Late Gadolinium Enhancement Quantification Research Articles

Prognostic significance of late gadolinium enhancement quantification in cardiac magnetic resonance imaging of hypertrophic cardiomyopathy with systolic dysfunction.

Hypertrophic cardiomyopathy (HCM) with systolic dysfunction carries a poor prognosis. Although late gadolinium enhancement (LGE) on cardiac magnetic resonance is associated with adverse cardiac events in HCM and is inversely related to left ventricular ejection fraction (LVEF), it is unknown whether LGE or LVEF more accurately predicts adverse cardiac events in HCM with systolic dysfunction. We retrospectively assessed the extent of LGE with a threshold of 6 standard deviations in 46 consecutive HCM patients with systolic dysfunction defined as LVEF <50% (average 35±12%) who underwent cardiac magnetic resonance (35 males, mean age 59±14years). They were followed up over 1755±594days. The composite adverse cardiac events end point included cardiovascular death, lethal arrhythmia, cardioembolic stroke, and unplanned heart failure hospitalization. LGE was detected in all patients, and the mean extent was 30±15%. Twenty-nine patients developed adverse cardiac events. Multivariate Cox proportional hazard analysis revealed the extent of LGE as a good independent predictor of adverse cardiac events. Risk increased with the extent of LGE (hazard ratio=1.62/10% increase in LGE, 95% confidence interval=1.23-2.15, p<0.001). LVEF was inversely related to the extent of LGE (r=-0.44; p=0.002) and was also an independent predictor of adverse cardiac events. Risk decreased with LVEF (hazard ratio=0.68/10% increase in LVEF, 95% confidence interval=0.51-0.91, p=0.010). The Akaike information criterion evaluating the fit of a model demonstrated that the extent of LGE was a better independent predictor of MACE than LVEF (Akaike information criterion=172.20 and 178.09, respectively).The extent of LGE was a good independent predictor of adverse cardiac events and reflected mortality and morbidity more precisely than LVEF in HCM with systolic dysfunction.

Quantification of myocardial late gadolinium enhancement using synthetic inversion recovery imaging

Background Inversion recovery (IR) late gadolinium enhancement (LGE) cardiac magnetic resonance (CMR) is generally used for post-contrast infarct detection in the myocardium. Novel technological advancements allow for the generation of synthetic IR images based on the pixel-bypixel T1 values. Theoretically, synthetic IR images can be retrospectively generated at any inversion time (TI). In this study, we aimed to evaluate the diagnostic value of synthetic phase-sensitive IR (PSIR) images for the quantification of myocardial LGE. Methods

Prognostic significance of the extent of septal fibrosis quantified on late gadolium enhanced images in patients with nonischemic cardiomyopathy

Background Midwall septal fibrosis on late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR) imaging has been shown to be an independent predictor of adverse events in patients with non-ischemic dilated cardiomyopathy (NICM). Recent studies in other cardiomyopathy cohorts, such as Hypertrophic Cardiomyopathy, suggest that LGE extent provides incremental prognostic value over its binary presence or absence. The objective of this study was to investigate the prognostic value of septal LGE quantification for the prediction of arrhythmic events among patients with NICM.

Cardiac magnetic resonance imaging findings predict major adverse events in apical hypertrophic cardiomyopathy.

The purpose of this study was to determine the prognostic significance of cardiac magnetic resonance imaging (MRI) findings in patients with apical hypertrophic cardiomyopathy (HCM). Cardiac MRI studies of 93 consecutive patients with apical HCM were retrospectively evaluated. Quantification of late gadolinium enhancement (LGE) was determined and expressed as a percentage of total left ventricular (LV) myocardial mass (%LGE). Morphologic features including presence of apical aneurysm, right ventricular hypertrophy, and LV thrombus were also assessed. Clinical data were collected during follow-up to assess for occurrence of major adverse events, defined as: heart failure, stroke, appropriate automatic implantable cardioverter defibrillator discharge, sustained ventricular tachycardia, aborted sudden cardiac death, and/or all-cause death. The mean age of the patients was 54.9±13.8 years, and 72.0% (n=67) were male. LGE, right ventricular hypertrophy, apical aneurysm, and LV thrombus were identified in 69.4%, 25.8%, 18.3%, and 4.3%, respectively. Mean %LGE was 10.8%±11.1%. Over 2.4±1.7 years of follow-up, 14 subjects (15.1%) experienced a major adverse event (event rate, 6.3%/y): heart failure (6.5%), stroke (6.5%), appropriate automatic implantable cardioverter defibrillator discharge (2.2%), sustained ventricular tachycardia (2.2%), aborted sudden cardiac death (1.1%), and all-cause death (0.0%). Presence of apical aneurysm and extent of LGE were significant predictors of major adverse events [odds ratio (OR) 4.6, P=0.015; and OR 1.4/5% LGE, P=0.030, respectively]. Patients with both apical aneurysm and >5% LGE were at highest risk for major adverse events (OR 6.7, P=0.004) and had shortest event-free survival (P=0.001). Within our population of apical HCM patients, the extent of LGE and the presence of an apical aneurysm identified by cardiac MRI were both significant predictors of major adverse clinical events.

Precision and reproducibility of semi-automated late gadolinium enhancement quantification techniques in patients with hypertrophic cardiomyopathy

Precision and reproducibility of semi-automated late gadolinium enhancement quantification techniques in patients with hypertrophic cardiomyopathy

CMR Quantification of Myocardial Scar Provides Additive Prognostic Information in Nonischemic Cardiomyopathy

This study sought to determine whether the extent of late gadolinium enhancement (LGE) can provide additive prognostic information in patients with a nonischemic dilated cardiomyopathy (NIDC) with an indication for implantable cardioverter-defibrillator (ICD) therapy for the primary prevention of sudden cardiac death (SCD). Data suggest that the presence of LGE is a strong discriminator of events in patients with NIDC. Limited data exist on the role of LGE quantification. The extent of LGE and clinical follow-up were assessed in 162 patients with NIDC prior to ICD insertion for primary prevention of SCD. LGE extent was quantified using both the standard deviation-based (2-SD) method and the full-width half-maximum (FWHM) method. We studied 162 patients with NIDC (65% male; mean age: 55 years; left ventricular ejection fraction [LVEF]: 26 ± 8%) and followed up for major adverse cardiac events (MACE), including cardiovascular death and appropriate ICD therapy, for a mean of 29 ± 18 months. Annual MACE rates were substantially higher in patients with LGE (24%) than in those without LGE (2%). By univariate association, the presence and the extent of LGE demonstrated the strongest associations with MACE (LGE presence, hazard ratio [HR]: 14.5 [95% confidence interval (CI): 6.1 to 32.6; p < 0.001]; LGE extent, HR: 1.15 per 1% increase in volume of LGE [95% CI: 1.12 to 1.18; p < 0.0001]). Multivariate analyses showed that LGE extent was the strongest predictor in the best overall model for MACE, and a 7-fold hazard was observed per 10% LGE extent after adjustments for patient age, sex, and LVEF (adjusted HR: 7.61; p < 0.0001). LGE quantitation by 2-SD and FWHM both demonstrated robust prognostic association, with the highest MACE rate observed in patients with LGE involving >6.1% of LV myocardium. LGE extent may provide further risk stratification in patients with NIDC with a current indication for ICD implantation for the primary prevention of SCD. Strategic guidance on ICD therapy by cardiac magnetic resonance in patients with NIDC warrants further study.

Automated analysis of atrial late gadolinium enhancement imaging that correlates with endocardial voltage and clinical outcomes: A 2-center study

BackgroundFor late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR) assessment of atrial scar to guide management and targeting of ablation in atrial fibrillation (AF), an objective, reproducible method of identifying atrial scar is required.ObjectiveTo describe an automated method for operator-independent quantification of LGE that correlates with colocated endocardial voltage and clinical outcomes.MethodsLGE CMR imaging was performed at 2 centers, before and 3 months after pulmonary vein isolation for paroxysmal AF (n = 50). A left atrial (LA) surface scar map was constructed by using automated software, expressing intensity as multiples of standard deviation (SD) above blood pool mean. Twenty-one patients underwent endocardial voltage mapping at the time of pulmonary vein isolation (11 were redo procedures). Scar maps and voltage maps were spatially registered to the same magnetic resonance angiography (MRA) segmentation.ResultsThe LGE levels of 3, 4, and 5SDs above blood pool mean were associated with progressively lower bipolar voltages compared to the preceding enhancement level (0.85 ± 0.33, 0.50 ± 0.22, and 0.38 ± 0.28 mV; P = .002, P < .001, and P = .048, respectively). The proportion of atrial surface area classified as scar (ie, >3 SD above blood pool mean) on preablation scans was greater in patients with postablation AF recurrence than those without recurrence (6.6% ± 6.7% vs 3.5% ± 3.0%, P = .032). The LA volume >102 mL was associated with a significantly greater proportion of LA scar (6.4% ± 5.9% vs 3.4% ± 2.2%; P = .007).ConclusionsLA scar quantified automatically by a simple objective method correlates with colocated endocardial voltage. Greater preablation scar is associated with LA dilatation and AF recurrence.

Quantification of the ischemic burden on cardiac magnetic resonance perfusion maps by perfusion threshold analysis

Background High-resolution quantitative analysis of myocardial blood flow (MBF) by cardiac magnetic resonance (CMR) perfusion has been recently proposed and validated in preclincal studies. It aims to combine the advantages of both visual assessment and quantitative analysis in a single test. However, incorrect registration between stress and rest images can hamper myocardial perfusion reserve (MPR) calculation from high-resolution perfusion maps. The aim of this study was to test the feasibility of MPR analysis from high-resolution perfusion maps as well as to test MBF threshold analysis, a novel analysis approach capable to measure the extent of ischemic myocardium with high spatial accuracy. Methods Ten patients with single-vessel coronary artery disease (CAD) and ten control subjects were analyzed at 3 Tesla. Perfusion data were analyzed on high-resolution maps and at segmental level to simulate MPR for variable degrees of image misregistration. MBF threshold analysis was then applied to high-resolution perfusion maps. In analogy to one of the methods currently in use for the quantification of late gadolinium enhancement, pixels with abnormally reduced coronary flow reserve were defined on the basis of the average MBF in areas with visually normal perfusion. In this exploratory analysis, the ischemic myocardium was defined as pixels with MBF reduced below the 90th, 95th and 99th percentile of the average epicardial MBF of the reference segment. MBF threshold analysis defines the amount of ischemic myocardium as a percentage of the LV (global ischemic burden) or of a perfusion territory (territorial ischemic burden).

The extent of late gadolinium enhancement can be assessed fast and reproducible using semi-quantitative method in patients with hypertrophic cardiomyopathy

Background In hypertrophic cardiomyopathy (HCM) assessment of late gadolinium enhancement (LGE) is increasingly important as LGE has been demonstrated to be an adverse prognosticator. Manual delineation of LGE after visual assessment is labour-intensive. Automatic quantification is limited by its dependence on signal/noise ratio and varying definition of LGE. Our aim is to assess inter-individual agreement of a fast semi-quantitative method based on visual assessment for quantification of LGE in HCM, which is feasible for daily clinical practice.

Auto‐Threshold quantification of late gadolinium enhancement in patients with acute heart disease

To assess the Otsu-Auto-Threshold (OAT) for accuracy and reproducibility for sizing irreversible injury in late gadolinium enhancement (LGE) images of patients with acute heart disease. The OAT method automatically identifies high signal intensity areas using a cutoff derived from the signal intensity histogram and therefore is user-independent. LGE was performed in 28 patients with acute myocardial infarction (MI) and 30 patients with acute myocarditis. LGE mass was compared between OAT and thresholds using 2 standard deviations (SD), 3SD, and 5SD above remote myocardium, and full-width-at-half-maximum (FWHM). A separate, blinded visual assessment served as the standard of truth. In patients with acute MI, OAT and 5SD did not differ (26.1 ± 11.4 g vs. 25.4 ± 11.1 g, P = 0.088), but thresholds of 2SD and 3SD overestimated LGE mass by 37% and 20%, respectively, and FWHM underestimated by 15%. In acute myocarditis, OAT was not different from a visual quantification, but thresholds of 2SD and 3SD overestimated LGE mass by 46% and 19%, respectively, and thresholds of 5SD and FWHM underestimated LGE mass by 17% and 26%, respectively. OAT and FWHM showed the best intraobserver and interobserver reproducibility. Automatic thresholding using OAT may serve as an accurate and reproducible method to quantify irreversible myocardial injury in acute heart disease.

Insights Into Left Ventricular Remodeling Through Noninvasive Measures of Myocardial Matrix Expansion With Cardiovascular Magnetic Resonance

Cardiovascular disease is the leading cause of morbidity and mortality in the United States. Although clinical assessment is the cornerstone of patient management, clinicians often demand additional laboratory or imaging studies (disease markers or biomarkers) to assess differential diagnosis and to help formulate a management plan.1 There are growing, consistent data supporting an important role for noninvasive cardiac imaging studies as clinically and cost-effective tools in the diagnosis and risk stratification of patients with known or suspected cardiovascular disease. The past decade has witnessed an accelerated evolution of cardiovascular imaging, not only in its growing body of evidence to support its use, but also the development of novel technologies (eg, cardiac magnetic resonance, multidetector computed tomography, positron emission tomography) that will likely expand our ability to see more (eg, atherosclerosis, plaque morphology, myocardial tissue characterization) and possibly extend our treatment options. Article see p 1206 Cardiac magnetic resonance (CMR) imaging has emerged as a powerful imaging technique that allows precise tissue characterization in a wide range of myocardial disorders. Several CMR techniques have been described and used for diagnosis, risk stratification, and to guide patient management. One of the most widely used and validated approaches is the detection and quantification of late gadolinium enhancement (LGE) in myocardial tissue. Myocardial tissue characterization with LGE is one of the unique biomarkers of CMR, which reflects the relative differences in the volume of distribution of the gadolinium contrast between normal and abnormal myocardium. Gadolinium is normally confined to the extracellular space. Expansion of the extracellular space resulting from infiltrative processes, fibrosis, or edema increases the myocardial volume of distribution, thereby allowing a larger amount of gadolinium to leak and accumulate in the tissue. This excess gadolinium accumulation combined with its slower washout (compared with normal myocardium) leads to the characteristic bright signal …

137 A novel method for automatic quantification of late gadolinium enhancement in acute myocarditis

137 A novel method for automatic quantification of late gadolinium enhancement in acute myocarditis

Evaluation of Techniques for the Quantification of Myocardial Scar of Differing Etiology Using Cardiac Magnetic Resonance

The aim of this study was to compare the reproducibility of 7 late gadolinium enhancement (LGE) quantification techniques across 3 conditions in which LGE is known to be important: acute myocardial infarction (AMI), chronic myocardial infarction (CMI), and hypertrophic cardiomyopathy (HCM). LGE by cardiac magnetic resonance is the gold-standard technique for assessing myocardial scar. No consensus exists on the best method for its quantification, and research in this area is scant. Techniques include manual quantification, thresholding by 2, 3, 4, 5, or 6 SDs above remote myocardium, and the full width at half maximum (FWHM) technique. To date, LGE has been linked to outcome in 3 conditions: AMI, CMI, and HCM. Sixty patients with 3 LGE etiologies (AMI, n = 20; CMI, n = 20; HCM, n = 20) were scanned for LGE. LGE volume was quantified using the 7 techniques. Mean LGE volume, interobserver and intraobserver reproducibility, and impact on sample size were assessed. LGE volume varied significantly with the quantification method used. There was no statistically significant difference between LGE volume by the FWHM, manual, and 6-SD or 5-SD techniques. The 2-SD technique generated LGE volumes up to 2 times higher than the FWHM, 6-SD, and manual techniques. The reproducibility of all techniques was worse in HCM than AMI or CMI. The FWHM technique was the most reproducible in all 3 conditions compared with any other method (p < 0.001). Use of the FWHM technique for LGE quantification in paired analysis would lead to at least a 60% reduction in required sample size compared with any other method. Regardless of the disease under study, the FWHM technique for LGE quantification gives LGE volume mean results similar to manual quantification and is statistically the most reproducible, reducing required sample sizes by up to one-half.

Hypertrophic Cardiomyopathy: Quantification of Late Gadolinium Enhancement with Contrast-enhanced Cardiovascular MR Imaging

To determine the most reproducible semiautomated gray-scale thresholding technique for quantifying late gadolinium enhancement (LGE) in a large cohort of patients with hypertrophic cardiomyopathy (HCM). All study patients signed a statement approved by the internal review boards of the participating institutions, agreeing to the use of their medical information for research purposes. LGE cardiovascular magnetic resonance (MR) imaging was performed in 201 patients (71% male) with a mean age of 41.5 years ± 17.6 (standard deviation [SD]) by using standard techniques with administration of 0.2 mmol of gadopentetate dimeglumine per kilogram of body weight. The presence and quantity of LGE were determined first with visual assessment; then with gray-scale thresholds of 2 SDs, 4 SDs, and 6 SDs above the mean signal intensity for the normal remote myocardium; and then with 2 SDs above noise. The LGE quantifications were repeated 4 or more weeks apart to assess reproducibility. Bland-Altman analysis and correlation coefficients were used to compare the visual and various thresholding methods, with normally distributed variables expressed as means ± SDs. LGE was identified in 103 (51%) subjects. The mean quantity of LGE at visual analysis was 13 g ± 20 compared with 12 g ± 17 at 6 SDs, 25 g ± 23 at 4 SDs, 55 g ± 31 at 2 SDs, and 64 g ± 69 at 2 SDs above noise. All gray-scale thresholds were significantly correlated with visual assessment. The 6-SD threshold had the strongest correlation (r = 0.913, P < .0001) compared with thresholds of 2 SDs (r = 0.81) and 4 SDs (r = 0.91) above the mean and 2 SDs above noise (r = 0.53) (P < .001 for all comparisons). In addition, compared with visual assessment, the 6-SD threshold yielded less intraobserver variability (difference, 0.6 g ± 8, κ = 0.66 [P < .0001] vs 1.4 g ± 9, κ = 0.49 [P < .0001]) and less interobserver variability (difference, 5.4 g ± 18, κ = 0.20 [P < .0001] vs -18.4 g ± 18, κ = 0.08 [P < .0001]). Semiautomated LGE cardiovascular MR gray-scale thresholding with 6 or more SDs above the mean signal intensity for the visually normal remote myocardium yields the closest approximation of the extent of LGE identified with visual assessment and is highly reproducible. This objective method should be considered for quantifying LGE in patients with HCM.

The Full Width Half Maximum technique is superior for LGE quantification regardless of its aetiology

Introduction No consensus exists on how to quantify late gadolinium enhancement (LGE) even though it is now the gold standard for the assessment of focal myocardial fibrosis. SCMR official reporting recommendations suggest that LGE be defined as signal intensity 2SD above remote myocardium. However, 3, 4, 5 or 6 SD, manual quantification and the Full Width Half Maximum (FWHM) technique are also used, with the FWHM technique reported to be accurate in an animal infarct model.

Comparison of different quantification methods of late gadolinium enhancement in patients with hypertrophic cardiomyopathy

Aim There is no consensus regarding the technique of quantification of late gadolinium enhancement (LGE). The aim of the study was to compare different methods of LGE quantification in patients with hypertrophic cardiomyopathy (HCM). Methods Cardiac magnetic resonance was performed in 33 patients with HCM. First, LGE was quantified by visual assessment by the team of experienced readers and compared with different thresholding techniques: from 1SD to 6SD above mean signal intensity (SI) of remote myocardium, above 50% of maximal SI of the enhanced area (full-width at half maximum, FWHM) and above peak SI of remote myocardium. Results LGE was present in 25 (78%) of patients. The median mass of LGE varied greatly depending on the quantification method used and was highest with the utilization of 1SD threshold [75.5 g, interquartile range (IQR): 63.3–112.3 g] and lowest for FWHM method (8.4 g, IQR: 4.3–13.3 g). There was no difference in mass of LGE as assessed with 6SD threshold and FWHM when compared to visual assessment ( p = 0.19 and p = 0.1, respectively); all other thresholding techniques provided significant differences in the median LGE size when compared to visual analysis. Results for all thresholds, except FWHM were significantly correlated with visual assessment with the strongest correlation for 6SD (rho = 0.956, p < 0.0001). Conclusions LGE quantification with the use of a threshold of 6SD above the mean SI of the remote myocardium provided the best agreement with visual assessment in patients with HCM.

Assessment of Late Gadolinium Enhancement in Nonischemic Cardiomyopathy

Reliable detection of myocardial scarring in nonischemic cardiomyopathy is time-consuming using techniques that require determination of optimal inversion time. Therefore we evaluated an inversion-time-insensitive approach using a fast phase-sensitive inversion recovery (PSIR) sequence to detect and quantify late gadolinium enhancement (LGE). Twenty patients (mean age 40 years, 9 females) with nonischemic cardiomyopathy and evidence of LGE were evaluated. After administration of 0.2 mmol/kg gadolinium diethylene triamine pentaacetic acid, a segmented 2D inversion recovery turbo fast low-angle shot gradient echo recall (GRE) sequence [echo time (TE) 4.3 milliseconds, repetition time (TR) 750 milliseconds, alpha 30 degrees , voxel size 1.7 x 1.3 x 8-10 mm] was obtained and served as the standard of reference. Second, a fast multislice single-shot 2D PSIR sequence (TE 1.1 millisecond, TR 700 milliseconds, alpha 40 degrees , voxel size 2.5 x 1.7 x 8-10 mm) was acquired in the same slice positions. The PSIR(IR) images were used to analyze LGE. Altogether 53 short-axis slices with LGE were evaluated. Contrast-to-noise ratio and area of LGE were calculated and compared by 2 experienced readers. Image quality and confidence level for identification of LGE were rated on 5-point scales. Interobserver variability was evaluated in 10 patients. All images were interpretable. Imaging time was reduced from 385 +/- 127 seconds to 20 +/- 3 seconds (P < 0.001). Contrast-to-noise ratio was 8.29 for PSIRmag and 12.07 for the conventional GRE images (P < 0.001). The mean area of LGE was 1.01 +/- 0.62 cm(2) for the GRE sequence and 1.10 +/- 0.62 cm(2) for PSIR(IR) (P = NS). The general linear model showed no interaction between the results and no significant difference of the mean (r = 0.09, mean difference 0.09 cm(2)). The overall interobserver variability of PSIR(IR) and GRE was excellent, with Pearson's correlation coefficients of r = 0.96 for PSIR(IR) and r = 0.98 for GRE. PSIR(IR) and conventional GRE were comparable in terms of image quality and confidence level (image quality: 1.6 +/- 0.67 vs. 1.5 +/- 0.93, P = NS; confidence level: 1.4 +/- 0.84 vs. 1.3 +/- 0.5; P = NS). Fast PSIR sequences enable accurate detection and quantification of LGE in nonischemic cardiomyopathies. The examination time can be significantly shortened using the single-shot approach of the PSIR technique.