Gated magnetic resonance imaging for assessment of cardiac function and myocardial infarction

Gated magnetic resonance imaging (MRI) is a promising noninvasive imaging modality capable of evaluating cardiac function and blood flow in the great vessels. MRI detects acute and chronic myocardial infarctions in experimental animals and in man.     

Gated cardiac magnetic resonance structural imaging: optimization by electronic axial rotation

Most magnetic resonance imaging has used body orthogonal axes with the Z axis placed along the length of the body and the X and Y axes at right angles to the body. This orientation is not optimum for the heart; visualization of sections along the short and long cardiac axes would best define cardiac structural detail and functional status. The new orientation was accomplished by selection of electronic angulation of the magnetic fields for each subject rather than by attempting to approximate the cardiac axes by altering the position of the patient. This technique improved visualization of comparative wall segments, valvular structures, and the true four-chamber view of the heart, and also gave the best visualization of the pericardium. In addition, more accurate estimates of chamber size and myocardial mass can be made from the short-axis orientation, since the sections are orthogonal to the myocardium.     

Gated magnetic resonance imaging of the normal and diseased heart

Gated cardiac magnetic resonance (MR) images were obtained in two normal volunteers and 21 adults with a variety of cardiovascular abnormalities. The images were correlated with data from clinical examinations, electrocardiograms, and cardiac catheterization. Gated cardiac images were superior to nongated images. Combined cardiac and respiratory gated images were superior to images obtained with cardiac gating only, but acquisition time was longer. Portions of the coronary arteries were visualized in seven of 23 examinations (30%), and subacute and old myocardial infarcts were seen in five of nine patients (55%) as areas of thinned myocardium. No signal changes were observed in the patients with subacute infarctions or the patient with myocarditis. Coronary atherosclerotic lesions were not visualized in any of the patients. Normal cardiac anatomy (chambers, valves, and papillary muscles) was well visualized. Examples of aortic stenosis and atherosclerosis of the abdominal aorta are shown.     

Gated magnetic resonance imaging of metastatic intracardiac malignant fibrous histiocytoma

We report a patient with right intraventricular metastatic sarcoma who underwent gated magnetic resonance (MR) imaging. The study provided good images of the tumor, though definition was degraded by signal from slow flowing blood. The demonstration of cardiac anatomy was excellent, and this was helpful in planning subsequent radiotherapy. We conclude that gated MR imaging is a valuable supplement to two-dimensional echocardiography in the diagnosis and management of cardiac metastases. This case also illustrates that extensive intracardiac disease can be present in the absence of marked clinical symptoms.     

脊髓血管畸形病变磁共振成像技术分析

目的 探讨脊髓血管畸形(SVM)病变的磁共振成像技术方法及临床应用价值.方法 回顾分析16例椎管内SVM患者资料,并由DSA检查证实.使用GE Signa 1.5T EXCITE HD磁共振机,GE ADW4.3工作站进行图像后处理,磁共振脉冲序列:矢状面T1WI、T2WI,轴位T2WI及斜冠状面CE-MRA.扫描完后将数据传至工作站,进行图像后处理,观察椎管内SVM的磁共振影像学特征.结果 16例椎管内SVM中,椎管内血管流空现象是椎管内SVM特征性MRI表现,CE-MRA常显示为蚯蚓样或杂乱无章高信号影.结论 MR对诊断椎管内SVM病变安全可靠,可作为首选筛查方法.     

Gated blood-pool SPECT versus cardiac magnetic resonance imaging for the assessment of left ventricular volumes and ejection fraction

Background  

We evaluated the accuracy of planar radionuclide angiography and different count-based and space-based electrocardiogram (ECG)-gated blood-pool single-photon emission computed tomography (GBPS) algorithms for assessment of left ventricular end-diastolic volume (LVEDV), end-systolic volume (LVESV), and ejection fraction (LVEF) compared with the gold standard of cardiac magnetic resonance imaging (cMRI). The goal is to assess the accuracy of a recently developed GBPS algorithm.     

Three-dimensional magnetic resonance imaging of congenital heart disease

Three-dimensional surface reconstruction images of the heart and great vessels have been produced from contiguous sequences of EKG-triggered MRI scans in more than 35 patients with congenital heart disease and 5 normal subjects. The scan data was semiautomatically processed to separate the epi- and endocardial surfaces and to define the outlines of the enclosed blood volumes on a slice by slice basis. Surface reconstruction images aid communication with clinicians, establish the size and location of intracardiac defects, and image the pulmonary venous drainage. The method is practical for use in the evaluation of cardiac morphologic abnormalities, especially for planning cardiac surgery.     

Myocardial perfusion imaging by cardiac magnetic resonance

Cardiovascular magnetic resonance (CMR) has been shown to provide high quality data on cardiac and valvular function, perfusion, viability, blood flow, and potentially, on cardiac metabolism as well. Several of these CMR applications (eg, function and viability assessment) matured during the past years and are now established components of a cardiac workup. Perfusion-CMR is close to this status and is already a major contributor to cardiac examinations in a growing number of expert centers. Large multicenter perfusion-CMR trials comparing the diagnostic performance of CMR with other techniques were recently reported yielding areas under the receiver-operator-characteristics curve as a high as 0.85 for coronary artery disease detection (MR-IMPACT). Anticipating a growing role for perfusion-CMR in cardiology in the near future, this article discusses the principles of perfusion-CMR and its integration into the workup of patient with coronary artery disease (CAD). In addition to a functional study, this integration is mainly composed of a perfusion-CMR part, followed by a viability assessment by late enhancement CMR techniques. The principal characteristics of these CMR techniques are compared with those of single photon emission computed tomography (SPECT) and positron emission tomography (PET). After introduction into principles and techniques of perfusion-CMR, some open questions in perfusion-CMR and challenges for the future are addressed. Finally, newer CMR applications are shortly mentioned utilizing hyperpolarized carbon-13 compounds in experimental models for quantification of myocardial perfusion and for real-time assessment of metabolic pathways in postischemic myocardium. (J Nucl Cardiol 2006;13: 841-54.)     

Evaluation of cardiac tumors with magnetic resonance imaging

Primary cardiac neoplasms are rare, and are more commonly benign than malignant. However, metastases are by far the most common cardiac neoplasms. MRI allows evaluation of myocardial infiltration, pericardial involvement and/or extracardiac extension. MRI overcomes the usual limitations of echocardiography and assesses more accurately changes in cardiac function. Specific tumoral characterization is only possible in cases of myxoma, lipoma, fibroma and hemangioma. Suggestive features of malignancy are right side location, extracardiac extension, inhomogeneity in signal intensity of the tumor and pericardial effusion. The use of intravenous contrast material improves tumor characterization and depiction of tumor borders. MRI also allows differentiation of tumor from other nontumoral masses such as intracavitary tumors or fibromuscular elements of the posterior wall of the right atrium.     

Evaluation of congenital heart disease by magnetic resonance imaging

Magnetic resonance imaging has proven to be useful in the assessment of patients with complex congenital heart disease and in the post-surgical follow-up of patients with corrected congenital heart disease. A thorough understanding of the congenital cardiac malformations that can be encountered is needed and the use of the sequential segmental analysis helps to standardize the evaluation and diagnosis of (complex) congenital heart disease. After surgical correction of congenital heart defects, patients must be followed over extended periods of time, because morphological and functional abnormalities may still be present or may develop. The use of echocardiography may be hampered in these patients as scar tissue and thorax deformities limit the acoustic window. Magnetic resonance imaging has proven to be advantageous in the follow-up of these post-surgical patients and with the use of several different techniques the morphological as well as functional abnormalities can be evaluated and followed over time.     

Right heart dilatation in adult congenital heart disease: imaging appearance on cardiac magnetic resonance

Imaging morphology and function of the right heart is of paramount importance in patients with adult congenital heart disease, since right ventricular dysfunction is associated with adverse cardiac events. Cardiac MRI has been shown to be a powerful tool for the non-invasive precise assessment of right ventricular and valvular dysfunction. Differential diagnoses of congenital heart disease characterised by, or combined with, right heart dilatation are diverse and necessitate a systematic approach.     

Advanced cardiac magnetic resonance imaging in takotsubo cardiomyopathy

Takotsubo cardiomyopathy (TC) is a reversible condition in which there is transient left ventricular (LV) dysfunction characterised most commonly by basal hyperkinesis and mid-apical LV ballooning and hypokinesia. It is said to be triggered by stress and mimics, such as acute coronary syndrome (ACS) clinically. Diagnosis is usually suspected on echocardiography due to the characteristic contraction pattern in a patient with symptoms and signs of ACS but normal coronary arteries on catheter angiography. Cardiac magnetic resonance (CMR), with its latest advancements, is the diagnostic modality of choice for diagnosis, prognosis and follow-up of patients. The advances in CMR (including T1, T2, ECV mapping and threshold-based late gadolinium enhancement (LGE) measurements have revolutionised the role of CMR in tissue characterisation and prognostication in patients with TC. In this review, we highlight the current role of CMR in management of TC and enumerate the CMR findings in TC as well the current advances in the field of CMR, which could help in prognosticating these patients.     

Extracardiac findings detected by cardiac magnetic resonance imaging

Objective

To determine the prevalence and importance of extracardiac findings (ECF) in patients undergoing clinical CMR and to test the hypothesis that the original CMR reading focusing on the heart may underestimate extracardiac abnormalities.

Methods

401 consecutive patients (mean age 53?years) underwent CMR at 1.5?T. Main indications were ischaemic heart disease (n?=?183) and cardiomyopathy (n?=?164). All CMR sequences, including scout images, were reviewed with specific attention to ECF in a second reading by the same radiologist who performed the first clinical reading. Potentially significant findings were defined as abnormalities requiring additional clinical or radiological follow-up.

Results

250 incidental ECF were detected, of which 84 (34%) had potentially significant ECF including bronchial carcinoma (n?=?1), lung consolidation (n?=?7) and abdominal abnormalities. In 166 CMR studies (41%) non-significant ECF were detected. The number of ECF identified at second versus first reading was higher for significant (84 vs. 47) and non-significant (166 vs. 36) findings (P?Conclusions About one fifth of patients undergoing CMR were found to have potentially significant ECF requiring additional work-up. The second dedicated reading detected significantly more ECF compared with the first clinical reading emphasising the importance of active search for extracardiac abnormalities when evaluating CMR studies.

Key Points

? Many patients undergoing cardiac MR have significant extracardiac findings (ECF) ? These impact on management and require additional work-up. ? Wide review of scout and cine sequences will detect most ECFs. ? Education of radiologists is important to identify ECFs on CMR studies.     

Characterisation of peripartum cardiomyopathy by cardiac magnetic resonance imaging

Peripartum cardiomyopathy (PPCM) is a rare cause of heart failure. Only half of the patients recover normal cardiac function. We assessed the usefulness of magnetic resonance imaging (MRI) and late enhancement imaging to detect myocardial fibrosis in order to predict cardiac function recovery in patients with peripartum cardiomyopathy. Among a consecutive series of 1,037 patients referred for heart failure treatment or prognostic evaluation between 1999 and 2006, eight women had confirmed PPCM. They all underwent echocardiography and cardiac MRI for assessment of left ventricular anatomy, systolic function and detection of myocardial fibrosis through late enhancement imaging. Mean (± SD) baseline left ventricular ejection fraction (LVEF) was 28 ± 4%. After a follow-up of 50 ± 9 months, half the patients recovered normal cardiac function (LVEF = 58 ± 4%) and four did not (LVEF = 35 ± 6%). None of the eight patients exhibited abnormal myocardial late enhancement. No difference in MRI characteristics was observed between the two groups. Patients with PPCM do not exhibit a specific cardiac MRI pattern and particularly no myocardial late enhancement. It suggests that myocardial fibrosis does not play a major role in the limitation of cardiac function recovery after PPCM. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Cardiac magnetic resonance imaging of congenital heart defects in adults

The study of congenital cardiopathies (CC) is one of the most clearly established indications of cardiac magnetic resonance imaging (CMRI). Different sequences, including anatomic, functional, flow (phase contrast), and 3D angiographic sequences, enable the diagnosis, treatment planning, and follow-up of these conditions. CMRI allows the anatomy, function, and alterations of flow in these cardiopathies to be evaluated in a single examination. Three-dimensional MR angiography enables the study of the great vessels and the anomalies associated to congenital heart defects in adults. This article describes an examination protocol and provides examples of MR images of the most common CC in adults: atrial septal defect, interventricular communication, atrioventricular canal, tetralogy of Fallot, transposition of the great arteries, congenitally corrected transposition of the great arteries, bicuspid aortic valve, subaortic stenosis, aortic coarctation, and Ebstein's anomaly.     

儿童心脏良性肿瘤的CMR影像特征分析

目的 研究儿童心脏良性肿瘤的心脏MR（CMR）特征及其对儿童良性肿瘤的诊断价值。方法 回顾性收集2006年9月-2018年3月于我院进行CMR检查的心脏肿瘤病例资料,共38例心脏良性肿瘤患儿纳入研究,其中男21例,女17例,年龄0.2~153.3个月,中位年龄13个月。分析各病理类型肿瘤在CMR上的特征,包括累及部位、大小、信号特点、血流动力学改变等,以及是否伴发心包和胸腔积液。通过与病理结果对照,计算CMR对心脏良性肿瘤诊断的敏感度和准确度。结果 肿瘤累及心肌、心腔、心包、心室流出道及纵隔,形态大小不一,临床症状与肿瘤发生部位有一定相关性而不具有特异性,但各类肿瘤具有一定的影像特征。所有的心脏肿瘤均被CMR清晰显示,CMR的诊断与病理结果相符的有32例,诊断的敏感度及准确度分别为100%（38/38）和84.21%（32/38）。结论 CMR能够同时提供心脏良性肿瘤的形态学特征及组织学信号特征,对心脏良性肿瘤诊断的敏感性及准确性均较高,是评估心脏肿瘤的重要检查方法。     

Giant cell myocarditis depicted by cardiac magnetic resonance imaging

Giant cell myocarditis is a rare condition, the cardiac magnetic resonance imaging findings of which have not been previously described. The disease usually occurs in young previously healthy people and is typified by rapidly progressive cardiac dysfunction, often requiring cardiac transplantation. A case of giant cell myocarditis is presented, with associated pathologic and imaging findings.     

Why cardiac magnetic resonance imaging will not make it

Coronary artery disease is currently the largest killer in the western world, and is estimated to become the leading cause of death worldwide by the year 2020. The question therefore is whether magnetic resonance imaging currently has a place in the already extremely well equipped armamentarium of cardiac testing. Although it is promising, its clinical use is somewhat limited by high cost and low availability of equipment and trained personnel. The absence of portable systems for cardiac application make cardiac magnetic resonance imaging in the emergency room, at the patient's bedside or in the doctor's office impossible. The comparison of the cardiac magnetic resonance imaging with proven and cost-effective techniques like echocardiography and nuclear imaging will be decisive in terms of the choice of imaging modalities in cardiology.