Assessment of Left Ventricular Mass and Hypertrophy by Cardiovascular Magnetic Resonance Imaging in Pediatric Hypertension

Cardiovascular magnetic resonance (CMR) imaging in adults is considered the gold standard for assessment of left ventricular mass (LVM) and left ventricular hypertrophy (LVH). The authors aimed to evaluate agreement of LVM measurements and LVH determination between echocardiography (ECHO) and CMR imaging in children with hypertension (HTN) confirmed by 24‐hour ambulatory blood pressure monitoring (ABPM). The children (n=22) underwent contemporaneous ECHO, CMR imaging, and ABPM. Patients had a mean body mass index of 30.9±7.5 (kg/m²), and 81.8% had severe HTN. LVM measured by ECHO was 189.6±62.1 g and by CMR imaging was 164.6±44.7 g (P<.0001). Bland‐Altman analysis revealed significant variability between ECHO and CMR imaging in the measurement of LVM. Interobserver error was higher with ECHO than with CMR imaging. ECHO had high sensitivity and low specificity in LVH determination. In conclusion, ECHO overestimates LVM and is less accurate in measuring LVM as compared with CMR imaging in children with HTN. Further prospective study using CMR imaging to assess LVM in children is warranted.     

The complementary role of cardiac magnetic resonance imaging in the evaluation of patients with aortic stenosis.

OBJECTIVE: To compare direct planimetry of aortic valve area (AVA) by cardiac magnetic resonance (CMR) imaging with transthoracic echocardiography (TTE), using the continuity equation. METHODS: 15 symptomatic patients with aortic stenosis were studied. AVA was measured with CMR from steady state free precession imaging by planimetry. AVA was also calculated by TTE images using the continuity equation. RESULTS: The evaluation of AVA by both CMR and TTE was possible in twelve out of fifteen patients. CMR was able to determine the AVA in all fifteen patients. AVAs obtained by CMR and TTE were very similar and a good correlation existed between the values obtained by either technique. CONCLUSION: CMR planimetry is highly reliable and reproducible. AVAs obtained by CMR compare well with those obtained by TTE. Therefore, CMR planimetry of AVA with steady state free precession is a useful diagnostic tool, particularly if uncertainty exists.     

Usefulness of pericardial effusion as new diagnostic criterion for noninvasive detection of myocarditis

Cardiovascular magnetic resonance (CMR) imaging holds promise for diagnosing myocarditis in vivo. The CMR diagnosis of myocarditis is determined by the ventricular morphology/function, late gadolinium enhancement, and T(2)-weighted imaging for myocardial edema. However, in routine clinical practice, we encounter patients with suspected myocarditis in the absence of left ventricular dysfunction, myocardial edema, or late gadolinium enhancement. In the present study, we sought to determine whether the presence of pericardial effusion could serve as a new diagnostic criterion and improve the sensitivity of CMR imaging to detect myocarditis. A total of 35 consecutive patients with biopsy proven virus-associated myocarditis, onset of clinical symptoms within the past 3 months, and normal left ventricular function were enrolled in the present study. All patients underwent echocardiography, CMR imaging, and endomyocardial biopsy for workup of myocarditis. Late gadolinium enhancement was present in 16 patients (46%). Myocardial edema on T(2)-weighted imaging was present in 4 patients, but in just 1, it was the only abnormal finding. Pericardial effusion was present in 14 patients (40%). In 7 patients with myocarditis (20%), pericardial effusion was the only abnormal finding. Pericardial effusion, used as an additional diagnostic criterion, improved the sensitivity of CMR imaging for myocarditis from 46% to 66% (p = 0.023). In conclusion, pericardial effusion detected by CMR imaging might serve as a new diagnostic criterion for the noninvasive diagnosis of myocarditis in patients with recent onset of clinical symptoms and normal left ventricular function.     

Assessment of non-ST-segment elevation acute coronary syndromes with cardiac magnetic resonance imaging

OBJECTIVES: The goal of this study was to determine: 1) if the presence of significant coronary stenosis in patients presenting with non-ST-segment elevation acute coronary syndromes (NSTE-ACS) can be predicted by cardiac magnetic resonance (CMR) imaging; and 2) if the analysis of several CMR methods improves its diagnostic yield compared with analysis of individual methods. BACKGROUND: With modern acquisition techniques, several CMR methods for the assessment of coronary artery disease (CAD) can be combined in a single noninvasive scanning session. Such a multicomponent CMR examination has not previously been applied to a large patient population, in particular those with a high prevalence of CAD in an acute situation. METHODS: Sixty-eight patients presenting with NSTE-ACS underwent CMR imaging of myocardial function, perfusion (rest and adenosine-stress), viability (by late contrast enhancement), and coronary artery anatomy. Visual analysis of CMR was carried out. First, all CMR data were reviewed in combination ("comprehensive analysis"). In further separate analyses, each CMR method was analyzed individually. The ability of CMR to detect coronary stenosis >/=70% on X-ray angiography was determined. RESULTS: Comprehensive CMR analysis yielded a sensitivity of 96% and a specificity of 83% to predict the presence of significant coronary stenosis and was more accurate than analysis of any individual CMR method; CMR was significantly more sensitive and accurate than the Thrombolysis In Myocardial Infarction risk score (p < 0.001). CONCLUSIONS: Cardiac magnetic resonance imaging accurately predicts the presence of significant CAD in patients with NSTE-ACS. In this study, a comprehensive analysis of several CMR methods improved the accuracy of the test.     

磁共振评价冠状动脉非阻塞型心肌梗死的应用价值

目的 冠状动脉非阻塞性心肌梗死（MINOCA）是一种潜在多病因综合征,心脏磁共振（CMR）可以寻找MINOCA潜在的发病原因,本文旨在探讨CMR在MINOCA病因诊断和鉴别诊断中的价值。 方法 回顾性研究2017年~2019年26例急性胸痛伴血肌钙蛋白升高的患者,冠状动脉造影未见明显阻塞或狭窄<50%,临床诊断为MINOCA。所有患者冠状动脉造影后行CMR扫描,分析磁共振图像特点,观察心脏结构、功能及有无灌注异常和延迟强化。 结果 26例MINOCA中CMR诊断心肌梗死15例（58%）、心肌炎3例（12%）、Takotsubo心肌病3例（12%）,有4例（15%）CMR检查未见明显异常,1例（4%）无法明确具体病因,根据磁共振特征归为非缺血性心肌病。CMR最终确诊26例MINOCA中21例,诊断率81%。 结论 CMR一站式成像对于诊断MINOCA有独特作用,能够鉴别心肌炎、Takotsubo心肌病与急性心肌梗死等不同病因引起的MINOCA。     

Diagnosis and management of ischemic cardiomyopathy: Role of cardiovascular magnetic resonance imaging

Coronary artery disease (CAD) represents an important cause of mortality. Cardiovascular magnetic resonance (CMR) imaging evolved as an imaging modality that allows the assessment of myocardial function, perfusion, contractile reserve and extent of fibrosis in a single comprehensive exam. This review highlights the role of CMR in the differential diagnosis of acute chest pain by detecting the location of obstructive CAD or necrosis and identifying other conditions like stress cardiomyopathy or myocarditis that can present with acute chest pain. Besides, it underlines the prognostic implication of perfusion abnormalities in the setting of acute chest pain. Furthermore, the review addresses the role of CMR to detect significant CAD in patients with stable CAD. It elucidates the accuracy and clinical utility of CMR with respect to other imaging modalities like single-photon emission computed tomography and positron emission tomography. Besides, the prognostic value of CMR stress testing is discussed. Additionally, it summarizes the available CMR techniques to assess myocardial viability and describes algorithm to identify those patient who might profit from revascularization those who should be treated medically. Finally, future promising imaging techniques that will provide further insights into the fundamental disease processes in ischemic cardiomyopathy are discussed.     

The emerging clinical role of cardiovascular magnetic resonance imaging

Starting as a research method little more than a decade ago, cardiovascular magnetic resonance (CMR) imaging has rapidly evolved to become a powerful diagnostic tool used in routine clinical cardiology. The contrast in CMR images is generated from protons in different chemical environments and, therefore, enables high-resolution imaging and specific tissue characterization in vivo, without the use of potentially harmful ionizing radiation.CMR imaging is used for the assessment of regional and global ventricular function, and to answer questions regarding anatomy. State-of-the-art CMR sequences allow for a wide range of tissue characterization approaches, including the identification and quantification of nonviable, edematous, inflamed, infiltrated or hypoperfused myocardium. These tissue changes are not only used to help identify the etiology of cardiomyopathies, but also allow for a better understanding of tissue pathology in vivo. CMR tissue characterization may also be used to stage a disease process; for example, elevated T2 signal is consistent with edema and helps differentiate acute from chronic myocardial injury, and the extent of myocardial fibrosis as imaged by contrast-enhanced CMR correlates with adverse patient outcome in ischemic and nonischemic cardiomyopathies.The current role of CMR imaging in clinical cardiology is reviewed, including coronary artery disease, congenital heart disease, nonischemic cardiomyopathies and valvular disease.     

Cardiovascular magnetic resonance imaging assessment of outcomes in acute myocardial infarction

Cardiovascular magnetic resonance(CMR) imaging uniquely characterizes myocardial and microvascular injury in acute myocardial infarction(AMI), providing powerful surrogate markers of outcomes. The last 10 years have seen an exponential increase in AMI studies utilizing CMR based endpoints. This article provides a contemporary, comprehensive review of the powerful role of CMR imaging in the assessment of outcomes in AMI. The theory, assessment techniques, chronology, importance in predicting left ventricular function and remodelling, and prognostic value of each CMR surrogate marker is described in detail. Major studies illustrating the importance of the markers are summarized, providing an up to date review of the literature base in CMR imaging in AMI.     

High-Resolution Late Gadolinium Enhancement Magnetic Resonance for the Diagnosis of Myocardial Infarction With Nonobstructed Coronary Arteries

ObjectivesThe aim of this study was to assess the diagnostic yield of cardiac magnetic resonance (CMR) including high-resolution (HR) late gadolinium enhancement (LGE) imaging using a 3-dimensional respiratory-navigated method in patients with myocardial infarction with nonobstructed coronary arteries (MINOCA).BackgroundCMR plays a pivotal role for the diagnosis of patients with MINOCA. However, the diagnosis remains inconclusive in a significant number of patients, the results of CMR being either negative or uncertain (i.e., compatible with multiple diagnoses).MethodsConsecutive patients categorized as having MINOCA after blood testing, electrocardiography, coronary angiography, and echocardiography underwent conventional CMR, including cine, T2-weighted, first-pass perfusion, and conventional breath-held LGE imaging. HR LGE imaging using a free-breathing method allowing improved spatial resolution (voxel size 1.25 × 1.25 × 2.5 mm) was added to the protocol when the results of conventional CMR were inconclusive and was optional otherwise. Diagnoses retained after reviewing conventional CMR were compared with those retained after the addition of HR LGE imaging.ResultsFrom 2013 to 2016, 229 patients were included (mean age 56 ± 17 years, 45% women). HR LGE imaging was performed in 172 patients (75%). In this subpopulation, definite diagnoses were retained after conventional CMR in 86 patients (50%): infarction in 39 (23%), myocarditis in 32 (19%), takotsubo cardiomyopathy in 13 (8%), and other diagnoses in 2 (1%). In the remaining 86 patients (50%), results of CMR were inconclusive: negative in 54 (31%) and consistent with multiple diagnoses in 32 (19%). HR LGE imaging led to changes in final diagnosis in 45 patients (26%) and to a lower rate of inconclusive final diagnosis (29%) (p < 0.001). In particular, HR LGE imaging could reveal or ascertain the diagnosis of infarction in 14% and rule out the diagnosis of infarction in 12%. HR LGE imaging was particularly useful when the results of transthoracic echocardiography, ventriculography, and conventional CMR were negative, with a 48% rate of modified diagnosis in this subpopulation.ConclusionsHR LGE imaging has high diagnostic value in patients with MINOCA and inconclusive findings on conventional CMR. This has major diagnostic, prognostic, and therapeutic implications.     

Cardiovascular magnetic resonance imaging for valvular heart disease

Valvular heart disease (VHD) is a clinically important diagnosis, with significant associated morbidity and mortality. Multiple imaging modalities exist to characterize valvular and associated cardiac anatomy. Cardiovascular magnetic resonance (CMR) has emerged as a comprehensive noninvasive imaging modality for VHD. With use of well-established, standardized imaging sequences, CMR can accurately and precisely diagnose valvular structural abnormalities, assess severity of regurgitant and stenotic lesions, and potentially define patient prognosis. This article reviews the clinical applications of CMR in assessment of VHD.     

Cardiac magnetic resonance imaging: A teaching atlas with emphasizing current clinical indications

Cardiovascular magnetic resonance (CMR) is an amazing technology that continues to provide new innovative approaches for evaluating the heart and blood vessels. It can assess cardiac morphology, function, perfusion, viability, coronary and peripheral arteries, and metabolism and tissue characterization. The basic pulse sequences of CMR include; Spin Echo, Gradient echo, and Steady stet free precision. Current clinical indications of CMR are multiple and continuously evolving. CMR often works in complementary fashions to other cardiac imaging techniques or to resolve residual diagnostic dilemma. The purpose of this illustrative review is to review current clinical applications of CMR and to provide physicians and technologists with simple, and regular CMR cases form daily practice. Each case discusses briefly the related clinical history, followed by CMR imaging findings, and simple discussion to highlight the role of CMR in a particular cardiovascular disorder.     

Impact of cardiac magnetic resonance imaging in nonischemic cardiomyopathies

Non-ischemic cardiomyopathies include a wide spectrum of disease states afflicting the heart, whether a primary process or secondary to a systemic condition. Cardiac magnetic resonance imaging(CMR) has established itself as an important imaging modality in the evaluation of non-ischemic cardiomyopathies. CMR is useful in the diagnosis of cardiomyopathy, quantification of ventricular function, establishing etiology, determining prognosis and risk stratification. Technical advances and extensive research over the last decade have resulted in the accumulation of a tremendous amount of data with regards to the utility of CMR in these cardiomyopathies. In this article, we review CMR findings of various non-ischemic cardiomyopathies and focus on current literature investigating the clinical impact of CMR on risk stratification, treatment, and prognosis.     

Management of Patients With Single-Ventricle Physiology Across the Lifespan: Contributions From Magnetic Resonance and Computed Tomography Imaging

Cardiovascular magnetic resonance (CMR) and cardiac computed tomography (CCT) are robust cross-sectional imaging modalities that are increasingly being used to guide the diagnosis and management of those born with single-ventricle physiology. The purpose of this review is to acquaint the reader with the wide range of cross-sectional imaging applications that can be applied in this population. Illustrative examples of information provided by CMR and CCT are included, such as delineation of cardiac anatomy, measurement of ventricular volumetry, interrogation of vascular anatomy and flows, evaluation of myocardial viability, and exclusion of thromboembolic disease. Focus is placed on the appropriate selection and timing of advanced cardiac imaging modalities, and differentiations are made between established indications for imaging and emerging applications (such as 4-dimensional [4D] flow assessment and parametric imaging for identification of diffuse fibrosis using CMR). Potential CMR and CCT contributions in the selection of interventional strategies in the child and for surveillance of postoperative complications in the adult are highlighted. Furthermore, the importance of extracardiac cross-sectional imaging in the single-ventricle population is emphasized given the recognition that complications post-Fontan palliation are not limited to the cardiovascular system but will often include extracardiac manifestations of disease (such as hepatic disease or lymphatic abnormalities), While the value of CMR and CCT for contemporary clinical care of individuals born with single-ventricle physiology appears to be well-established, further research will be necessary to explore the impact of risk stratification using imaging biomarkers on clinical outcomes following Fontan palliation.     

Canadian Society for Cardiovascular Magnetic Resonance (CanSCMR) Recommendations for Cardiovascular Magnetic Resonance Image Analysis and Reporting

Cardiovascular magnetic resonance (CMR) imaging is a rapidly developing technology that is becoming increasingly important in the diagnostic assessment of heart disease. Recognizing the need for recommendations to optimize the use of this technique, the Canadian Society for Cardiovascular Magnetic Resonance developed a task force to generate recommendations on the clinical use of parameters acquired by CMR imaging and how they should be reported. This article is the consensus report generated by the task force. The online material of this report provides such parameters for all relevant clinical settings, including pediatric and congenital applications. It considers the current clinical role of CMR, general requirements for CMR imaging, components of CMR studies, quantitative CMR image analysis, and appropriate contents of CMR reports. The recommendations are based on previously published recommendations on analysis and reporting and are the first of their kind. It is hoped that the use of these recommendations to guide daily clinical routine will help institutions offering CMR to adhere to high standards of quality according to the present state of the art.     

Cardiac MRI For Myocardial Ischemia

Proper assessment of the physiologic impact of coronary artery stenosis on the LV myocardium can affect patient prognosis and treatment decisions. Cardiac magnetic resonance imaging (CMR) assesses myocardial perfusion by imaging the myocardium during a first-pass transit of an intravenous gadolinium bolus, with spatial and temporal resolution substantially higher than nuclear myocardial perfusion imaging. Coupled with late gadolinium enhancement (LGE) imaging for infarction during the same imaging session, CMR with vasodilating stress perfusion imaging can qualitatively and quantitatively assess the myocardial extent of hypoperfusion from coronary stenosis independent of infarcted myocardium. This approach has been validated experimentally, and multiple clinical trials have established its diagnostic robustness when compared to stress single-photon emission computed tomography. In specialized centers, dobutamine stress CMR has been shown to have incremental diagnostic value above stress echocardiography due to its high imaging quality and ability to image the heart with no restriction of imaging window. This paper reviews the technical aspects, diagnostic utility, prognostic values, challenges to clinical adaptation, and future developments of stress CMR imaging.     

Cardiovascular magnetic resonance imaging in myocarditis

Cardiovascular magnetic resonance imaging (CMR) has become the leading modality in noninvasive imaging of myocarditis. Consensus on the use of 3 CMR criteria for myocarditis, referred to as edema, early, and late enhancement, has standardized CMR protocol for assessing myocarditis. Although definite diagnosis of myocarditis remains challenging, the outcome of this disease necessitates further investigation with the objective of providing robust noninvasive tests. Moreover, relative to current tools such as endomyocardial biopsy, CMR is a promising technique in the setting of this insidious and complex disease.     

Future prospects in cardiac magnetic resonance imaging

To appreciate the impact that key developments will have on the future of cardiovascular magnetic resonance (CMR) imaging, it is instructive to consider its present status. CMR has passed the threshold of being used primarily by innovators, and is now in the early adopter stage. To reach this threshold has taken many years, but its adoption by early majority users is expected to accelerate the growth of CMR. A number of factors govern its natural growth potential, including physician education and credentialing, scanner availability, technology, and reimbursement policies. The intrinsic dimensional accuracy of CMR, coupled with its high level of reproducibility, make it ideal for inclusion in trials, potentially with dramatic reductions in trial duration and the number of subjects required. Clinically, there are a number of applications for which CMR is widely regarded as being the diagnostic test of choice. Software and hardware developments that speed up the basic CMR procedure are being incorporated into scanners, extending the functionality of routine applications such as flow imaging and tag visualization. Exciting areas that are close to routine application include coronary artery imaging, and evaluation of myocardial perfusion and viability status.     

Training cardiovascular fellows in cardiovascular magnetic resonance and vascular imaging; Current status following the core cardiovascular training symposium (COCATS-2) guidelines

OBJECTIVES: This survey study sought to characterize the current training environment in cardiovascular magnetic resonance (CMR) and vascular imaging and to quantify the magnitude of any gaps between current training practice and the recommendations of the Core Cardiovascular Training Symposium (COCATS-2) guidelines. BACKGROUND: The COCATS-2 guidelines published in 2002 newly included specific educational components of CMR and vascular imaging. An understanding of the current capabilities of training programs to meet these guidelines could produce efforts to improve training opportunities. METHODS: We surveyed all accredited adult cardiovascular training programs by using a 21-question, multiple-response survey. Data were collected on center and program characteristics, clinical activities, control of clinical activities, and needs and attitudes. Parallel data were collected for nuclear cardiology capabilities as a "base case." RESULTS: Only 13% of training programs reported "ownership" of CMR equipment, compared with 48% for nuclear equipment (p = 0.001). Dedicated fellow rotations in nuclear imaging are nearly universally present, whereas vascular (64%) and CMR imaging (29%) lag behind. A majority of programs do not use formal educational curricula for CMR and vascular imaging. Among centers with CMR training capabilities, the breadth of training opportunities is typically very limited, with most having only aortic imaging as their sole capability, except in predominately large training centers. The greatest need expressed by programs was educational assistance in the form of written and lecture curriculum materials. CONCLUSIONS: A substantial gap exists between the current training environment in CMR and vascular imaging and the recommendations of COCATS-2. Sharing training opportunities between centers is encouraged, particularly for smaller training programs, in order to capitalize on limited equipment, personnel, and curriculum resources.     

Comparison of left and right atrial volume by echocardiography versus cardiac magnetic resonance imaging using the area-length method

Increased atrial volumes predict adverse cardiovascular events. Accordingly, accurate measurement of atrial size has become increasingly important in clinical practice. The area-length method is commonly used to estimate the volume. Disagreements between atrial volumes using echocardiography and other imaging modalities have been found. It is unclear whether this has resulted from differences in the measurement method or discrepancies among imaging modalities. We compared the right atrial (RA) and left atrial (LA) volume estimates using the area-length method for transthoracic echocardiography and cardiovascular magnetic resonance (CMR) imaging. Patients undergoing echocardiography and CMR imaging within 1 month were identified retrospectively. For both modalities, the RA and LA long-axis dimension and area were measured using standard 2- and 4-chamber views, and the volume was calculated using the area-length method for both atria. The echocardiographic and CMR values were compared using the Bland-Altman method. A total of 85 patients and 18 controls were included in the present study. The atrial volumes estimated using the area-length method were significantly smaller when measured using echocardiography than when measured using CMR imaging (LA volume 35 ± 20 vs 49 ± 30 ml/m2, p <0.001, and RA volume 32 ± 23 vs 43 ± 29 ml/m2, p = 0.012). The mean difference (CMR imaging minus echocardiography) was 14 ± 14 ml/m2 for the LA and 10 ± 16 ml/m2 for the RA volume. Similar results were found in the healthy controls. No significant intra- or interobserver variability was found within each modality. In conclusion, echocardiography consistently underestimated the atrial volumes compared to CMR imaging using the area-length method.     

Use of Cardiac Magnetic Resonance Imaging in Assessing Mitral Regurgitation: Current Evidence

Accurate quantification of regurgitant volume is a central component to the management of mitral regurgitation. Cardiac magnetic resonance imaging (CMR) accurately quantifies mitral regurgitation as the difference between left ventricular stroke volume and forward stroke volume using steady state free precession and phase contrast imaging. The CMR measurement of mitral regurgitant volume is reproducible and can quantify mitral regurgitation in patients without regard to regurgitant jet morphology, such as patients with multiple and eccentric jets. It can be used to quantify regurgitant volume in patients with multiple valve lesions and concomitant intracardiac shunts without the use of intravenous contrast. Studies have highlighted the accuracy and reproducibility of CMR in quantifying mitral regurgitation and have begun to link CMR to clinical outcomes.