心脏磁共振特征组织追踪成像定量评价健康人群左心室心肌形变

目的:探讨3.0T心脏磁共振(CMR)特征组织追踪成像(FT)测量中国汉族健康人群左心室心肌形变参数的可行性,并分析年龄、性别对各应变参数的影响。方法:本研究共纳入健康志愿者53例。其中男27例,女26例。随后每组纳入人群按照年龄分为青年、中年及老年3个亚组。所有纳入者均行3.0TCMR检查。分析、对比不同性别和不同年龄组人群左心室整体及局部的径向、周向及纵向峰值应变(PS)、峰值收缩期应变率(PSSR)、峰值舒张期应变率(PDSR)。结果:其中,女性整体周向PS、纵向PS、心基底段周向PS大于男性;男性整体周向PSSR及心中间段周向PSSR、纵向PSSR大于女性。分析不同年龄段心肌形变结果显示,整体径向PS在男女性中老年组均明显高于中年组和青年组;女性组整体周向PS、周向PDSR老年组低于青年组。左心室整体径向、周向、纵向PS分别与部分心功能参数相关。结论:3.0TCMR-FT能客观地量化健康人群左心室心肌形变的相关参数,且不同性别、不同年龄段心肌各形变参数也存在差异,制定相应正常人群心肌形变参数范围需考虑性别及年龄的影响。     

Prognostic Impact of Ischemic Mitral Regurgitation Severity and Myocardial Infarct Quantification by Cardiovascular Magnetic Resonance

ObjectivesThis study sought to evaluate the role of cardiac magnetic resonance (CMR) for the quantification of ischemic mitral regurgitation (IMR) and myocardial infarct size (MIS) in patients with ischemic cardiomyopathy (ICM). This study also sought to explore the interaction between IMR severity and MIS and its association with outcomes in patients with ICM.BackgroundIMR occurs secondary to a disease of the left ventricle and is associated with poor outcomes. The role of CMR for the evaluation and risk stratification of patients with ICM and IMR remains uncertain.MethodsConsecutive patients with ICM who underwent baseline CMR were included. MIS was quantified on late gadolinium enhancement imaging as the proportion of left ventricular mass. IMR was quantified with CMR by calculating the mitral regurgitant fraction (MRFraction). Cox proportional hazards models were built to assess the association of IMR and MIS quantification with the combined endpoint of all-cause death or heart transplant.ResultsWe evaluated 578 patients (mean age: 62 ± 11 years, 76% males). The mean left ventricular ejection fraction was 25 ± 11%, with an MIS of 24 ± 16% and MRFraction of 18 ± 17%. Over a median follow-up time of 4.9 years, 198 (34%) patients experienced death or cardiac transplant. On multivariable analysis, after comprehensive medical risk score, subsequent revascularization, implantable cardioverter-defibrillator insertion, and surgical mitral valve intervention were controlled for, the interaction of IMR severity and MIS emerged as a powerful predictor of adverse outcomes (p = 0.008). For patients with significant IMR (MRFraction: ≥35%), the hazard ratio comparing moderate MIS (15% to 29%) versus small MIS (<15%) was 1.51 (0.57 to 3.98), and the hazard ratio comparing large MIS (≥30%) versus small MIS was 5.41 (2.34 to 12.7).ConclusionsRisk associated with IMR is more comprehensively described as an interaction between IMR severity and MIS. Further studies in patients IMR using comprehensive CMR evaluation are needed to verify whether this approach can improve patient selection and procedural outcomes to address IMR.     

Relationship between measures of left ventricular systolic and diastolic dysfunction and clinical and biomarker status in patients with hypertrophic cardiomyopathy

The evaluation of left ventricular (dys)function is at the core of clinical cardiology practice in patients with hypertrophic cardiomyopathy. Hypertrophic cardiomyopathy proceeds along paradigms that are profoundly different and follows disease-specific patterns of progression towards heart failure. By automatically applying a standard approach, much information is lost or misplaced, and severe degrees of dysfunction may be erroneously interpreted as mild by such an assumption. This is mostly evident during the assessment of systolic function, in which a superficial evaluation of standard variables, often relatively preserved (even in advanced stages), may lead to underestimation of clinical severity, with potential consequences, such as late referral for transplantation. Currently, specific biomarkers–particularly N-terminal prohormone of B-type natriuretic peptide and high-sensitivity cardiac troponin I–play a key role in the diagnosis, treatment and risk stratification of hypertrophic cardiomyopathy. Elevated biomarkers seem to depict patients with more severe disease, adding diagnostic and prognostic information to conventional assessments, such as left ventricular ejection fraction, New York Heart Association class and left ventricular outflow tract obstruction. For all these reasons, we provide a review of current knowledge on systo-diastolic function in patients with hypertrophic cardiomyopathy, in an attempt to define clinically significant degrees of dysfunction, biomarker status and specific “red alert” thresholds in clinical practice.     

急性缺血性脑卒中患者超早期磁共振血管造影对判断预后的价值

目的探讨急性缺血性脑卒中患者超早期磁共振血管造影(MRA)所示有无大血管闭塞对判断预后的价值。方法选择在超早期(发病6 h内)完成MRA检查的急性缺血性脑卒中患者44例,根据MRA显示,将患者分为大血管闭塞组和无大血管闭塞组。患者行MRA检查前完成美国国立卫生研究院卒中量表评分,在3个月时,随访改良的Ranking量表(mRS)评分。结果44例患者中大血管闭塞组21例,无大血管闭塞组23例,两组3个月随访时,mRS 0~2分的比例分别为28.6%和82.6%,两组临床结局的差异有显著性意义(P<0.001)。结论急性缺血性脑卒中患者超早期MRA所示有无大血管闭塞可帮助判断患者的预后。     

Quantitative Myocardial Perfusion Imaging Versus Visual Analysis in Diagnosing Myocardial Ischemia: A CE-MARC Substudy

Objectives

This study sought to compare the diagnostic accuracy of visual and quantitative analyses of myocardial perfusion cardiovascular magnetic resonance against a reference standard of quantitative coronary angiography.

Osteoporosis in children and young adults

Osteoporosis is a major public health problem with serious long-term complications. In children, the definition of osteoporosis is not only based on densitometric criteria but also takes into account vertebral and long bone fragility fractures. Several factors, such as long-term high-dose steroids, chronic inflammation, malnutrition, immobility, lack of sex steroids, and medication can reduce bone density and increase the risk for fragility fractures when left untreated. Also, genetic conditions can predispose to primary bone fragility disorders, with osteogenesis imperfecta being the most common. Furthermore, since the growing skeleton is at an increased rate of bone remodeling, the ability to heal long bone fractures and reshape vertebral fractures differentiates children from adults. The scope of this chapter is to review the risk factors of osteoporosis and fragility fractures and describe the commonest causes of primary and secondary osteoporosis and their management in children and young adults.     

Assessment of inflamed synovial membrane in the knee joint by dynamic magnetic resonance imaging

Dynamic magnetic resonance imaging (dynamic MRI) was used to examine the synovial membrane in the knee joints of 15 patients with rheumatoid arthritis (RA) in order to investigate the relationship between pathological and MRI findings. Signal intensities in the regions of interest (ROI), identified as the synovial membrane of the suprapatellar pouch, were measured on MR images. Signal intensities at various times after the injection of contrast medium Gd–diethylenetriaminopentoacetic acid (Gd–DTPA) were normalized relative to the signal intensity at 80s, and designated as the normalized signal intensity (NSI). Pathological findings were quantified, and the types of inflamed synovial membrane were classified as either acute or chronic. A significant difference in NSI was observed between acute and chronic types (P 0.05). Dynamic MRI was capable of classifying acute and chronic RA by measuring NSI 20s after contrast medium injection. Dynamic MRI was therefore shown to be useful for assessing regional synovial inflammation.     

Assessment of Multivessel Coronary Artery Disease Using Cardiovascular Magnetic Resonance Pixelwise Quantitative Perfusion Mapping

ObjectivesThe authors sought to compare the diagnostic accuracy of quantitative perfusion maps to visual assessment (VA) of first-pass perfusion images for the detection of multivessel coronary artery disease (MVCAD).BackgroundVA of first-pass stress perfusion cardiac magnetic resonance (CMR) may underestimate ischemia in MVCAD. Pixelwise perfusion mapping allows quantitative measurement of regional myocardial blood flow, which may improve ischemia detection in MVCAD.MethodsOne hundred fifty-one subjects recruited at 2 centers underwent stress perfusion CMR with myocardial perfusion mapping, and invasive coronary angiography with coronary physiology assessment. Ischemic burden was assessed by VA of first-pass images and by quantitative measurement of stress myocardial blood flow using perfusion maps.ResultsIn patients with MVCAD (2-vessel [2VD] or 3-vessel disease [3VD]; n = 95), perfusion mapping identified significantly more segments with perfusion defects (median segments per patient 12 [interquartile range (IQR): 9 to 16] by mapping vs. 8 [IQR: 5 to 9.5] by VA; p < 0.001). Ischemic burden (IB) measured using mapping was higher in MVCAD compared with IB measured using VA (3VD mapping 100 % (75% to 100%) vs. first-pass 56% (38% to 81%) ; 2VD mapping 63% (50% to 75%) vs. first-pass 41% (31% to 50%); both p < 0.001), but there was no difference in single-vessel disease (mapping 25% (13% to 44%) vs. 25% (13% to 31%). Perfusion mapping was superior to VA for the correct identification of extent of coronary disease (78% vs. 58%; p < 0.001) due to better identification of 3VD (87% vs. 40%) and 2VD (71% vs. 48%).ConclusionsVA of first-pass stress perfusion underestimates ischemic burden in MVCAD. Pixelwise quantitative perfusion mapping increases the accuracy of CMR in correctly identifying extent of coronary disease. This has important implications for assessment of ischemia and therapeutic decision-making.