Incremental value of cardiac deformation analysis in acute myocarditis: a cardiovascular magnetic resonance imaging study

Layer-specific fast strain-encoded cardiac magnetic resonance imaging aids in the identification and discrimination of acute myocardial injury: a prospective proof-of-concept study

BACKGROUND

Acute myocardial injury is a common diagnosis in the emergency department and differential diagnoses are numerous. Cardiac magnetic resonance (CMR) strain sequences, such as fast strain ENCoded (fSENC), are early predictors of myocardial function loss. This study assessed the potential diagnostic and prognostic benefits of a layer-specific approach.

METHODS

For this prospective study, patients in the emergency department fulfilling rule-in criteria for non-ST-elevation myocardial infarction (NSTEMI) received an ultra-fast fSENC CMR. Volunteers without cardiac diseases (controls) were recruited for comparison. Measurements were performed in a single heartbeat acquisition to measure global longitudinal strain (GLS) and segmental longitudinal strain and dysfunctional segments. The GLS was measured in two layers and a difference (GLSdifference = GLSepicardial - GLSendocardial) was calculated. The performance of those strain features was compared to standard care (physical examination, cardiac biomarkers, electrocardiogram). According to the final diagnosis after discharge, patients were divided into groups and followed up for 2 years.

RESULTS

A total of 114 participants, including 50 controls, were included. The 64 patients (51 male) were divided into a NSTEMI (25), myocarditis (16), and other myocardial injury group (23). GLS served as a potent predictor of myocardial injury (area under the curve (AUC) 91.8%). The GLSdifference provided an excellent diagnostic performance to identify a NSTEMI (AUC 83.2%), further improved by including dysfunctional segments (AUC 87.5%, p = 0.01). An optimal test was achieved by adding fSENC to standard care (AUC 95.5%, sensitivity 96.0%, specificity 86.5%, p = 0.03). No death occurred in 2 years for patients with normal GLS and ≤5 dysfunctional segments, while three patients died that showed abnormal GLS or >5 dysfunctional segments.

CONCLUSIONS

Layer-specific strain is a potential new marker with high diagnostic performance in the identification and differentiation of acute myocardial injuries.

Cardiac magnetic resonance feature tracking myocardial strain analysis in suspected acute myocarditis: diagnostic value and association with severity of myocardial injury

BACKGROUND

Albeit that cardiac magnetic resonance feature tracking (CMR-FT) has enabled quantitative assessment of global myocardial strain in the diagnosis of suspected acute myocarditis, the cardiac segmental dysfunction remains understudied. The aim of the present study was using CMR-FT to assess the global and segmental dysfunction of the myocardium for diagnosis of suspected acute myocarditis.

METHODS

Forty-seven patients with suspected acute myocarditis (divided into impaired and preserved left ventricular ejection fraction [LVEF] groups) and 39 healthy controls (HCs) were studied. A total of 752 segments were divided into three subgroups, including segments with non-involvement (S_Ni), segments with edema (S_E), and segments with both edema and late gadolinium enhancement (S_E+LGE). 272 healthy segments served as the control group (S_HCs).

RESULTS

Compared with HCs, patients with preserved LVEF showed impaired global circumferential strain (GCS) and global longitudinal strain (GLS). Segmental strain analysis showed that the peak radial strain (PRS), peak circumferential strain (PCS), and peak longitudinal strain (PLS) values significantly reduced in S_E+LGE compared with S_HCs, S_Ni, S_E. PCS significantly reduced in S_Ni (-15.3 ± 5.8% vs. -20.3 ± 6.4%, p < 0.001) and S_E (-15.2 ± 5.6% vs. -20.3 ± 6.4%, p < 0.001), compared with S_HCs. The area under the curve (AUC) values of GLS (0.723) and GCS (0.710) were higher than that of global peak radial strain (0.657) in the diagnosis of acute myocarditis, but the difference was not statistically significant. Adding the Lake Louise Criteria to the model resulted in a further increase in diagnostic performance.

CONCLUSIONS

Global and segmental myocardial strain were impaired in patients with suspected acute myocarditis, even in the edema or relatively non-involved regions. CMR-FT may serve as an incremental tool for assessment of cardiac dysfunction and provide important additional imaging-evidence for distinguishing the different severity of myocardial injury in myocarditis.

Multimodality imaging in acute myocarditis

The diagnosis of acute myocarditis often involves several noninvasive techniques that can provide information regarding volumes, ejection fraction, and tissue characterization. In particular, echocardiography is extremely helpful for the evaluation of biventricular volumes, strain and ejection fraction. Cardiac magnetic resonance, beyond biventricular volumes, strain, and ejection fraction allows to characterize myocardial tissue providing information regarding edema, hyperemia, and fibrosis. Contemporary cardiac computed tomography angiography (CCTA) can not only be extremely important for the assessment of coronary arteries, pulmonary arteries and aorta but also tissue characterization using CCTA can be an additional tool that can explain chest pain with a diagnosis of myocarditis.

Reduced Circumferential Strain in Athletes with Prior COVID-19

Purpose

To characterize global and segmental circumferential systolic strain (CS) measured by cardiac MRI in athletes after SARS-CoV-2 infection.

Materials and Methods

This retrospective observational cohort study included 188 soldiers and collegiate athletes referred for cardiac MRI after SARS-CoV-2 infection (C19+) between July 2020 and February 2021 and a control group of 72 soldiers, collegiate, and high school athletes who underwent cardiac MRI from May 2019 to February 2020, prior to the first SARS-CoV-2 case detected in our region (C19-). Global and segmental CS were measured by feature tracking, then compared between each group using unadjusted and multivariable- adjusted models. Acute myocarditis was diagnosed according to the modified Lake Louise criteria and the location of pathologic late gadolinium enhancement (LGE) was ascertained.

Results

Among the 188 C19+ athletes (median age, 25 years [IQR, 23-30]; 131 men), the majority had mild illness. Global CS significantly differed between C19+ and C19- groups, with a median of -24.0 (IQR -25.8, -21.4) versus. -25.0 (-28.0, -22.4), respectively (p = .009). This difference in CS persisted following adjustment for age, sex, body mass index, heart rate, and systolic blood pressure β coefficient 1.29 [95% CI: 0.20, 2.38], p = .02). In segmental analysis, the basal- and mid- inferoseptal, septal and inferolateral segments were significantly different (p < .05), which had a higher frequency of post-COVID late gadolinium enhancement. The global and segmental differences were similar after exclusion of athletes with myocarditis.

Conclusion

Among athletes, SARS-CoV-2 infection was associated with a small but statistically significant reduced CS.

Impact of myocardial injury on regional left ventricular function in the course of acute myocarditis with preserved ejection fraction: insights from segmental feature tracking strain analysis using cine cardiac MRI

The aim of this study was to provide insights into myocardial adaptation over time in myocyte injury caused by acute myocarditis with preserved ejection fraction. The effect of myocardial injury, as defined by the presence of late gadolinium enhancement (LGE), on the change of left ventricular (LV) segmental strain parameters was evaluated in a longitudinal analysis. Patients with a first episode of acute myocarditis were enrolled retrospectively. Peak radial (PRS), longitudinal (PLS) and circumferential (PCS) LV segmental strain values at baseline and at follow-up were computed using feature tracking cine cardiac magnetic resonance imaging. The change of segmental strain values in LGE positive (LGE+) and LGE negative (LGE-) segments was compared over a course of 89 ± 20 days. In 24 patients, 100 LGE+ segments and 284 LGE- segments were analysed. Between LGE+ and LGE- segments, significant differences were found for the change of segmental PCS (p < 0.001) and segmental PRS (p = 0.006). LGE + segments showed an increase in contractility, indicating recovery, and LGE- segments showed a decrease in contractility, indicating normalisation after a hypercontractile state or impairment of an initially normal contracting segment. No significant difference between LGE+ and LGE- segments was found for the change in segmental PLS. In the course of acute myocarditis with preserved ejection fraction, regional myocardial function adapts inversely in segments with and without LGE. As these effects seem to counterbalance each other, global functional parameters might be of limited use in monitoring functional recovery of these patients.

The utility of cardiac magnetic resonance imaging in the diagnosis of adult patients with acute myocarditis: A systematic review and meta-analysis

BACKGROUND

The presence of myocardial late gadolinium enhancement (LGE) indicates myocyte necrosis, and assists with the diagnosis of acute myocarditis (AM). Cardiac magnetic resonance (CMR) measures other than LGE i.e. tissue characterization and myocardial structural and functional parameters, play an important diagnostic role in assessment for inflammation, as seen in AM. The aim of this systematic review was to appraise the evidence for the use of quantitative CMR measures to identify myocardial inflammation in order to diagnose of AM in adult patients.

METHODS

A systematic literature search of medical databases was performed using PRISMA principles to identify relevant CMR studies on AM in adults (2005-2020; English; PROSPERO registration CRD42020180605). Data for a range of quantitative CMR measures were extracted. Continuous variables with low heterogeneity were meta-analyzed using a random-effects model for overall effect size measured as the standard mean difference (SMD).

RESULTS

Available data from 25 studies reporting continuous quantitative 1.5 T CMR measures revealed that AM is most reliably differentiated from healthy controls using T1 mapping (SMD 1.80, p < 0.01) and T2 mapping (SMD 1.63, p < 0.01), respectively. All other measures examined including T2-weighted ratio, extracellular volume, early gadolinium enhancement ratio, right ventricular ejection fraction, and LV end-diastolic volume, mass, ejection fraction, longitudinal strain, circumferential strain, and radial strain also had discriminatory ability although with smaller standard mean difference values (|SMD| 0.32-0.96, p < 0.01 for all).

CONCLUSIONS

Meta-analysis shows that myocardial tissue characterization (T1 mapping>T2 mapping) followed by measures of left ventricular structure and function demonstrate diagnostic discriminatory ability in AM.

Emerging Role of Cardiac Magnetic Resonance Imaging in Diagnosing Myocarditis: A Blunder or The Way To Get the Problem Sorted?

Acute myocarditis is a disease affecting the myocardial tissue, which is caused by infections, rheumatic diseases, especially sarcoidosis, or certain therapies. Its diagnosis may be difficult, owing to its variable clinical presentation. In this setting, cardiac magnetic resonance plays a pivotal role in detecting myocardial inflammation through qualitative, semiquantitative, and quantitative parameters, in particular with the new quantitative techniques such as T1 and T2 mapping, combined or not with late gadolinium enhancement evaluation. This is in accordance with the revised Lake Louise criteria. In this review, the emerging role of the new cutting-edge cardiac magnetic resonance imaging techniques in diagnosing myocarditis is extensively presented.

Application of Multiparametric Quantitative Cardiac Magnetic Resonance for Detection and Monitoring of Myocardial Injury in Patients with Fulminant Myocarditis

RATIONALE AND OBJECTIVES

To investigate whether multiparametric cardiac magnetic resonance (CMR) could detect and monitor inflammatory myocardial alterations in fulminant myocarditis.

MATERIALS AND METHODS

Nineteen patients (35 ± 14 years, 37% male) with clinical diagnosis of fulminant myocarditis underwent CMR examinations at 3.0T in the acute phase and at 3-months follow up. The control group consisted of 19 healthy volunteers. The CMR protocol included cine, black blood T2-weighted imaging, T1 mapping, T2 mapping and late gadolinium enhancement (LGE). Cardiac parameters, such as edema ratio, LGE mass, native T1, T2 and extracellular volume were measured.

RESULTS

The left ventricular mass index (67 ± 15 versus 55 ± 12 g/m², p < 0.05) and interventricular septum thickness (10.4 ± 1.5 versus 8.3 ± 1.8 mm, p < 0.001) in acute stage was significantly higher compared to controls, and normalized at the chronic stage. All quantitative inflammation metrics, including edema ratio, LGE mass, native T1, T2 and extracellular volume were significantly (all p < 0.001) decreased in the follow-up scan, but still higher compared to controls. Compared to the controls, all global strain indices including circumferential, longitudinal and radial strain values were significantly impaired in acute stage (all p < 0.001). Native T1 and T2 values led to excellent diagnostic accuracy for discriminating fulminant myocarditis from healed myocarditis, with AUC of 0.947 and 0.931.

CONCLUSION

Multiparametric CMR could detect and monitor inflammation myocardial injuries in patients with fulminant myocarditis. Native T1 and T2 values achieved excellent diagnostic performance in distinguishing acute from healed myocarditis.

Fast manual long-axis strain assessment provides optimized cardiovascular event prediction following myocardial infarction

AIMS

Cardiovascular magnetic resonance feature tracking (CMR-FT) global longitudinal strain (GLS) provides incremental prognostic value following acute myocardial infarction (AMI) but requires substantial post-processing. Alternatively, manual global long-axis strain (LAS) can be easily assessed from standard steady state free precession images. We aimed to define the prognostic value of LAS in a large multicentre study in patients following AMI.

METHODS AND RESULTS

A total of 1235 patients with myocardial infarction [n = 795 with ST-elevation myocardial infarction (STEMI) and 440 with non-ST-elevation myocardial infarction (NSTEMI)] underwent cardiovascular magnetic resonance imaging after primary percutaneous coronary intervention in eight centres across Germany. Assessment of LAS was performed in a blinded core-laboratory measuring the systolic shortening between the epicardial apical border and the middle of a line connecting the origins of the mitral leaflets. Primary clinical endpoint was the occurrence of major adverse clinical events (MACE) including death, reinfarction, and congestive heart failure within 1 year after AMI. During 1-year follow-up, 76 patients suffered from MACE. Impaired LAS was associated with higher MACE occurrence both in STEMI (P < 0.001) and NSTEMI (P = 0.001) patients. Association of LAS remained significant (P = 0.017) after correction for univariate significant parameters for MACE prediction. C-statistics revealed incremental value of additional LAS assessment for optimized event prediction compared with left ventricular ejection fraction (MACE P = 0.044; mortality P = 0.013) and a combination of established clinical and imaging parameters (MACE P = 0.084; mortality P = 0.027), but not CMR-FT GLS (MACE P = 0.075; mortality P = 0.380).

CONCLUSION

LAS provides software independent, widely available, easy and fast approximation of longitudinal left ventricular shortening early after reperfused AMI with incremental prognostic value beyond established risk stratification parameters.

CLINICAL TRIALS.GOV

NCT00712101 and NCT01612312.

Performance of cardiovascular magnetic resonance strain in patients with acute myocarditis

Background

To explore the value of myocardial strain derived from cardiac magnetic resonance (CMR) feature tracking in evaluating left ventricular function in acute myocarditis and its relationship with the left ventricular ejection fraction (LVEF) and late gadolinium enhancement (LGE).

Methods

A total of 115 cases of clinically suspected acute myocarditis, confirmed by CMR, were collected from two centers and divided into groups with reduced and preserved ejection fraction (EF). Fifty normal volunteers were enrolled as the control group. The myocardial strain analysis was based on feature tracking imaging (FTI).

Results

Compared with the control group, the group with myocarditis and preserved EF showed an increased peak ejecting rate (PER), end diastolic volume (EDV), end systolic volume (ESV), stroke volume (SV), EDV index (EDVi), ESV index (ESVi), SV index (SVi) and decreased strain indices. In patient with myocarditis, the group with reduced EF showed increased EDV, ESV, LGE, LGE% and decreased strain indices compared to the group with preserved EF. EF showed good correlation with LGE, PSC, PSSRC (r>0.6). Peak strain circumferential (PSC) showed good correlation with LGE (r=0.62). The AUC of PSC was optimal to detect early left ventricular dysfunction in myocarditis patient with preserved EF using a cutoff of -19.72% (sensitivity of 68% and specificity of 88%).

Conclusions

Myocardial strain analysis using CMR FTI can provide information about early ventricular dysfunction in myocarditis patient with preserved EF. PSC showed best diagnostic performance, and correlated with LGE.

Tissue-tracking in the assessment of late gadolinium enhancement in myocarditis and myocardial infarction

PURPOSE

To test the diagnostic performance of cardiovascular magnetic resonance (CMR) tissue-tracking (TT) to detect the presence of late gadolinium enhancement (LGE) in patients with a diagnosis of myocardial infarction (MI) or myocarditis (MYO), preserved left ventricular ejection fraction (LVEF) and no visual regional wall motion abnormalities (RWMA).

METHODS

We selected consecutive CMR studies of 50 MI, 50 MYO and 96 controls. Receiving operating characteristic (ROC) curve and net reclassification index (NRI) analyses were used to assess the predictive ability and the incremental diagnostic yield of 2D and 3D TT-derived strain parameters for the detection of LGE and to measure the best cut-off values of strain parameters.

RESULTS

Overall, cases showed significantly reduced 2D global longitudinal strain (2D-GLS) values compared with controls (-20.1 ± 3.1% vs -21.6 ± 2.7%; p = 0.0008). 2D-GLS was also significantly reduced in MYO patients compared with healthy controls (-19.7 ± 2.9% vs -21.9 ± 2.4%; p = 0.0001). 3D global radial strain (3D-GRS) was significantly reduced in MI patients compared with controls with risk factors (34.3 ± 11.8% vs 40.3 ± 12.5%, p = 0.024) Overall, 2D-GLS yielded good diagnostic accuracy for the detection of LGE in the MYO subgroup (AUROC 0.79; NRI (95% CI) = 0.6 (0.3, 1.02) p = 0.0004), with incremental predictive value beyond risk factors and LV function parameters (p for AUROC difference = 0.048). In the MI subgroup, 2D-GRS (AUROC 0.81; NRI (95% CI) = 0.56 (0.17, 0.95) p = 0.004), 3D-GRS (AUROC 0.82; NRI (95% CI) = 0.57 (0.17, 0.97) p = 0.006) and 3D global circumferential strain (3D-GCS) (AUROC 0.81; NRI (95% CI) = 0.62 (0.22, 1.01) p = 0.002) emerged as potential markers of disease. The best cut-off for 2D-GLS was -21.1%, for 2D- and 3D-GRS were 39.1% and 37.7%, respectively, and for 3D-GCS was -16.4%.

CONCLUSIONS

At CMR-tissue tracking analysis, 2D-GLS was a significant predictor of LGE in patients with myocarditis but preserved LVEF and no visual RWMA. Both 2D- and 3D-GRS and 2D-GCS yielded good diagnostic accuracy for LGE detection in patients with previous MI but preserved LVEF and no visual RWMA.

Diagnostic Value of Global Cardiac Strain in Patients With Myocarditis

BACKGROUND

Cardiac strain represents an imaging biomarker of contractile dysfunction.

PURPOSE

The purpose of this study was to investigate the diagnostic value of cardiac strain obtained by feature-tracking cardiac magnetic resonance (MR) in acute myocarditis.

MATERIALS AND METHODS

Cardiac MR examinations of 46 patients with myocarditis and preserved ejection fraction at acute phase and follow-up were analyzed along with cardiac MR of 46 healthy age- and sex-matched controls. Global circumferential strain and global radial strain were calculated for each examination, along with myocardial edema and late gadolinium enhancement, and left ventricle functional parameters, through manual contouring of the myocardium. Correlations were assessed using Spearman ρ. Wilcoxon and Mann-Whitney U test were used to assess differences between data. Receiver operating characteristics curves and reproducibility were obtained to assess the diagnostic role of strain parameters.

RESULTS

Global circumferential strain was significantly lower in controls (median, -20.4%; interquartile range [IQR], -23.4% to -18.7%) than patients in acute phase (-18.4%; IQR, -21.0% to -16.1%; P = 0.001) or at follow-up (-19.2%; IQR, -21.5% to -16.1%; P = 0.020). Global radial strain was significantly higher in controls (82.4%; IQR, 62.8%-104.9%) than in patients during the acute phase (65.8%; IQR, 52.9%-79.5%; P = 0.001). Correlations were found between global circumferential strain and global radial strain in all groups (acute, ρ = -0.580, P < 0.001; follow-up, ρ = -0.399, P = 0.006; controls, ρ = -0.609, P < 0.001), and between global circumferential strain and late gadolinium enhancement only in myocarditis patients (acute, ρ = 0.035, P = 0.024; follow-up, ρ = 0.307, P = 0.038).

CONCLUSIONS

Cardiac strain could potentially have a role in detecting acute myocarditis in low-risk acute myocarditis patients where cardiac MR is the main diagnosing technique.

Tissue Characterization by Mapping and Strain Cardiac MRI to Evaluate Myocardial Inflammation in Fulminant Myocarditis

BACKGROUND

The clinical value of novel mapping techniques and strain measures to assess myocardial inflammation in fulminant myocarditis (FM) has not been fully explored.

PURPOSE

To evaluate the ability of mapping and strain cardiac MRI to assess myocardial inflammation in patients with FM, and to which degree the strain metrics correlate with myocardial edema.

STUDY TYPE

Prospective.

POPULATION

Twenty-nine patients (37 ± 16 years, 48% male) with FM and 29 patients with nonfulminant acute myocarditis (NFAM) (29 ± 14 years, 69% male).

FIELD STRENGTH/SEQUENCE

3.0T; Cine imaging, black blood T₂ -weighted imaging, T₁ mapping, T₂ mapping, and late gadolinium enhancement.

ASSESSMENT

Native T₁ , extracellular volume (ECV), and T₂ were measured. Myocardial strain was evaluated by feature tracking.

STATISTICAL TESTS

Student's t- or Mann-Whitney U-test. Spearman correlation analysis.

RESULTS

The myocardial edema rate (2.6 ± 0.7 vs. 1.6 ± 0.2, P < 0.001) and late gadolinium enhancement (LGE) mass (16.5 [11.7, 41.7] vs. 6.9 [2.2, 15.8] g, P < 0.001) were significantly increased in FM patients when compared to the NFAM group. LGE in the FM group was predominantly located in the septal wall, and 38% of the patients showed a diffuse LGE pattern. Native T₁ , ECV, and T₂ values in the FM group were significantly more elevated than those with NFAM, while global peak radial, circumferential, and longitudinal strain values were significantly reduced (all P < 0.001). Circumferential strain showed the strongest correlations with ECV (r = 0.72, P < 0.001).

DATA CONCLUSION

Patients with FM showed significant differences in LGE patterns, increased edema, and decreased strain measurements compared to those with NFAM. Circumferential strain showed significant associations with quantitative cardiac MRI parameters of myocardial inflammation.

LEVEL OF EVIDENCE

2 TECHNICAL EFFICACY STAGE: 2 J. Magn. Reson. Imaging 2020;52:930-938.

Myocardial deformation measures by cardiac magnetic resonance tissue tracking in myocarditis: Relationship with systolic function and myocardial damage

INTRODUCTION AND OBJECTIVES

Cardiac magnetic resonance (CMR)-based tissue tracking (TT) enables quantification of myocardial deformation and may be used as an objective measure of myocardial involvement in myocarditis. The aims of this study were to characterize myocardial deformation alterations in myocarditis and to determine their relationship with the extent of late gadolinium enhancement (LGE), regional wall motion abnormalities (WMA) and left ventricular ejection fraction (LVEF).

METHODS

A single-center, retrospective study was conducted by identifying patients with clinically suspected myocarditis who underwent CMR between 2012 and 2016. The myocardial deformation parameters were derived by TT and correlated with LVEF, LGE and WMA, through Spearman's coefficient.

RESULTS

A cohort of 78 patients with myocarditis (aged 42.7±17.2 years) were included. CMR characteristics including morphologic parameters (LVEF 52.1±12.8%), extent of WMA (29.3±41.0%) and of LGE (30.5±21.8%) were assessed. Significant correlations were found between all deformation parameters (strain, strain rate, velocity and displacement) and both LVEF and extent of WMA. LGE was significantly correlated with systolic radial strain (r: -0.32, p=0.004), strain rate (r: -0.27, p=0.017) and displacement (r: -0.32, p=0.004) as well as systolic circumferential strain (r: 0.28, p=0.013).

CONCLUSION

Deformation parameters are an objective method for quantification of myocardial function in myocarditis. They correlate with LVEF, extent of WMA and degree of myocardial damage. Further studies are needed to assess their incremental beneficial value for the diagnosis and risk stratification of myocarditis.

Strain analysis reveals subtle systolic dysfunction in confirmed and suspected myocarditis with normal LVEF. A cardiac magnetic resonance study

AIMS

Lake Louise Criteria (LLC) are time-dependent and some acute myocarditis (AM) with preserved left ventricular ejection fraction (LVEF) could be missed, due to the limited accessibility of Cardiac Magnetic Resonance (CMR). We aimed to assess the potential value of cardiac strain measured by feature tracking (FT) imaging in this population.

METHODS AND RESULTS

Eighty-three patients with clinically suspected AM and normal LVEF were divided into 39 "confirmed AM" (positive LLC) and 44 "suspected AM" (negative LLC). An age and gender-matched sample of 42 normal subjects underwent CMR. In all groups, FT-derived biventricular strains and STE- global longitudinal strain (GLS) were assessed, being regularly measurable. Strain values < 5th percentile of the control group were considered abnormal. "Suspected" and "confirmed" AM were similar, except for medium time of CMR evaluation (5.2 vs 1 months from presentation, respectively; p = 0.004). Compared to healthy controls, both "suspected" and "confirmed" AM showed significantly impaired strain values. LV-global circumferential strain (GCS), right ventricular GCS and LV-GLS were abnormal in 15.4% and 15.9%, 20.5% and 15.9%, 7.7% and 9.1% in "confirmed" and "suspected" AM, respectively. STE analysis confirmed the results on LV-GLS, however a weak correlation emerged between STE and CMR-FT LV-GLS (p = 0.08).

CONCLUSIONS

Compared to STE, CMR-FT analysis provided a more comprehensive and complementary biventricular strain evaluation that resulted similar in "confirmed" and "suspected" AM with normal LVEF. Conversely, mostly biventricular GCS was significantly reduced in up to 20% of patients, compared to healthy controls.

Non-contrast enhanced diagnosis of acute myocarditis based on the 17-segment heart model using 2D-feature tracking magnetic resonance imaging

PURPOSE

The aim of this study was to investigate the diagnostic value of myocardial deformation analysis based on the 17-segment heart model using non-contrast enhanced (CE) 2D tissue feature tracking (2D-FT) technique.

MATERIAL AND METHODS

Seventy patients with suspected myocarditis underwent a cardiovascular magnetic resonance (CMR) examination at 1.5 Tesla. A contrast-agent-free part of this CMR protocol was additionally performed in forty healthy volunteers (HV). Besides standard CMR data sets, 2D-FT derived segmental and global longitudinal, radial, and circumferential deformation parameters were analyzed. The 2D-FT results were compared to the combined findings from CMR imaging and endomyocardial biopsy (EMB).

RESULTS

Patients were assigned to three groups depending on their ejection fraction (EF) (<40%, 40-55%, ≥55%). Compared to HV, impaired EF (<55%) was significantly correlated to reduced segmental and global strain and strain rate values. The circumferential deformation analysis was more sensitive to myocardial changes than longitudinal and radial analysis. The segmental strain/strain rate had an accuracy of 84.3%/70.0% for the diagnosis of an acute myocarditis, stated by EMB and CMR in 42 of 70 patients. In patients with preserved EF, acute myocarditis could be ruled out using only segmental strain analysis with a negative predictive value of 87.5%.

CONCLUSION

In patients with suspected myocarditis, the deformation analysis based on the 17-segment heart model provides valuable information about functional myocardial inhomogeneity. This quantitative approach could be used in addition to the clinical standard CMR protocol and represents a promising tool in the framework of a prospective automatized multiparametric CMR imaging analysis.

Diagnostic and prognostic value of cardiac magnetic resonance in acute myocarditis: a systematic review and meta-analysis

While diagnostic criteria were elaborated for acute myocarditis using cardiac magnetic resonance (CMR) in 2009, studies have since examined the yield of traditional and novel CMR parameters to achieve greater accuracy and to predict clinical outcomes. The purpose of this systematic review and meta-analysis was to determine the diagnostic and prognostic value of CMR parameters for acute myocarditis. MEDLINE and EMBASE were systematically searched for original studies that reported CMR parameters in adult patients suspected of acute myocarditis. Each CMR parameter's binary prevalence, mean value and standard deviation were extracted. Parameters were meta-analyzed using a random-effects model to generate standardized mean differences. After screening 1492 abstracts, 53 studies were included encompassing 2823 myocarditis patients and 803 controls. Pooled standardized mean differences between myocarditis patients and controls were: T2 mapping time 2.26 (95% CI 1.50-3.02), extracellular volume 1.64 (95% CI 0.87-2.42), LGE percentage 1.30 (95% CI 0.95-1.64), T1 mapping time 1.18 (95% CI 0.35-2.01), T2 ratio 1.17 (95% CI 0.80-1.54), and EGE ratio 0.93 (95% CI 0.66-1.19). Prolonged T1 mapping time had the highest sensitivity (82%), pericardial effusion had the highest specificity (99%). Baseline LV dysfunction and the presence of LGE were predictive of major adverse cardiac events. The results support integration of parametric mapping criteria in the diagnostic criteria for myocarditis. The presence of baseline LV dysfunction and LGE predict patients at higher risk of adverse events.

Two-dimensional and three-dimensional cardiac magnetic resonance feature-tracking myocardial strain analysis in acute myocarditis patients with preserved ejection fraction

To explore the potential role of two- (2D) and three-dimensional (3D) cardiac magnetic resonance (CMR) feature tracking (FT) myocardial strain analysis in identifying sub-clinical myocardial systolic and diastolic dysfunction in acute myocarditis patients with preserved ejection fraction (EF). Prospective two centre study-control study. Thirty patients (9 female, 37.2 ± 11.8 years.) with a CMR diagnosis of acute myocarditis according to the Lake Louise Criteria and preserved EF (≥ 55%) were included in the analysis. CMR data from 24 healthy volunteers (11 female, 36.2 ± 12.5 years.) served as control. 2D and 3D LV tissue tracking analysis were performed in a random fashion by two double-blinded operators. Variables were checked for normality and analysed with parametric test. The baseline characteristics of myocarditis patients with preserved EF and the healthy volunteers were perfectly comparable, except for the LV mass index and T1 and T2 mapping values (p < 0.001). The results of the interobserver variability in the 2D and 3D LV CMR FT myocardial strain analysis were p > 0.42, ICC > 0.80 and η² > 0.98. There was no statistical difference in 2D and 3D global radial, circumferential and longitudinal strain peak (%) and both systolic and diastolic strain rate (1/s) between acute myocarditis with preserved EF and healthy volunteers (all p = ns). There were no difference in 2D and 3D global radial, circumferential and longitudinal strain peak and both systolic and diastolic strain rate of the LV between acute myocarditis patients with preserved ejection fraction and healthy volunteers.

Diagnostic role of strain imaging in atypical myocarditis by echocardiography and cardiac MRI

BACKGROUND

The diagnosis of myocarditis presenting as isolated acute chest pain with elevated troponins but normal systolic function is challenging with significant drawbacks even for the gold-standard endomyocardial biopsy.

OBJECTIVE

This study aimed to evaluate the diagnostic role of strain imaging by echocardiography and cardiac MRI in these patients.

MATERIALS AND METHODS

This was a retrospective review of children with cardiac MRI for acute chest pain with elevated troponins compared to normal controls. Echocardiographic fractional shortening, ejection fraction, speckle-tracking-derived peak longitudinal, radial, and circumferential strain were compared to cardiac MRI ejection fraction, T2 imaging, late gadolinium enhancement, speckle-tracking-derived peak longitudinal strain, radial strain, and circumferential strain.

RESULTS

Group 1 included 10 subjects diagnosed with myocarditis, 9 (90%) males with a median age of 15.5 years (range: 14-17 years) compared with 10 age-matched controls in group 2. All subjects in group 1 had late gadolinium enhancement consistent with myocarditis and troponin ranged from 2.5 to >30 ng/ml. Electrocardiogram changes included ST segment elevation in 6 and abnormal Q waves in 1. Qualitative echocardiographic function was normal in both groups and mean fractional shortening was similar (35±6% in group 1 vs. 34±4% in group 2, P=0.70). Left ventricle ejection fraction by cardiac MRI, however, was lower in group 1 (52±9%) compared to group 2 at (59±4%) (P=0.03). Cardiac MRI derived strain was lower in group 1 vs. group 2 for speckle-tracking-derived peak longitudinal strain (-12.8±2.8% vs. -17.1±1.5%, P=0.001), circumferential strain (-12.3±3.8% vs. -15.8±1.2%, P=0.020) and radial strain (13.6±3.7% vs. 17.2±3.2%, P=0.040). Echocardiography derived strain was also lower in group 1 vs. group 2 for speckle-tracking-derived peak longitudinal strain (-15.6±3.9% vs. -20.8±2.2%, P<0.002), circumferential strain (-16±3% vs. -19.8±1.9%, P<0.003) and radial strain (17.3±6.1% vs. 24.8±6.3%, P=0.010).

CONCLUSION

In previously asymptomatic children, myocarditis can present with symptoms of acute chest pain suspicious for coronary ischemia. Cardiac MRI and echocardiographic strain imaging are noninvasive, radiation-free tests of immense diagnostic utility in these situations. Long-term studies are needed to assess prognostic significance of these findings.

A novel multiparametric imaging approach to acute myocarditis using T2-mapping and CMR feature tracking

BACKGROUND

The aim of this study was to evaluate the diagnostic potential of a novel cardiovascular magnetic resonance (CMR) based multiparametric imaging approach in suspected myocarditis and to compare it to traditional Lake Louise criteria (LLC).

METHODS

CMR data from 67 patients with suspected acute myocarditis were retrospectively analyzed. Seventeen age- and gender-matched healthy subjects served as control. T2-mapping data were acquired using a Gradient-Spin-Echo T2-mapping sequence in short-axis orientation. T2-maps were segmented according to the 16-segments AHA-model and segmental T2 values and pixel-standard deviation (SD) were recorded. Afterwards, the parameters maxT2 (the highest segmental T2 value) and madSD (the mean absolute deviation (MAD) of the pixel-SDs) were calculated for each subject. Cine sequences in three long axes and a stack of short-axis views covering the left and right ventricle were analyzed using a dedicated feature tracking algorithm.

RESULTS

A multiparametric imaging model containing madSD and LV global circumferential strain (GCSLV) resulted in the highest diagnostic performance in receiver operating curve analyses (area under the curve [AUC] 0.84) when compared to any model containing a single imaging parameter or to LLC (AUC 0.79). Adding late gadolinium enhancement (LGE) to the model resulted in a further increased diagnostic performance (AUC 0.93) and yielded the highest diagnostic sensitivity of 97% and specificity of 77%.

CONCLUSIONS

A multiparametric CMR imaging model including the novel T2-mapping derived parameter madSD, the feature tracking derived strain parameter GCSLV and LGE yields superior diagnostic sensitivity in suspected acute myocarditis when compared to any imaging parameter alone and to LLC.

Predictive Value of Cardiac Magnetic Resonance Imaging-Derived Myocardial Strain for Poor Outcomes in Patients with Acute Myocarditis

Objective

To evaluate the utility of cardiovascular magnetic resonance (CMR)-derived myocardial strain measurement for the prediction of poor outcomes in patients with acute myocarditis.

Materials and Methods

We retrospectively analyzed data from 37 patients with acute myocarditis who underwent CMR. Left ventricular (LV) size, LV mass index, ejection fraction and presence of myocardial late gadolinium enhancement (LGE) were analyzed. LV circumferential strain (Ecc_SAX), radial strain (Err_SAX) from mid-ventricular level short-axis cine views and LV longitudinal strain (Ell_LV), radial strain (Err_Lax) measurements from 2-chamber long-axis views were obtained. In total, 31 of 37 patients (83.8%) underwent follow-up echocardiography. The primary outcome was major adverse cardiovascular event (MACE). Incomplete LV functional recovery was a secondary outcome.

Results

During an average follow-up of 41 months, 11 of 37 patients (29.7%) experienced MACE. Multivariable Cox proportional hazard regression analysis, which included LV mass index, LV ejection fraction, the presence of LGE, Ecc_SAX, Err_SAX, Ell_LV, and Err_Lax values, indicated that the presence of LGE (hazard ratio, 42.88; p = 0.014), together with ErrLax (hazard ratio, 0.77 per 1%, p = 0.004), was a significant predictor of MACE. Kaplan-Meier analysis demonstrated worse outcomes in patient with LGE and an Err_Lax value ≤ 9.48%. Multivariable backward regression analysis revealed that Err_Lax values were the only significant predictors of LV functional recovery (hazard ratio, 0.54 per 1%; p = 0.042).

Conclusion

CMR-derived Err_Lax values can predict poor outcomes, both MACE and incomplete LV functional recovery, in patients with acute myocarditis, while LGE is only a predictor of MACE.

Feature-tracking myocardial strain analysis in acute myocarditis: diagnostic value and association with myocardial oedema

OBJECTIVES

To investigate the diagnostic value of cardiac magnetic resonance (CMR) feature-tracking (FT) myocardial strain analysis in patients with suspected acute myocarditis and its association with myocardial oedema.

METHODS

Forty-eight patients with suspected acute myocarditis and 35 control subjects underwent CMR. FT CMR analysis of systolic longitudinal (LS), circumferential (CS) and radial strain (RS) was performed. Additionally, the protocol allowed for the assessment of T1 and T2 relaxation times.

RESULTS

When compared with healthy controls, myocarditis patients demonstrated reduced LS, CS and RS values (LS: -19.5 ± 4.4% vs. -23.6 ± 3.1%, CS: -23.0 ± 5.8% vs. -27.4 ± 3.4%, RS: 28.9 ± 8.5% vs. 32.4 ± 7.4%; P < 0.05, respectively). LS (T1: r = 0.462, P < 0.001; T2: r = 0.436, P < 0.001) and CS (T1: r = 0.429, P < 0.001; T2: r = 0.467, P < 0.001) showed the strongest correlations with T1 and T2 relaxations times. Area under the curve of LS (0.79) was higher compared with those of CS (0.75; P = 0.478) and RS (0.62; P = 0.008).

CONCLUSIONS

FT CMR myocardial strain analysis might serve as a new tool for assessment of myocardial dysfunction in the diagnostic work-up of patients suspected of having acute myocarditis. Especially, LS and CS show a sufficient diagnostic performance and were most closely correlated with CMR parameters of myocardial oedema.

KEY POINTS

• Myocardial strain measures are considerably reduced in patients with suspected myocarditis. • Myocardial strain measures can sufficiently discriminate between diseased and healthy patients. • Myocardial strain measures show basic associations with the extent of myocardial oedema/inflammation.

Current Understanding of the Pathophysiology of Myocardial Fibrosis and Its Quantitative Assessment in Heart Failure

Myocardial fibrosis is an important part of cardiac remodeling that leads to heart failure and death. Myocardial fibrosis results from increased myofibroblast activity and excessive extracellular matrix deposition. Various cells and molecules are involved in this process, providing targets for potential drug therapies. Currently, the main detection methods of myocardial fibrosis rely on serum markers, cardiac magnetic resonance imaging, and endomyocardial biopsy. This review summarizes our current knowledge regarding the pathophysiology, quantitative assessment, and novel therapeutic strategies of myocardial fibrosis.

Left and right atrial feature tracking in acute myocarditis: A feasibility study

PURPOSE

The present study aims at evaluating the feasibility and reproducibility of cardiac magnetic resonance (CMR) feature tracking (FT) derived strain and strain rate (SR) parameters of the left and right atrium (LA, RA) in patients with acute myocarditis as well as their potential to detect diastolic dysfunction. In addition, the diagnostic value of LA and RA strain parameters in the setting of acute myocarditis is investigated.

METHODS

CMR cine data of 30 patients with CMR-positive acute myocarditis were retrospectively analyzed. 25 age- and gender-matched healthy individuals served as a control. Analysis of longitudinal strain and SR of both atria was performed in two long-axis views using a dedicated FT-software. LA and RA deformation was analyzed including reservoir function (total strain [ε_s], peak positive SR [SR_s]), conduit function (passive strain [ε_e], peak early negative SR [SR_e]) and booster pump function (active strain [ε_a], peak late negative SR [SR_a]). Intra- and inter-observer reproducibility was assessed for all strain and SR parameters using Bland-Altman analyses, intra-class correlation coefficients (ICCs) and coefficients of variation (CV).

RESULTS

FT analyses of both atria were feasible in all patients and controls. Reproducibility was good for reservoir and conduit function parameters and moderate for booster pump function parameters. Myocarditis patients demonstrated an impaired LA reservoir and conduit function when compared to healthy controls (LA ε_s: 32±17 vs. 46±13, p=0.019; LA SR_s: 1.5±0.5 vs. 1.8±0.5, p=0.117; LA SR_e: -1.3±0.5 vs. -1.9±0.5, p<0.001), while LA booster pump function was preserved. In logistic regression and ROC-analyses, LA SR_e proved to be the best independent predictor of acute myocarditis (AUC 0.80), and using LA SR_e with a cut-off of -1.6s^-1 resulted in a diagnostic sensitivity of 83% and a specificity of 80%. Changes in RA phasic function parameters showed a tendency to parallel those of the LA and showed no additional effect with respect to the diagnostic potential in acute myocarditis.

CONCLUSIONS

Myocarditis patients exhibit an impaired atrial reservoir and conduit function, what might be indicative of ventricular diastolic dysfunction. LA SR_e was the best predictor for the presence of acute myocarditis in our study, pointing towards the discriminative power of atrial strain analysis in the CMR-based diagnosis of acute myocarditis.

Quantification of myocardial deformation in children by cardiovascular magnetic resonance feature tracking: determination of reference values for left ventricular strain and strain rate

BACKGROUND

The objective assessment of global and regional cardiac function in children has shown to be clinically relevant but is challenging to conduct. Cardiovascular magnetic resonance (CMR) has emerged as a valuable diagnostic modality especially in patients with cardiomyopathy or congenital heart disease. However, data on the normal cardiac deformation in children assessed by CMR is lacking at present. Thus, the aim of this study was to provide reference values for cardiac strain and strain rate in children and adolescents derived from CMR feature tracking (FT) measurements.

METHODS

In this binational study, eighty children and adolescents (age 0.4-18.0 years, 41 male, 39 female) free from cardiac diseases from two centers underwent CMR in 1.5 T whole-body scanners in supine position. Global peak radial, circumferential and longitudinal systolic strains as well as the corresponding early peak diastolic strain rates were assessed applying FT on short axis as well as 3- and 4-chamber views of standard cine steady-state free precession images.

RESULTS

The difference between genders yielded no significance for all assessed strains. Yet, all strains showed a significant parabolic relation to age and an even stronger one to body surface area (BSA). Therefore, BSA-specific reference values were determined using a polynomial regression model. The apical cardiac segments featured significant higher peak circumferential but lower peak radial systolic strains than the midventricular and basal segments (all p < 0.001).

CONCLUSIONS

The assessment of cardiac deformation by CMR-FT is feasible in children. This is the first CMR study providing specific reference values for FT-derived strain and strain rate in the pediatric age range.