心肌T1、T2mapping技术和细胞外容积分数对急性心肌梗死的诊断价值

目的 探讨心肌T1、T2 mapping技术和细胞外容积分数(extracellularvolume fraction,ECV)在急性心肌梗死中的诊断价值.方法 采用西门子1.5T Aera磁共振扫描仪对24例急性心梗的患者行心肌T1、T2 mapping序列和延迟灌注检查,将扫描图像输入到syng MR D13后处理...     

钆延迟强化联合心脏磁共振T1 mapping在心肌淀粉样变性和肥厚性心肌病的应用:95例患者前瞻性研究

  目的  研究钆延迟强化联合心脏磁共振T1 mapping在心肌淀粉样变性（CA）和肥厚性心肌病（HCM）患者临床检查中的应用。  方法  采用前瞻性研究方法,以我院2018年12月~2020年12月诊断的CA患者40例和HCM患者55例作为研究对象,另选取同期进行健康体检的患者54例作为对照组,比较3组患者的心功能、心脏形态学、MRI相关指标之间的差异。  结果  左心室收缩期末容积、左心室射血分数在3组间的差异存在统计学意义（P < 0.05）,通过两两比较,左心室收缩期末容积、左心室射血分数从高到低依次为HCM组、对照组、CA组,3组患者的LVEF差异不存在统计学意义（P > 0.05）;左室壁厚度以及左心室质量从高到低依次为HCM组、CA组以及对照组（P < 0.05）;增强前T1值从高到低依次为CA组、HCM组以及对照组（P < 0.05）;增强后T1值从高到低依次为HCM组、对照组以及CA组（P < 0.05）;细胞外容积从高到低依次为CA组、对照组以及HCM组（P < 0.05）。  结论  钆延迟强化联合心脏磁共振T1 mapping在CA和HCM患者临床检查中具有较好的鉴别诊断能力,建议临床推广。      

3.0T磁共振延迟强化技术检测存活心肌评估CTO-PCI术后心功能恢复情况

目的 探讨利用3.0T磁共振电影成像及心肌钆延迟强化(LGE)技术检测存活心肌,评估冠状动脉慢性完全闭塞(CTO)行经皮冠状动脉介入术(PCI)患者术后心功能恢复情况.方法 连续收集2017年12月至2019年12月就诊的CTO患者32例,所有患者在PCI术前及术后6个月行3.0T心脏磁共振检查,评估心脏结构、功能、心...     

3.0T磁共振钆延迟强化技术评价小型猪慢性阻塞性肺病模型心肌纤维化的实验研究

目的利用3.0 T心脏磁共振(cardiovascular magnetic resonance,CMR)钆延迟强化(late gadolinium enhancement,LGE)技术评估巴马小型猪慢性阻塞性肺病(chronic obstructive pulmonary disease,COPD)模型左心室(lef...     

急性心肌梗死后心肌内出血

在急性心肌梗死患者中, 通过经皮冠状动脉介入治疗进行血管重建能够有效降低死亡率。然而, 即使成功开通了心外膜血管, 仍有相当比例的急性心肌梗死患者发展为慢性心力衰竭。研究发现, 冠状动脉微血管阻塞引起的"无复流"现象及随后出现的心肌内出血是参与此过程的重要因素。了解心肌内出血在"无复流"现象和心肌损伤中的作用, 对制定新的急性心肌梗死治疗策略至关重要。本文将对心肌内出血的病理生理学、影像学、临床意义和治疗策略等最新进展进行综述。     

初始T1值及细胞外容积分数对心脏淀粉样变的诊断价值：Meta分析

目的 采用Meta分析方法探讨初始T1值及细胞外容积分数(extracellular volume fraction,ECV)对心脏淀粉样变性(cardiac amyloidosis,CA)的诊断价值。材料与方法检索数据库PubMed、 Embase、 Cochrane Library、 Web of Science、Wanfang Database、CBM、VIP及CNKI中有关探讨初始T1值及ECV对CA诊断价值的文献,检索时间为从建库开始至2022年11月。由2名研究者单独完成文献筛选,提取纳入文献的相关资料并进行质量评估。应用Revman 5.3、Stata 16.0和Meta-Disc1.4软件进行偏倚风险评价和统计分析,进行异质性、发表偏倚分析。使用敏感性分析验证Meta分析结果的稳定性与可靠性。结果 最终纳入文献12篇,共1 045例患者。Meta分析显示初始T1值诊断CA的合并敏感度(sensitivity,Sen)、特异度(specificity,Spe)、阳性似然比(positive likelihood ratio,PLR)、阴性似然比(negative like...     

7.0T MR T2* mapping与T2 mapping检测急性心肌梗死再灌注模型大鼠心肌内出血

目的 观察7.0T MR T2^* mapping与T2 mapping检测急性心肌梗死(AMI)再灌注模型大鼠心肌内出血(IMH)的图像质量及其价值。方法 以42只SD大鼠制备AMI再灌注模型,于其后2 d及7 d采集左心室7.0T MR T2^* mapping与T2 mapping,获得后处理T2^* map与T2 map图;之后处死大鼠,取心脏进行病理检查,评估IMH。观察IMH大鼠各序列原始图像的信噪比(SNR)、对比噪声比(CNR)、图像质量评分及T2^* map与T2 map图像的信号均一性。以病理结果为标准,分析2个序列图像检出IMH的效能。结果 造模后2 d (9只)和7 d (16只)后,共25只大鼠造模成功并检出IMH (IMH组),10只存在AMI但无IMH,6只无心肌梗死(无心肌梗死组),另1只在扫描过程中死亡;2 d和7 d IMH组心脏T2 mapping原始图像的SNR＞T2^* mapping原始图像(P均=0.001),而CNR差异均无统计学意义(P均＞0.05)。造模后2 d,IMH组心脏T2 mapping原始图像质量评分(3.90±0.30)高于T2^* mapping (3.80±0.40,t=3.67,P＜0.01);造模后7 d,T2 mapping原始图像质量评分(3.60±0.50)与T2^* mapping差异无统计学意义(3.50±0.50,t=1.65,P=0.10)。IMH组T2 map与T2^* map图像的出血心肌及远端心肌的变异系数(COV)差异均无统计学意义(P均＞0.05),提示信号均一性无明显差异。T2 mapping及T2^* mapping检出IMH的敏感度分别为88.00%(22/25)及96.00%(24/25)。结论 7.0T MR T2^* mapping图像信号均一性、SNR及图像质量略低于T2 mapping,二者CNR相当,均可用于检测AMI再灌注大鼠模型IMH。     

T1 mapping和细胞外容积分数在诊断急性胰腺炎及复发性急性胰腺炎的应用价值初探

目的探讨T1 mapping参数及细胞外容积分数(extracellular volume fraction,ECV)在诊断急性胰腺炎(acute pancreatitis,AP)及复发性急性胰腺炎(recurrent acute pancreatitis,RAP)中的应用价值.材料与方法回顾性分析2018年12月至2020年6月行常规胰腺MRI平扫及增强、T1 mapping检查的患者,纳入AP患者40例及正常对照组22例.其中AP患者根据胰腺炎发作次数分为初次AP发作(single acute pancreatitis,SAP)组及RAP组.分别测量所有患者增强扫描前后的胰腺实质的T1 mapping参数(T1pre pancreas及T1post pancreas)及同层面腹主动脉T1值(T1pre blood及T1post blood),通过公式计算获得胰腺实质强化率(pancreatic enhancement ratio,PER)及ECV值.采用独立样本t检验和Mann-Whitney U检验进行SAP组及RAP组、AP组及正常组两两组间T1 mapping参数及ECV的比较.结果AP组的T1pre pancreas、T1post pancreas、PER及ECV参数值[分别为(1145.20±25.90)ms、(473.50±13.20)ms、0.65±0.00、0.39±0.00]均高于正常对照组的相应值[分别为(802.20±12.20)ms、(434.60±8.40)ms、0.38±0.00、0.28±0.00],其差异具有统计学意义(P<0.05).在SAP组与RAP组间,仅有ECV值(0.35±0.20及0.41±0.10)的差异具有统计学意义(P=0.01),其ROC曲线下面积为0.72.结论T1 mapping参数和细胞外容积分数可有效鉴别AP及RAP.     

T1 mapping评价扩张型心肌病心肌纤维化

目的探讨T1 mapping评价扩张型心肌病(DCM)心肌纤维化的应用价值。方法对32例DCM患者(DCM组)和16名健康体检者(对照组)行T1mapping和延迟钆增强(LGE)扫描。根据DCM患者是否存在LGE分为LGE(+)亚组和LGE(-)亚组。根据LGE形态和区域,将LGE(+)亚组心肌分为线状LGE区、斑片状LGE区、弥漫性LGE区及远程区(正常心肌区)。分别测量对照组、DCM组、线状LGE区、斑片状LGE区、弥漫性LGE区、远程区T1值,并进行统计学分析。结果 DCM组T1值[(1332.55±61.34)ms]明显高于对照组[(1222.52±45.59)ms,P<0.001]。对照组心肌T1值与线状LGE区[(1359.44±77.93)ms]、斑片状LGE区[(1456.49±110.27)ms]、弥漫性LGE区[(1524.17±52.30)ms]及远程区[(1329.11±64.12)ms]比较,差异均有统计学意义(P均<0.001)。LGE(+)亚组T1值[(1341.35±65.01)ms]与LGE(-)亚组[(1310.06±45.57)ms]差异无统计学意义(P=0.199)。LGE和T1mapping成像诊断DCM组心肌纤维化的ROC曲线下面积分别为0.84、0.95。结论 T1mapping评价DCM心肌纤维化具有较高的应用价值。     

心脏磁共振评价扩张型心肌病患者心肌纤维化和左心室功能

目的 采用MRI技术评价扩张型心肌病(DCM)患者心肌纤维化,并分析其与左心室功能的关系。方法 连续收集44例DCM患者(DCM组)和23名健康志愿者(对照组);根据DCM患者心肌是否存在LGE,将DCM组再分为LGE(+)亚组和LGE(-)亚组。所有被检者首先行左心室短轴电影扫描;并于注射对比剂前、后分别行改良的look-locker反转恢复和相位敏感反转恢复序列扫描,以取得短轴位T1 mapping和延迟增强图像。通过短轴电影序列获得左心室心功能参数,包括左心室射血分数(LVEF)、左心室舒张末期容积(LVEDV)、左心室收缩末期容积(LVESV)、左心室每搏量(LVSV)、左心室心排出量(LVCO)、左心室心肌质量(LVMM),并获得除LVEF外其余参数的标准化指数;获得左心室短轴平均T1值。对以上参数进行统计学分析。结果 DCM组LVEF和LVEDV指数、LVESV指数、LVSV指数及LVMM指数值与对照组比较差异均有统计学意义(P均<0.01);LGE(+)亚组LVEDV指数 明显大于LGE(-)亚组;DCM组心肌T1值 显示明显大于对照组;DCM组心肌T1值与LVEF呈负相关(r=-0.324,P<0.05),与LVEDV指数、LVESV指数呈正相关(r=0.385、0.384,P均<0.05)。结论 T1 mapping技术和LGE均可检测DCM心肌纤维化,且弥漫性心肌纤维化的程度与左心功能存在一定关系。     

Cardiovascular magnetic resonance characterization of peri-infarct zone remodeling following myocardial infarction

Background

Clinical studies implementing late gadolinium-enhanced (LGE) cardiovascular magnetic resonance (CMR) studies suggest that the peri-infarct zone (PIZ) contains a mixture of viable and non-viable myocytes, and is associated with greater susceptibility to ventricular tachycardia induction and adverse cardiac outcomes. However, CMR data assessing the temporal formation and functional remodeling characteristics of this complex region are limited. We intended to characterize early temporal changes in scar morphology and regional function in the PIZ.

Methods and results

CMR studies were performed at six time points up to 90 days after induction of myocardial infarction (MI) in eight minipigs with reperfused, anterior-septal infarcts. Custom signal density threshold algorithms, based on the remote myocardium, were applied to define the infarct core and PIZ region for each time point. After the initial post-MI edema subsided, the PIZ decreased by 54% from day 10 to day 90 (p = 0.04). The size of infarct scar expanded by 14% and thinned by 56% from day 3 to 12 weeks (p = 0.004 and p < 0.001, respectively). LVEDV increased from 34.7. ± 2.2 ml to 47.8 ± 3.0 ml (day3 and week12, respectively; p < 0.001). At 30 days post-MI, regional circumferential strain was increased between the infarct scar and the PIZ (-2.1 ± 0.6 and -6.8 ± 0.9, respectively;* p < 0.05).

Conclusions

The PIZ is dynamic and decreases in mass following reperfused MI. Tensile forces in the PIZ undergo changes following MI. Remodeling characteristics of the PIZ may provide mechanistic insights into the development of life-threatening arrhythmias and sudden cardiac death post-MI.     

CMR of microvascular obstruction and hemorrhage in myocardial infarction

Microvascular obstruction (MO) or no-reflow phenomenon is an established complication of coronary reperfusion therapy for acute myocardial infarction. It is increasingly recognized as a poor prognostic indicator and marker of subsequent adverse LV remodeling. Although MO can be assessed using various imaging modalities including electrocardiography, myocardial contrast echocardiography, nuclear scintigraphy, and coronary angiography, evaluation by cardiovascular magnetic resonance (CMR) is particularly useful in enhancing its detection, diagnosis, and quantification, as well as following its subsequent effects on infarct evolution and healing. MO assessment has become a routine component of the CMR evaluation of acute myocardial infarction and will increasingly play a role in clinical trials of adjunctive reperfusion agents and strategies. This review will summarize the pathophysiology of MO, current CMR approaches to diagnosis, clinical implications, and future directions needed for improving our understanding of this common clinical problem.     

Incremental value of cardiovascular magnetic resonance over echocardiography in the detection of acute and chronic myocardial infarction

Background

Although echocardiography is used as a first line imaging modality, its accuracy to detect acute and chronic myocardial infarction (MI) in relation to infarct characteristics as assessed with late gadolinium enhancement cardiovascular magnetic resonance (LGE-CMR) is not well described.

Methods

One-hundred-forty-one echocardiograms performed in 88 first acute ST-elevation MI (STEMI) patients, 2 (IQR1-4) days (n = 61) and 102 (IQR92-112) days post-MI (n = 80), were pooled with echocardiograms of 36 healthy controls. 61 acute and 80 chronic echocardiograms were available for analysis (53 patients had both acute and chronic echocardiograms). Two experienced echocardiographers, blinded to clinical and CMR data, randomly evaluated all 177 echocardiograms for segmental wall motion abnormalities (SWMA). This was compared with LGE-CMR determined infarct characteristics, performed 104 ± 11 days post-MI. Enhancement on LGE-CMR matched the infarct-related artery territory in all patients (LAD 31%, LCx 12% and RCA 57%).

Results

The sensitivity of echocardiography to detect acute MI was 78.7% and 61.3% for chronic MI; specificity was 80.6%. Undetected MI were smaller, less transmural, and less extensive (6% [IQR3-12] vs. 15% [IQR9-24], 50 ± 14% vs. 61 ± 15%, 7 ± 3 vs. 9 ± 3 segments, p < 0.001 for all) and associated with higher left ventricular ejection fraction (LVEF) and non-anterior location as compared to detected MI (58 ± 5% vs. 46 ± 7%, p < 0.001 and 82% vs. 63%, p = 0.03). After multivariate analysis, LVEF and infarct size were the strongest independent predictors of detecting chronic MI (OR 0.78 [95%CI 0.68-0.88], p < 0.001 and OR 1.22 [95%CI0.99-1.51], p = 0.06, respectively). Increasing infarct transmurality was associated with increasing SWMA (p < 0.001).

Conclusions

In patients presenting with STEMI, and thus a high likelihood of SWMA, the sensitivity of echocardiography to detect SWMA was higher in the acute than the chronic phase. Undetected MI were smaller, less extensive and less transmural, and associated with non-anterior localization and higher LVEF. Further work is needed to assess the diagnostic accuracy in patients with non-STEMI.     

急性心肌梗死早期患者血清中可溶型ST2水平及其与心肌活性的关系

目的探讨急性心肌梗死患者早期血清可溶性ST2(sST2)水平及其与心肌活性的关系。方法采用ELISA法检测30例发病12 h以内的非ST段抬高型心肌梗死(NSTEMI)患者血清sST2水平,于发病后第7天行心脏磁共振检查并根据磁共振结果将患者分为透壁增强组、非透壁增强组和混合组。于7¹4 d行PCI术,并于术后6个月再次行心脏磁共振检查评估心肌活性,观察指标包括梗死心肌质量、左心室射血分数及室壁运动异常评分在术前及术后的变化及其与心肌梗死早期血清sST2水平的关系。结果透壁增强组血清sST2的水平较之非透壁增强组及混合组明显升高(P<0.05),混合组较非透壁增强组高(P<0.05);梗死心肌质量及室壁运动异常评分在3组患者PCI术后均减少,梗死心肌质量在非透壁增强组及混合组中减少有统计学差异(P<0.05),室壁运动异常评分在非透壁增强组降低显著(P<0.05);左心室射血分数在3组患者PCI术后均增加,在非透壁增强组及混合组中增加有统计学差异(P<0.05)。心肌梗死早期血清sST2水平与PCI术前及PCI术后6个月的心肌活性相关。结论急性心肌梗死早期血清中sST2的水平可反映心肌受损情况并可预测心肌梗死7 d PCI术前及PCI术后6个月的心肌活性。     

Susceptibility-weighted cardiovascular magnetic resonance in comparison to T2 and T2 star imaging for detection of intramyocardial hemorrhage following acute myocardial infarction at 3 Tesla

Background

Intramyocardial hemorrhage (IMH) identified by cardiovascular magnetic resonance (CMR) is an established prognostic marker following acute myocardial infarction (AMI). Detection of IMH by T2-weighted or T2 star CMR can be limited by long breath hold times and sensitivity to artefacts, especially at 3T. We compared the image quality and diagnostic ability of susceptibility-weighted magnetic resonance imaging (SW MRI) with T2-weighted and T2 star CMR to detect IMH at 3T.

Methods

Forty-nine patients (42 males; mean age 58 years, range 35–76) underwent 3T cardiovascular magnetic resonance (CMR) 2 days following re-perfused AMI. T2-weighted, T2 star and SW MRI images were obtained. Signal and contrast measurements were compared between the three methods and diagnostic accuracy of SW MRI was assessed against T2w images by 2 independent, blinded observers. Image quality was rated on a 4-point scale from 1 (unusable) to 4 (excellent).

Results

Of 49 patients, IMH was detected in 20 (41%) by SW MRI, 21 (43%) by T2-weighted and 17 (34%) by T2 star imaging (p = ns). Compared to T2-weighted imaging, SW MRI had sensitivity of 93% and specificity of 86%. SW MRI had similar inter-observer reliability to T2-weighted imaging (κ = 0.90 and κ = 0.88 respectively); both had higher reliability than T2 star (κ = 0.53). Breath hold times were shorter for SW MRI (4 seconds vs. 16 seconds) with improved image quality rating (3.8 ± 0.4, 3.3 ± 1.0, 2.8 ± 1.1 respectively; p < 0.01).

Conclusions

SW MRI is an accurate and reproducible way to detect IMH at 3T. The technique offers considerably shorter breath hold times than T2-weighted and T2 star imaging, and higher image quality scores.     

2D 与3D 延迟增强扫描对心肌梗死诊断的对比研究

目的对比一次屏气3D反转恢复梯度回波序列与多次屏气2D反转恢复梯度回波对于评价心肌梗死及其范围作用。方法对19例（34灶）心肌梗死的患者的2D和3D反转恢复的梯度回波序列扫描结果进行分析。分别评价心肌有无延迟增强及其延迟增强的类型，并且测量心肌梗死的范围（延迟强化累及的层数）及透壁程度。结果2D和3D反转恢复的梯度回波序列对于心肌梗死的诊断和分类以及显示心肌梗死的范围无统计学差异，但2D和3D反转恢复的梯度回波序列对于显示心肌梗死的透壁厚度有统计学差异，3D序列过度估计了心肌梗死的透壁程度。结论3D的反转恢复的梯度回波序列可以快速地评价有无心肌的梗死，与标准的2D反转恢复梯度回波序列有高度地一致性。     

Minor troponin T elevation in patients 6 months after acute myocardial infarction: an observational study

Background  Troponin elevation in patients with stable coronary heart disease is associated with adverse outcome and prognosis. However, the mechanism is not yet clearly understood. Our objectives were to examine the prevalence and range of cardiac troponin T (cTnT) in stable patients, 6 months after acute myocardial infarction (AMI) using a new high sensitive cTnT assay and to investigate the association of minor cTnT elevation in these patients to clinical variables, NT-proBNP and cardiac MRI-findings. Study design and methods  cTnT was measured in 98 patients 6 months after AMI with a precommercial assay by electrochemiluminescence methods (Roche Diagnostics, Mannheim, Germany). cTnT values were correlated with clinical and angiographic variables, NT-proBNP concentrations and with cardiac MRI-findings. Results  Minor cTnT concentrations were detectable in 90% of the entire cohort, of whom 16% had cTnT values above the 99th percentile (>12 ng/L). These patients were also significantly older, suffered more frequently from hypertension, had a higher New York Heart Association class and received more often diuretics at follow up. Patients with cTnT elevation had a more impaired left ventricular ejection fraction (P = 0.02) but did not have an increased infarct size (P = 0.73). Conclusions  Elevated minor cTnT levels are frequently detectable in patients 6 months after AMI. Increased cTnT level were associated with clinical parameter for heart failure, impaired ejection fraction and higher NT-proBNP levels suggesting that myocardial dysfunction is a main cause for cTnT elevation in these patient group.