Associations of Infarct Size and Regional Myocardial Function Examined by Cardiac Magnetic Resonance Feature Tracking Strain Analysis with the Infarct Location in Patients with Acute ST-Segment Elevation Myocardial Infarction

Objective To quantitatively evaluate the associations of infarct size,regional myocardial function examined by cardiac magnetic resonance feature tracking(CMR-FT)strain analysis with infarct location in patients with ST-segment elevation myocardial infarction(STEMI)treated by primary percutaneous coronary intervention.Methods Cardiac magnetic resonance images were retrospectively analyzed in 95 consecutive STEMI patients with successful reperfusion.The patients were divided into the anterior wall myocardial infarction(AWMI)and nonanterior wall myocardial infarction(NAWMI)groups.Infarct characteristics were assessed by late gadolinium enhancement.Global and regional strains and associated strain rates in the radial,circumferential and longitudinal directions were assessed by CMR-FT based on standard cine images.The associations of infarct size,regional myocardial function examined by CMR-FT strain analysis with infarct location in STEMI patients were evaluated by the Spearman or Pearsonmethod.Results There were 44 patients in the AWMI group and 51 in the NAWMI group.The extent of left ventricular enhanced mass was significantly larger in patients with AWMI compared with the NAWMI group(24.47±11.89,21.06±12.08%LV;t=3.928,P=0.008).In infarct zone analysis,strains in the radial,circumferential and longitudinal directions were remarkably declined in the AWMI group compared with the NAWMI group(z=-20.873,-20.918,-10.357,all P<0.001).The volume(end-systolic volume index),total enhanced mass and extent of enhanced mass of the left ventricular were correlated best with infarct zone strain in the AWMI group(all P<0.001).Conclusion In STEMI patients treated by percutaneous coronary intervention,myocardial damage is more extensive and regional myocardial function in the infarct zone is lower in the AWMI group compared with the NAWMI group.

Interaction between the left ventricular ejection fraction and left ventricular strain and its relationship with coronary stenosis

BACKGROUND Coronary artery stenosis(CAS)is the most common type of heart disease and the leading cause of death in both men and women globally.CAS occurs when the arteries that supply blood to the heart muscle harden and become narrower due to plaque buildup-cholesterol and other material-on their inner walls.As a result,the heart muscle cannot receive the blood or oxygen it needs.Most heart attacks happen when a blood clot suddenly cuts off the hearts'blood supply,causing permanent heart damage.AIM To analyze the relationship between the left ventricular ejection fraction(LVEF),left ventricular strain(LVS),and coronary stenosis.METHODS A total of 190 participants were enrolled in this trail.The control group comprised 93 healthy individuals,and observation group comprised 97 patients with coronary heart disease who were hospitalized between July 2020 and September 2021.Coronary lesions were assessed using the Gensini score,and the LVEF and LVS were measured using magnetic resonance imaging(MRI).The interaction between the LVEF and LVS was examined using a linear regression model.The relationship between LVEF and coronary stenosis was examined using Spearman’s correlation.RESULTS The LVEF of the observation group was lower than that of the control group.The left ventricular end-systolic volume(LVESV)and left ventricular end-diastolic volume(LVEDV)of the observation group were significantly higher than those of the control group(P<0.05).The longitudinal and circumferential strains(LS,CS)of the observation group were significantly higher than those of the control group;however,the radial strain(RS)of the observation group was significantly lower than that of the control group(P<0.05).LVS,LS,and CS were significantly negatively correlated with the LVEF,and RS was positively correlated with the LVEF.There were significant differences in the LVEF,LVESV,and LVEDV of patients with different Gensini scores;the LVEF significantly decreased and the LVESV and LVEDV increased with increasing Gensini scores(P<0.05).In the observation group,the LVEF was negatively correlated and the LVESV and LVEDV were positively correlated with coronary stenosis(P<0.05).CONCLUSION The LVEF measured using MRI is significantly linearly correlated with LVS and negatively correlated with coronary stenosis.

Seg-CapNet:A Capsule-Based Neural Network for the Segmentation of Left Ventricle from Cardiac Magnetic Resonance Imaging

Deep neural networks(DNNs)have been extensively studied in medical image segmentation.However,existing DNNs often need to train shape models for each object to be segmented,which may yield results that violate cardiac anatomical structure when segmenting cardiac magnetic resonance imaging(MRI).In this paper,we propose a capsulebased neural network,named Seg-CapNet,to model multiple regions simultaneously within a single training process.The Seg-CapNet model consists of the encoder and the decoder.The encoder transforms the input image into feature vectors that represent objects to be segmented by convolutional layers,capsule layers,and fully-connected layers.And the decoder transforms the feature vectors into segmentation masks by up-sampling.Feature maps of each down-sampling layer in the encoder are connected to the corresponding up-sampling layers,which are conducive to the backpropagation of the model.The output vectors of Seg-CapNet contain low-level image features such as grayscale and texture,as well as semantic features including the position and size of the objects,which is beneficial for improving the segmentation accuracy.The proposed model is validated on the open dataset of the Automated Cardiac Diagnosis Challenge 2017(ACDC 2017)and the Sunnybrook Cardiac Magnetic Resonance Imaging(MRI)segmentation challenge.Experimental results show that the mean Dice coefficient of Seg-CapNet is increased by 4.7%and the average Hausdorff distance is reduced by 22%.The proposed model also reduces the model parameters and improves the training speed while obtaining the accurate segmentation of multiple regions.

Left ventricular systolic function assessment in patients with dilated heart failure using cardiovascular magnetic resonance

Cardiovascular magnetic resonance (CMR) has become a reference standard for the measure-ment of cardiac volumes, function, and mass. This study aims to reconstruct three dimen-sional modeling of the left ventricle (LV) in pa-tients with heart failure (HF) using CMRtools and thereby derive the LV functional indices. CMR images were acquired in 41 subjects (6 females) with heart failure (HF) and 12 normal controls (4 females). Five comparisons were made (i) nor-mal and dilated heart failure subjects, (ii) male and female normal heart, (iii) male and female dilated heart, (iv) male normal and dilated heart failure and (v) female normal and dilated heart failure. In HF, a significant higher values of EDV (320 刡 79 vs. 126 刡 22 ml, P&amp;amp;amp;amp;amp;lt;0.0001), ESV (255 刡 68 vs. 54 刡 12 ml, P&amp;amp;amp;amp;amp;lt;0.00001) and lower values of EF (20 刡 7 vs. 58 刡 5 %) were found compared that of normal control. There were significant difference on LV EDV and ESV between sex in both normal and HF subjects.

Clinical applications of feature-tracking cardiac magnetic resonance imaging

Cardiovascular diseases represent the leading cause of mortality and morbidity in the western world. Assessment of cardiac function is pivotal for early diag-nosis of primitive myocardial disorders, identification of cardiac involvement in systemic diseases, detection of drug-related cardiac toxicity as well as risk stratification and monitor of treatment effects in patients with heart failure of various etiology. Determination of ejection fraction with different imaging modalities currently represents the gold standard for evaluation of cardiac function. However, in the last few years, cardiovascular magnetic resonance feature tracking techniques has emerged as a more accurate tool for quantitative evalu-ation of cardiovascular function with several parameters including strain, strain-rate, torsion and mechanical dispersion. This imaging modality allows precise quantification of ventricular and atrial mechanics by directly evaluating myocardial fiber deformation. The purpose of this article is to review the basic principles, current clinical applications and future perspectives of cardiovascular magnetic resonance myocardial feature tracking, highlighting its prognostic implications.

Isolated left ventricular apical hypoplasia:Systematic review and analysis of the 37 cases reported so far

BACKGROUND Isolated left ventricular apical hypoplasia(ILVAH),also known as truncated left ventricle(LV),is a very unusual cardiomyopathy.It is characterised by a truncated,spherical,and non-apex forming LV.The true apex is occupied by the right ventricle.Due to the rarity of the disease,just a few case reports and limited case series have been published in the field.AIM To analysing the so far 37 reported ILVAH cases worldwide.METHODS The electronic databases PubMed and Scopus were investigated from their establishment up to December 13,2022.RESULTS The majority of cases reported occurred in males(52.7%).Mean age at diagnosis was 26.1±19.6 years.More than a third of the patients were asymptomatic(35.1%).The most usual clinical presentation was breathlessness(40.5%).The most commonly detected electrocardiogram changes were T wave abnormalities(29.7%)and right axis deviation with poor R wave progression(24.3%).Atrial fibrillation/flutter was detected in 24.3%.Echocardiography was performed in 97.3%of cases and cardiac MRI in 91.9%of cases.Ejection fraction was reduced in more than a half of patients(56.7%).An associated congenital heart disease was found in 16.2%.Heart failure therapy was administered in 35.1%of patients.The outcome was favorable in the vast majority of patients,with just one death.CONCLUSION ILVAH is a multifaceted entity with a so far unpredictable course,ranging from benign until the elderly to sudden death during adolescence.

Automated Segmentation of Left Ventricle Using Local and Global Intensity Based Active Contour and Dynamic Programming

The aim of this work is to develop an improved region based active contour and dynamic programming based method for accurate segmentation of left ventricle （LV） from multi-slice cine short axis cardiac magnetic resonance （MR） images. Intensity inhomogeneity and weak object boundaries present in MR images hinder the segmentation accuracy. The proposed active contour model driven by a local Gaussian distribution fitting （LGDF） energy and an auxiliary global intensity fitting energy improves the accuracy of endocardial boundary detection. The weightage of the global energy fitting term is dynamically adjusted using a spatially varying weight function. Dynamic programming scheme proposed for the segmentation of epicardium considers the myocardium probability map and a distance weighted edge map in the cost matrix. Radial distance weighted technique and conical geometry are employed for segmenting the basal slices with left ventricle outflow tract （LVOT） and most apical slices. The proposed method is validated on a public dataset comprising 45 subjects from medical image computing and computer assisted interventions （MICCAI） 2009 segmentation challenge. The average percentage of good endocardial and epicardial contours detected is about 99%, average perpendicular distance of the detected good contours from the manual reference contours is 1.95 mm, and the dice similarity coefficient between the detected contours and the reference contours is 0.91. Correlation coefficient and the coefficient of determination between the ejection fraction measurements from manual segmentation and the automated method are respectively 0.9781 and 0.9567, for LV mass these values are 0.9249 and 0.8554. Statistical analysis of the results reveals a good agreement between the clinical parameters determined manually and those estimated using the automated method.

特征追踪心脏MRI定量评估非梗阻性肥厚型心肌病左房功能的应用研究

目的:应用特征追踪心脏MRI(FT-cMRI)对非梗阻性肥厚型心肌病(NOHCM)患者进行左房应变分析来评估左心房功能,并探究NOHCM对左心结构和功能的影响。方法:回顾性分析2020年1月-2022年12月本院58例非梗阻性肥厚型心肌病患者(NOHCM组)和30例健康对照者(HC组)的临床和MRI资料。MRI扫描序列主要为单次激发FSE亮血序列,扫描平面包括两腔、四腔和短轴位。应用CVI42软件测量左房容积指数(LAVI)和左房整体功能参数,后者包括心肌储备功能参数[总应变(εs)、峰值正向应变率(SRs)、左房总射血分数(LATEF)]、导管功能参数[主动应变(εe)、峰值早期负向应变率(SRe)、左房被动射血分数(LAPEF)]和升压泵功能参数[被动应变(εa)、峰值晚期负向应变率(SRa)、左房主动射血分数(LAAEF)],以及左室的功能[左室射血分数(LVEF)、左室心输出量(LVCO)和左室心脏指数(LVCI)]和大小参数[左室最大室壁厚度(LVWT_(max))、左室心肌质量(LVM)、左室质量指数(LVMI)、左室舒张末期容积指数(LVEDVi)和左室收缩末期容积指数(LVESVi)]。采用两样本t检验、Mann-Whitney U检验等统计学方法比较两组间各项定量参数值的差异,并采用Pearson或Spearman相关系数分析左房功能参数与左室的结构和功能参数之间的相关性。结果:NOHCM组的LVWT_(max)、LVM、LVMI和LAVI值均显著高于HC组(P<0.05),NOHCM组的左房功能参数值(LATEF、LAPEF、LAAEF、εs、εe、εa,SRs、SRe和SRa)均显著低于HC组(P<0.05)。NOHCM组左室心肌不同肥厚部位的LVWT_(max)的差异有统计学意义(P<0.05),两组之间其它的左房、左室结构和功能参数值的差异无统计学意义(P>0.05)。左房大小正常的NOHCM患者的LATEF、LAPEF、εs、εe、SRs和SRe值均显著低于HC组(P<0.05),而LAAEF、εa和SRa值在两组之间的差异无统计学意义(P>0.05)。所有受试者的LATEF与εs、LAPEF与εe、LAAEF与εa之间均具有显著相关性(r>0.70)。结论:与健康对照组相比,NOHCM患者各时相左房功能均下降。在左房增大之前,左房的心肌储备和导管功能下降,而升压泵功能正常。各时相左房功能受损与左室的肥厚部位无显著相关性。各时相左房的LAEF与各项应变参数之间具有较强的相关性。

心脏磁共振组织特征追踪技术评估左心衰合并肺高压的临床价值

目的基于心脏磁共振特征追踪(cardiac magnetic resonance feature tracking,CMR-FT)技术定量分析左心衰合并肺高压(pulmonary hypertension due to left heart failure,PH-LHF)患者的心肌应变参数并探讨心脏磁共振(cardiac magnetic resonance,CMR)在评估PH-LHF患者中的应用价值。材料与方法回顾性分析2018年9月至2020年9月期间215例确诊为左心衰(left heart failure,LHF)患者的临床和CMR参数,根据心脏超声测量的收缩期肺动脉压将患者分为两组,即LHF组(n=129)和PH-LHF组(n=86)。比较两组的基线资料和CMR参数包括心血管形态参数、心室容积功能参数以及心室心房应变参数。通过单因素及多因素logistic回归分析CMR参数中PH-LHF的独立预测因子,并绘制受试者工作特征(receiver operating characteristics,ROC)曲线评估CMR参数的诊断价值。结果PH-LHF患者组左右心室舒张末期容积指数、收缩末期容积指数、右心室心肌质量指数、室间隔角、左心房最大直径及面积、初始T1值均高于LHF组,而左右心室射血分数、右心室每搏输出量指数、右心室心脏指数低于LHF组。PH-LHF组左心室整体纵向应变、整体周向应变以及应变率、右心室整体周向应变、左心房主动应变、被动应变、总应变均不同程度下降。多因素logistic回归分析显示CMR参数中右心室射血分数,左心室整体周向应变,左心房主动应变和左心房最大直径是PH-LHF的独立预测因子。ROC曲线分析结果显示临床模型、CMR模型、联合模型诊断PH-LHF的AUC值分别为0.773、0.777、0.828,并且DeLong检验显示当加入CMR参数后,临床模型诊断效能提升(0.773 vs.0.828,P<0.05)。结论基于CMR-FT技术的心肌应变参数可以定量评估心室心房应变,反映PH-LHF患者的心肌功能以及运动情况,多参数CMR在诊断评估LHF是否合并PH中具有较好的临床增益价值。

CMR特征追踪技术在帕金森病患者左心评估中的价值

目的应用心脏磁共振特征追踪(cardiac magnetic resonance feature tracking,CMR-FT)技术评估帕金森病(Parkinson’s disease,PD)患者的左心结构和功能,并探讨影响其结构和功能的因素。材料与方法前瞻性纳入2022年3月至2023年8月于四川大学华西医院就诊的PD患者(PD组)39例,同期招募年龄及性别匹配的健康对照者(对照组)34例,均完成常规心脏磁共振(cardiac magnetic resonance,CMR)检查。使用专业后处理软件CVI42分别获得左心室及左心房的常规心功能及心肌应变参数。左心室参数包括:收缩末期容积、舒张末期容积、心肌质量、射血分数、整体周向、径向及纵向应变。左心房参数包括:储备期、导管期及泵血期的射血分数、容积、应变及应变率。采用独立样本t检验或Mann-Whitney U检验分析各参数的组间差异。采用Pearson或Spearman相关系数模型分析常规心功能及应变参数与运动功能及自主神经功能的相关性。结果PD组相较于对照组,左室射血分数[(62.01±6.59)%vs.(64.84±4.70)%]及整体的纵向应变[(-17.25±1.57)%vs.(-18.28±1.99)%]均较低(P均<0.05)。PD组相较于对照组,左心室收缩末期容积(left ventricular end-systolic volume,LVESV)[(51.17±16.56)mL vs.(42.56±9.06)mL]、LVESV指数(LVESV index,LVESVi)[(30.44±8.00)mL·m^(-2)vs.(25.56±5.14)m L·m^(-2)]、左心室舒张末期容积指数(left ventricular end-diastolic volume index,LVEDVi)[(79.31±10.76)m L·m^(-2)vs.(72.97±12.51)mL·m^(-2)]及左心室心肌质量指数(left ventricular mass index,LV massi)[41.82(33.11,47.77)g·m^(-2)vs.33.71(32.27,38.78)g·m^(-2)]均较高(P<0.05)。PD组的左心房储备期、导管期及泵血期的射血分数、应变及应变率较对照组明显减低(P均<0.05)。相关性分析显示,左心房储备期应变及应变率与统一帕金森评定量表Ⅲ(Unified Parkinson’s Disease Rating ScaleⅢ,UPDRSⅢ)评分呈负相关(r=-0.409、-0.355,P<0.05)。左心房导管期射血分数、应变与UPDRSⅢ评分呈负相关(r=-0.326、-0.482,P<0.05)、应变率与UPDRSⅢ评分呈正相关(r=0.417,P=0.008)。左心房储备期应变、应变率与自主神经症状自评量表(The Scales for Outcomes in Parkinson’s Disease-Autonomic,SCOPA-AUT)评分呈负相关(r=-0.535、-0.319,P均<0.05)。左心房导管期应变与SCOPA-AUT评分呈负相关(r=-0.319,P=0.048),应变率与SCOPA-AUT评分呈正相关(r=0.359,P=0.025)。左心房泵血期应变与SCOPA-AUT呈负相关(r=-0.342,P=0.033)。结论CMR-FT获得的应变及应变率参数可早期评估PD患者的心功能受损程度。PD患者左室收缩功能及左心房储备、导管、泵功能受损;左心房储备功能及导管功能与运动功能障碍及自主神经功能障碍的严重程度相关。

心脏磁共振在左心房评估中的应用

作为左心室的延续,左心房与左心室相互影响,在整个心脏的功能中发挥重要作用。目前评估心房结构及功能的技术很多,但是由于左心房结构复杂且心肌较薄,给相关评估带来了一定挑战。本文从心肌应变、延迟强化方面介绍左心房评估的参数、评估过程中的注意事项及相关临床应用。

CMR在高血压心脏病中的应用进展

高血压作为各种心血管疾病的最重要诱因,会引起心脏结构变化、冠脉微循环障碍等一系列适应性改变,因此,对高血压患者心脏结构和功能的评价显得格外重要。临床上常用于评价心脏结构和功能的工具为超声心动图,但心脏磁共振(cardiac magnetic resonance,CMR)较其具有更好的软组织分辨率及多功能、多参数成像的优点,可通过电影序列、T2WI、灌注成像序列、早期强化序列以及延迟强化序列(late gadolinium enhancement,LGE)、增强前后T1 mapping对高血压心脏病(hypertensiveheartdisease,HHD)进行全方位评估。本文通过总结这些技术对高血压引起的左室肥厚(leftventricular hypertrophy,LVH)、心肌纤维化、收缩舒张功能降低、冠脉微循环障碍等方面进行的定量、定性分析,对指导临床决策、改善患者预后有重要意义,并有望为将来的研究提供参考方向。

心脏磁共振成像整体纵向应变对急性ST段抬高型心肌梗死后左心室重构的预测价值:403例前瞻性研究

目的 分析心脏磁共振成像(CMR)特征追踪技术测量的整体纵向应变(GLS)对急性ST段抬高型心肌梗死(STEMI)患者接受经皮冠状动脉介入治疗后(PCI)左心室重构(LVR)的预测价值。方法 前瞻性纳入来自国内多中心的经PCI术后的STEMI患者共403例,分别于心肌梗死后1周(7±2 d)和6月进行CMR检查,获得GLS、整体径向应变(GRS)、整体周向应变(GCS)、射血分数(LVEF)和心肌梗死面积(IS)。主要终点为LVR,其定义是随访中通过CMR检查左心室舒张末期容积从基线到6月增加≥20%或左心室收缩末期容积增加≥15%,根据LVR的发生情况将患者分为LVR组(n=101)和无LVR组(n=302)。采用Logistic回归分析CMR参数对LVR的预测价值。结果 与无LVR组相比,LVR组的GLS、GCS更大(P<0.001),GRS、LVEF更小(P<0.001)。Logistic回归分析显示,GLS(OR:1.387,95%CI:1.223~1.573,P<0.001)和LVEF(OR:0.951,95%CI:0.914~0.990,P=0.015)是LVR的独立预测因子。ROC曲线分析显示,GLS预测LVR的最佳临界值为-10.6%,灵敏度为74.3%,特异度为71.9%。GLS预测LVR的AUC与LVEF的差异无统计学意义(P=0.146),但优于GCS、GRS和IS等其他参数(P<0.05)。LVEF与其他参数的AUC差异无统计学意义(P>0.05)。结论 基于CMR测定的GLS是STEMI患者PCI术后LVR的重要预测因子,与GRS、GCS、IS和LVEF相比具有明显的优势。

2型糖尿病对非缺血性扩张型心肌病患者左心室应变影响

目的:采用心脏磁共振特征追踪技术(CMR-FT)定量及延迟钆增强(LGE)特征定量、定性评估2型糖尿病(T2DM)对非缺血性扩张型心肌病(NIDCM)患者左室应变及组织特征的影响。方法:回顾性纳入行CMR检查的38例NIDCM患者及20名健康对照者,将NIDCM根据有无T2DM病史分为两组,比较三组间一般临床资料、左室结构及功能、应变参数及两组NIDCM患者的组织特征差异,并通过一元线性回归分析判断NIDCM患者左室心肌应变的临床重要预测因子。结果:NIDCM(T2DM+)组HbA1c、高血压患病率均高于NIDCM(T2DM-)组及对照组,差异具有统计学意义(P<0.05)。NIDCM(T2DM+)组心尖部周向及纵向应变、整体周向应变均较NIDCM(T2DM-)组降低,差异具有统计学意义(P<0.05)。两组NIDCM患者的LGE特征差异均无统计学意义。在一元线性回归分析中T2DM为NIDCM患者左室整体周向(β=0.35,P=0.031)及纵向应变(β=0.354,P=0.029)降低的重要临床预测因子。结论:CMR-FT技术可准确评估合并T2DM的NIDCM患者左室应变下降,且T2DM与NIDCM患者左室整体周向及纵向应变的降低显著相关。

Left atrial physiology and pathophysiology:Role of deformation imaging

The left atrium(LA) acts as a modulator of left ventricular(LV) filling. Although there is considerable evidence to support the use of LA maximum and minimum volumes for disease prediction,theoretical considerations and a growing body of literature suggest to focus on the quantification of the three basic LA functions:(1) Reservoir function:collection of pulmonary venous return during LV systole;(2) Conduit function:passage of blood to the left ventricle during early LV diastole; and(3) Contractile booster pump function(augmentation of ventricular filling during late LV diastole. Tremendous advances in our ability to non-invasively characterize all three elements of atrial function include speckle tracking echocardiography(STE),and more recently cardiovascular magnetic resonance myocardial feature tracking(CMR-FT). Corresponding imaging biomarkers are increasingly recognized to have incremental roles in determining prognosis and risk stratification in cardiac dysfunction of different origins. The current editorial introduces the role of STE and CMR-FT for the functional assessment of LA deformation as determined by strain and strain rate imaging and provides an outlook of how this exciting field may develop in the future.

心脏磁共振成像对急性ST段抬高型心肌梗死后左心室不良重构的预测价值

目的评估心脏磁共振(CMR)对ST段抬高型心肌梗死(STEMI)后左心室不良重构的价值。方法回顾性分析86例STEMI患者经皮冠状动脉介入术后1周及5个月的临床资料和CMR图像。所有受试者均采集电影和LGE序列。将患者分为左心室不良重构组(n=25)和无左心室不良重构组(n=61)。左心室不良重构定义为第2次CMR检查时左心室收缩末期容积(LVESV)较初始CMR增加15%或更多。CMR分析包括左心室容积、心肌梗死特征、整体和区域心肌功能。采用Logistic回归法分析左心室不良重构的独立预测因素。结果在初始CMR时,两组患者的左心室容积及左心室射血分数(LVEF)差异均无统计学意义(P>0.05),但左心室不良重构组梗死质量百分比[(34.07±10.04)%vs(22.20±11.29)%,P<0.001]和微血管阻塞(MVO)质量百分比[1.9(0,3.8)%vs 0(0,1.06)%,P<0.001]明显大于无左心室不良重构组。随时间推移,两组患者的心肌损伤和心功能均有恢复。但在第2次CMR时,左心室不良重构患者有更低的LVEF[(42.01±9.51)%vs(55.23±10.04)%,P<0.001]、更大的左心室收缩末期容积指数[55.58(43.15,69.91)mL/m^(2)vs 35.79(26.70,45.04)mL/m^(2),P<0.001]和梗死质量百分比[(26.71±24.51)%vs(17.08±9.25)%,P<0.001]。左心室不良重构组整体峰值应变及应变率、梗死区峰值应变、径向和周向峰值应变率更小(均P<0.05)。多因素分析显示,只有3个因素是左心室不良重构的独立预测因素,其中梗死质量百分比预测左心室不良重构的AUC为0.793(95%CI 0.693~0.873),截断值为30.67%;整体径向舒张期峰值应变率的AUC为0.645(95%CI 0.534~0.745),截断值为0.58%;肾素血管紧张素醛固酮系统(RAAS)抑制剂的AUC为0.699(95%CI 0.590~0.793)。结论在急性期,左心室不良重构组和无左心室不良重构患者的左心室容积、整体及节段的心功能没有显著差异;但随时间推移,左心室不良重构组的左心室容积明显变大,整体及节段的心功能明显更差。梗死质量百分比、径向舒张期峰值应变率及RAAS抑制剂是左心室不良重构的独立预测因子。

A Ring-Reinforced Right Ventricle to Pulmonary Artery Conduit Is Associated with Better Regional Mechanics after Stage I Norwood Operation

Background:The right ventricle to pulmonary artery conduit(RVPAC)may impair right ventricular(RV)function in patients with functional single right ventricles.Modification of the RVPAC using a ring-reinforced end with dunked insertion into the RV through a limited ventriculotomy may reduce the impact on RV function.We compared RV segmental strain between patients with a traditional RVPAC and ring-reinforced RVPAC using feature tracking cardiovascular magnetic resonance(CMR)imaging.Methods:Patients with CMR examinations after Stage I operation with RVPAC between 2000 and 2018 were reviewed.Ventricular mass,volumes,late gadolinium enhancement(LGE),and peak radial and circumferential strain of the 4 segments near the RVPAC insertion site were analyzed.Results:The study included 71 CMR examinations in 61 patients(30 traditional RVPAC,31 ring-reinforced RVPAC).Prior to Stage II,the ring-reinforced RVPAC group had better peak radial strain and circumferential strain in 1 of 4 segments proximal to the RVPAC insertion site compared to the traditional RVPAC group.Prior to Stage III operation,the ring-reinforced group had better peak radial and circumferential strain in 2 of 4 segments.LGE at the RVPAC insertion site was observed in 97%of patients before Stage II and 95%of patients before Stage III.RVPAC type and regional strain were not associated with transplant-free survival during a median follow-up of 6.3 years.Conclusions:Compared to a traditional RVPAC,the ring-reinforced RVPAC is associated with improved regional mechanics at the conduit insertion site.Further investigation of long-term outcomes after ring-reinforced RVPAC is warranted.

磁共振特征追踪技术在急性心肌炎中的临床应用

目的:应用心脏磁共振特征追踪(CMR-FT)技术评价急性心肌炎(aMC)患者左心室心肌应变功能,探讨应变参数与左心室射血分数(LVEF)的相关性。方法:回顾性搜集49例aMC患者和32例健康志愿者(对照组)电影序列心脏MRI图像(标准两腔、三腔、四腔及短轴位),采用磁共振后处理站计算两组被试者的LVEF,并应用CMR-FT技术测量左心室各项心肌应变参数值(左心室心肌整体径向应变、周向应变和纵向应变及各向应变率)并进行组间比较,采用受试者工作特征(ROC)曲线评价左心室应变参数诊断aMC的效能,并对aMC组中收缩期和舒张期各项应变参数与LVEF的相关性进行统计学分析。结果:aMC组和对照组的心肌整体径向应变、周向应变和纵向应变值分别为26.07%±13.60%vs.38.95%±8.90%、-15.58%±5.97%vs.-20.79%±2.33%、-10.86%±5.25%vs.-15.22%±3.30%,aMC组的左心室各项应变参数值均低于对照组,差异均具有统计学意义(P<0.05)。左心室周向应变和径向应变预测急性心肌炎组的敏感度分别为77.55%和61.22%,特异度分别为75.00%和84.38%。左心室各项应变参数与LVEF之间均具有相关性,其中左心室径向应变、周向应变与LVEF呈高度相关(r=0.809、-0.904,P均<0.05)。结论:CMR-FT技术能够定量评价急性心肌炎患者左心室心肌应变功能,为临床评估aMC患者的心肌损伤程度提供参考依据,其测得的心肌应变参数和LVEF在反映心肌收缩功能受损方面具有较好的一致性。

基于心脏磁共振的左心房应变在心脏疾病中的应用进展

左心房(left atrium,LA)功能与多种心脏疾病的发生发展、预后密切相关。近年来,随着后处理软件的成熟,心脏磁共振特征追踪技术(cardiac magnetic resonance feature tracking,CMR-FT)可对多种心脏疾病的LA心肌应变进行无创综合分析,克服了单一LA体积测量的局限性,且LA心肌应变更能反映早期心功能障碍及预后情况。本文基于CMR-FT评估LA应变在各种心脏疾病的早期功能改变、危险分层、预后等方面的应用进展予以综述,旨在为进一步探索LA应变在心脏疾病的应用提供影像依据。

非酒精性脂肪肝病MR mDixon脂肪分数与左室心肌应变的相关性:早期心功能改变探索

目的:采用心脏磁共振特征追踪(CMR-FT)技术探索非酒精性脂肪肝病(NAFLD)患者早期心功能是否改变,并分析NAFLD患者的MR mDixon肝脏脂肪分数(HFF)与左室心肌应变的相关性。方法:纳入左室射血分数正常(LVEF≥50%)的NAFLD患者和性别、年龄相匹配的健康志愿者(对照组)。所有纳入者均行CMR检查,利用CMR-FT分析三个方向的整体应变及应变率,即:整体纵向应变(GLS)、整体周向应变(GCS)、整体径向应变(GRS)、舒张期整体纵向峰值应变率(GLPDSR)、舒张期整体周向峰值应变率(GCPDSR)、舒张期整体径向峰值应变率(GRPDSR)、收缩期整体纵向峰值应变率(GLPSSR)、收缩期整体周向峰值应变率(GCPSSR)、收缩期整体径向峰值应变率(GRPSSR)。结果:NAFLD组25例,对照组25例。与对照组相比,NAFLD患者的GLS、GCS、GLPDSR、GCPDSR受损(均P<0.05),但GRS、GRPDSR、GLPSSR、GCPSSR、GRPSSR在两组间差异无统计学意义(均P>0.05)。Spearman相关性分析显示,NAFLD患者的HFF与GLPDSR、GCPDSR呈中度负相关(rs=-0.441、-0.466,P=0.027、0.019),与GLS、GCS、GRS、GRPDSR、GLPSSR、GCPSSR、GRPSSR无相关性(均P>0.05)。结论:在LVEF正常的NAFLD患者中,可以通过CMR-FT检测到患者早期左室功能障碍,且HFF与GLPSSR、GCPSSR呈中度负相关。