measures of fibrosis within the kidney cortex or myocardium in people with CKD at risk of progression. There was no effect of treatment on measures of cardiac structure or function. Further MRI measures will be available for presentation by the time of the ERA congress. Funding Boehringer Ingelheim, Eli Lilly and others; Clinicaltrials.gov:NCT03594110.

MRI Investigation of the Differential Impact of Left Ventricular Ejection Fraction After Myocardial Infarction in Elderly vs. Nonelderly Patients to Predict Readmission for Heart Failure.

Patients with ST-segment elevation myocardial infarction (STEMI), especially elderly individuals, have an increased risk of readmission for acute heart failure (AHF). To study the impact of left ventricular ejection fraction (LVEF) by MRI to predict AHF in elderly (>70 years) and nonelderly patients after STEMI. Prospective. Multicenter registry of 759 reperfused STEMI patients (23.3% elderly). 1.5-T. Balanced steady-state free precession (cine imaging) and segmented inversion recovery steady-state free precession (late gadolinium enhancement) sequences. One-week MRI-derived LVEF (%) was quantified. Sequential MRI data were recorded in 579 patients. Patients were categorized according to their MRI-derived LVEF as preserved (p-LVEF, ≥50%), mildly reduced (mr-LVEF, 41%-49%), or reduced (r-LVEF, ≤40%). Median follow-up was 5 [2.33-7.54] years. Univariable (Student's t, Mann-Whitney U, chi-square, and Fisher's exact tests) and multivariable (Cox proportional hazard regression) comparisons and continuous-time multistate Markov model to analyze transitions between LVEF categories and to AHF. Hazard ratios (HR) with 95% confidence intervals (CIs) were computed. P < 0.05 was considered statistically significant. Over the follow-up period, 79 (10.4%) patients presented AHF. MRI-LVEF was the most robust predictor in nonelderly (HR 0.94 [0.91-0.98]) and elderly patients (HR 0.94 [0.91-0.97]). Elderly patients had an increased AHF risk across the LVEF spectrum. An excess of risk (compared to p-LVEF) was noted in patients with r-LVEF both in nonelderly (HR 11.25 [5.67-22.32]) and elderly patients (HR 7.55 [3.29-17.34]). However, the mr-LVEF category was associated with increased AHF risk only in elderly patients (HR 3.66 [1.54-8.68]). Less transitions to higher LVEF states (n=19, 30.2% vs. n=98, 53%) and more transitions to AHF state (n=34, 53.9% vs. n=45, 24.3%) were observed in elderly than nonelderly patients. MRI-derived p-LVEF confers a favorable prognosis and r-LVEF identifies individuals at the highest risk of AHF in both elderly and nonelderly patients. Nevertheless, an excess of risk was also found in the mr-LVEF category in the elderly group. 2. Stage 2.

Fetal Cardiac Cine MRI with Doppler US Gating in Complex Congenital Heart Disease.

To apply Doppler US (DUS)-gated fetal cardiac cine MRI in clinical routine and investigate diagnostic performance in complex congenital heart disease (CHD) compared with that of fetal echocardiography. In this prospective study (May 2021 to March 2022), women with fetuses with CHD underwent fetal echocardiography and DUS-gated fetal cardiac MRI on the same day. For MRI, balanced steady-state free precession cine images were acquired in the axial and optional sagittal and/or coronal orientations. Overall image quality was assessed on a four-point Likert scale (from 1 = nondiagnostic to 4 = good image quality). The presence of abnormalities in 20 fetal cardiovascular features was independently assessed by using both modalities. The reference standard was postnatal examination results. Differences in sensitivities and specificities were determined by using a random-effects model. The study included 23 participants (mean age, 32 years ± 5 [SD]; mean gestational age, 36 weeks ± 1). Fetal cardiac MRI was completed in all participants. The median overall image quality of DUS-gated cine images was 3 (IQR, 2.5-4). In 21 of 23 participants (91%), underlying CHD was correctly assessed by using fetal cardiac MRI. In one case, the correct diagnosis was made by using MRI only (situs inversus and congenitally corrected transposition of the great arteries). Sensitivities (91.8% [95% CI: 85.7, 95.1] vs 93.6% [95% CI: 88.8, 96.2]; P = .53) and specificities (99.9% [95% CI: 99.2, 100] vs 99.9% [95% CI: 99.5, 100]; P > .99) for the detection of abnormal cardiovascular features were comparable between MRI and echocardiography, respectively. Using DUS-gated fetal cine cardiac MRI resulted in performance comparable with that of using fetal echocardiography for diagnosing complex fetal CHD.Keywords: Pediatrics, MR-Fetal (Fetal MRI), Cardiac, Heart, Congenital, Fetal Imaging, Cardiac MRI, Prenatal, Congenital Heart DiseaseClinical trial registration no. NCT05066399 Supplemental material is available for this article. © RSNA, 2023See also the commentary by Biko and Fogel in this issue.

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.

Quantification of left atrial function by the area-length method overestimates left atrial emptying fraction

PurposeThe biplane area-length method is commonly used in cardiac magnetic resonance (CMR) to assess left atrial (LA) volume (LAV) and function. Associations between left atrial emptying fraction (LAEF) and clinical outcomes have been reported. However, only limited data are available on the calculation of LAEF using the biplane method compared to 3D assessment. This study aimed to compare volumetric and functional LA parameters obtained from the biplane method with 3D assessment in a large, multiethnic cohort. Method158 participants of MESA (Multi-Ethnic Study of Atherosclerosis) underwent CMR that included standard two- and four-chamber steady-state free precession (SSFP) cine imaging for the biplane method. For 3D-based assessment, short-axis SSFP cine series covering the entire LA were obtained, followed by manual delineation of LA contours to create a time-resolved 3D LAV dataset. Paired t-tests and Bland-Altman plots were used to analyze the data. ResultsStandard volumetric assessment showed that LAVmin (bias: −8.35 mL, p < 0.001), LAVmax (bias: −9.38 mL, p < 0.001) and LAVpreA (bias: −10.27 mL, p < 0.001) were significantly smaller using the biplane method compared to 3D assessment. Additionally, the biplane method reported significantly higher LAEFtotal (bias: 7.22 %, p < 0.001), LAEFactive (bias: 6.08 %, p < 0.001), and LAEFpassive (bias: 4.51 %, p < 0.001) with wide limits of agreement. ConclusionsLA volumes were underestimated using the biplane method compared to 3D assessment, while LAEF parameters were overestimated. These findings demonstrate a lack of precision using the biplane method for LAEF assessment. Our results support the usage of 3D assessment in specific settings when LA volumetric and functional parameters are in focus.

Novel Approach for Assessing Postinfarct Myocardial Injury and Inflammation Using Hybrid Somatostatin Receptor Positron Emission Tomography/Magnetic Resonance Imaging.

Novel Approach for Assessing Postinfarct Myocardial Injury and Inflammation Using Hybrid Somatostatin Receptor Positron Emission Tomography/Magnetic Resonance Imaging.

Unmasking early diastolic dysfunction in type 2 diabetes using the peak early-to-late diastolic strain rate ratio by cardiac MRI feature tracking

Abstract Introduction Type 2 diabetes (T2D) is associated with early alterations in left ventricular (LV) diastolic function, which precedes the development of heart failure. These may be quantified by cardiac MRI feature tracking, which permits a direct assessment of myocardial relaxation through calculation of diastolic strain rates. Previous studies have not fully exploited this technique by integrating early and late LV diastolic relaxation in asymptomatic adults with T2D. Purpose To explore whether the peak early-to-late diastolic strain rate ratio (PEDSR:PLDSR), derived from cardiac MRI feature tracking, could: 1) identify diastolic dysfunction in an asymptomatic cohort of adults with T2D, 2) compare this technique with conventional echocardiographic measures of diastolic function. Methods Prospective cross-sectional study. People with T2D (n=253, mean age 63±7 years, 62% male, diabetes duration 11±8 years) without signs, symptoms or history of cardiovascular disease and non-diabetic controls (n=40, mean age 61±8 years, 63% male) underwent comprehensive phenotyping including echocardiography and cardiac MRI. The LV PEDSR:PLDSR was derived from cardiac MRI balanced steady-state free precession cine images using feature tracking. Correlations between circumferential PEDSR:PLDSR and echocardiography-derived E:A and E/e' were explored. Results Compared to controls, people with T2D had evidence of concentric LV remodelling, diastolic dysfunction, and diffuse myocardial fibrosis as demonstrated by increased LV mass/volume, E/e' ratio, and extracellular volume fraction, respectively (Table 1). People with T2D had lower PEDSR (0.87±0.23 vs 0.95±0.24 s–1, p=0.043), higher PLDSR (0.80±0.22 vs 0.67±0.16 s–1, p&amp;lt;0.001), and lower PEDSR:PLDSR ratio (1.18±0.46 vs 1.53±0.61, p&amp;lt;0.001). PEDSR:PLDSR was moderately correlated with E:A (r=0.495, p&amp;lt;0.001) (Figure 1) but not E/e' (r=0.087, p=0.182). Conclusions Compared to people without diabetes, lower PEDSR:PLDSR in asymptomatic subjects with T2D highlights impaired myocardial relaxation in early diastole and greater dependence on atrial contraction for LV filling in this group. This novel MRI measure may be promising tool to assess global diastolic function in people undergoing cardiac MRI and especially useful in those with poor echocardiographic windows. The functional and prognostic significance of PEDSR:PLDSR warrants further assessment in longitudinal studies. Funding Acknowledgement Type of funding sources: Public Institution(s). Main funding source(s): National Institute for Health Research (NIHR) United Kingdom through a Research Professorship award (RP-2017-08-ST2-007).British Heart Foundation through a Clinical Research Training Fellowship (FS/16/47/32190).

Ferumoxytol-enhanced 4D multiphase, steady-state imaging with magnetic resonance in congenital heart disease: ventricular volume and function across 2D and 3D software platforms.

BackgroundQuantitative ventricular volumetry and function are important in the management of congenital heart disease (CHD). Ferumoxytol-enhanced (FE) 4D multiphase, steady state imaging with contrast enhancement (MUSIC) enables high-resolution, 3D cardiac phase-resolved magnetic resonance imaging (MRI) of the beating heart and extracardiac vessels in a single acquisition and without concerns about renal impairment. We aim to evaluate the semi-automatic quantification of ventricular volumetry and function of 4D MUSIC MRI using 2D and 3D software platforms.MethodsThis HIPAA-compliant and IRB-approved study prospectively recruited 50 children with CHD (3 days to 18 years) who underwent 4D MUSIC MRI at 3.0T between 2013–2017 for clinical indications. Each patient was either intubated in the neonatal intensive care unit (NICU) or underwent general anesthesia at MRI suite. For 2D analysis, we reformatted MUSIC images in Digital Imaging and Communications in Medicine (DICOM) format into ventricular short-axis slices with zero interslice gap. For 3D analysis, we imported DICOMs into a commercially available 3D software platform. Using semi-automatic thresholding, we quantified biventricular volume and ejection fraction (EF). We assessed the bias between MUSIC-derived 2D vs. 3D measurements and correlation between MUSIC vs. conventional 2D balanced steady-state free precession (bSSFP) cine images. We evaluated intra- and inter-observer agreement.ResultsThere was a high degree of correlation between MUSIC-derived volumetric and functional measurements using 2D vs. 3D software (r=0.99, P<0.001). Volumes derived using 3D software platforms were larger than 2D by 0.2 to 2.0 mL/m2 whereas EF measurements were higher by 1.2–3.0%. MUSIC volumetric and functional measures derived from 2D and 3D software platforms corresponded highly with those derived from multi-slice SSFP cine images (r=0.99, P<0.001). The mean difference in volume for reformatted 4D MUSIC relative to bSSFP cine was 1.5 to 3.9 mL/m2. Intra- and inter-observer reliability was excellent.ConclusionsAccurate and reliable ventricular volumetry and function can be derived from FE 4D MUSIC MRI studies using commercially available 2D and 3D software platforms. If fully validated in multicenter studies, the FE 4D-MUSIC pulse sequence may supercede conventional multislice 2D cine cardiovascular MRI acquisition protocols for functional evaluation of children with complex CHD.

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

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

Non-invasive quantification of pressure–volume loops in patients with Fontan circulation

BackgroundPressure–volume (PV) loops provide comprehensive information of cardiac function, but commonly implies an invasive procedure under general anesthesia. A novel technique has made it possible to non-invasively estimate PV loops with cardiac magnetic resonance (CMR) and brachial pressure which would enable good volume estimation of often anatomically complex ventricles without the need of anesthesia in most cases. In this study we aimed to compare how hemodynamic parameters derived from PV loops in patients with Fontan circulation differ to controls.MethodsPatients with Fontan circulation (n = 17, median age 12 years, IQR 6–15) and healthy controls (n = 17, 14 years, IQR 13–22) were examined with CMR. Short axis balanced steady-state free-precession cine images covering the entire heart were acquired. PV loops were derived from left ventricular volumes in all timeframes and brachial blood pressure from cuff sphygmomanometry.ResultsFontan patients had lower stroke work, ventricular mechanical efficiency and external power compared to controls. Fontan patients with dominant right ventricle had higher potential energy indexed to body surface area but lower contractility (Ees) compared to controls. Fontan patients had higher arterial elastance (Ea) and Ea/Ees ratio than controls. Contractility showed no correlation with ejection fraction (EF) in Fontan patients irrespective of ventricular morphology. No difference was seen in energy per ejected volume between Fontan patients and controls.ConclusionsThis non-invasive PV-loop method could be used in future studies to show the potential prognostic value of these measures and if changes in ventricular function over time can be detected earlier by this method compared to changes in ventricular volumes and EF. In contrast to patients with acquired heart failure, Fontan patients had similar energy per ejected volume as controls which suggests similar ventricular oxygen consumption to deliver the same volume in Fontan patients as in controls.

Compressed Sensing Cardiac Cine Imaging Compared with Standard Balanced Steady-State Free Precession Cine Imaging in a Pediatric Population.

To compare real-time compressed sensing (CS) and standard balanced steady-state free precession (bSSFP) cardiac cine imaging in children. Twenty children (mean age, 15 years ± 5 [SD], range, 7-21 years; 10 male participants) with biventricular congenital heart disease (n = 11) or cardiomyopathy (n = 9) were prospectively included. Examinations were performed with 1.5-T imagers by using both bSSFP and CS sequences in all participants. Quantification of ventricular volumes and function was performed for all images by two readers blinded to patient diagnosis and type of sequence. Values were correlated with phase-contrast flow measurements by one reader. Intra- and interreader agreement were analyzed. There were no significant differences between ventricular parameters measured on CS compared with those of bSSFP (P > .05) for reader 1. Only ejection fraction showed a significant difference (P = .02) for reader 2. Intrareader agreement was considerable for both sequences (bSSFP: mean difference range, +1 to -2.6; maximum CI, +7.9, -13; bias range, 0.1%-4.1%; intraclass correlation coefficient [ICC] range, 0.931-0.997. CS: mean difference range, +7.4 to -5.6; maximum CI, +37.2, -48.8; bias range, 0.5%-7.5%; ICC range, 0.717-0.997). Interreader agreement was acceptable but less robust, especially for CS (bSSFP: mean difference range, +2.6 to -5.6; maximum CI, +60.7, -65.3; bias range, 1.6%-6.2%; ICC range, 0.726-0.951. CS: mean difference range, +10.7 to -9.1; maximum CI, +87.5, -84.6; bias range, 1.1%-17.3%; ICC range, 0.509-0.849). The mean acquisition time was shorter for CS (20 seconds; range, 17-25 seconds) compared with that for bSSFP (160 seconds; range, 130-190 seconds) (P < .001). CS cardiac cine imaging provided equivalent ventricular volume and function measurements with shorter acquisition times compared with those of bSSFP and may prove suitable for the pediatric population.Keywords: Compressed Sensing, Balanced Steady-State Free Precession, Cine Imaging, Cardiovascular MRI, Pediatrics, Cardiac, Heart, Cardiomyopathies, Congenital, Segmentation© RSNA, 2022.

Lifestyle intervention improves Left atrial strain in type 2 diabetes: results from the DIASTOLIC randomised trial

Abstract Introduction Left atrial (LA) strain has been shown to be an independent predictor of cardiovascular events in many conditions and superior to conventional measures of LA function (LA volumes and emptying fraction). The effects of low-energy diet or exercise on cardiovascular function in younger adults with type 2 diabetes (DIASTOLIC) study has previously demonstrated an improvement in left ventricle peak early diastolic strain rate in response to aerobic exercise in patients with type-2 diabetes (T2D). However, the effect of lifestyle intervention on LA function, assessed by cardiac magnetic resonance (CMR) imaging, is unknown. Methods The DIASTOLIC study was a prospective, randomised, open-label, blind endpoint trial, that randomised 90 obese participants with T2D (aged 18–65 years) to a 12-week intervention of: (i) routine care, (ii) aerobic exercise training, or (iii) low energy (≈810kcal/day) meal replacement plan (MRP). CMR was performed at baseline and week-12. Images were analysed using Medis v3.1. LA strain (LAS) was assessed using Feature Tracking (QStrain v2.0), corresponding to LA reservoir (LAS-r), conduit (LAS-cd), and booster pump (LAS-bp) using 4- and 2-chamber standard steady-state free precession cine images, and average values calculated. LA emptying fraction (LAEF) was calculated using biplane area-length method (QMass v8.1) for total, passive and active EF. Results 73 participants with T2D completed the trial and had analysable LA images (28 routine care, 22 exercise and 23 MRP). There was no significant change in CMR measured standard LA volumetric function (LAV/LAEF) and echocardiogram measured LV filling pressures (E/e') in any groups. The routine care arm showed no significant change in body mass index (BMI) or LAS (see Table). In the MRP group, there were significant reductions in BMI (4.8 kg/m2), mean systolic blood pressure (SBP) (13mmHg), and a significant increase in LAS-r and LAS-bp (29.9±7.0 to 32.3±7.0,p=0.036 and 14.6±5.3 to 17.2±3.7,p=0.034). The exercise arm showed a small reduction in BMI (0.8kg/m2), with no significant change in BP or LAS. Conclusion There was significant improvement in LAS post-lifestyle intervention in young adults with T2D, despite no change in volumetric measurements. MRP led to weight loss and improved SBP, with associated improved LA filling and contraction. Funding Acknowledgement Type of funding sources: Public grant(s) – National budget only. Main funding source(s): National Institute for Health Research (NIHR) a career development fellowship.

Myocardial Deformation in Fontan Patients Assessed by Cardiac Magnetic Resonance Feature Tracking: Correlation with Function, Clinical Course, and Biomarkers

Cardiac MR (CMR) is a standard modality for assessing ventricular function of single ventricles. CMR feature-tracking (CMR-FT) is a novel application enabling strain measurement on cine MR images and is used in patients with congenital heart diseases. We sought to assess the feasibility of CMR-FT in Fontan patients and analyze the correlation between CMR-FT strain values and conventional CMR volumetric parameters, clinical findings, and biomarkers. Global circumferential (GCS) and longitudinal (GLS) strain were retrospectively measured by CMR-FT on Steady-State Free Precession cine images. Data regarding post-operative course at Fontan operation, and medication, exercise capacity, invasive hemodynamics, and blood biomarkers at a time interval ± 6 months from CMR were collected. Forty-seven patients underwent CMR 11 ± 6 years after the Fontan operation; age at CMR was 15 ± 7 years. End-diastolic volume (EDV) of the SV was 93 ± 37 ml/m2, end-systolic volume (ESV) was 46 ± 23 ml/m2, and ejection fraction (EF) was 51 ± 11%. Twenty (42%) patients had a single right ventricle (SRV). In single left ventricle (SLV), GCS was higher (p < 0.001), but GLS was lower (p = 0.04) than in SRV. GCS correlated positively with EDV (p = 0.005), ESV (p < 0.001), and EF (p ≤ 0.0001). GLS correlated positively with EF (p = 0.002), but not with ventricular volumes. Impaired GCS correlated with decreased ventricular function (p = 0.03) and atrioventricular valve regurgitation (p = 0.04) at echocardiography, direct atriopulmonary connection (p = 0.02), post-operative complications (p = 0.05), and presence of a rudimentary ventricle (p = 0.01). A reduced GCS was associated with increased NT-pro-BNP (p = 0.05). Myocardial deformation can be measured by CMR-FT in Fontan patients. SLVs have higher GCS, but lower GLS than SRVs. GCS correlates with ventricular volumes and EF, whereas GLS correlates with EF only. Myocardial deformation shows a relationship with several clinical parameters and NT-pro-BNP.

Magnetic Resonance Assessment of Left Ventricular Ejection Fraction at Any Time Post-Infarction for Prediction of Subsequent Events in a Large Multicenter STEMI Registry.

Magnetic resonance imaging (MRI) is the most accurate imaging technique for left ventricular ejection fraction (LVEF) quantification, but as yet the prognostic value of LVEF assessment at any time after ST-segment elevation myocardial infarction (STEMI) for subsequent major adverse cardiac event (MACE) prediction is uncertain. To explore the prognostic impact of MRI-derived LVEF at any time post-STEMI to predict subsequent MACE (cardiovascular death or re-admission for acute heart failure). Prospective. One thousand thirteen STEMI patients were included in a multicenter registry. 1.5-T. Balanced steady-state free precession (cine imaging) and segmented inversion recovery steady-state free precession (late gadolinium enhancement) sequences. Post-infarction MRI-derived LVEF (reduced [r]: <40%; mid-range [mr]: 40%-49%; preserved [p]: ≥50%) was sequentially quantified at 1 week and after >3 months of follow-up. Multi-state Markov model to determine the prognostic value of each LVEF state (r-, mr- or p-) at any time point assessed to predict subsequent MACE. A P-value <0.05 was considered to be statistically significant. During a 6.2-year median follow-up, 105 MACE (10%) were registered. Transitions toward improved LVEF predominated and only r-LVEF (at any time assessed) was significantly related to a higher incidence of subsequent MACE. The observed transitions from r-LVEF, mr-LVEF, and p-LVEF states to MACE were: 15.3%, 6%, and 6.7%, respectively. Regarding the adjusted transition intensity ratios, patients in r-LVEF state were 4.52-fold more likely than those in mr-LVEF state and 5.01-fold more likely than those in p-LVEF state to move to MACE state. Nevertheless, no significant differences were found in transitions from mr-LVEF and p-LVEF states to MACE state (P-value=0.6). LVEF is an important MRI index for simple and dynamic post-STEMI risk stratification. Detection of r-LVEF by MRI at any time during follow-up identifies a subset of patients at high risk of subsequent events. 2 TECHNICAL EFFICACY STAGE: 2.

Left ventricular myocardial strain quantification with two- and three-dimensional cardiovascular magnetic resonance based tissue tracking.

Cardiovascular magnetic resonance based tissue tracking (CMR-TT) was reported to provide detailed insight into left ventricular (LV) contractile function and deformation with both of two- and three-dimensional (2/3D) algorithms. This study was designed to investigate the feasibility and reproducibility of these two techniques for measuring LV global and segmental strain, and establish gender- and age-related reference values of global multi-dimensional peak strains among large healthy population. We retrospectively recruited 150 healthy volunteers (75 males/females) and divided them into three age groups (G20-40, G41-60 and G61-80). LV global mean and peak strains as well as segmental strains in radial, circumferential and longitudinal directions were derived from post-hoc 2/3D CMR-TT analysis of standard steady-state free precession (SSFP) cine images acquired at 1.5T field strength. Both 2D and 3D CMR-TT modalities enable the tracking of LV myocardial tissues and generate global and segmental strain data. By comparison, 3D CMR-TT was more feasible in measuring segmental deformation since it could generate values at all segments. The amplitudes of LV 3D global peak strain were the smallest among those of 2/3D corresponding global mean or peak strains except in the radial direction, and was highly correlated with 2D global mean strains (correlation coefficient r=0.71-0.90), 2D global peak strains (r=0.75-0.89) and 3D global mean strains (all r=0.99). In healthy cohort, LV 3D global peak values were 44.4%±13.0% for radial, -17.0%±2.7% for circumferential and -15.4%±2.3% for longitudinal strain. Females showed significantly larger amplitude of strains than males, especially in G61-80 (P<0.05). The subjects in G61-80 showed larger amplitude of strains than the volunteers in younger groups. The intra- and inter-observer agreement of 2/3D CMR-TT analysis in evaluating LV myocardial global deformation was better than segmental measurement. CMR-TT is a feasible and reproducible technique for assessing LV myocardial deformation, especially at the global level. The establishment of specific reference values of LV global and segmental systolic strains and the investigation of dimension-, gender- and age-related differences provide a fundamental insight into the features of LV contraction and works as an essential step in clinical routine.