Cardiac Magnetic Resonance Approach Research Articles

Incremental value of high-risk CMR attributes to predict adverse remodeling after ST-segment elevation myocardial infarction across LVEF categories

BackgroundA couple of cardiac magnetic resonance (CMR) attributes strongly predict adverse remodeling after ST-segment elevation myocardial infarction (STEMI); however, the value of incorporating high-risk CMR attributes, particularly, in patients with non-reduced ejection fraction, remains undetermined. This study sought to evaluate the independent and incremental predictive value of a multiparametric CMR approach for adverse remodeling after STEMI across left ventricular ejection fraction (LVEF) categories. MethodsA total of 157 patients with STEMI undergoing primary percutaneous coronary intervention were prospectively enrolled. Adverse remodeling was defined as ≥20% enlargement in left ventricular end-diastolic volume from index admission to 3 months of follow-up. ResultsAdverse remodeling occurred in 23.6% of patients. After adjustment for clinical risk factors, a stroke volume index <29.6 mL/m2, a global longitudinal strain >−7.5%, an infarct size >39.2%, a microvascular obstruction >4.9%, and a myocardial salvage index <36.4 were independently associated with adverse remodeling. The incidence of adverse remodeling increased with the increasing number of high-risk CMR attributes, regardless of LVEF (LVEF ≤ 40%: P = 0.026; 40% < LVEF < 50%: P = 0.001; LVEF ≥ 50%: P < 0.001). The presence of ≥4 high-risk attributes was an independent predictor of LV adverse remodeling (70.0% vs. 16.8%, adjusted OR 9.68, 95 CI% 3.25–28.87, P < 0.001). Furthermore, the number of high-risk CMR attributes had an incremental predictive value over reduced LVEF and baseline clinical risk factors (AUC: 0.81 vs. 0.68; P = 0.002). ConclusionsHigh-risk CMR attributes showed a significant association with adverse remodeling after STEMI across LVEF categories. This imaging-based model provided incremental value for adverse remodeling over traditional clinical factors and LVEF.

Cardiac magnetic resonance assessment of cardiac involvement in autoimmune diseases.

Cardiac magnetic resonance (CMR) is emerging as the modality of choice to assess early cardiovascular involvement in patients with autoimmune rheumatic diseases (ARDs) that often has a silent presentation and may lead to changes in management. Besides being reproducible and accurate for functional and volumetric assessment, the strength of CMR is its unique ability to perform myocardial tissue characterization that allows the identification of inflammation, edema, and fibrosis. Several CMR biomarkers may provide prognostic information on the severity and progression of cardiovascular involvement in patients with ARDs. In addition, CMR may add value in assessing treatment response and identification of cardiotoxicity related to therapy with immunomodulators that are commonly used to treat these conditions. In this review, we aim to discuss the following objectives: •Illustrate imaging findings of multi-parametric CMR approach in the diagnosis of cardiovascular involvement in various ARDs;•Review the CMR signatures for risk stratification, prognostication, and guiding treatment strategies in ARDs;•Describe the utility of routine and advanced CMR sequences in identifying cardiotoxicity related to immunomodulators and disease-modifying agents in ARDs;•Discuss the limitations of CMR, recent advances, current research gaps, and potential future developments in the field.

Comprehensive Cardiac Magnetic Resonance to Detect Subacute Myocarditis.

(1) Background: Compared to acute myocarditis in the initial phase, detection of subacute myocarditis with cardiac magnetic resonance (CMR) parameters can be challenging due to a lower degree of myocardial inflammation compared to the acute phase. (2) Objectives: To systematically evaluate non-invasive CMR imaging parameters in acute and subacute myocarditis. (3) Methods: 48 patients (age 37 (IQR 28–55) years; 52% female) with clinically suspected myocarditis were consecutively included. Patients with onset of symptoms ≤2 weeks prior to 1.5T CMR were assigned to the acute group (n = 25, 52%), patients with symptom duration >2 to 6 weeks were assigned to the subacute group (n = 23, 48%). CMR protocol comprised morphology, function, 3D-strain, late gadolinium enhancement (LGE) imaging and mapping (T1, ECV, T2). (4) Results: Highest diagnostic performance in the detection of subacute myocarditis was achieved by ECV evaluation either as single parameter or in combination with T1 mapping (applying a segmental or global increase of native T1 > 1015 ms and ECV > 28%), sensitivity 96% and accuracy 91%. Compared to subacute myocarditis, acute myocarditis demonstrated higher prevalence and extent of LGE (AUC 0.76) and increased T2 (AUC 0.66). (5) Conclusions: A comprehensive CMR approach allows reliable diagnosis of clinically suspected subacute myocarditis. Thereby, ECV alone or in combination with native T1 mapping indicated the best performance for diagnosing subacute myocarditis. Acute vs. subacute myocarditis is difficult to discriminate by CMR alone, due to chronological connection and overlap of pathologic findings.

Advances in Myocardial Perfusion MR Imaging: Physiological Implications, the Importance of Quantitative Analysis, and Impact on Patient Care in Coronary Artery Disease.

Stress myocardial perfusion imaging (MPI) is the preferred test in patients with intermediate-to-high clinical likelihood of coronary artery disease (CAD) and can be used as a gatekeeper to avoid unnecessary revascularization. Cardiac magnetic resonance (CMR) has a number of favorable characteristics, including: (1) high spatial resolution that can delineate subendocardial ischemia; (2) comprehensive assessment of morphology, global and regional cardiac functions, tissue characterization, and coronary artery stenosis; and (3) no radiation exposure to patients. According to meta-analysis studies, the diagnostic accuracy of perfusion CMR is comparable to positron emission tomography (PET) and perfusion CT, and is better than single-photon emission CT (SPECT) when fractional flow reserve (FFR) is used as a reference standard. In addition, stress CMR has an excellent prognostic value. One meta-analysis study demonstrated the annual event rate of cardiovascular death or non-fatal myocardial infarction was 4.9% and 0.8%, respectively, in patients with positive and negative stress CMR. Quantitative assessment of perfusion CMR not only allows the objective evaluation of regional ischemia but also provides insights into the pathophysiology of microvascular disease and diffuse subclinical atherosclerosis. For accurate quantification of myocardial perfusion, saturation correction of arterial input function is important. There are two major approaches for saturation correction, one is a dual-bolus method and the other is a dual-sequence method. Absolute quantitative mapping with myocardial perfusion CMR has good accuracy in detecting coronary microvascular dysfunction. Flow measurement in the coronary sinus (CS) with phase contrast cine CMR is an alternative approach to quantify global coronary flow reserve (CFR). The measurement of global CFR by quantitative analysis of perfusion CMR or flow measurement in the CS permits assessment of microvascular disease and diffuse subclinical atherosclerosis, which may provide improved prediction of future event risk in patients with suspected or known CAD. Multi-institutional studies to validate the diagnostic and prognostic values of quantitative perfusion CMR approaches are required.

Salivary Gland Focus Score Is Associated With Myocardial Fibrosis in Primary Sjögren Syndrome Assessed by a Cardiac Magnetic Resonance Approach.

Salivary Gland Focus Score Is Associated With Myocardial Fibrosis in Primary Sjögren Syndrome Assessed by a Cardiac Magnetic Resonance Approach.

Salivary Gland Focus Score Is Associated With Myocardial Fibrosis in Primary Sjögren Syndrome Assessed by a Cardiac Magnetic Resonance Approach.

The risk of clinically manifested major cardiovascular (CV) events in primary Sjögren syndrome (pSS) remains unclear. This study aimed to assess myocardial fibrosis in pSS and investigate the associated disease characteristics by cardiac magnetic resonance imaging (cMRI). We performed a cross-sectional study of patients with pSS without cardiac symptoms. Labial gland biopsy was documented in 44 patients (85%). Patients without CV risk factors underwent contrast-enhanced cMRI. Late gadolinium enhancement (LGE) was used to assess myocardial fibrosis. Myocardial edema was assessed using T2-weighted imaging (T2WI). We compared the left ventricular (LV) geometry and function between the groups with and without LGE. Further, we explored the associations of cMRI abnormalities with pSS characteristics. Fifty-two women with pSS (median age 55, IQR 47.0-65.7 yrs) were enrolled in the study. LGE was observed in 10 patients (19%), two of whom showed high intensity on T2WI. High intensity on T2WI was observed in 3 patients (5.8%). LV mass index and LV mass/end-diastolic volume tended to be higher in the LGE-positive group than in the LGE-negative group (P = 0.078 and 0.093, respectively). Salivary gland focus score (FS) ≥ 3 was independently associated with LGE-positive in the multivariable analysis (OR 11.21, 95% CI 1.18-106.80). Subclinical myocardial fibrosis, as detected by cMRI, was frequent in patients with pSS without cardiac symptoms. Abnormal cMRI findings were associated with salivary gland FS ≥ 3.

CMR for myocardial iron overload quantification: calibration curve from the MIOT Network.

R2* cardiac magnetic resonance (CMR) allows the non-invasive measurement of myocardial iron. We calibrated cardiac R2* values against myocardial tissue-measured iron concentration by using a segmental approach and we assessed the iron distribution. Five hearts of thalassemia patients were donated after death/transplantation to the CoreLab of the Myocardial Iron Overload in Thalassemia Network. A multislice multiecho R2* approach was adopted. After CMR, used as guidance, the heart was cut in three short-axis slices and each slice was cut into different equiangular segments according to AHA segmentation and differentiated into endocardial and epicardial layers. Tissue iron concentration was measured by atomic absorption spectrometer technique. Fifty-five samples were used since only for two hearts all the 16 samples were analyzed. Mean iron concentration was 4.71 ± 4.67mg/g dw. Segmental iron levels ranged from 0.24 to 13.78mg/g dw. The coefficient of variability of iron for myocardial segments ranged from 8.08 to 24.54% (mean 13.49 ± 6.93%). Iron concentration was significantly higher in the epicardial than in the endocardial layer (5.99 ± 6.01 vs 4.84 ± 4.87mg/g dw; p = 0.042). Four different circumferential regions (anterior, septal, inferior, and lateral) were defined. A circumferential heterogeneity was noted, with more iron in the anterior region, followed by the inferior region. The direct nonlinear fitting of R2* and [Fe] data led to the calibration curve: [Fe] = 0.0022 ∙ (R2*-ROI)1.462 (R-square = 0.956). Our data further validate R2* CMR using a segmental approach as a sensitive and early technique for quantifying iron distribution in the current clinical practice. • Calibration in humans for cardiovascular magnetic resonance R2* against myocardial iron concentration was provided. • A circumferential heterogeneity in cardiac iron distribution was detected: more iron was observed in the anterior region, followed by the inferior region. This finding corroborates the use of a segmental T2* CMR approach in the clinical practice to detect a heterogeneous iron distribution. • The comparison between the cardiac T2* values obtained with the region-based and the pixel-wise approaches showed a significant correlation and no significant difference but, in presence of significant iron load, the region-based approach resulted in significantly higher T2* values.

A machine learning cardiac magnetic resonance approach to extract disease features and automate pulmonary arterial hypertension diagnosis.

AimsPulmonary arterial hypertension (PAH) is a progressive condition with high mortality. Quantitative cardiovascular magnetic resonance (CMR) imaging metrics in PAH target individual cardiac structures and have diagnostic and prognostic utility but are challenging to acquire. The primary aim of this study was to develop and test a tensor-based machine learning approach to holistically identify diagnostic features in PAH using CMR, and secondarily, visualize and interpret key discriminative features associated with PAH.Methods and resultsConsecutive treatment naive patients with PAH or no evidence of pulmonary hypertension (PH), undergoing CMR and right heart catheterization within 48 h, were identified from the ASPIRE registry. A tensor-based machine learning approach, multilinear subspace learning, was developed and the diagnostic accuracy of this approach was compared with standard CMR measurements. Two hundred and twenty patients were identified: 150 with PAH and 70 with no PH. The diagnostic accuracy of the approach was high as assessed by area under the curve at receiver operating characteristic analysis (P < 0.001): 0.92 for PAH, slightly higher than standard CMR metrics. Moreover, establishing the diagnosis using the approach was less time-consuming, being achieved within 10 s. Learnt features were visualized in feature maps with correspondence to cardiac phases, confirming known and also identifying potentially new diagnostic features in PAH.ConclusionA tensor-based machine learning approach has been developed and applied to CMR. High diagnostic accuracy has been shown for PAH diagnosis and new learnt features were visualized with diagnostic potential.

In This Issue of the Journal

In This Issue of the Journal

P1596Tissue characterization in Arrhythmogenic Cardiomyopathy: diagnostic impact of combined endomyocardial biopsy and cardiac magnetic resonance approach

P1596Tissue characterization in Arrhythmogenic Cardiomyopathy: diagnostic impact of combined endomyocardial biopsy and cardiac magnetic resonance approach

High-risk patients with mild-moderate left ventricular dysfunction after a previous myocardial infarction. A long-term prognostic data by cardiac magnetic resonance

BackgroundFew studies have explored prognosis in patients with previous myocardial infarction (MI) with mild-moderate (MM) left ventricular (LV) dysfunction (D).The aim of our study was to investigate whether combining LV parameters obtained by cardiac magnetic resonance (CMR) improves risk stratification of patients with previous MI and MM-LV-D. MethodsIn 418 consecutive patients (63.3±11.3years old, female 12.9%) with previous MI, we quantified LVEF, volumes and wall motion score index (WMSI) and measured the infarct extent by late gadolinium enhancement (LGE). According to LVEF, patients were considered with normal LVEF (>55%), MM-LV-D (LVEF>30 and ≤55%) and severe (S) LV-D (LVEF ≤30). ResultsDuring follow-up (median, 39.7months) cardiac events (cardiac death or appropriate intra-cardiac defibrillator shocks) occurred in 17/99 of patients with S-LV-D, in 15/201 with MM-LV-D, and in only 1/118 of those with normal LV-EF.After adjustment for age, an extent of LGE >11.3%, a dilated LV (male >112ml/m2; female >92ml/m2) and a WMSI>1.59 were associated with adverse cardiac events in patients with MM-LV-D. In patients with MM-LV-D, when each of these 3 factors was observed, the prognosis was worse respect to those with 1–2 factors and no factor (p=0.035 and p=0.004, respectively). Prognosis was similar (p=0.61) between MM-LV-D patients with all 3 factors and those with S-LV-dysfunction. CONCLUSIONS. A multiparametric CMR approach, which includes LGE, dilated LV and WMSI, permits to identify post MI patients with MM-LV-D with a risk of cardiac events similar to those with S-LV-D. Further multicenter studies are needed to confirm our data.

Utility of cardiac magnetic resonance for evaluation of mitral regurgitation prior to mitral valve surgery.

Mitral regurgitation (MR) is a common cause of morbidity worldwide and an accepted indication for interventional therapies which aim to reduce or resolve adverse clinical outcomes associated with MR. Cardiac magnetic resonance (CMR) provides highly accurate means of assessing MR, including a variety of approaches that can measure MR based on quantitative flow. Additionally, CMR is widely accepted as a reference standard for cardiac chamber quantification, enabling reliable detection of subtle changes in cardiac chamber size and function so as to guide decision-making regarding timing of mitral valve directed therapies. Beyond geometric imaging, CMR enables tissue characterization of ischemia and infarction in the left ventricular (LV) myocardium as well as within the mitral valve apparatus, thus enabling identification of structural substrates for MR. This review provides an overview of established and emerging CMR approaches to measure valvular regurgitation, including relative utility of different approaches for patients with primary or secondary MR. Clinical outcomes studies are discussed with focus on data demonstrating advantages of CMR for guiding diagnosis, risk stratification, and management of patients with known or suspected MR. Comparative data is reviewed with focus on diagnostic performance of CMR in comparison to conventional assessment via echocardiography (echo). Emerging literature is reviewed concerning potential new approaches that utilize CMR tissue characterization to guide clinical decision-making in order to improve therapeutic outcomes and clinical prognosis for patients with MR.

Recent advances in cardiac magnetic resonance.

Cardiac magnetic resonance (CMR) is a non-invasive imaging modality that has rapidly emerged during the last few years and has become a valuable, well-established clinical tool. Beside the evaluation of anatomy and function, CMR has its strengths in providing detailed non-invasive myocardial tissue characterization, for which it is considered the current diagnostic gold standard. Late gadolinium enhancement (LGE), with its capability to detect necrosis and to separate ischemic from non-ischemic cardiomyopathies by distinct LGE patterns, offers unique clinical possibilities. The presence of LGE has also proven to be a good predictor of an adverse outcome in various studies. T2-weighted (T2w) images, which are supposed to identify areas of edema and inflammation, are another CMR approach to tissue characterization. However, T2w images have not held their promise owing to several technical limitations and potential physiological concerns. Newer mapping techniques may overcome some of these limitations: they assess quantitatively myocardial tissue properties in absolute terms and show promising results in studies for characterization of diffuse fibrosis (T1 mapping) and/or inflammatory processes (T2 mapping). However, these techniques are still research tools and are not part of the clinical routine yet. T2* CMR has had significant impact in the management of thalassemia because it is possible to image the amount of iron in the heart and the liver, improving both diagnostic imaging and the management of patients with thalassemia. CMR findings frequently have clinical impact on further patient management, and CMR seems to be cost effective in the clinical routine.

Role of tissue characterization by Cardiac Magnetic Resonance in the diagnosis of constrictive pericarditis.

Cardiac Magnetic Resonance (CMR) allows evaluation of the functional and flow changes in pericardial constriction as well as detection of acute pericardial inflammation, fusion and thickening of pericardial layers and pericardial effusion. We sought to evaluate the diagnostic role of tissue characterization by CMR in constrictive pericarditis (CP). We performed a CMR exam in 70 patients (mean age 58 ± 16) with clinical suspicion of constrictive pericarditis and constrictive pattern at echocardiography and/or catheterization. A multiparametric CMR approach was used to evaluate the initial diagnostic suspicion. A clinical follow-up was performed in all patients for a median of 551 days. The diagnosis of CP was confirmed in 53 patients while 12 patients presented signs of predominant pericardial active inflammation suggesting a diagnosis of transient constrictive pericarditis and five presented effusive-constrictive pericarditis. Patients with a final diagnosis of CP had worse prognosis than those with transient constrictive or effusive constrictive pericarditis. The presence of myocardial late gadolinium enhancement was associated to adverse events. Results of the current study confirmed the value of CMR in the differential diagnosis of pericardial disease. A multiparametric CMR approach allowed to distinguish between active inflammation, chronic pericarditis with constriction and effusion without inflammation.

Improved Detection of Cardiac Sarcoidosis Using Magnetic Resonance with Myocardial T2 Mapping

Improved Detection of Cardiac Sarcoidosis Using Magnetic Resonance with Myocardial T2 Mapping

OP0313 Effect of Tocilizumab on Left Ventricular Function Assessed Using a Comprehensive Cardiac Magnetic Resonance Approach in Rheumatoid Arthritis Patients without Cardiac Symptoms

BackgroundRheumatoid arthritis (RA) is associated with an increased risk of congestive heart failure, possibly via shared mechanisms of inflammation. This study was undertaken to test the hypothesis that the powerful...

Circulation: Clinical Summaries

<i>Circulation:</i> Clinical Summaries

Scar extent, left ventricular end-diastolic volume, and wall motion abnormalities identify high-risk patients with previous myocardial infarction: a multiparametric approach for prognostic stratification

We sought to investigate whether combining left ventricular (LV) volumes, regional wall motion abnormalities, and scar tissue extent obtained by cardiac magnetic resonance (CMR) improves risk stratification of patients with previous myocardial infarction (MI). In 231 consecutive patients (age 64 ± 11 years, males 89%) with previous MI, we quantified LV volumes and regional wall motion abnormalities by cine CMR, and measured the extent of the infarction scar by late gadolinium enhancement (LGE). During follow-up (median, 3.2 years) cardiac events (cardiac death or appropriate intra-cardiac defibrillator shocks) occurred in 19 patients. After adjustment for age, an extent of LGE >12.7%, an LV end-diastolic volume >105 mL/m(2), and a wall motion score index >1.7 were independent associated with adverse cardiac events at multivariate analysis (P < 0.05, P < 0.001, and P < 0.01, respectively). The patients with none of these factors, and those with one or two factors, showed a lower risk of cardiac events [hazard ratio (HR) = 0.112, P < 0.01 and HR = 0.261, P < 0.05] than those with three factors. The cumulative event-rate estimated at 4 years was 29.6% in patients with all three factors, 7.7% in those with one or two factors, and 3.5% in patients with none of these factors. A multiparametric CMR approach, which includes the measure of scar tissue extent, LV end-diastolic volume and regional wall motion abnormalities, improves risk stratification of patients with previous MI.

Importance of standardized assessment of late gadolinium enhancement for quantification of infarct size by cardiac magnetic resonance: implications for comparison with electrocardiogram

Background Cardiac magnetic resonance (CMR) is currently considered the reference standard for in vivo assessment of myocardial infarction (MI). There is, however, no international consensus on how MI quantification from CMR should be performed. The aim of this study was to test how previously published manual quantification of MI using CMR images compares with MI quantification using a semiautomated, validated method and how this impacts the relationship with MI size estimated by 12-lead electrocardiogram (ECG). Methods Twenty-five patients, from a previously published cohort, were included in the study. All patients had presented with clinical signs of acute coronary syndrome 6 to 12 months before undergoing a CMR examination. The patients had a standard 12-lead ECG recorded at the time of the CMR examination. The previously reported manually quantified MI size was compared with MI size determined using a semiautomated method validated by computer phantom data, experimental in vivo and ex vivo data, and patient data. The MI sizes from the 2 CMR approaches were then compared with the ECG-estimated MI size. Results There was a strong correlation between MI size determined with the 2 CMR methods ( r 2 = 0.94, P < .001). There was, however, a systematic overestimation of MI size of approximately 50% by the previously published manually quantified MI size compared with the semiautomated method. This affected the comparison with estimated MI size by ECG, which showed a significant underestimation of MI size compared with manual CMR measurements, but no bias compared with the semiautomated CMR method. Conclusions Manual quantification of MI size by CMR can differ significantly from semiautomated, validated methods taking partial volume effects into account and can lead to erroneous conclusions when compared with ECG.

Navigator-Gated 3D Blood Oxygen Level–Dependent CMR at 3.0-T for Detection of Stress-Induced Myocardial Ischemic Reactions

This study determined the value of navigator-gated 3-dimensional blood oxygen level-dependent (BOLD) cardiac magnetic resonance (CMR) at 3.0-T for the detection of stress-induced myocardial ischemic reactions. Although BOLD CMR has been introduced for characterization of myocardial oxygenation status, previously reported CMR approaches suffered from a low signal-to-noise ratio and motion-related artifacts with impaired image quality and a limited diagnostic value in initial patient studies. Fifty patients with suspected or known coronary artery disease underwent CMR at 3.0-T followed by invasive X-ray angiography within 48 h. Three-dimensional BOLD images were acquired during free breathing with full coverage of the left ventricle in a short-axis orientation. The BOLD imaging was performed at rest and under adenosine stress, followed by stress and rest first-pass perfusion and delayed enhancement imaging. Quantitative coronary X-ray angiography (QCA) was used for coronary stenosis definition (diameter reduction > or =50%). The BOLD and first-pass perfusion images were semiquantitatively evaluated (for BOLD imaging, signal intensity differences between stress and rest [DeltaSI]; for perfusion imaging, myocardial perfusion reserve index [MPRI]). The image quality of BOLD CMR at rest and during adenosine stress was considered good to excellent in 90% and 84% of the patients, respectively. The DeltaSI measurements differed significantly between normal myocardium, myocardium supplied by a stenotic coronary artery, and infarcted myocardium (p < 0.001). The receiver-operator characteristic analysis identified a cutoff value of DeltaSI = 2.7% for the detection of coronary stenosis, resulting in a sensitivity and specificity of 85.0% and 80.5%, respectively. An MPRI cutoff value of 1.35 yielded a sensitivity and specificity of 89.5% and 85.8%, respectively. The DeltaSI significantly correlated with the degree of coronary stenosis (r = -0.65, p < 0.001). Additionally, DeltaSI and MPRI showed substantial agreement (kappa value 0.66). Navigator-gated 3-dimensional BOLD imaging at 3.0-T reliably detected stress-induced myocardial ischemic reactions and may be considered a valid alternative to first-pass exogenous contrast-enhancement studies.