Magnetic resonance coronary angiography in the era of multimodality imaging.

Cardiovascular magnetic resonance is currently the reference standard for non-invasive measurements of ventricular dimensions and ejection fraction, and may offer a comprehensive assessment of all myocardial tissue properties (including oedema, fibrosis, fat, iron, and protein deposition), as well as of stress perfusion, conveniently as part of a single examination. It also has a well-established role for coronary assessment in paediatric patients, especially with congenital heart disease and vasculitides, such as Kawasaki disease, and it should be considered as a first-line technique in these cases. Despite being recognised as a safe, non-radiating, and non-contrast technique, it is yet to be implemented widely in clinical use as an efficient alternative to computed tomography coronary angiography. Currently impressive progress is being made in the development of sequences and overcoming technical challenges, which are thoroughly discussed in this article, while further development is required to convert this into a robust, non-invasive technique for routine clinical decision-making in cardiovascular disease, particularly in adult patients. In this review, we will summarise current clinical applications of magnetic resonance coronary imaging, both in adult and paediatric populations, with reference to currently established imaging techniques, focusing also on ongoing research and future development.

Rest perfusion abnormalities in hypertrophic cardiomyopathy: correlation with myocardial fibrosis and risk factors for sudden cardiac death.

AIM: To measure the prevalence of abnormal rest perfusion in a population of consecutive patients with known hypertrophic cardiomyopathy (HCM) referred for cardiovascular MRI (CMR), and to assess any associations between abnormal rest perfusion and the presence, pattern, and severity of myocardial scar and the presence of risk factors for sudden death. MATERIALS AND METHODS: Eighty consecutive patients with known HCM referred for CMR underwent functional imaging, rest first-pass perfusion, and late gadolinium enhancement (LGE). RESULTS: Thirty percent of the patients had abnormal rest perfusion, all of them corresponding to areas of mid-myocardial LGE and to a higher degree of segmental hypertrophy. Rest perfusion abnormalities correlated with more extensive and confluent LGE. The subgroup of patients with myocardial fibrosis and rest perfusion abnormalities (fibrosis+/perfusion+) had more than twice the incidence of episodes of non-sustained ventricular tachycardia on Holter monitoring in comparison to patients with myocardial fibrosis and normal rest perfusion (fibrosis+/perfusion-) and patients with no fibrosis and normal rest perfusion (fibrosis-/perfusion-). CONCLUSIONS: First-pass perfusion CMR identifies abnormal rest perfusion in a significant proportion of patients with HCM. These abnormalities are associated with the presence and distribution of myocardial scar and the degree of hypertrophy. Rest perfusion abnormalities identify patients with increased incidence of episodes of non-sustained ventricular tachycardia on Holter monitoring, independently from the presence of myocardial fibrosis.

The diagnostic role of cardiac magnetic resonance imaging in detecting myocardial inflammation in systemic lupus erythematosus. Differentiation from viral myocarditis.

OBJECTIVE: The objective of this paper is to evaluate the diagnostic role of cardiac magnetic resonance imaging (CMR) in detecting myocardial inflammation in systemic lupus erythematosus (SLE) and its differentiation from viral myocarditis. PATIENTS AND METHODS: Fifty patients with suspected infective myocarditis (IM), with chest pain, dyspnoea or altered ECG, increase in troponin I and/or NT-pro BNP, with or without a history of flu-like syndrome or gastroenteritis and elevated C-reactive protein (CRP) within three to five (median four) weeks before admission, 25 active SLE patients, aged 38 ± 3 years, and 20 age-matched controls were prospectively evaluated by clinical assessment, ECG, echocardiogram and CMR. All patients underwent coronary angiography, and those with significant coronary artery disease (CAD) were excluded. CMR was performed using STIR T2-W (T2W), early T1-W (EGE) and late T1-W (LGE). Endomyocardial biopsies were performed when clinically indicated by current guidelines. Specimens were examined by immunohistological and polymerase chain reaction (PCR) analysis. RESULTS: Positive coronary angiography for CAD excluded 10/50 suspected IM and 5/25 active SLE. Positive clinical criteria for acute myocarditis were fulfilled by 28/40 suspected IM and only 5/20 active SLE. CMR was positive for myocarditis in 35/40 suspected IM and in 16/20 active SLE. Endomyocardial biopsy (EMB), performed in 25/35 suspected IM and 7/16 active SLE with positive CMR, showed positive immunohistology in 18/25 suspected IM and 3/7 active SLE. Infectious genomes were identified in 24/25 suspected IM and 1/7 active SLE. CONCLUSIONS: CMR-positive IM patients were more symptomatic than active SLE. More than half of CMR-positive patients also had positive EMB. PCR was positive in almost all IM, but unusual in SLE. Due to the subclinical presentation of SLE myocarditis and the limitations of EMB, CMR presents the best alternative for the diagnosis of SLE myocarditis.

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.

Pathophysiology of Q waves in II, III, avF in systemic lupus erythematosus. Evaluation using cardiovascular magnetic resonance imaging.

OBJECTIVES: To investigate the pathophysiology of Q waves in II, III, avF in systemic lupus erythematosus (SLE) by cardiovascular magnetic resonance (CMR). METHODS: Inflammation evaluation by CMR using T2, early (EGE) and late gadolinium enhanced images (LGE) was performed in 20 SLE patients with mild cardiac symptoms and Q in leads II, III, avF of ECG. Their results were compared with 20 SLE patients with the same symptoms and normal ECG. RESULTS: In both groups, T2, EGE and left ventricular ejection fraction were normal. However, in 3/20 with Q in II, III, avF, CMR revealed lesions indicative of acute myocarditis. In the rest of them, CMR documented transmural LGE, due to past inferior myocardial infarction in 4/20 and epicardial LGE due to past myocarditis in 8/20 (4/8 in the inferior and 4/8 in the lateral wall of left ventricle). No LGE was found in 5/20 and the Q was attributed to the position of the heart. In 3/20 with normal ECG, CMR detected past myocarditis in 2/3 and myocardial infarction in 1/3. Coronary angiography assessed coronary artery disease in all SLE with evidence of myocardial infarction and normal coronaries in 9/10 patients with past myocarditis. CONCLUSION: Q in II, III, avF in SLE may indicate myocardial infarction, acute or past inflammation or be a positional finding. The lack of Q does not exclude the possibility of infarction or inflammation. CMR is the best tool to reveal the pathophysiology of Q waves in SLE and guide treatment of heart involvement in these patients.

Cardiovascular magnetic resonance in autoimmune rheumatic diseases: a clinical consensus document by the European Association of Cardiovascular Imaging.

Autoimmune rheumatic diseases (ARDs) involve multiple organs including the heart and vasculature. Despite novel treatments, patients with ARDs still experience a reduced life expectancy, partly caused by the higher prevalence of cardiovascular disease (CVD). This includes CV inflammation, rhythm disturbances, perfusion abnormalities (ischaemia/infarction), dysregulation of vasoreactivity, myocardial fibrosis, coagulation abnormalities, pulmonary hypertension, valvular disease, and side-effects of immunomodulatory therapy. Currently, the evaluation of CV involvement in patients with ARDs is based on the assessment of cardiac symptoms, coupled with electrocardiography, blood testing, and echocardiography. However, CVD may not become overt until late in the course of the disease, thus potentially limiting the therapeutic window for intervention. More recently, cardiovascular magnetic resonance (CMR) has allowed for the early identification of pathophysiologic structural/functional alterations that take place before the onset of clinically overt CVD. CMR allows for detailed evaluation of biventricular function together with tissue characterization of vessels/myocardium in the same examination, yielding a reliable assessment of disease activity that might not be mirrored by blood biomarkers and other imaging modalities. Therefore, CMR provides diagnostic information that enables timely clinical decision-making and facilitates the tailoring of treatment to individual patients. Here we review the role of CMR in the early and accurate diagnosis of CVD in patients with ARDs compared with other non-invasive imaging modalities. Furthermore, we present a consensus-based decision algorithm for when a CMR study could be considered in patients with ARDs, together with a standardized study protocol. Lastly, we discuss the clinical implications of findings from a CMR examination.

Variability in quantitative cardiac magnetic resonance perfusion analysis.

By taking advantage of its high spatial resolution, noninvasive and nontoxic nature first-pass perfusion cardiovascular magnetic resonance (CMR) has rendered an indispensable tool for the noninvasive detection of reversible myocardial ischemia. A potential advantage of perfusion CMR is its ability to quantitatively assess perfusion reserve within a myocardial segment, as expressed semi- quantitatively by myocardial perfusion reserve index (MPRI) and fully- quantitatively by absolute myocardial blood flow (MBF). In contrast to the high accuracy and reliability of CMR in evaluating cardiac function and volumes, perfusion CMR is adversely affected by multiple potential reasons during data acquisition as well as post-processing. Various image acquisition techniques, various contrast agents and doses as well as variable blood flow at rest as well as variable reactions to stress all influence the acquired data. Mechanisms underlying the variability in perfusion CMR post processing, as well as their clinical significance, are yet to be fully elucidated. The development of a universal, reproducible, accurate and easily applicable tool in CMR perfusion analysis remains a challenge and will substantially enforce the role of perfusion CMR in improving clinical care.