心脏磁共振在低危急性冠状动脉综合征中的诊断价值

目的 探讨心脏磁共振(CMR)负荷心肌灌注显像在低危急性冠状动脉综合征(ACS)中的早期诊断价值.方法 前瞻性入选22例怀疑或确诊低危ACS患者,均行CMR与单光子发射计算机断层(SPECT)负荷心肌灌注显像及冠状动脉造影(CAG).以CAG作为参考标准,分析CMR诊断效能,并与SPECT结果作对比.结果 以患者为基础分析,CMR诊断ACS敏感性和特异性分别为93%,75%;SPECT相应值分别为79%,63%.CMR诊断效能为0.897, 略高于SPECT 0.723 (P=0.19).以血管为基础分析,CMR诊断ACS敏感性和特异性分别为89%,87%;SPECT相应值分别为68%, 83%.CMR诊断效能0.923, 高于SPECT 0.774 (P<0.05).在左前降支(LAD)供血区,CMR诊断效能明显高于SPECT(0.900,0.553,P=0.009 6).结论 CMR负荷心肌灌注显像能准确探测低危ACS患者心肌缺血,诊断效能好于SPECT负荷心肌灌注显像.     

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。     

Advances in Myocardial Perfusion MR Imaging: Physiological Implications,the Importance of Quantitative Analysis,and Impact on Patient Care in Coronary Artery Disease

Stress myocardial perfusion imaging (MPI) is the preferred test in patients with intermediate-to-high clinical likelihood of coronary artery disease (CAD) and can be used as a gatekeeper to avoid unnecessary revascularization. Cardiac magnetic resonance (CMR) has a number of favorable characteristics, including: (1) high spatial resolution that can delineate subendocardial ischemia; (2) comprehensive assessment of morphology, global and regional cardiac functions, tissue characterization, and coronary artery stenosis; and (3) no radiation exposure to patients. According to meta-analysis studies, the diagnostic accuracy of perfusion CMR is comparable to positron emission tomography (PET) and perfusion CT, and is better than single-photon emission CT (SPECT) when fractional flow reserve (FFR) is used as a reference standard. In addition, stress CMR has an excellent prognostic value. One meta-analysis study demonstrated the annual event rate of cardiovascular death or non-fatal myocardial infarction was 4.9% and 0.8%, respectively, in patients with positive and negative stress CMR. Quantitative assessment of perfusion CMR not only allows the objective evaluation of regional ischemia but also provides insights into the pathophysiology of microvascular disease and diffuse subclinical atherosclerosis. For accurate quantification of myocardial perfusion, saturation correction of arterial input function is important. There are two major approaches for saturation correction, one is a dual-bolus method and the other is a dual-sequence method. Absolute quantitative mapping with myocardial perfusion CMR has good accuracy in detecting coronary microvascular dysfunction. Flow measurement in the coronary sinus (CS) with phase contrast cine CMR is an alternative approach to quantify global coronary flow reserve (CFR). The measurement of global CFR by quantitative analysis of perfusion CMR or flow measurement in the CS permits assessment of microvascular disease and diffuse subclinical atherosclerosis, which may provide improved prediction of future event risk in patients with suspected or known CAD. Multi-institutional studies to validate the diagnostic and prognostic values of quantitative perfusion CMR approaches are required.     

Imaging hypertrophic heart diseases with cardiovascular MR

The assessment of ventricular hypertrophy is an increasingly common indication for cardiac MR (CMR) in every day clinical practice. CMR is useful to confirm the presence of hypertrophy and to help to define the underlying cause through a combination of a detailed assessment of ventricular function and tissue characterising sequences. As well as being a useful diagnostic tool, some CMR imaging features are of prognostic significance. In this article, we review the typical appearances of common forms of ventricular hypertrophy, focussing principally on left ventricular hypertrophy, and demonstrate the techniques that can be used to differentiate one form of hypertrophy from another.     

Diagnostic performance of combined cardiac MRI for detection of coronary artery disease

Objective

To evaluate the diagnostic performance of stress perfusion cardiac MR (CMR) for detecting significant CAD (≥70% narrowing) in comparison with invasive coronary angiography (ICA) as a reference standard.

Methods

Examinations of 54 patients who underwent both stress perfusion CMR and ICA for investigation of CAD between 2007 and 2009 were evaluated. The CMR protocol included dipyridamole stress and rest perfusion, stress and rest cine MRI for assessment of ventricular function and delayed gadolinium enhancement for assessment of myocardial viability and detection of infarction. CMR interpretation was performed by 2 observers blinded to the results of ICA and the clinical history.

Results

From a total of 54 patients, 37 (68.5%) showed significant CAD in 71 coronary territories. A perfusion defect was detected in 35 patients and in 69 coronary territories. Individual stress perfusion CMR evaluation showed the highest accuracy (83%) of the CMR techniques. The combined analysis using all sequences increased the overall accuracy of CMR to 87%.

Conclusion

Combination of perfusion and cine-MR during stress/rest, associated to delayed enhancement in the same protocol improves CMRI diagnostic accuracy and sensitivity for patients with significant coronary stenosis, and may therefore be helpful for risk stratification and defining treatment strategies.     

Cardiac magnetic resonance imaging in dilated cardiomyopathy in adults��towards identification of myocardial inflammation

Objective

To assess active myocardial inflammation by cardiovascular magnetic resonance (CMR) and endomyocardial biopsy (EMB) amongst adult patients with dilated cardiomyopathy (DCM).

Methods

We evaluated 23 adults with chronic DCM, who had successfully undergone both CMR and EMB within 3.5?±?2.6?days. EMB was considered the gold standard. CMR assessment of myocardial inflammation used the following parameters as recommended by the recently published ??Lake Louise Criteria??: global myocardial oedema, global relative enhancement (RE), and late gadolinium enhancement (LGE). According to ??Lake Louise Criteria??, myocardial inflammation was diagnosed if two or more of the three above-mentioned parameters were positive.

Results

Myocardial inflammation was confirmed by immunohistology in 12 patients (52.2%). Sensitivity, specificity, and diagnostic accuracy of CMR to detect immunohistologically confirmed myocardial inflammation were 75.0%, 72.7%, and 73.9%, respectively. Sensitivity, specificity, and diagnostic accuracy of the individual CMR parameters to detect myocardial inflammation were as follows: global myocardial oedema, 91.7%, 81.8%, and 87.0%, respectively; global RE, 58.3%, 63.6%, and 60.9%, respectively; LGE, 58.3%, 45.4%, and 52.2%, respectively.

Conclusion

Global myocardial oedema was identified as a promising CMR parameter for assessment of myocardial inflammation in patients with DCM. In these patients, global myocardial oedema yielded superior diagnostic performance compared to ??Lake Louise Criteria??.     

Evaluation of pectus excavatum indexes during standard cardiac magnetic resonance: Potential for single preoperative tool

PurposePreoperative assessment of patients with pectus excavatum (PE) demands evaluation of malformation indexes, generally with chest computed tomography (CT). In addition, assessment of the cardiac impact of sternal depression has become a rule in high referral centers, thus requiring two independent imaging modalities and use ionizing radiation in a very young population. The objective of this study was to explore the agreement between chest CT and standard cardiac MR (CMR) for the evaluation of chest wall malformation indexes.MethodsWe included consecutive patients with PE referred to undergo chest CT and CMR to establish surgical candidacy and/or to define treatment strategies. Both CT and CMR were performed at full-expiration. In both modalities, the Haller index (HI) and the Correction index (CI) were calculated by two independent observers. In CMR, only scout images were used. Agreement was evaluated using intra-class correlation coefficients (ICC).ResultsFifty patients comprised the study population (median age 19.0 years) and underwent chest CT and CMR within the same month. CMR assessment of chest malformation indexes was reproducible, with a very good inter-observer agreement for HI [ICC 0.93 (0.88–0.96), p < 0.0001] and CI [ICC 0.91 (0.83–0.95), p < 0.0001]. CMR also had a very good agreement with chest CT for HI [ICC 0.90 (0.82–0.94), p < 0.0001] and CI measurements [ICC 0.93 (95% CI 0.88–0.96), p < 0.0001].ConclusionsWe demonstrated an excellent agreement between chest CT and standard CMR for the assessment of chest wall malformations, thus potentially enabling preoperative assessment of PE severity and cardiac involvement with a single diagnostic tool.     

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.)     

心脏磁共振评估肺动脉高压的研究进展

肺动脉高压（PH）是一组恶性进展性疾病,可以导致右心衰竭甚至死亡,因此对其进行早期诊断和评估至关重要。心脏磁共振（CMR）作为评估心血管的“一站式”检查,不仅可以采用多参数对PH病人心脏结构、功能、血流动力学及心肌组织特征等进行评价,还可以鉴别不同类型的PH,在PH的诊疗评估中发挥着重要作用,特别是基于CMR的人工智能的应用更是成为PH临床实践的新方向。     

Diagnosis of coronary artery disease with dobutamine-stress MRI

Dobutamine-stress cardiovascular magnetic resonance (CMR) is a new diagnostic tool for the non-invasive detection of coronary artery disease. Technological advances in CMR have evolved this technique to an adequate alternative to the standard cardiac stress tests. Its high reproducibility and excellent image quality of the anatomical features of the left ventricle and left ventricular function at rest and during stress make it an ideal technique for the comprehensive evaluation of patients with suspected coronary artery disease. Besides its ability to detect myocardial ischemia, CMR has proved to be diagnostic for myocardial viability as well. A recent technical refinement in CMR using myocardial tagging has improved the diagnostic accuracy for myocardial ischemia even further. Dobutamine-stress CMR is used to identify wall motion abnormalities of the left ventricle in patients with proven or suspected coronary artery disease [1-4]. Dobutamine-stress CMR has emerged as a highly accurate and safe diagnostic modality [1-4]. Recently, the use of high-dose dobutamine CMR in combination with the myocardial tagging technique has been reported, with excellent diagnostic results. The use of this new technique and the clinical applications are discussed.     

Quantitative myocardial perfusion imaging by cardiovascular magnetic resonance and positron emission tomography

Recent studies have demonstrated that a detailed knowledge of the extent of angiographic coronary artery disease (CAD) is not a prerequisite for clinical decision making, and the clinical management of patients with CAD is more and more focused towards the identification of myocardial ischemia and the quantification of ischemic burden. In this view, non-invasive assessment of ischemia and in particular stress imaging techniques are emerging as preferred and non-invasive options. A quantitative assessment of regional myocardial perfusion can provide an objective estimate of the severity of myocardial injury and may help clinicians to discriminate regions of the heart that are at increased risk for myocardial infarction. Positron emission tomography (PET) has established itself as the reference standard for myocardial blood flow (MBF) and myocardial perfusion reserve (MPR) quantification. Cardiac magnetic resonance (CMR) is increasingly used to measure MBF and MPR by means of first-pass signals, with a well-defined diagnostic performance and prognostic value. The aim of this article is to review the currently available evidence on the use of both PET and CMR for quantification of MPR, with particular attention to the studies that directly compared these two diagnostic methods.     

Diagnostic work up of arrhythmogenic right ventricular cardiomyopathy by cardiovascular magnetic resonance (CMR). Consensus statement

Cardiovascular Magnetic Resonance (CMR) has become a widespread diagnostic tool. Since its introduction CMR has been used to image patients with known or suspected arrhythmogenic right ventricular cardiomyopathy (ARVC). Several abnormalities have been found and described by CMR and at present this diagnostic tool is considered very important for the diagnosis. However, the diagnosis of ARVC relies upon the fulfillment of both clinical and functional criteria and CMR can provide several but not all the information useful for the diagnosis. Furthermore, some findings such as evidence of right ventricular epicardial fat once considered a peculiar marker of ARVC, have been shown to possess a low specificity. This document was prepared by representatives of the three Italian official Organizations involved in CMR. Its main scope is to highlight the problems encountered when studying patients with suspected ARVC by CMR, to indicate the basic technical equipment needed, to recommend a proper imaging protocol and to offer a consensus on the main diagnostic features relevant for the diagnosis.     

Left ventricular function studied with MDCT

Accurate determination of left ventricular (LV) myocardial function is fundamental for clinical diagnosis, risk stratification, and estimation of prognosis in patients with ischemic and nonischemic cardiomyopathy. Primarily, multi-detector-row spiral CT (MDCT) of the heart aimed at detecting coronary artery obstruction and cardiac morphology. Multiple studies have demonstrated that retrospectively, ECG-gated MDCT determination of LV volumes and consequently global LV function parameters is feasible in good agreement with established imaging modalities such as cineventriculography, echocardiography, and cine magnetic resonance imaging (CMR). Post-processing tools allow fast and semi-automatic determination of LV function parameters from MDCT data in analogy to known CMR evaluation approaches. Although MDCT is not considered to be first-line modality for LV function assessment, this technique provides accessory dynamic information in patients undergoing MDCT coronary angiography, contributing to combined assessment of cardiac morphology and function without need of additional radiation exposure. MDCT regional LV wall motion analysis at rest is feasible, but further improvement in temporal resolution seems mandatory to match results obtained from competing modalities. This paper will discuss the diagnostic potential of MDCT for assessment of LV function with regards to accuracy and clinical applications, as well as limitations, particularly in comparison with CMR as modality of reference.     

Role of cardiac MRI in assessment of patients with dilated cardiomyopathy

Purpose

To study additive role of CMR to echocardiography in assessment of dilated cardiomyopathy and if LGE-CMR myocardial enhancement pattern can differentiate between ischemic and non-ischemic dilated cardiomyopathy compared to coronary catheterization as a reference standard.

Multimodality imaging of left atrium in patients with atrial fibrillation

Atrial fibrillation (AF) is the most common arrhythmia worldwide associated with significant morbidity and mortality and represents a significant health care burden. Goals of AF treatment include prevention of cardioembolic stroke using anticoagulation and device therapy and restoration of sinus rhythm using antiarrhythmic drugs or catheter ablation techniques. A comprehensive assessment of cardiac chamber size and function is often started with echocardiography as a first line diagnostic imaging strategy. Recently, innovations in advanced imaging using cardiac magnetic resonance (CMR) and cardiac computed tomography (CCT) provide a detailed characterization of atrial anatomy and have been shown to accurately exclude thrombus and guide left atrial appendage (LAA) closure or catheter ablation (CA) of atrial fibrillation. Compared to echocardiography, CCT offers an uncompromised spatial resolution and a fast dataset acquisition, with the disadvantages of the need of iodine contrast agent and radiation exposure. CMR, conversely, can rely on very high temporal resolution, the unique feature of tissue characterization and the absence of radiation exposure. However, the main drawbacks of this diagnostic tool are long scan times and low availability. This review will illustrate the vital role of multimodality cardiac imaging in the accurate identification of left atrial, pulmonary vein and LAA size and function, discuss advanced imaging techniques to rule out thrombus and highlight novel CMR and CCT techniques to guide catheter ablation of AF and LAA occlusion.     

Assessment of global and regional left ventricular function using 64-slice multislice computed tomography and 2D echocardiography: a comparison with cardiac magnetic resonance

OBJECTIVES: To compare the assessment of global and regional left ventricular (LV) function using 64-slice multislice computed tomography (MSCT), 2D echocardiography (2DE) and cardiac magnetic resonance (CMR). METHODS: Thirty-two consecutive patients (mean age, 56.5+/-9.7 years) referred for evaluation of coronary artery using 64-slice MSCT also underwent 2DE and CMR within 48h. The global left ventricular function which include left ventricular ejection fraction (LVEF), left ventricular end diastolic volume (LVdV) and left ventricular end systolic volume (LVsV) were determine using the three modalities. Regional wall motion (RWM) was assessed visually in all three modalities. The CMR served as the gold standard for the comparison between 64-slice MSCT with CMR and 2DE with CMR. Statistical analysis included Pearson correlation coefficient, Bland-Altman plots and kappa-statistics. RESULTS: The 64-slice MSCT agreed well with CMR for assessment of LVEF (r=0.92; p<0.0001), LVdV (r=0.98; p<0.0001) and LVsV (r=0.98; p<0.0001). In comparison with 64-slice MSCT, 2DE showed moderate correlation with CMR for the assessment of LVEF (r=0.84; p<0.0001), LVdV (r=0.83; p<0.0001) and LVsV (r=0.80; p<0.0001). However in RWM analysis, 2DE showed better accuracy than 64-slice MSCT (94.3% versus 82.4%) and closer agreement (kappa=0.89 versus 0.63) with CMR. CONCLUSION: 64-Slice MSCT correlates strongly with CMR in global LV function however in regional LV function 2DE showed better agreement with CMR than 64-slice MSCT.     

Roles of nuclear cardiology, cardiac computed tomography, and cardiac magnetic resonance: assessment of patients with suspected coronary artery disease.

Noninvasive cardiac imaging is now central to the diagnosis and management of patients with known or suspected chronic coronary artery disease (CAD). Although rest echocardiography has become the most common of the techniques, nuclear cardiology and more recently cardiac computed tomography (CCT) and cardiac magnetic resonance (CMR) play important roles in this regard. This review examines the current applications and interactions of noninvasive cardiac imaging approaches for the assessment of patients with suspected CAD. In addition to considering the strengths and weaknesses of each technique, this review attempts to provide a guide to the selection of a test (or tests) that is based on the question being asked and the ability of each test to answer this question. In patients with suspected CAD, the pretest likelihood of disease, a clinical assessment, becomes the most important determinant of the initial test. If the likelihood is very low, no testing is needed. However, if the likelihood is low, recent data suggest that assessment of early atherosclerosis is likely to be the most useful and cost-effective test. In patients who have an intermediate likelihood of CAD, nuclear cardiology with myocardial perfusion SPECT (MPS) becomes highly valuable; however, coronary CT angiography (CTA), with fast 16-slice or greater scanners, may emerge as the initial test of choice. MPS would then be used if the CTA is inconclusive or if there is a need to assess the functional significance of a stenosis defined by CTA. Coronary CTA, however, is not yet widely available and is limited in patients with dense coronary calcification. In older patients with a high likelihood of CAD, MPS may be the initial test of choice, since a high proportion of these patients have too much coronary calcium to allow accurate assessment of the presence of coronary stenoses. PET/CT or SPECT/CT could emerge as important modalities combining the advantages of each modality. While CMR has great promise as a radiation-free and contrast-free "one-stop" shop, it currently lags behind CTA for noninvasive coronary angiography. Nonetheless, CMR clearly has the potential for this application and has already emerged as a highly effective method for assessing ventricular function, myocardial mass, and myocardial viability, and there is increasing use of this approach for clinical rest and stress perfusion measurements. CMR is particularly valuable in distinguishing ischemic from nonischemic cardiomyopathy. While CT and CMR are likely to grow considerably in diagnostic evaluation over the next several years, MPS and PET will continue to be very valuable techniques for this purpose.     

CMR在法洛四联症术后评估中的应用

心脏磁共振（CMR）是法洛四联症（TOF）术后评估的一站式影像诊断工具。随着四维血流CMR技术、CMR-特征追踪技术和纵向弛豫时间定量成像等新技术的发展和应用,CMR可以同时实现心肌运动、血流动力学及心肌组织定量评估,特别对于评价术后TOF（rTOF）早期的血流动力学改变,早期预判rTOF的功能异常,以及反映心肌纤维化与rTOF心律失常的关系是非常有价值的。就上述CMR新技术及其在TOF术后的应用进行综述。     

CMR assessment after a transapical-transcatheter aortic valve implantation

Aims

To describe the time course of myocardial scarring after transapical-transcatheter aortic valve implantation (TA-TAVI) with the Edwards SAPIEN XT™ and the Edwards SAPIEN™ prosthesis in a 3-month follow-up study using cardiac magnetic resonance imaging (CMR).

Methods

In 20 TA-TAVI patients, CMR was performed at discharge and 3 months (3M). Cine-MRI was used for left ventricular (LV) functional assessment, and late gadolinium enhancement (LGE) imaging was employed for detecting the presence of myocardial scarring. Special attention was given to any artifacts caused by the prosthesis, which were consequently defined using a three-grade artifact scale.

Results

We systematically reported the presence of small LGE hyperintensity relating to the apical segment, with no variation found between discharge and 3 M (2.8 ± 1.6 g vs. 2.35 ± 1.1 g). LV ejection fraction, end-diastolic, and end-systolic volumes did not significantly vary. A small area of apical akinesia was observed, with no improvement at follow-up. Whereas the Edwards SAPIEN XT™ prosthesis and the Edwards SAPIEN™ prosthesis are both constituted by metallic stenting structure, the Edwards SAPIEN™ was responsible for a larger signal void, thus potentially limiting the diagnostic performance of CMR.

Conclusions

CMR may be performed safely in the context of TA-TAVI. The presence of a very small apical infarction correlating with focal akinesia was observed. As expected, the Edwards SAPIEN XT™ prosthesis was shown to be particularly suitable for CMR assessment.     

Magnetic resonance imaging in valvular heart disease: clinical application and current role for patient management

Noninvasive imaging provides important information on cardiac anatomy and function and is a key element in clinical management of valvular heart disease (VHD). Beside echocardiography, which is still considered the first-line modality for assessment of valvular anatomy and longitudinal evaluation of VHD, cardiovascular magnetic resonance (CMR) has evolved during the last two decades as an essential tool for evaluation of cardiac diseases. Today, CMR not only represents the reference standard for measuring cardiac volumes, function, and mass, but also enables accurate assessment of morphology and function of cardiac valves. It can play an important role in clinical decision-making for patients with VHD. This review addresses current applications and limitations of CMR imaging techniques that are used in VHD including cine-balanced steady-state free precession (b-SSFP), phase contrast MR (pcMR), gradient-recalled echo (GRE), and turbo-spin echo (TSE) sequences. Moreover, it describes their application for evaluation of valvular pathologies and gives an overview on the current role of valvular CMR in patient management.