Feature Tracking Strain Research Articles

Fully Automated, Quality-Controlled Cardiac Analysis From CMR: Validation and Large-Scale Application to Characterize Cardiac Function

ObjectivesThis study sought to develop a fully automated framework for cardiac function analysis from cardiac magnetic resonance (CMR), including comprehensive quality control (QC) algorithms to detect erroneous output. BackgroundAnalysis of cine CMR imaging using deep learning (DL) algorithms could automate ventricular function assessment. However, variable image quality, variability in phenotypes of disease, and unavoidable weaknesses in training of DL algorithms currently prevent their use in clinical practice. MethodsThe framework consists of a pre-analysis DL image QC, followed by a DL algorithm for biventricular segmentation in long-axis and short-axis views, myocardial feature-tracking (FT), and a post-analysis QC to detect erroneous results. The study validated the framework in healthy subjects and cardiac patients by comparison against manual analysis (n = 100) and evaluation of the QC steps’ ability to detect erroneous results (n = 700). Next, this method was used to obtain reference values for cardiac function metrics from the UK Biobank. ResultsAutomated analysis correlated highly with manual analysis for left and right ventricular volumes (all r > 0.95), strain (circumferential r = 0.89, longitudinal r > 0.89), and filling and ejection rates (all r ≥ 0.93). There was no significant bias for cardiac volumes and filling and ejection rates, except for right ventricular end-systolic volume (bias +1.80 ml; p = 0.01). The bias for FT strain was <1.3%. The sensitivity of detection of erroneous output was 95% for volume-derived parameters and 93% for FT strain. Finally, reference values were automatically derived from 2,029 CMR exams in healthy subjects. ConclusionsThe study demonstrates a DL-based framework for automated, quality-controlled characterization of cardiac function from cine CMR, without the need for direct clinician oversight.

Feature-tracking myocardial strain in healthy adults- a magnetic resonance study at 3.0 tesla

We analyzed feature-tracking derived circumferential and longitudinal strain in healthy volunteers who underwent cardiac magnetic resonance imaging (CMR) at 3.0 T. 88 healthy adults (44.6 ± 18.0 years old, 49% male), without prior cardiovascular disease, underwent CMR at 3.0 T including cine, and late gadolinium enhancement in subjects >45 years. LV functional analysis and feature-tracking strain analyses were carried out. Global strain had better reproducibility than segmental strain. There was a sex specific difference global longitudinal strain (mean ± SD, −18.48 ± 3.65% (male), −21.91 ± 3.01% (female), p < 0.001), but not global circumferential strain (mean ± SD, −25.41 ± 4.50% (male), −27.94 ± 3.48% (female), p = 0.643). There was no association of strain with ageing after accounting for sex for both global longitudinal and circumferential strain. Feature-tracking strain analysis is feasible at 3.0 T. Healthy female volunteers demonstrated higher magnitudes of global longitudinal strain when compared to male counterparts. Whilst global cine-strain has good reproducibility, segmental strain does not.

Non-invasive evaluation of the relationship between electrical and structural cardiac abnormalities in patients with myotonic dystrophy type 1.

Cardiac involvement in myotonic dystrophy type 1 (MD1) includes conduction disease, arrhythmias, and left-ventricular (LV) systolic dysfunction leading to an increased sudden cardiac death risk. An understanding of the interplay between electrical and structural myocardial changes could improve the prediction of adverse cardiac events. We aimed to explore the relationship between signs of cardiomyopathy by conventional and advanced cardiovascular magnetic resonance (CMR), and electrical abnormalities in MD1. Fifty-seven MD1 patients (43 ± 13 years, 46% male) and 15 matched controls (41 ± 7 years, 53% male) underwent CMR including cine-imaging with feature-tracking strain analysis, late gadolinium enhancement (LGE), and native/post-contrast T1-mapping with extracellular volume calculation. Standard 12-lead and long-term ECG monitoring were performed as screening for rhythm and/or conduction abnormalities. Abnormal ECGs were recorded in 40% of MD1; a pathologic CMR was found in 44%: 21% had an impaired LV-EF and 32% showed non-ischemic LGE. When looking at MD1 patients with available long-term ECG monitoring (n = 39), those with atrial fibrillation (Afib)/flutter(Afl) episodes had lower LV-EF (52 ± 7 vs. 60 ± 5%, p = 0.002), lower global longitudinal strain (- 17 ± 3 vs. - 20 ± 3%, p = 0.034), a trend to lower left atrial emptying fraction (LA-EF) (44 ± 14 vs. 55 ± 8%, p = 0.08), and higher prevalence of LGE (88% vs. 23%, p = 0.001) with an intramural (75% vs. 23%, p = 0.01) and septal (63% vs. 13%, p = 0.009) pattern. In a model including LV-EF (OR 0.8, 95% CI 0.7-1.0, p = NS) and LGE presence (OR 14.8, 95% CI 1.4-159.0, p = 0.026), only LGE was independently associated with the occurrence of Afib/Afl episodes. Myocardial abnormalities depicted by non-ischemic LGE-CMR were the only independent predictor for the occurrence of Afib/Afl on ECG monitoring, previously shown to predict adverse cardiac events in MD1.

Myocardial tissue characterization in patients with hereditary gelsolin (AGel) amyloidosis using novel cardiovascular magnetic resonance techniques

Gelsolin (AGel) amyloidosis is a hereditary condition with common neurological effects. Myocardial involvement, especially strain, T1, or extracellular volume (ECV), in this disease has not been investigated before. Local myocardial effects and possible amyloid accumulation were the targets of interest in this study. Fifty patients with AGel amyloidosis were enrolled in the study. All patients underwent cardiovascular magnetic resonance imaging, including cine imaging, T1 mapping, tagging, and late gadolinium enhancement (LGE) imaging at 1.5 T. Results for volumetry, myocardial feature-tracking strain, rotation, torsion, native T1, ECV, and LGE were investigated. The population mean native T1 values in different segments of the left ventricle (LV) varied between 1003 and 1080 ms. Myocardial mean T1 was 1031 ± 37 ms. T1 was highest in the basal plane of the LV (1055 ± 40 ms), similarly to ECV (30.0% ± 4.4%). ECV correlated with native T1 in all LV segments (p < 0.005). Basal LGE was detected in 76% of patients, and mid-ventricular LGE in 32%. LV longitudinal strain was impaired (− 17.4% ± 2.6%), significantly decreasing apical rotation (p = 0.018) and concurrently myocardial torsion (p = 0.005). LV longitudinal strain correlated with mean T1 and ECV of different LV planes (p < 0.04; basal p < 0.01). Myocardial involvement in AGel amyloidosis is significant, but the effects are local, focusing on the basal plane of the LV.

Associations of Infarct Size and Regional Myocardial Function Examined by Cardiac Magnetic Resonance Feature Tracking Strain Analysis with the Infarct Location in Patients with Acute ST-Segment Elevation Myocardial Infarction

ObjectiveTo quantitatively evaluate the associations of infarct size, regional myocardial function examined by cardiac magnetic resonance feature tracking (CMR-FT) strain analysis with infarct location in patients with ST-segment elevation myocardial infarction (STEMI) treated by primary percutaneous coronary intervention. MethodsCardiac magnetic resonance images were retrospectively analyzed in 95 consecutive STEMI patients with successful reperfusion. The patients were divided into the anterior wall myocardial infarction (AWMI) and nonanterior wall myocardial infarction (NAWMI) groups. Infarct characteristics were assessed by late gadolinium enhancement. Global and regional strains and associated strain rates in the radial, circumferential and longitudinal directions were assessed by CMR-FT based on standard cine images. The associations of infarct size, regional myocardial function examined by CMR-FT strain analysis with infarct location in STEMI patients were evaluated by the Spearman or Pearson method. ResultsThere were 44 patients in the AWMI group and 51 in the NAWMI group. The extent of left ventricular enhanced mass was significantly larger in patients with AWMI compared with the NAWMI group (24.47+11.89, 21.06+12.08 %LV; t = 3.928, P = 0.008). In infarct zone analysis, strains in the radial, circumferential and longitudinal directions were remarkably declined in the AWMI group compared with the NAWMI group (z = -20.873, -20.918, -10.357, all P < 0.001). The volume (end-systolic volume index), total enhanced mass and extent of enhanced mass of the left ventricular were correlated best with infarct zone strain in the AWMI group (all P < 0.001). ConclusionIn STEMI patients treated by percutaneous coronary intervention, myocardial damage is more extensive and regional myocardial function in the infarct zone is lower in the AWMI group compared with the NAWMI group.

Validation of aortic valve 4D flow analysis and myocardial deformation by cardiovascular magnetic resonance in patients after the arterial switch operation

BackgroundAortic regurgitation (AR) and subclinical left ventricular (LV) dysfunction expressed by myocardial deformation imaging are common in patients with transposition of the great arteries after the arterial switch operation (ASO). Echocardiographic evaluation is often hampered by reduced acoustic window settings. Cardiovascular magnetic resonance (CMR) imaging provides a robust alternative as it allows for comprehensive assessment of degree of AR and LV function. The purpose of this study is to validate CMR based 4-dimensional flow quantification (4D flow) for degree of AR and feature tracking strain measurements for LV deformation assessment in ASO patients.MethodsA total of 81 ASO patients (median 20.6 years, IQR 13.5–28.4) underwent CMR for 4D and 2D flow analysis. CMR global longitudinal strain (GLS) feature tracking was compared to echocardiographic (echo) speckle tracking. Agreements between and within tests were expressed as intra-class correlation coefficients (ICC).ResultsEleven ASO patients (13.6%) showed AR > 5% by 4D flow, with good correlation to 2D flow assessment (ICC = 0.85). 4D flow stroke volume of the aortic valve demonstrated good agreement to 2D stroke volume over the mitral valve (internal validation, ICC = 0.85) and multi-slice planimetric LV stroke volume (external validation, ICC = 0.95). 2D flow stroke volume showed slightly less, though still good agreement with 4D flow (ICC = 0.78) and planimetric LV stroke volume (ICC = 0.87). GLS by CMR was normal (− 18.8 ± 4.4%) and demonstrated good agreement with GLS and segmental analysis by echocardiographic speckle tracking (GLS = − 17.3 ± 3.1%, ICC of 0.80).ConclusionsAortic 4D flow and CMR feature tracking GLS analysis demonstrate good to excellent agreement with 2D flow assessment and echocardiographic speckle tracking, respectively, and can therefore reliably be used for an integrated and comprehensive CMR analysis of aortic valve competence and LV deformation analysis in ASO patients.

MRI feature tracking strain is prognostic for all-cause mortality in AL amyloidosis

Objectives: Cardiac involvement is a major determinate of mortality in light chain (AL) amyloidosis. Cardiac magnetic resonance imaging (MRI) feature tracking (FT) strain is a new method for measuring myocardial strain. This study retrospectively evaluated the association of MRI FT strain with all-cause mortality in AL amyloidosis.Materials and methods: Seventy-six patients with newly diagnosed AL amyloidosis underwent cardiac MRI. 75 had images suitable for MRI FT strain analysis. MRI delayed enhancement, morphologic and functional evaluation, cardiac biomarker staging and transthoracic echocardiography were also performed. Subjects’ charts were reviewed for all-cause mortality. Cox proportional hazards analysis was used to evaluate survival in univariate and multivariate analysis.Results: There were 52 deaths. Median follow-up of surviving patients was 1.7 years. In univariate analysis, global radial (Hazard Ratio (HR) = 0.95, p <.01), circumferential (HR = 1.09, p < .01) and longitudinal (HR = 1.08, p < .01) strain were associated with all-cause mortality. In separate multivariate models, radial (HR = 0.96, p = .02), circumferential (HR = 1.09, p = .03) and longitudinal strain (HR = 1.07, p = .04) remained prognostic when combined with presence of biomarker stage 3.Conclusions: MRI FT strain is associated with all-cause mortality in patients with AL amyloidosis.

Myocardial Strain Using Cardiac MR Feature Tracking and Speckle Tracking Echocardiography in Duchenne Muscular Dystrophy Patients.

Duchenne muscular dystrophy (DMD) is an inherited X-linked disorder with an incidence of 1 in 3500 male births, and cardiomyopathy is becoming the leading cause of death. While Cardiac MRI (CMR) and late gadolinium enhancement (LGE) are important tools in recognizing myocardial involvement, myocardial strain imaging may demonstrate early changes and allow patients to avoid gadolinium contrast. We performed CMR feature tracking (FT) and echo-based speckle tracking (STE) strain measures on DMD patients and age/sex matched controls who had received a CMR with contrast and transthoracic echocardiogram. Data were collected for longitudinal strain in the apical four-chamber view and circumferential strain in the mid-papillary parasternal short axis. Segmental wall analysis was performed and compared with the presence of LGE. Data were analyzed using student's t tests or one-way ANOVA adjusting for multiple comparisons. We measured 24 subjects with DMD and 8 controls. Thirteen of 24 DMD subjects were LGE positive only in the lateral segments in short-axis views. Average circumferential strain (CS) measured by FT was significantly decreased in DMD compared to controls (- 18.8 ± 6.1 vs. - 25.5 ± 3.2; p < 0.001) and showed significant differences in the anterolateral, inferolateral, and inferior segments. Average CS by STE trended towards significance (p = 0.06) but showed significance in only the inferior segment. FT showed significant differences in the inferolateral segment between LGE positive (- 15.5 ± 9.0) and LGE negative (- 18.2 ± 8.3) in DMD subjects compared to controls (- 28.6 ± 7.3; p ≤ 0.04). FT also showed significant differences between anteroseptal and inferolateral segments within LGE-positive (p < 0.003) and LGE-negative (p < 0.03) DMD subjects while STE did not. There were no significant differences in longitudinal strain measures. CMR-FT-derived myocardial strain was able to demonstrate differences between subjects with DMD and controls not detected by STE. FT was also able to demonstrate differences in LGE-positive and LGE-negative segments within patients with DMD. FT may be able to predict LGE-positive segments in DMD without the use of gadolinium contrast.

EVALUATION OF RIGHT VENTRICULAR FUNCTION IN FONTAN PHYSIOLOGY USING FEATURE TRACKING MAGNETIC RESONANCE STRAIN, STRAIN RATE AND WALL MOTION DELAY

Background: Patients are commonly affected by ventricular dysfunction after Fontan palliation. Reliable quantification of ventricular function was hampered by complex ventricular anatomy and physiology. Cine-based feature tracking strain (FTS) is a new technique to assess cardiac function from

Cardiac Magnetic Resonance Feature Tracking Biventricular Two-Dimensional and Three-Dimensional Strains to Evaluate Ventricular Function in Children After Repaired Tetralogy of Fallot as Compared with Healthy Children.

Cardiac magnetic resonance imaging is an important tool to evaluate cardiac anatomy and ventricular size and function after repaired tetralogy of Fallot. Magnetic resonance tissue tagging is the gold standard for evaluation of myocardial strain. However, myocardial tagging strain requires tagged images to be obtained prospectively, during the scan and with limited temporal resolution. Cardiac magnetic resonance feature tracking is a new tool that allows the retrospective analysis of cine images. There is limited experience with cardiac magnetic resonance feature tracking strain analysis in children. The medical records of patients with repaired tetralogy of Fallot that had a cardiac magnetic resonance (CMR) study from December 2013 to June 2015 were reviewed. The control group included patients who underwent a CMR with normal cardiac anatomy and ventricular function. Global longitudinal, circumferential and radial strain parameters (2D and 3D) were obtained by retrospectively contouring cine images from ventricular short axis, two chamber and four chamber views using post-processing software (Circle CVi42, Calgary, Canada). The correlation between conventional ventricular function parameters and ventricular strain was performed using Pearson's correlation. The mean age of tetralogy of Fallot and control subjects was 12.4 and 14.1years, respectively. In patients after repaired tetralogy of Fallot, the mean left ventricular global 2D and 3D circumferential strains were -17.4±2.9 and -10.1±3, respectively. The mean indexed right ventricular end-diastolic volume was 135.4ccm2±46 compared to 75.7ccm2±17 in control subjects (P=0.0001, CI 95%). Left ventricular global circumferential 3D strain showed a statistically significant difference in patients after TOF repair compared to normal subjects (-10.1±3 vs. -14.71±1.9, P=0.00001). A strong correlation between left ventricular global circumferential 3D strain and right ventricular end-diastolic volume (P≤0.0001) was noted. We found a strong correlation between left ventricular circumferential 3D strain and indexed right ventricular end-diastolic volume, as well as a strong correlation between left ventricular longitudinal 2D strain and right ventricular ejection fraction. Circumferential 3D strain may be a suitable tool to detect early abnormalities of ventricular myocardium even before the ejection fraction becomes compromised. Large-scale prospective studies are recommended.

Evaluation of Myocardial Strain in Patients With Amyloidosis Using Cardiac Magnetic Resonance Feature Tracking

PurposeTo study the use of cardiac magnetic resonance (CMR) feature tracking technique in evaluation of myocardial amyloidosis. Materials and MethodsCMR scans of 28 patients with biopsy proven myocardial amyloidosis and 35 controls were reviewed. Conventional short axis, vertical long axis, and 4-chamber cine steady-state free precession images from CMR scans were used to generate radial, circumferential, and longitudinal myocardial strain maps using feature tracking software. Global and regional peak radial, circumferential, and longitudinal strain values were computed. ResultsThere were significant decreases in radial, circumferential, and longitudinal strains in patients with myocardial amyloidosis globally and across layers (all P < 0.001). Strain was relatively preserved for the apex and most affected for the basal level. The area under the receiver operating characteristic curve for base peak radial, circumferential, and longitudinal strain 0.899, 0.884, and 0.866 and cut offs of 22.9, −13.3, and −10.9, respectively, were determined by receiver operating characteristic analysis. CMR feature tracking strain analysis of base-level strain parameters was able to differentiate patients with myocardial amyloidosis from those without myocardial amyloid with high sensitivity (82.5%) and specificity (82.9%) particularly for radial strain. The maximum sensitivity (89.3%) was achieved if any of the 3 parameters were abnormal, and the maximum specificity (88.6%) when all 3 parameters were abnormal. ConclusionMyocardial amyloidosis produces significant changes in regional and global strain parameters, and the peak radial and circumferential strain are the most affected at the basal layer.

Assessment of myocardial function using MRI-based feature tracking in adults after atrial repair of transposition of the great arteries: Reference values and clinical utility

BackgroundEchocardiographic parameters of ventricular deformation of the systemic right ventricle (sRV) predict adverse clinical outcome in patients after atrial repair of transposition of the great arteries (TGA). We assessed myocardial deformation on cardiac MRI (CMR) and correlated these with clinical and conventional CMR parameters in TGA patients. MethodsRetrospective analysis of CMR studies in 91 TGA patients (66% male; mean age 30.1±5.1years) at two tertiary adult congenital heart centers was conducted. Myocardial deformation was assessed by CMR-based feature tracking (FT), providing longitudinal (LS), radial (RS), and circumferential (CS) global strain for the sRV and the subpulmonary left ventricle. A subgroup of optimal TGA was defined (NYHA class I, NT-proBNP <300pg/ml, max. exercise work load ≥100watt, no significant clinical events) as a reference cohort. ResultsThere was a significant correlation between FT and conventional CMR parameters. Left ventricular ejection fraction (LVEF) correlated significantly with LV LS, RS, and CS (r between 0.24 and 0.34, p values between 0.03 and 0.005). sRVEF correlated with RV CS (r=0.56, p<0.001), and RV RS (r=0.32, p=0.007). QRS duration showed a negative correlation with RV CS (r=−0.53, p<0.001), LV RS (r=−0.34, p=0.008), and LV CS (r=−0.34, p=0.006). Reference values for the novel FT method in clinically optimal TGA patients are provided. ConclusionAssessment of myocardial function using CMR-based FT is feasible in TGA patients. FT measurements related to important prognostic clinical parameters. Furthermore, we provide for the first time reference values for TGA patients in an optimal clinical status.

MRI feature tracking strain profiles distinguish patients with left ventricular systolic and diastolic dysfunction with and without clinical heart failure

Background Characterizing myocardial mechanical properties is valuable in understanding cardiomyopathy with and without clinical heart failure (HF). We sought to examine the incremental value of strain assessment in patients with left ventricular systolic dysfunction without HF (LVSD), HF with reduced ejection fraction (HFrEF), LV diastolic dysfunction without HF (LVDD) and HF with preserved EF (HFpEF) during routine cardiac MR (CMR) evaluation.

Myocardial Fibrosis and Left Ventricular Dysfunction in Duchenne Muscular Dystrophy Carriers Using Cardiac Magnetic Resonance Imaging.

The goal of our study was to characterize the degree of myocardial fibrosis and left ventricular dysfunction in our cohort of Duchenne muscular dystrophy (DMD) carriers using cardiac magnetic resonance imaging (CMR). Seventy percent of males with DMD have mothers who are carriers of the Xp21 mutation. Carrier phenotypic characteristics range from asymptomatic to left ventricular (LV) dysfunction and cardiomyopathy. The true prevalence of cardiac involvement in DMD carriers is unknown. We performed a retrospective observational study. All female DMD carriers who underwent clinical CMR studies at Cincinnati Children's Hospital Medical Center from December 6, 2006, to August 28, 2013, were evaluated. Patients underwent standard CMR assessment with LV function assessment and late gadolinium enhancement (LGE). In addition, offline feature tracking strain analysis was performed on the basal, mid, and apical short axis. Twenty-two patients were studied, of which 20 underwent adequate testing for myocardial LGE. Four of 22 patients (18 %) were found to have LV dysfunction (ejection fraction <55 %). Seven of 20 DMD carriers (35 %) were found to have LGE. The patients with evidence of LGE had an overall trend to lower absolute deformation parameters; however, this did not meet statistical significance when correcting for multiple comparisons. Our study demonstrates a high rate of LGE as well as LV dysfunction in DMD carriers. Cardiovascular and musculoskeletal symptoms were not statistically different between those with and without cardiac involvement. This study demonstrates the importance of surveillance CMR evaluation of DMD carriers.

19 The randomised complete vs. lesion only primary PCI trial – cardiovascular MRI substudy (CVLPRIT-CMR)

Background Multivessel disease (MVD) occurs in ~40% of STEMI. Management is controversial. PRAMI and CVLPRIT showed improved clinical outcomes with complete versus infarct-related artery (IRA)-only revascularisation at primary percutaneous coronary intervention (PPCI). However, non-IRA PCI may cause additional infarcts. We aimed to determine whether in-hospital complete revascularisation was associated with increased myocardial injury versus an IRA-only strategy. Methods Multicentre, prospective, randomised, blinded endpoint trial. STEMI patients with MVD and Validation studies optimised infarct, area-at-risk and strain quantification. Full-width half-maximum infarct quantification was more accurate, reproducible and correlated strongest with ejection fraction (LVEF) and infarct characteristics. Otsu’s Automated Thresholding most accurately and reproducibly assessed area-at-risk. Compared with tagging, Feature Tracking strain measurement was more robust, quicker, had better interobserver variability and correlated stronger with infarct, area-at-risk and MSI. Results (summarised in Table 1) 203 patients (98 complete revascularisation, 105 IRA-only) completed acute CMR. The groups were well matched. There was no difference in infarct size, MSI, LVEF, circumferential strain or ischaemic burden between groups. Complete revascularisation patients had increased non-IRA MI at acute CMR (Figure 1). 12 month MACE was reduced in complete revascularisation patients (8.2% vs. 17.1%, p = 0.055, hazard ratio 0.43). Conclusions Complete revascularisation in STEMI with MVD leads to a small increase in CMR-detected non-IRA MI, but total infarct size and 12 month MACE are not increased. This provides further reassurance that complete revascularisation can be considered at PPCI.

STRAIN TO EVALUATE VENTRICULAR FUNCTION IN FONTAN PATIENTS UNDERGOING EXERCISE CARDIAC MAGNETIC RESONANCE IMAGING

Feature tracking strain (FTS) is a new technique to assess cardiac function from cardiac magnetic resonance (CMR) images. We compared FTS with conventional function parameters in single ventricle undergoing exercise CMR. 28 Fontan subjects underwent a resting and exercise CMR. Segmented balanced

Feature tracking strain is similar to harmonic phase cardiac magnetic resonance in Fontan patients: a validation study

Background Feature tracking strain (FTS) is a new technique to evaluate myocardial deformation from routinely acquired cardiac magnetic resonance (CMR) cine images, however, it has not been validated in single ventricle patients. The purpose of this study is to validate FTS against myocardial tagged harmonic phase (HARP) images, considered the reference standard in non-invasive deformation analysis.

Abstract 18777: Right Ventricular Outflow Tract Strain is Reduced in Tetralogy of Fallot Compared to Valvar Pulmonary Stenosis Patients; Regional RV Function Defined by Strain Cardiac Magnetic Resonance Imaging

Introduction: The right ventricular outflow tract (RVOT) patch after Tetralogy of Fallot (ToF) surgery may contribute to ventricular dysfunction, but the specific effects on RV function are not clear. We aimed to investigate RV function in patients with ToF and RVOT patch by comparing to patients with valvar pulmonary stenosis (vPS) after balloon valvuloplasty (no RVOT patch). Methods: We conducted a retrospective review of 33 CMR studies of ToF and vPS patients with similar pulmonary regurgitation (PR) Table 1. Feature tracking strain (FTS) analysis of balanced steady state free precession (SSFP) cines was performed on the RV in apical 4-chamber (4ch), RVOT sagittal &amp; mid-RV short axis views (TomTec 2D Cardiac Performance Analysis, v1.0), Figure 1. Unpaired t-tests were applied for comparison of means between groups. Results: Lagrangian longitudinal strain (LS) at the RVOT was significantly lower in ToF compared to vPS (mean -14.1% vs -18.2%, unpaired t-test p = 0.03), Table 1. Analysis of regional S within the same group showed a trend towards lower RVOT strain compared to 4ch LS in ToF (p = 0.052). There were no significant inter-group differences in strain from the 4ch or mid-RV short axis views, with normal 4ch LS in both groups. Conclusion: In a population with preserved EF, RVOT strain is significantly lower in ToF patients with a transannular patch compared to vPS patients with similar amount &amp; duration of PR. Low RVOT LS appears to be a regional phenomenon, with strain in the 4ch and mid-RV similar between groups. Further investigation is warranted in a larger sample. FTS analysis is a promising technique to evaluate regional RV mechanics in this population.

Feature tracking strain is a promising functional analysis technique in single ventricle patients

Background Feature-tracking Strain (FT S) is a new technique that performs myocardial Strain evaluation on Steady State Free Precession (SSFP) cines without the need for myocardial tagging. As a pilot study to determine whether FT S may be useful in single ventricle patients, we applied this analysis to patients with hypoplastic left heart syndrome (HLHS) and tricuspid atresia (TA). Methods We retrospectively reviewed 22 patients with a history of Fontan palliation (median age 8.2, range 2 - 27.5 years) who had cardiac MRIs with a Siemens 1.5 Tesla Avanto (Siemens Medical Systems) scanner, 11 with TA, 11 with HLHS. All had steady-state free precession (SSFP) sequences of 4-chamber (4ch) cine and short axis (SAx) cine stacks from cardiac base to apex. Ejection fraction (EF) was calculated from the SAx stack on a Leonardo workstation (Siemens, Inc.). FT S analysis of the 4ch cine was performed off-line with TomTec 2D Cardiac Performance Analysis (version 1.0, TomTec Imaging Systems) following two tracking protocols: endocardial trace only (Endo), epicardial to endocardial trace (Endo-Epi) (Figure 1). Pearson correlation was used to test relationship between absolute global longitudinal Strain (GLSabs) and EF. Differences in GLS between tracking methods were tested with Bland Altman analysis. Results Mean EF was 60.2%, 95% CI 42.6% to 77.8%. Mean GLS was -15.7 (95% CI -6.8 to -24.7) by Endo., and -16.5 (95% CI -6.9 to -26.1) by Endo-Epi tracking methods. There was fair correlation (Figure 2) between GLSabs and EF using the Endo method (Pearson r = 0.67, p mean Endo GLS of 0.8, with a wide distribution in difference values, 95% CI 2.9 to -4.5. Morphologic ventricle type (single LV vs single RV) did not make a difference in GLS to EF correlations when compared to the mixed cohort. Mean GLS for single LVs was somewhat higher than single RVs, but this difference did not reach statistical significance. Conclusions There is fair correlation between GLS and EF in single ventricle patients with feature-tracking Strain analysis tracking the ventricular endocardium. Validation in a larger sample is warranted. Comparison of FT S with tagged harmonic phase MRI in single ventricle patients may further validate this promising technique in defining regional and global strain. Funding

Cardiac magnetic resonance myocardial feature tracking: feasibility for use in left ventricular non-compaction

Background Cardiac magnetic resonance (CMR) myocardial feature tracking (FT) is emerging as a sensitive and reproducible method for measuring myocardial strain parameters without the need to acquire additional images. Up until now adult CMRFT studies have primarily focussed on the reproducibility of the software,with very few studies addressing disease states beyond ischaemic cardiomyopathy. The aim of this pilot study was to assess the feasibility of cine-images derived quantitative CMR FT strain parameters to differentiate between normal individuals and patients with Left ventricular non-compaction (LVNC). Methods Patients were identified retrospectively from an established clinical CMR database. 8 LVNC patients with negative invasive angiography or stress CMR myocardial perfusion imaging were compared to 21 normal controls. LVNC was defined according to the Petersen criteria,with an end-diastolic ratio of non-compacted to compacted layer (NC/C) >2.3. LV morphological and functional parameters were performed off-line on a dedicated workstation. CMR 4chamber(4CH) and mid-ventricular short axis(SAX) cineimages were analysed in systole(S) and diastole(D) using dedicated FT software(Diogenes MRI,TomTec Imaging Systems,Munich Germany).