Cardiac Magnetic Resonance Imaging for the Assessment of Myocardial Angiogenesis

Research in biology and applications of growth factors in coronary artery disease (CAD) has progressed considerably over recent years. Vascular endothelial growth factor and fibroblast growth factor-2 have been more successful in animal models of myocardial ischemia and Phase I studies than in placebo-controlled trials. However, cardiac magnetic resonance (CMR), with its higher sensitivity and specificity indices for identification of CAD, has not been extensively used in trials of angiogenic therapies. Data in animals and in patients suggest that CMR can reliably identify collateral vessels. Therefore, we hypothesize that CMR may depict collateralization induced by angiogenic therapy better than currently used nuclear perfusion imaging modalities. Versatility of the assessment of myocardial function and perfusion in one imaging session, combined with the noninvasive nature of the test, may considerably lower the cost of clinical trials. Use of CMR-derived surrogate end points may provide better risk stratification and assessment of efficacy in patients receiving growth factor therapy.     

Asymptomatic Brain Lesions on Cranial Magnetic Resonance Imaging in Inflammatory Bowel Disease

Background/Aims

This study aimed to examine the frequency and type of asymptomatic neurological involvement in inflammatory bowel disease (IBD) using cranial magnetic resonance imaging (MRI).

Methods

Fifty-one IBD patients with no known neurological diseases or symptoms and 30 controls with unspecified headaches without neurological origins were included. Patients and controls underwent cranial MRI assessments for white matter lesions, sinusitis, otitis-mastoiditis, and other brain parenchymal findings.

Results

The frequencies of white matter lesions, other brainstem parenchymal lesions, and otitis-mastoiditis were similar in IBD patients and controls (p>0.05), whereas sinusitis was significantly more frequent in IBD patients (56.9% vs 33.3%, p=0.041). However, among those subjects with white matter lesions, the number of such lesions was significantly higher in IBD patients compared to controls (12.75±9.78 vs 3.20±2.90, p<0.05). The incidence of examined pathologies did not differ significantly with disease activity (p>0.05 for all).

Conclusions

The incidence of white matter lesions seemed to be similar in IBD patients and normal healthy individuals, and the lesions detected did not pose any clinical significance. However, long-term clinical follow-up of the lesions is warranted.     

Assessment of Ischemic Heart Disease Using Magnetic Resonance First-Pass Perfusion Imaging

METHODS: Cardiovascular magnetic resonance (MR) perfusion imaging has matured to a point where it can be routinely applied to assess patients with coronary artery disease and ischemic cardiomyopathy. The method has been compared to invasive, catheter-based as well as other noninvasive imaging modalities (echocardiography, single-photon emission computed tomography [SPECT], and positron emission tomography [PET]) for the evaluation of patients with coronary artery disease. Besides qualitative evaluation of MR perfusion images, an absolute quantification of global, regional and transmural myocardial perfusion is possible. A relative or absolute myocardial perfusion reserve has been determined noninvasively with MR perfusion imaging, and can provide good agreement with the invasive assessment. Based on the perfusion reserve, the severity of an epicardial coronary stenosis can be evaluated in patients with known or suspected coronary artery disease. Besides the absence of radiation exposure, MR perfusion imaging offers good temporal and excellent spatial resolution. In particular, the spatial resolution increases the sensitivity and specificity for the detection of coronary artery disease. New parameters such as the "endo-/epimyocardial resting perfusion ratio", may under some circumstances sufficiently enhance the sensitivity for detecting an abnormal perfusion, and thus avoid potentially harmful and expensive stress testing in patients with suspected ischemic heart disease. New revascularization modalities such as therapeutic angiogenesis need to be matched by sensitive imaging tools to prove their benefits. Thus, the optimization of therapeutic angiogenesis may profit from the diagnostic advantages provided by MR perfusion imaging. Furthermore, MR might yield new insights into the pathophysiology of cardiac diseases such as "syndrome X", or might help in the repetitive assessment of heart transplant recipients, possibly obviating the need for further invasive testing. CONCLUSION: The breadth of cardiac MRI allows the combined noninvasive assessment of myocardial perfusion, function, as well as myocardial viability. The combination gives MRI a unique and strong position in the field of noninvasive diagnostic cardiology.     

磁共振成像评价缺血性心脏病的价值和进展

本文综述了心脏磁共振成像在缺血性心脏病中的临床应用 ,对心脏形态学、功能学、心肌存活性评价的方法和磁共振表现进行了详细论述 ,探讨了磁共振波谱分析、磁共振冠状动脉成像、显示动脉硬化性斑块的MR技术及其进展。     

Magnetic Resonance Imaging in Chronic Chagas' Disease: Correlation with Endomyocardial Biopsy Findings and Gallium-67 Cardiac Uptake

BACKGROUND: We studied the correlation among cardiac magnetic resonance imaging (MRI), gallium-67 myocardial uptake, and right ventricular endomyocardial biopsy results in chronic Chagas' disease. To our knowledge, this represents the first attempt to correlate the histological findings with cardiac MRI and gallium-67 myocardial uptake for noninvasive diagnosis of inflammatory activity associated with Chagas' disease. METHODS: Ten male patients with cardiomyopathy secondary to Chagas' disease were studied (mean age, 47.7 +/- 7 years; congestive heart failure New York Heart Association [NYHA] functional class II [two patients], III [six patients], and IV [two patients]; and mean echocardiographic left ventricular [LV] ejection fraction [EF], 36 +/- 6%). The patients underwent right ventricular endomyocardial biopsy, cardiac MRI, and gallium-67 myocardial uptake testing. The results of this group were compared with those of a control group of patients with idiopathic dilated cardiomyopathy who were matched in age (mean age, 46 +/- 10 years), LV function (mean echocardiographic EF, 30 +/- 4%), and NYHA classification (one patient in class II, five patients in class III, and one patient in class IV). RESULTS: All patients with Chagas' disease showed higher signal intensity on MRI after the administration of gadolinium. The intensity of the septal signal changed from 0.90 +/- 0.11 to 1.56 +/- 0.19 (P < 0.001). In the control group, there was no difference in signal intensity with gadolinium (mean septal intensity, 0.94 +/- 0.12 before and 0.99 +/- 0.15 after; NS). On biopsy, eight chagasic patients had evident signs of myocarditis, and two patients had borderline evidence myocarditis. However, only one patient in the control group had a histological diagnosis of borderline myocarditis. Gallium-67 cardiac uptake was positive for myocardial inflammatory process in seven chagasic patients and borderline in one. On the other hand, only one patient in the control group had an uptake that was positive for inflammation, and one had a borderline result. CONCLUSIONS: In conclusion, the data from this study strongly suggest that myocarditis is frequently found in Chagas' disease. Cardiac MRI appears to be an accurate and alternative method for the diagnosis of inflammatory process associated with Chagas' disease.     

Defining Myocardial Abnormalities Across the Stages of Chronic Kidney Disease: A Cardiac Magnetic Resonance Imaging Study

ObjectivesA proof of concept cross-sectional study investigating changes in myocardial abnormalities across stages of chronic kidney disease (CKD). Characterizing noninvasive markers of myocardial fibrosis on cardiac magnetic resonance, echocardiography, and correlating with biomarkers of fibrosis, myocardial injury, and functional correlates including exercise tolerance.BackgroundCKD is associated with an increased risk of cardiovascular death. Much of the excess mortality is attributed to uremic cardiomyopathy, defined by increased left ventricular hypertrophy, myocardial dysfunction, and fibrosis. The prevalence of these abnormalities across stages of CKD and their impact on cardiovascular performance is unknown.MethodsA total of 134 nondiabetic, pre-dialysis subjects with CKD stages 2 to 5 without myocardial ischemia underwent cardiac magnetic resonance (1.5-T) including; T₁ mapping (biomarker of diffuse fibrosis), T₂ mapping (edema), late gadolinium enhancement, and assessment of aortic distensibility. Serum biomarkers including collagen turnover (P1NP, P3NP), troponin T, and N-terminal pro–B-type natriuretic peptide were measured. Cardiovascular performance was quantified by bicycle cardiopulmonary exercise testing and echocardiography.ResultsNative myocardial T₁ times increased incrementally from stage 2 to 5 (966 ± 21 ms vs. 994 ± 33 ms; p < 0.001), independent of hypertension and aortic distensibility. Left atrial volume, E/eʹ, N-terminal pro–B-type natriuretic peptide, P1NP, and P3NP increased with CKD stage (p < 0.05), while effort tolerance (% predicted VO₂Peak, %VO₂VT) decreased (p < 0.001). In multivariable linear regression models, estimated glomerular filtration rate was the strongest predictor of native myocardial T₁ time (p < 0.001). Native myocardial T₁ time, left atrial dilatation, and high-sensitivity troponin T were independent predictors of % predicted VO₂Peak (p < 0.001).ConclusionsImaging and serum biomarkers of myocardial fibrosis increase with advancing CKD independent of effects of left ventricular afterload and might be a key intermediary in the development of uremic cardiomyopathy. Further studies are needed to determine whether these changes lead to the increased rates of heart failure and death in CKD. (Left Ventricular Fibrosis in Chronic Kidney Disease [FibroCKD]; NCT03176862)     

Evaluation of Adult Congenital Heart Disease by Cardiac Magnetic Resonance Imaging

Cardiovascular magnetic resonance (CMR) imaging plays an essential role in the evaluation and follow‐up of adult congenital heart disease (ACHD), providing safe, high‐resolution imaging of some of the most complex anatomies encountered. Unlimited by acoustic windows and capable of tissue characterization, CMR is devoid of ionizing radiation and provides superior three‐dimensional spatial resolution to transthoracic echocardiography and superior temporal resolution to computed tomography, making it the gold standard for various cardiac and great vessel imaging indications in ACHD. In this state‐of‐the art review, we provide an overview of CMR examination methods and detail the various approaches and classical findings in the more common forms of ACHD. Although this review touches upon technical aspects of CMR imaging in ACHD, it is primarily geared toward the adult congenital caregiver (i.e., clinical, interventional, or surgical), highlighting relevant practical considerations. To enhance the clinical utility of this review, numerous examples with intraoperative correlates are provided to highlight our imaging approaches for various defects. As CMR image acquisition may be time consuming and requires patient collaboration (e.g., intermittent breath holding), a systemic approach is required to maximize efficiency. A thorough knowledge of ACHD anatomy and natural history is essential in maximizing image interpretation. Proficient scanning is further enabled by clearly outlined study objectives with prior documentation of interventional and surgical procedures, where applicable.     

Cardiac Magnetic Resonance Imaging in Peripartum Cardiomyopathy

BackgroundPeripartum cardiomyopathy (PPCM) is a rare life-threatening condition of unclear etiology. Data on the use of cardiac magnetic resonance (CMR) imaging to characterize PPCM are limited. This study was done to assess the role of CMR imaging for the diagnosis and prognostication of patients with PPCM.MethodsMedical records of a tertiary medical center were screened for PPCM patients with CMR imaging done within the past 5 years (2006-2011). Images were reviewed by 2 expert radiologists (blinded to clinical data) using cine sequences for chamber function and size, T2-weighted images for the determination of edema (T2-ratio), and late gadolinium enhancement (LGE) sequences for myocardial tissue characterization.ResultsTen PPCM patients (aged 28 ± 6 years, 90% African American) had a total of 15 CMR examinations: 4 in the acute phase (within 7 days of diagnosis) and 11 during follow-up (median, 12 months; range, 1-72 months). Left ventricular ejection fraction was decreased in all 4 initial scans. Elevated T2 ratio (> 2) seen in 1 patient decreased on follow-up imaging. LGE was seen in 1 of the 4 acute-phase scans and in 4 of the 11 follow-up phase scans. These 4 patients had multiple readmissions because of heart failure exacerbations and persistently low left ventricular ejection fraction on subsequent echo- cardiograms.ConclusionsLGE seems to be associated with a poor prognosis in the setting of PPCM. CMR imaging seems to have promising practical implications in the diagnosis and prognostication of PPCM patients.     

心脏核磁共振成像与心内电生理

透视介导的心脏内电生理术一个主要缺点为术中无法正确识别软组织及其与比邻结构关系,然而,心脏核磁共振成像介导的心内电生理术却弥补了这一缺陷.心脏核磁共振成像-心内电生理术不仅可精确地展示出心脏的三维空间形态结构,而且能直接识别心律失常病灶及观察射频消融的疗效,提高复杂心律失常手术成功率及减少并发症有重要作用.因而,心脏核磁共振成像被认为在心内电生理领域具有广泛运用前景.     

Classic Images in Cardiac Magnetic Resonance Imaging: A Case-based Atlas Highlighting Current Applications of Cardiac Magnetic Resonance Imaging

There have been tremendous technological advances in noninvasive cardiovascular imaging, offering the clinician unparalleled information from a variety of modalities. Cardiovascular magnetic resonance imaging (MRI) has the advantages of superior spatial resolution, detailed tissue characterization, and accurate quantitative assessment of cardiac structure and function, without the need for radiation exposure. Recent advances in image acquisition and postimage processing have led to clinically validated protocols for myocardial perfusion, late gadolinium enhancement, and coronary angiography. The following collection of images was selected to demonstrate the typical appearance of various cardiovascular conditions using MRI. There is, of course, much heterogeneity in both the phenotypic severity of a given condition as well as its appearance on MRI. This article, while not intended to be a comprehensive collection, aims to serve as an introduction to the current applications of cardiac MRI.     

Course of Cardiac Magnetic Resonance Imaging Findings in Acute Myocarditis after COVID-19 mRNA Vaccination

Myocarditis is being increasingly reported as a rare complication of coronavirus disease 2019 (COVID-19) mRNA vaccines. We herein report a case of myocarditis following COVID-19 mRNA vaccination in a man. Cardiac magnetic resonance imaging (CMRI) revealed an area of high signal intensity on short T1 inversion recovery (STIR) and late gadolinium enhancement (LGE), which are characteristic of myocarditis. Follow-up CMRI performed six months later revealed improvement in the myocardial edema and LGE findings. CMRI is a useful non-invasive imaging modality for making an initial diagnosis as well as for follow-up in cases of myocarditis after COVID-19 mRNA vaccination.