The role of cardiovascular magnetic resonance in the evaluation of patients with heart failure

Chronic heart failure is a common disorder placing significant burdens on patients and health-care services. Noninvasive imaging plays a central role in accurate diagnosis, determination of etiology and prognosis, and in monitoring therapy. Advances in technology mean cardiovascular magnetic resonance (CMR) imaging has established itself as both a valuable clinical and research tool in this arena. Not only is CMR the new gold standard for accurate and reproducible assessment of ventricular volumes and mass, but by using gadolinium contrast, underlying pathology can often be determined. In ischemic cardiomyopathy a 'one stop' assessment can be made of function, perfusion and mass. Continuing advances such as myocardial tagging and the increasing availability of CMR mean that it will become an increasingly important and useful tool for clinicians looking after patients with cardiomyopathy and heart failure.     

Prevalence of scarred and dysfunctional myocardium in patients with heart failure of ischaemic origin: A cardiovascular magnetic resonance study

Background

Cardiovascular magnetic resonance (CMR) with late gadolinium enhancement (LGE) can provide unique data on the transmural extent of scar/viability. We assessed the prevalence of dysfunctional myocardium, including partial thickness scar, which could contribute to left ventricular contractile dysfunction in patients with heart failure and ischaemic heart disease who denied angina symptoms.

Methods

We invited patients with ischaemic heart disease and a left ventricular ejection fraction < 50% by echocardiography to have LGE CMR. Myocardial contractility and transmural extent of scar were assessed using a 17-segment model.

Results

The median age of the 193 patients enrolled was 70 (interquartile range: 63-76) years and 167 (87%) were men. Of 3281 myocardial segments assessed, 1759 (54%) were dysfunctional, of which 581 (33%) showed no scar, 623 (35%) had scar affecting ≤50% of wall thickness and 555 (32%) had scar affecting > 50% of wall thickness. Of 1522 segments with normal contractile function, only 98 (6%) had evidence of scar on CMR. Overall, 182 (94%) patients had ≥1 and 107 (55%) patients had ≥5 segments with contractile dysfunction that had no scar or ≤50% transmural scar suggesting viability.

Conclusions

In this cohort of patients with left ventricular systolic dysfunction and ischaemic heart disease, about half of all segments had contractile dysfunction but only one third of these had > 50% of the wall thickness affected by scar, suggesting that most dysfunctional segments could improve in response to an appropriate intervention.     

心脏磁共振在扩张型心肌病危险分层及预后评估中的应用进展

扩张型心肌病(dilated cardiomyopathy,DCM)是一类以左心室扩张和左心室收缩功能障碍为主要特征的心脏病,可最终引起心力衰竭、心律失常和猝死,也是目前心脏移植的最主要病因.准确评估DCM患者心脏受累程度,对疾病进行危险分层,识别需密切随访及强化治疗的高危患者尤为重要.心脏磁共振(cardiovasc...     

心脏磁共振在肥厚型心肌病预后评估及危险分层中的应用进展

肥厚型心肌病(hypertrophic cardiomyopathy,HCM)是最常见的遗传性原发型心肌病,也是青年人猝死的最常见原因.心脏磁共振(cardiovascular magnetic resonance,CMR)多参数、多模态成像,能从多个方面综合评估患者心脏受累程度,从而为HCM患者危险分层及预后评估提供...     

Cardiovascular magnetic resonance imaging in heart failure

Introduction: Heart failure is a complex clinical syndrome resulting from heart structural remodeling and impaired function in ejecting blood; its incidence is increasing markedly worldwide. The observed variations in the structure and function of the heart are attributable to differences in etiology of heart failure. Cardiac magnetic resonance imaging (CMR) can characterize myocardial tissue, assess myocardial viability, and help diagnose specific cardiomyopathies. The emergence of T1 mapping techniques further improves our knowledge and the clinical assessment of myocardial diffuse fibrosis. Physicians, therefore, must identify the variations using CMR to improve patient’s symptoms, survival, and quality of life.

Area covered: Current reports regarding CMR and the evidence for heart failure diagnosis and therapy as a potential marker of therapeutic response, including low- and high-risk patients, were reviewed. Literature search was performed using PubMed and Google Scholar for literature relevant to CMR, late gadolinium enhancement, T1 mapping, assessment of fibrosis and remodeling, coronary artery, myocardial infarction, heart failure, and its outcomes.

Expert commentary: The authors review current evidence and discuss the potential ability of CMR to guide, diagnose, plan risk strategies, and treat patients with heart failure.     

Established and emerging cardiovascular magnetic resonance techniques for prognostication and guiding therapy in heart failure

The syndrome of heart failure is prevalent and a cause of significant morbidity and mortality. Cardiovascular magnetic resonance (CMR) offers a unique method to quantify the extent of left ventricular dysfunction and also characterize the myocardium, particularly according to the presence and distribution of late gadolinium enhancement. The prognostic value of late gadolinium enhancement in various etiologies of heart failure has been demonstrated. Newer techniques that non-invasively assess the extracellular volume may also add to the prognostic value of CMR in heart failure. Management decisions in patients with heart failure can often be complex. CMR can provide useful information when planning cardiac device therapy and the CMR assessment of viability is key when planning revascularization.     

Contrast-enhanced cardiovascular magnetic resonance imaging of coronary vessel wall: state of art

Coronary wall imaging by cardiovascular magnetic resonance (CMR) emerges as a promising method to detect vascular injury and remodeling directly within the coronary vascular wall. In this review, the current evidence on coronary wall enhancement using CMR is presented and summarized, with particular focus on its ability to detect inflammation in atherosclerosis, Takayasu's arteritis, acute coronary syndromes and immune-mediated inflammatory vasculitides. The authors review the possible mechanisms of coronary wall contrast enhancement on CMR and discuss the technical considerations and limitations. Lastly, the potential clinical applications and possibilities for future research are proposed.     

心脏磁共振成像预测酒精性心肌病心力衰竭患者心脏不良事件

目的 探讨心脏磁共振（CMR）心肌对比剂延迟强化（LGE）对酒精性心肌病（ACM）心力衰竭患者心脏不良事件的预测能力。方法 纳入临床诊断为ACM并出现心力衰竭症状的患者58例,对所有患者行CMR,根据是否出现LGE将患者分为LGE（+）组和LGE（-）组。对所有患者进行随访,随访终点定义为发生心脏不良事件,对两组患者随访期间出现的心脏不良事件进行生存分析;将LGE、左心室舒张末期容积、左心室收缩末期容积、左心室射血分数、左心室心肌质量指数、心力衰竭出现时间、饮酒时间纳入多因素Cox比例风险模型,分析心脏不良事件的预测因子。结果 LGE（+）组22例,LGE（-）组36例,共10例发生心脏不良事件,LGE（+）组发生率[31.82%(7/22)]显著高于LGE（-）组[8.33%(3/36),P=0.02]。LGE是心脏不良事件的强预测因子（风险比值：5.74, P=0.02）。结论 CMR心肌LGE是出现心力衰竭症状的ACM患者不良心脏事件的强预测因子。     

心脏磁共振参数列线图模型对扩张型心肌病老年患者不良心血管事件的预测价值

目的 探究心脏磁共振（CMR）参数列线图模型对扩张型心肌病（DCM）老年患者主要不良心血管事件（MACE）的预测价值。 方法 回顾性分析2017年7月~2020年7月在武汉科技大学附属孝感医院接受CMR检查的DCM老年患者173例,将患者按6:4的比例随机分为训练集（n=104）及测试集（n=69）。通过LASSO回归及多因素Cox回归筛选潜在预测因子,以此构建DCM患者MACE列线图预测模型。通过校准曲线、ROC曲线、决策曲线分析法、Kaplan-Meier生存分析对列线图模型进行评估及验证。 结果 中位随访时间为29.7（16.4,45.4）月。随访结束时,59例（34.1%）患者发生MACE。LASSO回归及交叉验证筛选出9个潜在预测因子。多因素Cox回归分析结果显示,纽约心功能分级Ⅲ~Ⅳ级、N末端-脑钠肽前体、β受体阻断药、CMR晚期钆增强、左心室整体纵向应变是DCM患者发生MACE风险因子,并以此构建列线图预测模型。在训练集和测试集中,校准图显示列线图预测1年、3年生存率与实际生存率一致性较好。训练集1年、3年生存预测ROC曲线下面积分别为0.850（95%CI：0.748~0.953）、0.853（95% CI：0.797~0.909）,测试集1年、3年生存预测ROC曲线下面积分别为0.858（95% CI：0.758~0.959）、0.887（95% CI：0.816~0.958）。决策曲线分析结果显示列线图模型的临床净获益率较高。Kaplan-Meier生存分析结果示,预测模型高风险组患者较低风险组生存概率降低（P＜0.05）。 结论 本研究通过临床和CMR特征参数构建了DCM老年患者MACE发生列线图预测模型,该模型具有较好校准度、区分度及临床应用价值。     

Varied distributions of late gadolinium enhancement found among patients meeting cardiovascular magnetic resonance criteria for isolated left ventricular non-compaction

Background

Late gadolinium enhancement (LGE) is identified frequently in LVNC. However, the features of this findings are limited. The purpose of the present study was to describe the frequency and distribution of LGE in patients meeting criteria for left ventricular non-compaction (LVNC), as assessed by cardiovascular magnetic resonance (CMR).

Methods

Forty-seven patients (37 males and 10 females; mean age, 39 ± 18 years) considered to meet standard CMR criteria for LVNC were studied. The LGE images were obtained 15 ± 5 min after the injection of 0.2 mmol/kg of gadolinium-DTPA using an inversion-recovery sequence, and analyzed using a 17-segment model.

Results

Mean number of non-compacted segments per patient was 7.4 ± 2.5 and the NC:C was 3.2 ± 0.7. Non-compaction was most commonly noted in the apical segments in all patients. LGE was present in 19 of the 47 patients (40%), and most often located in the ventricular septum. The distribution of LGE was subendocardial (n = 5; 6%), mid-myocardial (n = 61; 68%), subepicardial (n = 10; 11%), and transmural (n = 14; 15%) in total of 90 LGE (+) segments.

Conclusions

In patients considered to meet criteria for LVNC, LGE distributions visible were strikingly heterogeneous with appearances potentially attributable to three or more distinct cardiomyopathic processes. This may be in keeping with previous suggestions that the criteria may be of low specificity. Further work is needed to determine whether conditions such as dilated cardiomyopathy, previous myocardidtis or ischaemic heart disease increase the apparent depth of non-compact relative to compact myocardium.     

Sudden cardiac death in athletes and the value of cardiovascular magnetic resonance

Sudden cardiac death (SCD) is the nontraumatic death, due to loss of heart function that occurs suddenly and unexpectedly within 6 hours of a previously normal state of health . It is related to intense competitive sports promoting ventricular tachycardia (VT)/ventricular fibrillation (VF) in the presence of underlying abnormal substrate. A serial evaluation of cardiac physiologic changes taking place during training will allow the better understanding of athlete's heart and will facilitate its discrimination from other grey‐zone cardiomyopathies. According to the ESC recommendations, a pre‐participation evaluation should include medical history, physical examination as well as a 12‐lead electrocardiogram (ECG). Additional tests, such as echocardiography, 24‐hours Holter monitoring, stress testing and cardiovascular magnetic resonance (CMR) should be requested upon positive findings at the initial evaluation. Cardiovascular magnetic resonance can be of great value in the differential diagnosis between various cardiomyopathies including hypertrophic cardiomyopathy (HCM), arrhythmogenic right ventricular cardiomyopathy (ARVC), left ventricle noncompaction cardiomyopathy (LVNC) and athlete's heart. This is due to its great versatility that can provide reliable and reproducible anatomical, functional and tissue characterization information, which are operator and acoustic window independent.     

Preliminary experience with cardiovascular magnetic resonance in evaluation of fetal cardiovascular anomalies

Background

The cardiovascular system is the part of the fetal anatomy that most frequently suffers from congenital pathology. This study shows our preliminary experience with fetal cardiovascular magnetic resonance (CMR) to evaluate congenital cardiovascular abnormalities.

Methods

Between January 2006 and June 2011, Prenatal routine obstetric ultrasound (US), echocardiography and CMR data from 68 pregnant women carrying fetuses with congenital cardiovascular anomalies were compared with postnatal diagnoses (postnatal imagings, surgery and autopsy). All prenatal CMR was performed at 1.5 T. Imaging sequences included steady-state free-precession (SSFP) sequences, real-time SSFP and single-shot turbo spin echo (SSTSE) sequences. The images were analyzed with an anatomic segmental approach by two radiologists.

Results

Fetal CMR yielded the same diagnosis as postnatal findings in 79% (54/68) of patients. The diagnostic sensitivity of routine obstetric US for cardiac anomalies was 46% (31/68). The diagnostic sensitivity of fetal echocardiographic examination by a fetal cardiac specialist was 82% (56/68). In 2 (3%) of 68 cases, diagnoses with both echocardiography and CMR were incorrect when compared with postnatal diagnosis. In ten (15%) cases, diagnosis at echocardiography was incorrect and that at CMR was correct. In twelve (18%) cases, diagnosis at echocardiography was correct and that at CMR was incorrect. Ten cases missed or misdiagnosed by echocardiography but correctly diagnosed by fetal CMR included asplenia syndrome (n = 2), interrupted inferior vena cava of polysplenia syndrome (n = 1), tricuspid incompetence (n = 1), double outlet right ventricle (n = 2), double aortic arch (n = 1), right pulmonary artery hypoplasia (n = 1), right-sided aortic arch of tetralogy of Fallot (n = 1) and hypoplastic left heart syndrome of a twin fetus (n = 1).

Conclusion

Fetal CMR is a promising diagnostic tool for assessment of congenital cardiovascular abnormalities, especially in situations that limit echocardiography.     

Cardiac output and cardiac index measured with cardiovascular magnetic resonance in healthy subjects,elite athletes and patients with congestive heart failure

Background

Cardiovascular Magnetic Resonance (CMR) enables non-invasive quantification of cardiac output (CO) and thereby cardiac index (CI, CO indexed to body surface area). The aim of this study was to establish if CI decreases with age and compare the values to CI for athletes and for patients with congestive heart failure (CHF).

Methods

CI was measured in 144 healthy volunteers (39 ± 16 years, range 21–81 years, 68 females), in 60 athletes (29 ± 6 years, 30 females) and in 157 CHF patients with ejection fraction (EF) below 40% (60 ± 13 years, 33 females). CI was calculated using aortic flow by velocity-encoded CMR and is presented as mean ± SD. Flow was validated in vitro using a flow phantom and in 25 subjects with aorta and pulmonary flow measurements.

Results

There was a slight decrease of CI with age in healthy subjects (8 ml/min/m² per year, r² = 0.07, p = 0.001). CI in males (3.2 ± 0.5 l/min/m²) and females (3.1 ± 0.4 l/min/m²) did not differ (p = 0.64). The mean ± SD of CI in healthy subjects in the age range of 20–29 was 3.3 ± 0.4 l/min/m², in 30–39 years 3.3 ± 0.5 l/min/m², in 40–49 years 3.1 ± 0.5 l/min/m², 50–59 years 3.0 ± 0.4 l/min/m² and >60 years 3.0 ± 0.4 l/min/m². There was no difference in CI between athletes and age-controlled healthy subjects but HR was lower and indexed SV higher in athletes. CI in CHF patients (2.3 ± 0.6 l/min/m²) was lower compared to the healthy population (p < 0.001). There was a weak correlation between CI and EF in CHF patients (r² = 0.07, p < 0.001) but CI did not differ between patients with NYHA-classes I-II compared to III-IV (n = 97, p = 0.16) or patients with or without hospitalization in the previous year (n = 100, p = 0.72). In vitro phantom validation showed low bias (−0.8 ± 19.8 ml/s) and in vivo validation in 25 subjects also showed low bias (0.26 ± 0.61 l/min, QP/QS 1.04 ± 0.09) between pulmonary and aortic flow.

Conclusions

CI decreases in healthy subjects with age but does not differ between males and females. We found no difference in CI between athletes and healthy subjects at rest but CI was lower in patients with congestive heart failure. The presented values can be used as reference values for flow velocity mapping CMR.     

Oedema‐fibrosis in Duchenne Muscular Dystrophy: Role of cardiovascular magnetic resonance imaging

Duchenne muscular dystrophy (DMD) is an X‐linked muscle disorder characterized by progressive, irreversible loss of cardiac and skeletal muscular function. Muscular enlargement in DMD is attributed to oedema, due to the increased cytoplasmic Na+ concentration. The aim of this review was to present the current experience and emphasize the role of cardiovascular magnetic resonance (CMR) in the diagnosis of this condition. DMD patients' survival depends on ventilatory assistance, as respiratory muscle dysfunction was the most common cause of death in the past. Currently, due to improved ventilatory assistance, cardiomyopathy has become the main cause of death, even though clinically overt heart failure may be absent. CMR is the technique of choice to assess the pathophysiologic phenomena taking place in DMD, such as myocardial oedema and subepicardial fibrosis. The classic index to assess oedema is the T2‐weighted short‐tau inversion recovery (T2w‐STIR), as it suppresses the signal from flowing blood and resident fat and enhances sensitivity to tissue fluid. Furthermore, CMR is the most reliable technique to detect and quantify fibrosis in DMD. Recently, the new indices T2, T1 mapping (native and postcontrast) and the extracellular volume (ECV) allow a more accurate approach of myocardial oedema and fibrosis. To conclude, the assessment of cardiac oedema and subepicardial fibrosis in the inferolateral wall of the left heart ventricle are the most important early finding in DMD with preserved ventricular function, and CMR, using both the classic and the new indices, is the best technique to detect and monitor these lesions.     

Unveiling nonischemic cardiomyopathies with cardiac magnetic resonance

Cardiomyopathy is defined as a heterogeneous group of myocardial disorders with mechanical or electrical dysfunction. Identification of the etiology is important for accurate diagnosis, treatment and prognosis, but continues to be challenging. The ability of cardiac MRI to non-invasively obtain 3D-images of unparalleled resolution without radiation exposure and to provide tissue characterization gives it a distinct advantage over any other diagnostic tool used for evaluation of cardiomyopathies. Cardiac MRI can accurately visualize cardiac morphology and function and also help identify myocardial edema, infiltration and fibrosis. It has emerged as an important diagnostic and prognostic tool in tertiary care centers for work up of patients with non-ischemic cardiomyopathies. This review covers the role of cardiac MRI in evaluation of nonischemic cardiomyopathies, particularly in the context of other diagnostic and prognostic imaging modalities.     

Brain and heart magnetic resonance imaging/spectroscopy in duchenne muscular dystrophy

Duchenne muscular dystrophy (DMD) is an X‐linked muscle disorder characterized by progressive and irreversible loss of muscular function. As muscular disease progresses, the repair mechanisms cannot compensate for cellular damage, leading inevitably to necrosis and progressive replacement by fibrous and fatty tissue. Cardiomyopathy and respiratory failure are the main causes of death in DMD. In addition to the well‐described muscle and heart disease, cognitive dysfunction affects around 30% of DMD boys. Myocardial fibrosis, assessed by late gadolinium enhancement (LGE), using cardiovascular magnetic resonance imaging (CMR), is an early marker of heart involvement in both DMD patients and female carriers. In parallel, brain MRI identifies smaller total brain volume, smaller grey matter volume, lower white matter fractional anisotropy and higher white matter radial diffusivity in DMD patients. The in vivo brain evaluation of mdx mice, a surrogate animal model of DMD, showed an increased inorganic phosphate (P(i))/phosphocreatine (PCr) and pH. In this paper, we propose a holistic approach using techniques of magnetic resonance imaging, spectroscopy and diffusion tensor imaging as a tool to create a “heart and brain imaging map” in DMD patients that could potentially facilitate the patients’ risk stratification and also future research studies in the field.     

Evaluation of ischemic heart disease with cardiac magnetic resonance and computed tomography

Ischemic heart disease is the most common cardiac problem encountered by physicians in their daily practice. In the last few years, computed tomography and magnetic resonance have emerged as robust imaging modalities with great potential for the comprehensive evaluation of patients with this disorder. This article reviews current evidence of the applications where these techniques have demonstrated their usefulness and provides guidance for their use in the clinical management of coronary artery disease.     

血氧水平依赖磁共振成像技术在心血管疾病中的应用进展

传统的心脏磁共振检查需借助外源性对比剂才能评价心肌血供和代谢.血氧水平依赖磁共振成像技术(blood oxygen level dependent magnetic resonance,BOLD-MR)可不依赖对比剂,通过检测组织中脱氧血红蛋白水平高低即可反映局部血氧代谢情况.作为一种无创的功能磁共振成像技术,它在解释...     

Effectiveness of late gadolinium enhancement to improve outcomes prediction in patients referred for cardiovascular magnetic resonance after echocardiography

Background

Echocardiography (echo) is a first line test to assess cardiac structure and function. It is not known if cardiovascular magnetic resonance (CMR) with late gadolinium enhancement (LGE) ordered during routine clinical practice in selected patients can add additional prognostic information after routine echo. We assessed whether CMR improves outcomes prediction after contemporaneous echo, which may have implications for efforts to optimize processes of care, assess effectiveness, and allocate limited health care resources.

Methods and results

We prospectively enrolled 1044 consecutive patients referred for CMR. There were 38 deaths and 3 cardiac transplants over a median follow-up of 1.0 years (IQR 0.4-1.5). We first reproduced previous survival curve strata (presence of LGE and ejection fraction (EF) < 50%) for transplant free survival, to support generalizability of any findings. Then, in a subset (n = 444) with contemporaneous echo (median 3 days apart, IQR 1–9), EF by echo (assessed visually) or CMR were modestly correlated (R² = 0.66, p < 0.001), and 30 deaths and 3 transplants occurred over a median follow-up of 0.83 years (IQR 0.29-1.40). CMR EF predicted mortality better than echo EF in univariable Cox models (Integrated Discrimination Improvement (IDI) 0.018, 95% CI 0.008-0.034; Net Reclassification Improvement (NRI) 0.51, 95% CI 0.11-0.85). Finally, LGE further improved prediction beyond EF as determined by hazard ratios, NRI, and IDI in all Cox models predicting mortality or transplant free survival, adjusting for age, gender, wall motion, and EF.

Conclusions

Among those referred for CMR after echocardiography, CMR with LGE further improves risk stratification of individuals at risk for death or death/cardiac transplant.     

Cardiac magnetic resonance for prognostic assessment: present applications and future directions

Cardiac magnetic resonance is increasingly used in clinical practice for both diagnostic and prognostic purposes. In the field of ischemic heart disease, perfusion imaging permits the assessment of ischemia, which is strongly related to future cardiac events and mortality. Late gadolinium enhancement is also associated with the prognosis and can be used as a marker of functional recovery. Cardiac magnetic resonance also permits the detection of microvascular obstruction and infarct hemorrhage, both related to an adverse outcome. In non-ischemic heart disease, the presence of late gadolinium enhancement is linked to mortality and hard events. Finally, coronary angiography, as well as new techniques, such as T1 mapping, may also have a prognostic role.