Delayed Enhancement Magnetic Resonance Imaging Research Articles

Delayed Enhancement Magnetic Resonance Imaging Findings in Cardiac Amyloidosis

Delayed Enhancement Magnetic Resonance Imaging Findings in Cardiac Amyloidosis

Differentiation of myocardial scar from potential pitfalls and artefacts in delayed enhancement MRI

Delayed enhancement cardiac magnetic resonance (DE-CMR) imaging is used increasingly to identify and quantify focal myocardial scar. Our objective is to describe factors used in the interpretation of DE-CMR images and to highlight potential pitfalls and artefacts that mimic myocardial scar. Inversion recovery gradient recalled echo sequence is commonly accepted as the standard of reference for DE-CMR. There are also alternative sequences that can be performed in a single breath-hold or with free breathing. Radiologists need to be aware of factors affecting image quality, and potential pitfalls and artefacts that may generate focal hyperintense areas that mimic myocardial scar.

Experience with cardiac magnetic resonance imaging in patient management at the Markusovszky Hospital, County Vas, Hungary

At the Markusovszky Hospital, Vas County, Hungary, cardiac magnetic resonance imaging has been routinely used since July, 2009. In the majority of cases this method has been applied for the assessment of myocardial viability in patients with chronic ischemic heart disease and, in a smaller number of cases, for the evaluation of patients with myocarditis, cardiomyopathy and syncope with uncertain etiology in young athletes. The aim of the study was to analyze the clinical value of cardiac magnetic resonance imaging in assessing the viability of affected myocardial regions due to chronic occlusion of major coronary arteries. Delayed-enhancement cardiac magnetic resonance examination was performed in 88 patients who had 103 myocardial regions affected with chronic occlusion of the coronary arteries. The number of affected myocardial regions which proved to be treatable with coronary artery intervention and the number of regions where revascularization strategy was based on cardiac magnetic resonance imaging findings were analyzed. Based on findings from cardiac magnetic resonance imaging, revascularization strategy was set up in 88 myocardial regions corresponding to 83.5% of all affected myocardial regions included in this study. Delayed-enhancement cardiac magnetic resonance imaging appears to be a powerful tool to choose the optimal reperfusion strategy in patients with chronic coronary occlusion. Although this diagnostic method is relatively expensive, its accuracy regarding the features of myocardial viability such as transmural extension of the lesion within the affected region is higher than that of other methods (e.g. myocardium scintigraphy or stress echocardiography).

T2-weighted and delayed enhancement MRI of eosinophilic myocarditis: relationship with clinical phases and global cardiac function

To evaluate the usefulness of magnetic resonance imaging (MRI) for detection and quantification of myocardial damage related to clinical phases and cardiac function during eosinophilic myocarditis. Four eosinophilic myocarditis patients received seven MRI studies. The left ventricular myocardium was divided into 48 layers, and we quantified the extent of abnormal intensity detected by T2-weighted or delayed enhancement MRI relative to the clinical phase and global cardiac function. T2-weighted imaging detected extensive myocardial hyperintensity during the acute phase of eosinophilic myocarditis. Diffuse myocardial delayed enhancement was observed in one patient during the acute phase, but not in the other. Little or no hyperintensity was detected by T2-weighted imaging or myocardial delayed enhancement during the convalescent phase. The extent of hyperenhancing myocardial layers was inversely correlated with the ejection fraction (EF) (r = -0.87). MRI can evaluate the presence and extent of myocardial damage related to the clinical phases and EF during eosinophilic myocarditis.

Initial experience with magnetic resonance imaging of atrial scar and co-registration with electroanatomic voltage mapping during atrial fibrillation: Success and limitations

Ablation for atrial fibrillation (AF) frequently requires multiple procedures to achieve durable restoration of sinus rhythm. Early studies have suggested that delayed enhancement magnetic resonance imaging (DE-MRI) of the left atrium (LA) can assist in performing repeat ablation procedures. The purpose of this study was to investigate the utility of DE-MRI in delineating regions of LA low voltage and PV reconnection sites in patients undergoing repeat PV isolation for recurrent AF. We enrolled 10 patients undergoing repeat ablation for AF recurrence to undergo preprocedural DE-MRI of the LA in conjunction with high-density voltage mapping (>100 sites) of the LA during the ablation procedure. LA wall regions with hyperenhancement were segmented from DE-MRI images and retrospectively co-registered with the electroanatomic LA map. The association between scar on DE-MRI images and low-voltage regions of the LA was assessed, as was the association between scar gaps and electrogram-determined PV reconnection sites. Ten patients underwent successful DE-MRI imaging and repeat AF ablation without complication. In all 10 patients, the majority of PVs were found to have regained electrical continuity with the LA (30/37 PVs electrically active); all patients underwent successful reisolation of all PVs using standard ablation techniques. There was a significant association between scar identified by DE-MRI and low-voltage regions of the LA (-0.7±0.1 mV in scar regions; generalized estimating equations model clustered by patient, P<.001). However, there was no association between scar gaps and PV reconnection sites. We demonstrate the co-registration of DE-MRI scar imaging and electroanatomic LA mapping, with agreement between regions of scar on DE-MRI and low voltage by mapping. However, at our center, this technique did not provide accurate information on the location of PV reconnection sites in patients undergoing repeat ablation for AF.

Aborted Myocardial Infarction: Evaluation of Changes in Area at Risk, Late Gadolinium Enhancement, and Perfusion Over Time and Comparison With Overt Myocardial Infarction

The objective of our study was to analyze comprehensive MRI findings of aborted myocardial infarction (MI) in terms of the area at risk, late enhancement, and perfusion on initial and follow-up studies compared with overt MI. Eleven cases of aborted MI and 18 cases of overt MI were included in this study. We evaluated the location and signal pattern of infarction on both T2-weighted imaging and delayed enhancement MRI. For quantitative analysis, we calculated the size and contrast ratio of the myocardial signal abnormality compared with remote myocardium on T2-weighted imaging and delayed enhancement MRI. We also evaluated the regional systolic function on cine MRI and the perfusion abnormality on first-pass perfusion MRI. Six months after initial imaging, MRI was repeated to see changes in enhancement pattern and functional indexes. T2-weighted images of all patients showed homogeneous high signal intensity (SI) along the vascular territory of the culprit lesion. MRI of patients with aborted MI showed no (n = 5) or minimal (n = 6) delayed enhancement. Compared with overt MI cases, aborted MI cases also were significantly smaller (p = 0.001) and showed significantly lower SI (p = 0.002) of the enhancing region on delayed enhancement MRI. On follow-up delayed enhancement MRI, the enhancing region was smaller in most cases. All aborted MI cases except one showed hypokinesia and a perfusion defect at the corresponding vascular territory on the initial MRI, but these abnormal findings had normalized on follow-up MRI. The characteristic MRI findings of aborted MI are the absence of or minimal enhancement on delayed enhancement MRI compared with overt MI. On follow-up MRI of aborted MI cases, the area at risk, minimal enhancement, and perfusion defect had normalized.

Nonfluoroscopic Catheter Ablation of a Double-Loop Re-entry Tachycardia Guided by Real-Time Contact Force Information

Nonfluoroscopic catheter ablation has been demonstrated for typical arrhythmias. It is important to note that insufficient contact force may result in an ineffective lesion, whereas excessive contact force may result in complications. Herein, we demonstrate nonfluoroscopic mapping and ablation of a cavotricuspid isthmus-dependent double-loop re-entry tachycardia guided by real-time contact force information. Periprocedural delayed-enhancement magnetic resonance imaging supported the presence of the ablation lesion without any other evidence of a scar substrate for this arrhythmia.

Noninvasive magnetic resonance imaging evaluation of endothelial permeability in murine atherosclerosis using an albumin-binding contrast agent.

Endothelial dysfunction promotes atherosclerosis and precedes acute cardiovascular events. We investigated whether in vivo magnetic resonance imaging with the use of an albumin-binding contrast agent, gadofosveset, could detect endothelial damage associated with atherosclerosis in apolipoprotein E-deficient (ApoE(-/-)) mice. Furthermore, we tested whether magnetic resonance imaging could noninvasively assess endothelial function by measuring the endothelial-dependent vasodilation in response to acetylcholine. ApoE(-/-) mice were imaged at 4, 8, and 12 weeks after commencement of a high-fat diet. Statin-treated ApoE(-/-) mice were scanned after 12 weeks of a high-fat diet. Wild-type mice were imaged before and 48 hours after injection of Russell's viper venom, an endothelial toxin. Delayed enhancement magnetic resonance imaging and T1 mapping of the brachiocephalic artery, 30 minutes after injection of gadofosveset, showed increased vessel wall enhancement and relaxation rate (R(1)) with progression of atherosclerosis in ApoE(-/-)(R(1) [s(-1)]: R(4 weeks) 2.42±0.35, R(8 weeks) 3.45±0.54, R(12 weeks) 3.83±0.52) and Russell's viper venom-injected wild-type mice (R(1)=4.57±0.86). Conversely, wild-type (R(1)=2.15±0.34) and statin-treated ApoE(-/-) (R(1)=3.0±0.65) mice showed less enhancement. Uptake of gadofosveset correlated with Evans blue staining, morphological changes of endothelial cells, and widening of the cell-cell junctions, suggesting that uptake occurs in regions of increased vascular permeability. Endothelial-dependent vasomotor responses showed vasoconstriction of the arteries of the ApoE(-/-) (-22.22±7.95%) and Russell's viper venom-injected (-10.37±17.60%) mice compared with wild-type mice (32.45±12.35%). Statin treatment improved endothelium morphology and function (-8.12±8.22%). We demonstrate the noninvasive assessment of endothelial permeability and function with the use of an albumin-binding magnetic resonance contrast agent. Blood albumin leakage could be a surrogate marker for the in vivo evaluation of interventions that aim to restore the endothelium.

Automated quantification of myocardial infarction using graph cuts on contrast delayed enhanced magnetic resonance images.

In this work, we propose a semi-automated myocardial infarction quantification method for cardiac contrast delayed enhancement magnetic resonance images (DE-MRI). Advantages of this method include that it reduces manual contouring of the left ventricle, obviates a remote myocardium region, and automatically distinguishes infarct, healthy and heterogeneous ("gray zone") tissue despite variability in intensity and noise across images. Quantitative evaluation results showed that the automatically determined infarct core and gray zone size have high correlation with that derived from the averaged results of the manual full width at half maximum (FWHM) methods (R(2)=0.99 for infarct core and gray zone size). Compared with the manual method, a much better reproducibility was achieved with the proposed algorithm and it shortens the evaluation time to one second per image, compared with 2-5 min per image for the manual method.

Virtual Electrophysiological Study in a 3-Dimensional Cardiac Magnetic Resonance Imaging Model of Porcine Myocardial Infarction

This study sought to test the hypothesis that "virtual" electrophysiological studies (EPS) on an anatomic platform generated by 3-dimensional magnetic resonance imaging reconstruction of the left ventricle can reproduce the reentrant circuits of induced ventricular tachycardia (VT) in a porcine model of myocardial infarction. Delayed-enhancement magnetic resonance imaging has been used to characterize myocardial infarction and "gray zones," which are thought to reflect heterogeneous regions of viable and nonviable myocytes. Myocardial infarction by coronary artery occlusion was induced in 8 pigs. After a recovery period, 3-dimensional cardiac magnetic resonance images were obtained from each pig in vivo. Normal areas, gray zones, and infarct cores were classified based on voxel intensity. In the computer model, gray zones were assigned slower conduction and longer action potential durations than those for normal myocardium. Virtual EPS was performed and compared with results of actual in vivo programmed stimulation and noncontact mapping. The left ventricular volumes ranged from 97.8 to 166.2 cm(3), with 4.9% to 17.5% of voxels classified as infarct zones. Six of the 7 pigs in which VT developed during actual EPS were also inducible with virtual EPS. Four of the 6 pigs that had simulated VT had reentrant circuits that approximated the circuits seen with noncontact mapping, whereas the remaining 2 had similar circuits but propagating in opposite directions. This initial study demonstrates the feasibility of applying a mathematical model to magnetic resonance imaging reconstructions of the left ventricle to predict VT circuits. Virtual EPS may be helpful to plan catheter ablation strategies or to identify patients who are at risk of future episodes of VT.

Comparison of Selvester QRS score with magnetic resonance imaging measured infarct size in patients with ST elevation myocardial infarction

Background and PurposeRecent studies have shown that the Selvester QRS score is significantly correlated with delayed enhancement-magnetic resonance imaging (DE-MRI) measured myocardial infarct (MI) size in reperfused ST elevation MI (STEMI). This study further tests the hypothesis that Selvester QRS score correlates well with MI size determined by DE-MRI in reperfused STEMI. Methods and ResultsThe relationship was evaluated retrospectively in 55 first-time STEMI patients 3 months after receiving primary percutaneous coronary intervention. Selvester QRS score and DE-MRI MI size were significantly correlated, r = 0.41 (P < .01). The difference between the Selvester QRS score and DE-MRI was 5.8% MI of the left ventricle (95% confidence interval, 2.9%-8.6%). Furthermore, increasing difference between Selvester QRS score and DE-MRI was observed with increasing MI size. ConclusionSelvester QRS score correlated only moderately with DE-MRI MI size. Selvester QRS score overestimated MI size.

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050 Automated analysis of atrial delayed enhancement cardiac MRI correlates with voltage, AF recurrence post-ablation, and high stroke risk

IntroductionVisualisation of atrial scar using delayed-enhanced MRI (DE-MRI) may reveal causes for atrial fibrillation recurrence following ablation. To develop an objective method for delineating ablation-scar we compared DE-MRI before and...

Three-Dimensional Delayed-Enhanced Cardiac MRI Reconstructions to Guide Ventricular Tachycardia Ablations and Assess Ablation Lesions

Voltage mapping is the primary tool for identifying sites for substrate-guided ventricular tachycardia (VT) ablation, but there are limitations in its application. Delayed-enhanced cardiac MRI (DE-CMRI) can facilitate VT ablations by providing complementary detail about myocardial scar location and geometry. We present the case of a patient with recurrent VT with left bundle branch block (LBBB)-right-side inferior axis morphology and a challenging voltage map. The patient was a 76-year-old man with a history of hypertension, type 2 diabetes mellitus, atrial fibrillation, and newly diagnosed dilated nonischemic cardiomyopathy (ejection fraction, 30%). He was transferred to our facility because of multiple episodes of monomorphic VT with a heart rate of 160 beats/min and an LBBB-right-side inferior axis morphology (Figure 1) consistent with an origin in the right ventricular outflow tract (RVOT). He required 2 episodes of electric cardioversion and amiodarone therapy, but the VT was refractory to amiodarone, so the patient underwent a VT ablation procedure. Figure 1. Clinical ventricular tachycardia with left bundle branch block-right-side inferior axis morphology. CMRI with a 1.5-T Siemens Avanto scanner was performed in multiple anatomic planes using T1-weighted and cine steady-state free precision sequences. Gadolinium-enhanced sequences to evaluate early myocardial perfusion and delayed myocardial enhancement were also performed, using 0.1 mL/kg gadobenate dimeglumine. DE-CMRI demonstrated midmyocardial scar in the anteroseptal region of the RVOT (Figure 2), which raised the possibility of a substrate-mediated VT. Figure 2. Preablation 2D delayed-enhanced cardiac MRI. Preablation short-axis views from base to apex, showing delayed gadolinium enhancement corresponding to midseptal scar in the anteroseptal area of the right ventricular outflow tract (arrows). Reformatted 2D slices using Amira software allowed the reconstruction of 3D models of the right ventricle (RV) and left ventricle (LV) anatomy with embedded myocardial scar. These were exported as 3D Carto-readable mesh files …

In patients with hypertrophic cardiomyopathy myocardial fi brosis is associated with both left ventricular and left atrial dysfunction

Aims The aim of this study was to assess LA function by two-dimensional speckle-tracking echocardiography and its relation with myocardial fi brosis in hypertrophic cardiomyopathy (HCM).Methods We enrolled 30 consecutive HCM-patients in our study (20 males; age: 49.7 ± 10.4 years, NYHA-class: 1.9 ± 0.7). Echocardiography was performed with assessment of global longitudinal LV strain (Є) and LA Є and strain-rate parameters (systolic, early diastolic, and late diastolic during atrial contraction). Each patient received delayed-enhancement magnetic resonance imaging (DE-MRI) to check for myocardial fi brosis. We divided the patients into two groups. Patients of group 1 had no fi brosis, group 2 demonstrated moderate or severe fi brosis in ≥ 2 segments using a 17 segment-model of the LV.Results Moderate and severe fi brosis was observed in 20 patients (group 2: 66.7%). Global longitudinal LV Є (–13.0 ± 2.4 vs –20.6 ± 3.2%, P < 0.001) and peak LA Є (–0.2 ± 3.9 vs 17.9 ± 6.7%, P < 0.001) were reduced in group 2 in comparison with patients without myocardial fi brosis. In all patients peak LA Є correlated with global longitudinal LV Є (r = –0.78, P< 0.001). Patients with considerable myocardial fi brosis (group 2) had a higher indexed left atrial volume (35.7 ± 12.8 ml/m2 vs 24.1 ± 8.6 ml/m2, P= 0.016). New York Heart Association class (NYHA) was higher in patients with severe myocardial fi brosis (2.2 ± 0.7 vs 1.3 ± 0.5) and correlated with peak LA (r = –0.5, P= 0.008) and global LV Є (r = 0.5, P= 0.005).Conclusions Occurrence of myocardial fi brosis in hypertrophic cardiomyopathy is associated with left atrial and ventricular dysfunction as well as with the severity of heart failure symptoms.

Diagnosis and monitoring of cardiac sarcoidosis with delayed-enhanced MRI and 18F-FDG PET-CT

Diagnosis and monitoring of cardiac sarcoidosis with delayed-enhanced MRI and 18F-FDG PET-CT

Reentrant Ventricular Outflow Tract Tachycardia Arising from Focal Scar Detected by Delayed Enhancement Magnetic Resonance Imaging

A 58-year-old man was referred to our emergency room with hemodynamically unstable sustained ventricular tachycardia (VT). The morphology of the VT exhibited a left bundle branch block and inferior axis deviation. He had no past history of cardiovascular disease. Echocardiography, cardiac catheterization, cardiac biopsy, gallium scintigram, myocardial scintigram, T1,T2-weighted magnetic resonance imaging (MRI), and gadolinium-enhanced cine MRI did not detect any structural heart disease or abnormal cardiac function. However, delayed-enhancement MRI (DE-MRI) detected a focal intramural scar within the septal ventricular outflow tract. An electrophysiological study revealed a sustained VT with several morphologies and the entrainment phenomenon. Radiofrequency catheter ablation to the site corresponding to the focal scar detected by DE-MRI successfully eliminated the VT.

MRI classification of asymmetric septal hypertrophic cardiomyopathy and its relation to the presence of risk factors

Asymmetric septal hypertrophic cardiomyopathy (ASH) is the common phenotype of hypertrophic cardiomyopathy (HCM). We sought to classify ASH using magnetic resonance imaging (MRI) and to determine whether the MRI classification of ASH is related to the presence of risk factors for HCM. Ninety-three patients with ASH underwent cine and delayed-enhancement MRI. The ASH was classified morphologically using cine MRI at end-diastole. We evaluated the association between the MRI findings and the presence of risk factors in the ASH. The ASH was classified into three subtypes by MRI: contiguous subtype showing various clinical and MRI features (57%), sigmoid subtype (29%) with fewer risk factors, and reverse-curve subtype (14%) in younger patients with the larger myocardial mass and delayed-enhancement, which were significantly related to the risk factors. MRI was used to classify ASH into three subtypes, which might be related to the presence of risk factors.

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Correlation between clinical presentation and delayed-enhancement MRI pattern in myocarditis

The exact incidence of myocarditis is unknown, as the diagnosis is frequently delayed or missed. Clinical presentation and disease course are extremely variable, as there may be acute onset with acute coronary syndrome, or cardiogenic shock, or progressive heart failure or arrhythmias. The purpose of this study was to identify prognostic factors on magnetic resonance imaging (MRI) performed in patients with bioptically proven myocarditis at presentation and after 6 months. Fifty-six consecutive patients with different presentations of myocarditis (20 with acute coronary syndrome, 20 with heart failure, 16 with arrhythmias) were enrolled. All patients underwent B-mode echocardiography (echo) and tissue Doppler imaging, coronarography, ventriculography, endomyocardial biopsy and contrast-enhanced MRI examination, as well as clinical and echo follow-up at 6 months. At 6-month follow-up, patients were divided in two groups according to values of end-systolic volume and ejection fraction: patients with negative remodelling and those with positive remodelling. Late enhancement was found to be an independent predictor of negative remodelling. Contrast-enhanced MRI is useful both in the diagnosis and as a prognostic indicator in the clinical suspicion of myocarditis.