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Importance: Cardiac magnetic resonance (CMR) imaging can identify unrecognized myocardial infarction (UMI) in the general population. Unrecognized myocardial infarction by CMR portends poor prognosis in the short term but, to our knowledge, long-term outcomes are not known., Objective: To determine the long-term outcomes of UMI by CMR compared with clinically recognized myocardial infarction (RMI) and no myocardial infarction (MI)., Design, Setting, and Participants: Participants of the population-based, prospectively enrolled ICELAND MI cohort study (aged 67-93 years) were characterized with CMR at baseline (from January 2004-January 2007) and followed up for up to 13.3 years. Kaplan-Meier time-to-event analyses and a Cox regression were used to assess the association of UMI at baseline with death and future cardiovascular events., Main Outcomes and Measures: The primary outcome was all-cause mortality. Secondary outcomes were a composite of major adverse cardiac events (MACE: death, nonfatal MI, and heart failure)., Results: Of 935 participants, 452 (48.3%) were men; the mean (SD) age of participants with no MI, UMI, and RMI was 75.6 (5.3) years, 76.8 (5.2) years, and 76.8 (4.7) years, respectively. At 3 years, UMI and no MI mortality rates were similar (3%) and lower than RMI rates (9%). At 5 years, UMI mortality rates (13%) increased and were higher than no MI rates (8%) but still lower than RMI rates (19%). By 10 years, UMI and RMI mortality rates (49% and 51%, respectively) were not statistically different; both were significantly higher than no MI (30%) (P < .001). After adjusting for age, sex, and diabetes, UMI by CMR had an increased risk of death (hazard ratio [HR], 1.61; 95% CI, 1.27-2.04), MACE (HR, 1.56; 95% CI, 1.26-1.93), MI (HR, 2.09; 95% CI, 1.45-3.03), and heart failure (HR, 1.52; 95% CI, 1.09-2.14) compared with no MI and statistically nondifferent risk of death (HR, 0.99; 95% CI, 0.71-1.38) and MACE (HR, 1.23; 95% CI, 0.91-1.66) vs RMI., Conclusions and Relevance: In this study, all-cause mortality of UMI was higher than no MI, but within 10 years from baseline evaluation was equivalent with RMI. Unrecognized MI was also associated with an elevated risk of nonfatal MI and heart failure. Whether secondary prevention can alter the prognosis of UMI will require prospective testing.

Background: Fetal cardiovascular magnetic resonance (CMR) imaging may provide a valuable adjunct to fetal echocardiography in the evaluation of congenital cardiovascular pathologies. However, dynamic fetal CMR is difficult due to the lack of direct in-utero cardiac gating. The aim of this study was to investigate the effectiveness of a newly developed Doppler ultrasound (DUS) device in humans for fetal CMR gating., Methods: Fifteen fetuses (gestational age 30-39 weeks) were examined using 1.5 T CMR scanners at three different imaging sites. A newly developed CMR-compatible DUS device was used to generate gating signals from fetal cardiac motion. Gated dynamic balanced steady-state free precession images were acquired in 4-chamber and short-axis cardiac views. Gating signals during data acquisition were analyzed with respect to trigger variability and sensitivity. Image quality was assessed by measuring endocardial blurring (EB) and by image evaluation using a 4-point scale. Left ventricular (LV) volumetry was performed using the single-plane ellipsoid model., Results: Gating signals from the fetal heart were detected with a variability of 26 ± 22 ms and a sensitivity of trigger detection of 96 ± 4%. EB was 2.9 ± 0.6 pixels (4-chamber) and 2.5 ± 0.1 pixels (short axis). Image quality scores were 3.6 ± 0.6 (overall), 3.4 ± 0.7 (mitral valve), 3.4 ± 0.7 (foramen ovale), 3.6 ± 0.7 (atrial septum), 3.7 ± 0.5 (papillary muscles), 3.8 ± 0.4 (differentiation myocardium/lumen), 3.7 ± 0.5 (differentiation myocardium/lung), and 3.9 ± 0.4 (systolic myocardial thickening). Inter-observer agreement for the scores was moderate to very good (kappa 0.57-0.84) for all structures. LV volumetry revealed mean values of 2.8 ± 1.2 ml (end-diastolic volume), 0.9 ± 0.4 ml (end systolic volume), 1.9 ± 0.8 ml (stroke volume), and 69.1 ± 8.4% (ejection fraction)., Conclusion: High-quality dynamic fetal CMR was successfully performed using a newly developed DUS device for direct fetal cardiac gating. This technique has the potential to improve the utility of fetal CMR in the evaluation of congenital pathologies.

Purpose: To develop and assess a technique for self-gated fetal cardiac cine magnetic resonance imaging (MRI) using tiny golden angle radial sampling combined with iGRASP (iterative Golden-angle RAdial Sparse Parallel) for accelerated acquisition based on parallel imaging and compressed sensing., Materials and Methods: Fetal cardiac data were acquired from five volunteers in gestational week 29-37 at 1.5T using tiny golden angles for eddy currents reduction. The acquired multicoil radial projections were input to a principal component analysis-based compression stage. The cardiac self-gating (CSG) signal for cardiac gating was extracted from the acquired radial projections and the iGRASP reconstruction procedure was applied. In all acquisitions, a total of 4000 radial spokes were acquired within a breath-hold of less than 15 seconds using a balanced steady-state free precession pulse sequence. The images were qualitatively compared by two independent observers (on a scale of 1-4) to a single midventricular cine image from metric optimized gating (MOG) and real-time acquisitions., Results: For iGRASP and MOG images, good overall image quality (2.8 ± 0.4 and 2.6 ± 1.3, respectively, for observer 1; 3.6 ± 0.5 and 3.4 ± 0.9, respectively, for observer 2) and cardiac diagnostic quality (3.8 ± 0.4 and 3.4 ± 0.9, respectively, for observer 1; 3.6 ± 0.5 and 3.6 ± 0.9, respectively, for observer 2) were obtained, with visualized myocardial thickening over the cardiac cycle and well-defined myocardial borders to ventricular lumen and liver/lung tissue. For iGRASP, MOG, and real time, left ventricular lumen diameter (14.1 ± 2.2 mm, 14.2 ± 1.9 mm, 14.7 ± 1.1 mm, respectively) and wall thickness (2.7 ± 0.3 mm, 2.6 ± 0.3 mm, 3.0 ± 0.4, respectively) showed agreement and no statistically significant difference was found (all P > 0.05). Images with iGRASP tended to have higher overall image quality scores compared with MOG and particularly real-time images, albeit not statistically significant in this feasibility study (P > 0.99 and P = 0.12, respectively)., Conclusion: Fetal cardiac cine MRI can be performed with iGRASP using tiny golden angles and CSG. Comparison with other fetal cardiac cine MRI methods showed that the proposed method produces high-quality fetal cardiac reconstructions., Level of Evidence: 2 Technical Efficacy: Stage 1 J. MAGN. RESON. IMAGING 2017;46:207-217., (© 2017 International Society for Magnetic Resonance in Medicine.)

Background: Accurate assessment of myocardium at risk (MaR) after acute myocardial infarction (AMI) is necessary when assessing myocardial salvage. Contrast-enhanced steady-state free precession (CE-SSFP) is a recently developed cardiovascular magnetic resonance (CMR) method for assessment of MaR up to 1 week after AMI. Our aim was to validate CE-SSFP for determination of MaR in an experimental porcine model using myocardial perfusion single-photon emission computed tomography (MPS) as a reference standard and to test the stability of MaR-quantification over time after injecting gadolinium-based contrast., Methods: Eleven pigs were subjected to either 35 or 40 min occlusion of the left anterior descending artery followed by six hours of reperfusion. A technetium-based perfusion tracer was administered intravenously ten minutes before reperfusion. In-vivo and ex-vivo CE-SSFP CMR was performed followed by ex-vivo MPS imaging. MaR was expressed as % of left ventricular mass (LVM)., Results: There was good agreement between MaR by ex-vivo CMR and MaR by MPS (bias: 1 ± 3% LVM, r 2  = 0.92, p < 0.001), between ex-vivo and in-vivo CMR (bias 0 ± 2% LVM, r 2  = 0.94, p < 0.001) and between in-vivo CMR and MPS (bias -2 ± 3% LVM, r 2  = 0.87, p < 0.001. No change in MaR was seen over the first 30 min after contrast injection (p = 0.95)., Conclusions: Contrast-enhanced SSFP cine CMR can be used to measure MaR, both in vivo and ex vivo, in a porcine model with good accuracy and precision over the first 30 min after contrast injection. This offers the option to use the less complex ex-vivo imaging when determining myocardial salvage in experimental studies.

Targeted therapies in connective tissue diseases (CTDs) have led to improvements of disease-associated outcomes, but life expectancy remains lower compared to general population due to emerging co-morbidities, particularly due to excess cardiovascular risk. Cardiovascular magnetic resonance (CMR) is a noninvasive imaging technique which can provide detailed information about multiple cardiovascular pathologies without using ionizing radiation. CMR is considered the reference standard for quantitative evaluation of left and right ventricular volumes, mass and function, cardiac tissue characterization and assessment of thoracic vessels; it may also be used for the quantitative assessment of myocardial blood flow with high spatial resolution and for the evaluation of the proximal coronary arteries. These applications are of particular interest in CTDs, because of the potential of serious and variable involvement of the cardiovascular system during their course. The International Consensus Group on CMR in Rheumatology was formed in January 2012 aiming to achieve consensus among CMR and rheumatology experts in developing initial recommendations on the current state-of-the-art use of CMR in CTDs. The present report outlines the recommendations of the participating CMR and rheumatology experts with regards to: (a) indications for use of CMR in rheumatoid arthritis, the spondyloarthropathies, systemic lupus erythematosus, vasculitis of small, medium and large vessels, myositis, sarcoidosis (SRC), and scleroderma (SSc); (b) CMR protocols, terminology for reporting CMR and diagnostic CMR criteria for assessment and quantification of cardiovascular involvement in CTDs; and (c) a research agenda for the further development of this evolving field., (Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.)

Aims: Myocardial salvage, determined by cardiac magnetic resonance imaging (CMR), is used as end point in cardioprotection trials. To calculate myocardial salvage, infarct size is related to myocardium at risk (MaR), which can be assessed by T2-short tau inversion recovery (T2-STIR) and contrast-enhanced steady-state free precession magnetic resonance imaging (CE-SSFP). We aimed to determine how T2-STIR and CE-SSFP perform in determining MaR when applied in multicentre, multi-vendor settings., Methods and Results: A total of 215 patients from 17 centres were included after percutaneous coronary intervention (PCI) for ST-elevation myocardial infarction. CMR was performed within 1-8 days. These patients participated in the MITOCARE or CHILL-MI cardioprotection trials. Additionally, 8 patients from a previous study, imaged 1 day post-CMR, were included. Late gadolinium enhancement, T2-STIR, and CE-SSFP images were acquired on 1.5T MR scanners (Philips, Siemens, or GE). In 65% of the patients, T2-STIR was of diagnostic quality compared with 97% for CE-SSFP. In diagnostic quality images, there was no difference in MaR by T2-STIR and CE-SSFP (bias: 0.02 ± 6%, P = 0.96, r(2) = 0.71, P < 0.001), or between treatment and control arms. No change in size or quality of MaR nor ability to identify culprit artery was seen over the first week after the acute event (P = 0.44)., Conclusion: In diagnostic quality images, T2-STIR and CE-SSFP provide similar estimates of MaR, were constant over the first week, and were not affected by treatment. CE-SSFP had a higher degree of diagnostic quality images compared with T2 imaging for sequences from two out of three vendors. Therefore, CE-SSFP is currently more suitable for implementation in multicentre, multi-vendor clinical trials., (© The Author 2016. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Background: MRI physics simulators have been developed in the past for optimizing imaging protocols and for training purposes. However, these simulators have only addressed motion within a limited scope. The purpose of this study was the incorporation of realistic motion, such as cardiac motion, respiratory motion and flow, within MRI simulations in a high performance multi-GPU environment., Methods: Three different motion models were introduced in the Magnetic Resonance Imaging SIMULator (MRISIMUL) of this study: cardiac motion, respiratory motion and flow. Simulation of a simple Gradient Echo pulse sequence and a CINE pulse sequence on the corresponding anatomical model was performed. Myocardial tagging was also investigated. In pulse sequence design, software crushers were introduced to accommodate the long execution times in order to avoid spurious echoes formation. The displacement of the anatomical model isochromats was calculated within the Graphics Processing Unit (GPU) kernel for every timestep of the pulse sequence. Experiments that would allow simulation of custom anatomical and motion models were also performed. Last, simulations of motion with MRISIMUL on single-node and multi-node multi-GPU systems were examined., Results: Gradient Echo and CINE images of the three motion models were produced and motion-related artifacts were demonstrated. The temporal evolution of the contractility of the heart was presented through the application of myocardial tagging. Better simulation performance and image quality were presented through the introduction of software crushers without the need to further increase the computational load and GPU resources. Last, MRISIMUL demonstrated an almost linear scalable performance with the increasing number of available GPU cards, in both single-node and multi-node multi-GPU computer systems., Conclusions: MRISIMUL is the first MR physics simulator to have implemented motion with a 3D large computational load on a single computer multi-GPU configuration. The incorporation of realistic motion models, such as cardiac motion, respiratory motion and flow may benefit the design and optimization of existing or new MR pulse sequences, protocols and algorithms, which examine motion related MR applications.

In order to determine the cardioprotective efficacy of acute reperfusion therapy, assessed as myocardial salvage, in patients with acute coronary occlusion, the final myocardial infarct (MI) size needs to be related to the amount of ischemic myocardium during coronary occlusion, referred to as the myocardium at risk (MaR). There are currently several imaging approaches available for quantification of both MI size and MaR in vivo of which some have been validated both in pre-clinical and clinical settings. These methods often involve the use of either myocardial perfusion SPECT or cardiac magnetic resonance (CMR). These imaging methods could potentially be used to further develop and validate ECG methods for determination of MI size and MaR. Therefore, the aim of the present review is to give an overview of myocardial perfusion SPECT and CMR methods available for assessment of myocardial salvage by determination of MI size and MaR., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Objectives: This study's primary objective was to determine the sensitivity, specificity, and accuracy of fully quantitative stress perfusion cardiac magnetic resonance (CMR) versus a reference standard of quantitative coronary angiography. We hypothesized that fully quantitative analysis of stress perfusion CMR would have high diagnostic accuracy for identifying significant coronary artery stenosis and exceed the accuracy of semiquantitative measures of perfusion and qualitative interpretation., Background: Relatively few studies apply fully quantitative CMR perfusion measures to patients with coronary disease and comparisons to semiquantitative and qualitative methods are limited., Methods: Dual bolus dipyridamole stress perfusion CMR exams were performed in 67 patients with clinical indications for assessment of myocardial ischemia. Stress perfusion images alone were analyzed with a fully quantitative perfusion (QP) method and 3 semiquantitative methods including contrast enhancement ratio, upslope index, and upslope integral. Comprehensive exams (cine imaging, stress/rest perfusion, late gadolinium enhancement) were analyzed qualitatively with 2 methods including the Duke algorithm and standard clinical interpretation. A 70% or greater stenosis by quantitative coronary angiography was considered abnormal., Results: The optimum diagnostic threshold for QP determined by receiver-operating characteristic curve occurred when endocardial flow decreased to <50% of mean epicardial flow, which yielded a sensitivity of 87% and specificity of 93%. The area under the curve for QP was 92%, which was superior to semiquantitative methods: contrast enhancement ratio: 78%; upslope index: 82%; and upslope integral: 75% (p = 0.011, p = 0.019, p = 0.004 vs. QP, respectively). Area under the curve for QP was also superior to qualitative methods: Duke algorithm: 70%; and clinical interpretation: 78% (p < 0.001 and p < 0.001 vs. QP, respectively)., Conclusions: Fully quantitative stress perfusion CMR has high diagnostic accuracy for detecting obstructive coronary artery disease. QP outperforms semiquantitative measures of perfusion and qualitative methods that incorporate a combination of cine, perfusion, and late gadolinium enhancement imaging. These findings suggest a potential clinical role for quantitative stress perfusion CMR., (Copyright © 2014 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: In hypertrophic cardiomyopathy (HCM), myocardial abnormalities are commonly heterogeneous. Two patterns of late gadolinium enhancement (LGE) have been reported: a bright "confluent" and an intermediate intensity abnormality termed "diffuse," each representing different degrees of myocardial scarring. We used MRI to study the relation between intramural cardiac function and the extent of fibrosis in HCM. The aim of this study was to determine whether excess collagen or myocardial scarring, as determined by LGE MRI, are the primary mechanisms leading to heterogeneous regional contractile function in patients with HCM., Methods and Results: Intramural left ventricular strain, transmural left ventricular function, and regions of myocardial fibrosis/scarring were imaged in 22 patients with HCM, using displacement encoding with stimulated echoes (DENSE), cine MRI, and LGE. DENSE systolic strain maps were qualitatively and quantitatively compared with LGE images. Intramural systolic strain by DENSE was significantly depressed within areas of confluent and diffuse LGE but also in the core of the most hypertrophic nonenhanced segment (all P < 0.001 versus nonhypertrophied segments). DENSE demonstrated an unexpected inner rim of largely preserved contractile function and a noncontracting outer wall within hypertrophic segments in 91% of patients., Conclusions: LGE predicted some but not all of the heterogeneity of intramural contractile abnormalities. This indicates that myocardial scarring or excess interstitial collagen deposition does not fully explain the observed contractile heterogeneity in HCM. Thus, myofibril disarray or other nonfibrotic processes affect systolic function in a large number of patients with HCM.

Background: The area at risk (AAR) is a key determinant of myocardial infarction (MI) size. We investigated whether magnetic resonance imaging (MRI) measurement of AAR would be correlated with an angiographic AAR risk score in patients with acute MI., Methods and Results: Bright-blood, T2-prepared, steady-state, free-precession MRI was used to depict the AAR in 50 consecutive acute MI patients, whereas infarct size was measured on gadolinium late-contrast-enhancement images. AAR was also estimated by the APPROACH and DUKE angiographic jeopardy scores and ST-segment elevation score. Myocardial salvage was calculated as AAR minus infarct size. Results are mean ± SD unless specified otherwise. Patients were 61 ± 12 years of age, 76% had an ST-segment elevation MI, and 20% had a prior MI. All underwent MRI 4 ± 2 days after initial presentation. The relation between MRI and the APPROACH angiographic estimates of AAR was similar (overall size relative to left ventricular mass was 32 ± 12% vs 30 ± 12%, respectively, P=0.33), correlated well (r = 0.78, P < 0.0001), and had a 2.5% bias on Bland-Altman analysis. The DUKE jeopardy score underestimated AAR relative to infarct size and was correlated less well with MRI (r = 0.39, P = 0.0055). ST-segment elevation score underestimated infarct size in 19 subjects (50%) and was not correlated with MRI (r = 0.27, P = 0.06). Myocardial salvage varied according to Thrombolysis in Myocardial Infarction flow grade at the end of angiography/percutaneous coronary intervention (P = 0.04), and Thrombolysis in Myocardial Infarction flow grade was a univariable predictor of myocardial salvage (P = 0.011). In multivariable analyses, infarct size was predicted by T2-prepared, steady-state, free-precession MRI (P < 0.0001)., Conclusions: T2-prepared, steady-state, free-precession MRI delineates the AAR and enables estimation of myocardial salvage when coupled with a measurement of infarct size.

Displacement encoding with stimulated echoes (DENSE) with a low encoding strength phase-cycled meta-DENSE readout and a two fold SENSE acceleration (R = 2) is described. This combination reduces total breath-hold times for increased patient comfort during cardiac regional myocardial contractility studies. Images from phantoms, normal volunteers, and a patient are provided to demonstrate the SENSE-DENSE combination of methods. The overall breath-hold time is halved while preserving strain map quality.

Purpose: To test whether manganese-enhanced magnetic resonance (MR) imaging can safely depict the myocardial area at risk both during coronary artery occlusion and for at least 2 hours after reperfusion in dogs., Materials and Methods: All procedures were performed in accordance with the animal care and use committee of the National Institutes of Health. In eight dogs, the left anterior descending (LAD) coronary artery was occluded for 90 minutes, and 15 micromol of MnCl2 per kilogram of body weight was intravenously infused for 12 minutes. Phase-sensitive inversion-recovery MR imaging of the LAD arterial territory was performed before occlusion, during MnCl2 infusion, and for at least 2 hours after reperfusion. Hemodynamic responses were monitored continuously. Fluorescent microsphere enhancement was used as the reference standard for determining the area at risk ex vivo. Results are reported as percentages of left ventricular area. Correlation, Bland-Altman, and t test analyses were performed., Results: Significant differences in manganese-induced contrast enhancement of the area at risk, the normal myocardium, and the blood (P < .01) were measured during LAD artery occlusion and at least 2 hours after reperfusion. No significant changes in heart rate or blood pressure were detected during or after MnCl2 infusion. Measurements of the area at risk obtained with manganese-enhanced MR imaging during LAD artery occlusion and 2 hours after reperfusion correlated well with the size of the at-risk area demarcated by the fluorescent microspheres (during occlusion: y = 0.81x, R = 0.90; during reperfusion: y = 0.83x, R = 0.89). Bland-Altman analysis revealed small systematic errors in measurements at both occlusion and reperfusion., Conclusion: Manganese-enhanced MR imaging can depict the area at risk during LAD artery occlusion and at least 2 hours after reperfusion without hemodynamic compromise.

Objectives: The current study tested the hypothesis that gadolinium delayed enhancement assessment of infarct size correlates with clinical indices of myocardial infarction (MI) in humans. Acute infarct mass by cardiac magnetic resonance (CMR) was compared with peak troponin I, acute and chronic left ventricular (LV) systolic function, and chronic infarct mass in patients imaged after recent acute MI., Background: Cardiac magnetic resonance accurately determines myocardial viability in patients with chronic ischemic heart disease but is not well validated for recent MI., Methods: Patients with first acute MI (n = 33) or chronic MI (n = 10) underwent cine CMR followed by gadolinium delayed enhancement imaging. A follow-up CMR scan was performed on 20 of the 33 acute MI patients and all of the chronic MI patients., Results: In patients with acute percutaneous coronary intervention, acute MI mass correlated with peak troponin I (r = 0.83, p < 0.001, n = 23). In the 20 acute infarct patients with follow-up CMR scans, the acute infarct size correlated well with the follow-up LV ejection fraction (r = 0.86, p < 0.001). The transmural extent of delayed enhancement imaged acutely correlated inversely with wall thickening measured acutely (p < 0.001) and at follow-up (p < 0.001). Although chronic infarct size was reproducible (11 +/- 4% vs. 12 +/- 7%, p = NS), acute infarct size decreased from 16 +/- 12% to 11 +/- 9% (p < 0.003)., Conclusion: In humans imaged shortly after acute MI, gadolinium delayed enhancement acute CMR infarct size correlates with acute and chronic indices of infarct size but will appear to diminish in size on follow-up.

Purpose: To simultaneously differentiate stunned, infarcted, and normal myocardial regions by using gadolinium-enhanced cine magnetic resonance (MR) imaging with magnetization transfer contrast., Materials and Methods: Twelve dogs were imaged on days 1 and 8 after transient 90-minute coronary artery occlusion. A magnetization transfer contrast with echo-train readout (MTET) MR sequence was performed before and 30 minutes after gadolinium contrast enhancement. Ex vivo analysis consisted of MR imaging, microsphere blood flow analysis, and triphenyltetrazolium chloride (TTC) staining. A paired two-tailed t test was used to compare wall thickening from day 1 to day 8. Linear regression and Bland-Altman analyses were used to compare infarct size depicted with MTET imaging with that seen on TTC-stained tissue., Results: Severe wall motion abnormalities were detected in all dogs. At TTC analysis, seven dogs had evidence of myocardial infarction and five had evidence of stunned myocardium. The mean percentages of left ventricular wall thickening in infarcted, stunned, and remote myocardial regions were 2% +/- 4 (SD), 4% +/- 8, and 33% +/- 5, respectively. Wall thickening did not improve in the infarcted zones, but it improved to nearly normal levels in the stunned region 1 week after induced occlusion (mean, 40% +/- 8; P <.02). MTET images clearly depicted infarcted myocardium as brighter than both the normal and stunned myocardial regions but darker than the blood pool. In vivo MTET infarct volume correlated with ex vivo TTC analysis data (y = 1.01x + 0.00, R = 0.98, standard error of the estimate = 0.019)., Conclusion: One day after myocardial ischemia, MTET during one MR imaging examination enabled simultaneous differentiation of infarcted, stunned, and normal myocardial regions on the basis of gadolinium enhancement and regional function.