心脏磁共振延迟强化成像定量评价心肌梗死的研究

目的 研究计算机辅助测体积法(CAVM)与视觉评分法(VSM)在心脏磁共振延迟强化成像上评价梗死心肌大小的相关性,并探讨梗死心肌质量与室壁运动异常、左室功能的相关性.方法 采用多次屏气平衡稳态自由进动快速成像(FIESTA)序列,对21例心肌梗死患者行心脏电影MRI及钆喷替酸葡甲胺(Gd-DTPA)增强的延迟强化成像.①用CAVM及VSM分别评价患者的梗死心肌质量及梗死心肌范围程度.用VSM评价时根据延迟强化的透壁程度分为0～4分;0＝无强化,1＝1%～25%强化,2＝26%～50%强化,3=51%～75%,4=76%～100%强化;②评价患者的室壁运动异常及左室功能.结果 两种方法评价梗死心肌高度相关(r=0.825,P＜0.001);梗死心肌质量与室壁运动异常(r=0.740)、射血分数(r=-0.733)、收缩末期容积指数(r=0.702)、收缩末期容积(r=0.698)、舒张末期容积指数(r=0.657)、舒张末期容积(r=0.648)均密切相关(P≤0.001).结论 计算机辅助测体积法及视觉评分法均可准确定量梗死心肌,梗死心肌质量与室壁运动异常、左室功能有高度相关性.     

Diagnostic value of routine clinical parameters in acute myocardial infarction: a comparison to delayed contrast enhanced magnetic resonance imaging

Aims: Contrast enhanced magnetic resonance imaging (ceMRI) has been shown to reliably identify irreversible myocardial injury. The aim of this study was to compare the findings on ceMRI with routine clinical markers of myocardial injury in patients with acute myocardial infarction (MI). Methods and results: Twenty-four patients with acute MI were investigated at 1.5 T. The global myocardial function was analysed with a standard cine MR protocol and a stack of short axis slices encompassing the entire left ventricle. Corresponding short axis slices were acquired for delayed ceMRI 15–20 min after the administration of 0.2 mmol gadolinium–DTPA/kg body weight. Mass of hyperenhancement and peak creatine kinase release (peak CK) was determined for each patient. The presenting 12-lead ECG was analysed for ST-elevation on admission and later development of Q-waves. Mass of hyperenhancement correlated moderately well to peak CK (r = 0.65, p < 0.01) and endsystolic volume index (r = 0.55, p < 0.01). Mass of hyperenhancement was inversely correlated to ejection fraction (r = –0.50, p = 0.02). Neither the presence of ST elevation on the admission ECG nor the later development of Q-waves did relate to the transmural extent of hyperenhancement and to the mass of hyperenhancement. Conclusion: Mass of hyperenhancement significantly correlates to global myocardial function and to peak CK. However, there is no relationship between the findings in ceMRI and 12-lead ECG abnormalities on admission suggesting an advantage of ceMRI in defining transmural extent and depicting small areas of necrosis.     

心脏磁共振及实验室检查联合评估心肌缺血

目的探讨心脏磁共振(cardiac magnetic resonance imaging,CMR)及实验室检查指标在评估心肌缺血中的临床价值。材料与方法 7只巴马小型猪成功构建心肌缺血模型,分别于术前、术后2 h、12 h、24 h、48 h、72 h、1周、2周、3周、4周检测心肌酶谱、肌钙蛋白、肌红蛋白等实验室检查指标,并于上述各时段行CMR检查,最终行病理检查。结果巴马猪术后2 h肌钙蛋白及肌红蛋白即明显升高,分别为[(0.005±0.002)、(0.338±0.768) ng/ml,P<0.05],72 h内诸心肌损伤标志物变化显著(均P<0.05),提示心肌损伤,1周后趋于平稳;CMR示缺血早期T2WI黑血序列显示心肌水肿,即危险心肌,电影(cine)序列出现局部室壁运动异常,首过灌注术后2 h即出现灌注减低或缺损,术后24 h部分心肌节段出现延迟强化,透壁程度随着缺血时间的延长,不断增加,最终经病理证实心肌坏死、纤维化。4周CMR所测心功能指标较术前显著降低(左室射血分数%:分别为62.71±8.33、45.97±6.37,P<0.05)。结论心肌酶谱及肌钙蛋白、肌红蛋白对心肌损伤有提示意义,CMR可确切地显示心肌缺血微观组织学变化,联合评估可为急性冠脉综合症提供详细的诊断信息并指导治疗。     

MR心肌延迟增强扫描在常见非缺血性心脏病中初步应用

目的研究常见非缺血性心脏病患者心肌病变的磁共振心肌延迟强化的影像学特征。方法回顾性分析25例非缺血性心脏病患者的磁共振心肌延迟强化特点及相应临床表现。结果 25例患者中9例患者心肌病变未出现延迟强化。6例为病毒性心肌炎,4例出现左室后壁、下壁心外膜下心肌可见斑片状延迟强化,1例室间隔部出现散在线状强化;6例为肥厚性心肌病,4例出现室间隔及左室壁出现延迟强化,表现为片状强化;12例为扩张性心肌病,4例在左心室间隔壁、侧壁可见线样强化,左室后下壁、前间隔壁各1例可见小片状强化,以心肌中层及外膜下心肌为主。1例为致心律失常型右室心肌病,延迟强化提示右室下壁及前壁可见片状强化。结论非缺血性心脏病患者心肌病变的磁共振心肌延迟强化具有一定特征,鉴别非缺血性心脏病的病因有赖于密切结合临床病史。     

Assessment of myocardial viability in a porcine model of chronic coronary artery stenosis with dual dose dobutamine magnetic resonance imaging

In a non-surgical porcine coronary stenosis model resulting in chronic left ventricle dysfunction, we aimed in this study to evaluate the potential of magnetic resonance imaging (MRI) to distinguish dysfunctional but viable from necrotic myocardium by using multiple levels of dobutamine inotropic stimulation during a cine MRI protocol (F.P. van Rugge et al. Circulation 1994; 90: 127–138). We compared our results with histopathology. We were able to demonstrate a biphasic effect at increasing doses of dobutamine in a subgroup of animals with a high-grade coronary stenosis, while in another subgroup the coronary stenosis produced a chronic myocardial infarction, in which no functional recovery could be obtained. In this experimental protocol, dual dose dobutamine MRI proved to be an accurate and reproducible technique to perform viability studies in chronic obstructive coronary artery disease. It permits distinguishing chronic ischemic, but viable myocardium from infarcted tissue. The detection of chronically underperfused but potentially salvageable myocardium is of significant clinical importance since it may aid in determining which patients are eligible for revascularization.     

Contrast-enhanced magnetic resonance imaging reveals early decrease of transmural extent of reperfused acute myocardial infarction

In patients with myocardial infarction infarct size and transmural extent are of high prognostic value for clinical outcome and recovery of contractile function of the affected myocardium either spontaneously or after revascularisation. Delayed contrast-enhancement magnetic resonance imaging (DCE-MRI) is a non-invasive imaging technique of high accuracy for determination of myocardial infarct size and transmural extent. As decisions whether revascularisation procedures are promising in patients with coronary artery disease are increasingly based on the transmural infarct extent assessed by DCE-MRI we sought to examine whether the timing of MRI after acute myocardial infarction would influence the transmural extent. We performed DCE-imaging on a clinical 1.5 T scanner in patients at day-1 and day-7 after reperfused STEMI. We assessed the total number of segments displaying DCE as well as differentiated by the transmural infarct extent. The total number of affected segments as well as the number of segments with only subendocardial DCE did not change between day-1 and day-7. In contrast, we observed a significant decrease of the number of segments with DCE of ≥75% transmurality and a significant increase of segments with DCE grade III (51%–75% transmurality). We conclude that the transmural infarct extent is not stable over the first days after STEMI which should be taken into account when assessing viability in clinical and research settings. C. Merten and H. Steen contributed equally     

MRI增强延迟扫描在心肌梗塞后存活性评价中的价值探讨

目的探索评价MRI增强延迟扫描技术对判断心肌存活性的价值。方法 20例患者行MRI增强延迟扫描检查,分析心肌延迟扫描图像并探索评价心肌存活性。结果 17例左室心肌未见梗塞灶,增强延迟扫描MR表现为均匀一致低信号,心肌内无对比剂存留。3例陈旧性心肌梗死表现为左心室病变区局限性信号不均匀增高,对比剂存留。结论 MRI增强延迟扫描技术可对心肌存活性作出一定评价,为患者制订治疗方案和预后评价提供信息。     

乳腺磁共振背景实质强化的研究进展

乳腺癌作为女性最常见的恶性肿瘤,其发病率及死亡率都较高,且不同分子亚型乳腺癌生物学表现及临床治疗、预后各不相同,寻找乳腺癌针对性和个性化诊断及治疗的影像学标记物是目前研究的热点.乳腺背景实质强化(background parenchymal enhancement,BPE)是正常纤维腺体组织的生理性强化,受多种因素的影...     

Cine and tagged magnetic resonance imaging in short-term stunned versus necrotic myocardium

We investigated the potential of Cine and 2D Tagged Cardiac Magnetic Resonance (CMR) Imaging to distinguish stunned from necrotic left ventricular (LV) myocardium in the early postischemic phase in an open-chest animal model (N=12). Reversible and permanent occlusion of the LAD coronary artery resulted in global LV dysfunction in both groups without significant differences. LAD perfused segments revealed significant higher values for end systolic wall thickening (ESWT) and percentual systolic wall thickening in animals with stunned myocardium. Analysis of strain parameters showed significant regional differences (maximal principal strain ₁, deviation angle ) between postischemic and remote myocardium within both groups, however results were not significantly different comparing animals with stunned myocardium to animals with myocardial necrosis. In conclusion, at rest neither global LV functional nor regional strain parameters derived from Cine and 2D Tagged CMR Imaging can distinguish animals with short-term stunned myocardium from respective animals with necrotic myocardium. Diagnostic value of ESWT is limited due to the spatial resolution of the gradient-echo sequence used.Supported by a grant from the Interdisciplinary Center of Clinical Research (IZKF; B1, BMBF-01KS 9604).     

2020年心脏MR研究进展

MRI因具有可多平面、多参数及多序列成像且无创、无辐射的优势而成为心血管疾病的重要影像学检查方法。近年来,随着MR硬件与软件的发展,心脏磁共振（CMR）已逐渐成为集诊断与鉴别、判断预后与危险分层等于一体的综合性评估手段,为临床决策所不可或缺。本文对2020年CMR领域的代表性成果进行综述。     

多巴酚丁胺负荷磁共振成像检测存活心肌的临床研究

目的 评价小剂量多巴酚丁胺(10μg·kg-1·min-1)负荷磁共振成像(MRI)检测存活心肌的临床价值.方法 经彩色多普勒超声检查存在左心室壁节段运动障碍冠心病患者24例,进行MRI、小剂量多巴酚丁胺负荷MRI、冠状动脉造影(CAG)及经皮冠状动脉介入治疗(PCI),所有狭窄病变行完全血运重建.参照美国超声心动图学会16节段划分法,经MRI测得各运动异常节段小剂量多巴酚丁胺负荷前后舒张末期室壁厚度(EDWT),以应用小剂量多巴酚丁胺后室壁增厚为存活心肌标准;术后1、3、6个月时复查心脏超声,以冠状动脉血运重建后室壁节段收缩功能改善为判断存活心肌的金标准.结果 24例冠心病患者共获得符合条件的室壁运动异常节段170个,根据金标准判断其中115个为存活心肌,55个为非存活心肌;MRI检测存活心肌的敏感度、特异度、准确度分别是76.5%、90.9%、81.2%.结论 小剂量多巴酚丁胺负荷MRI检测存活心肌有较高的临床价值.     

Delayed contrast enhancement in a patient with perimyocarditis on contrast-enhanced cardiac MRI: case report

The findings of contrast-enhanced cardiac magnetic resonance imaging of a 19-year-old man with perimyocarditis in the subacute and chronic stage are presented. In perimyocarditis., it is useful to check the presence of delayed contrast enhancement to confirm the presence of the lesion and to evaluate the severity of inflammation in the acute stage as well as to determine the extent of fibrosis in the pericardium and myocardium in the chronic stage.     

Cardiac magnetic resonance simultaneously evaluates Leriche syndrome and prior inferior myocardial infarction

A woman with ECG findings suspicious of ischemic heart disease was referred for coronary angiography, but this was impossible via the left or right iliac arteries because of total occlusion. Cardiovascular magnetic resonance (CMR) was performed to assess the anatomy of the abdominal aorta, cardiac function, and myocardial viability in a single study. Contrast-enhanced magnetic resonance angiography (CE-MRA) revealed Leriche syndrome resulting from occlusion of the infrarenal aorta and common iliac arteries. Delayed contrast enhancement indicated full thickness nonviable myocardial infarction. Coronary angiography via the right radial artery revealed proximal occlusion of the right coronary artery. This is the first case that illustrates the value of CMR as a time-saving non-invasive imaging technique with the ability to do in a single study what might otherwise take two studies.     

Segmentation of tongue muscles from super-resolution magnetic resonance images

Imaging and quantification of tongue anatomy is helpful in surgical planning, post-operative rehabilitation of tongue cancer patients, and studying of how humans adapt and learn new strategies for breathing, swallowing and speaking to compensate for changes in function caused by disease, medical interventions or aging. In vivo acquisition of high-resolution three-dimensional (3D) magnetic resonance (MR) images with clearly visible tongue muscles is currently not feasible because of breathing and involuntary swallowing motions that occur over lengthy imaging times. However, recent advances in image reconstruction now allow the generation of super-resolution 3D MR images from sets of orthogonal images, acquired at a high in-plane resolution and combined using super-resolution techniques. This paper presents, to the best of our knowledge, the first attempt towards automatic tongue muscle segmentation from MR images. We devised a database of ten super-resolution 3D MR images, in which the genioglossus and inferior longitudinalis tongue muscles were manually segmented and annotated with landmarks. We demonstrate the feasibility of segmenting the muscles of interest automatically by applying the landmark-based game-theoretic framework (GTF), where a landmark detector based on Haar-like features and an optimal assignment-based shape representation were integrated. The obtained segmentation results were validated against an independent manual segmentation performed by a second observer, as well as against B-splines and demons atlasing approaches. The segmentation performance resulted in mean Dice coefficients of 85.3%, 81.8%, 78.8% and 75.8% for the second observer, GTF, B-splines atlasing and demons atlasing, respectively. The obtained level of segmentation accuracy indicates that computerized tongue muscle segmentation may be used in surgical planning and treatment outcome analysis of tongue cancer patients, and in studies of normal subjects and subjects with speech and swallowing problems.     

磁共振多序列诊断评价急性心肌梗死的应用进展

磁共振心血管检查技术为深入了解心脏结构和功能提供了无创的方法,具有较高诊断准确性,并且无电离辐射。灌注增强后的延迟显像技术能够对心肌梗死提供有价值的诊断和预后信息,但是对于心肌梗死的程度以及心肌弥漫性改变无法准确地评价。T1 mapping技术是一种能够定量评估心肌局限及弥漫性病变的新技术,其能定量地评估心肌梗死的程度及心肌水肿的范围,具有良好的诊断及预后价值,在临床实践中有更好的应用前景。     

心脏磁共振细胞外容积在高血压性心脏病中的应用

血压长期增高会引起心脏后负荷增加,导致高血压性心脏病.高血压性心脏病的主要改变是左心室肥厚及弥漫性心肌纤维化.通过心脏磁共振T1 mapping测量的细胞外容积作为无创性评估心肌纤维化的手段,在高血压性心脏病的诊断中发挥了重要的作用.作者就高血压性心脏病心肌纤维化的病理生理、高血压性心脏病细胞外容积的特点,治疗后细胞外...     

Cardiac magnetic resonance imaging in valvular heart disease

Cardiac magnetic resonance imaging (CMR) has rapidly gained acceptance as an accurate, reproducible and non‐invasive imaging method for assessment of a wide range of cardiovascular diseases. However, CMR has not been used widely for diagnostic purposes in valvular heart disease (VHD). Unlike echocardiography it has no body habitus‐related limitations and can thus be used to complement echocardiography. It is an especially good alternative for clinical follow‐up in patients with VHD, as it allows accurate measurement of valvular dysfunction and related ventricular burden. Additionally, CMR is an ideal method for evaluating complex congenital heart disease and determining the significance of its components. It can also be used to study the physiological course of valvular dysfunction and response to therapeutic interventions. In this review, we present a basic introduction to CMR methodology, including its advantages and potential problems, and the physiology and quantification in VHD. We also discuss clinical applications of CMR in VHD. Furthermore, we describe how a CMR study statement should be structured in order to increase clinical use of this valuable methodology in cardiology.     

Model tags: direct three-dimensional tracking of heart wall motion from tagged magnetic resonance images

Although magnetic resonance tissue tagging is a useful tool for the non-invasive measurement of three-dimensional (3-D) heart wall motion, the clinical utility of current analysis techniques is limited by the prohibitively long time required for image analysis. A method was therefore developed for the reconstruction of 3-D heart wall motion directly from tagged magnetic resonance images, without prior identification of ventricular boundaries or tag stripe locations. The method utilized a finite-element model to describe the shape and motion of the heart. Initially, the model geometry was determined at the time of tag creation by fitting a small number of guide points which were placed interactively on the images. Model tags were then created within the model as material surfaces which defined the location of the magnetic tags. An objective function was derived to measure the degree of match between the model tags and the image stripes. The objective was minimized by allowing the model to deform directly under the influence of the images, utilizing an efficient method for calculating image-derived motion constraints. The model deformation could also be manipulated interactively by guide points. Experiments were performed using clinical images of a normal volunteer, as well as simulated images in which the true motion was specified. The root-mean-squared errors between the known and calculated displacement and strain for the simulated images were similar to those obtained using previous stripe-tracking and model-fitting methods. A significant improvement in analysis time was obtained for the normal volunteer and further improvements may allow the method to be applied in a 'real-time' clinical environment.     

心脏磁共振心肌灌注成像在冠心病患者冠状动脉病变及微循环梗阻中的临床应用价值

目的  探讨心脏磁共振（CMR）心肌灌注成像在冠心病冠状动脉病变及微循环梗阻（MVO）中的临床应用价值。方法  选取2020年1月~2022年12月我院收治的106例冠心病患者,均在经皮冠状动脉介入治疗前和治疗后行CMR心肌灌注成像。以冠状动脉造影诊断结果为金标准,对比经皮冠状动脉介入治疗前CMR心肌灌注成像中延迟强化透壁局部室壁异常运动及病变区与正常心肌区CMR心肌灌注成像参数。分析CMR心肌灌注成像对冠心病冠状动脉病变的诊断效能。经皮冠状动脉介入治疗后根据患者是否存在MVO将其分为MVO组（n=29）和无MVO组（n=77）,对比两组CMR心肌灌注成像参数,并采用ROC曲线分析CMR心肌灌注成像参数对MVO的诊断价值。结果  106例患者中的1802个心肌节段被纳入评价。CMR心肌灌注成像显示106例患者共有147个延迟强化的心肌节段（每个患者至少有1个心肌节段延迟强化）,其中68个透壁强化,79个非透壁强化。病变心肌首过灌注时间、首过灌注最大上升斜率（Slope_max）、心肌延迟强化信号值与正常心肌间对比有统计学差异（P < 0.05）。以冠状动脉造影结果为金标准,CMR心肌灌注成像对左前降支、右冠状动脉、左回旋支病变的诊断敏感度分别为94.12%、88.64%、88.89%,特异性分别为95.00%、96.55%、94.74%,准确度分别为94.66%、93.89%、93.13%。经皮冠状动脉介入治疗后有MVO者29例,无MVO者77例。MVO组中首过灌注时间、Slope_max、心肌延迟强化信号值与无MVO组的差异有统计学意义（P < 0.05）。ROC曲线显示,CMR心肌灌注成像参数中首过灌注时间、Slope_max、心肌延迟强化信号值对冠心病患者MVO诊断的曲线下面积分别为0.803、0.718、0.851,敏感度分别为82.76%、72.41%、86.21%,特异性分别为66.23%、68.83%、67.53%,准确度分别为70.75%、69.81%、72.64%。结论  CMR心肌灌注成像可显示冠心病心血管病变区域的变化,对诊断冠心病冠状动脉病变及MVO情况有较高的诊断价值。     

磁共振波谱对早产儿缺血缺氧性脑病的诊断价值

目的:探讨氢质子磁共振波谱(proton magnetic resonance spectroscopy,~1 H-MRS)定量分析早产儿缺血缺氧性脑病(hypoxic ischemic encephalopathy,HIE)脑损伤的临床价值。方法:收集HIE早产儿28例,同时收集45例同胎龄段、同出生体质量的颅脑正常早产儿作为对照组。采用GE Signa 1.5T MR扫描仪进行~1 H-MRS扫描,通过GE工作站Functool软件计算得到~1 H-MRS图,测量右侧基底节区的乙酰天门冬氨酸/肌酸(NAA/Cr)、NAA/胆碱(NAA/Cho)、乳酸/Cr(Lac/Cr)比值。采用独立样本t检验分析HIE患儿与对照组右侧基底节区~1 H-MRS中各代谢物比值的差异。运用受试者工作特征(receiver operating characteristic,ROC)曲线分析~1 H-MRS中各代谢物比值鉴别HIE患儿的最佳阈值、灵敏度及特异度。结果:HIE患儿中,右侧基底节区NAA/Cho、NAA/Cr明显低于对照组(P0.05);右侧基底节区Lac/Cr高于对照组(P0.01)。右侧基底节区NAA/Cho与NAA/Cr为0.57、1.07时,鉴别HIE患儿与对照组新生儿的灵敏度分别为63.2%、89.5%、特异度分别为81.5%、55.6%;右侧基底节区Lac/Cr为0.09时,鉴别HIE患儿与对照组新生儿的灵敏度为89.5%、特异度为88.9%。结论:右侧基底节区的NAA/Cho、NAA/Cr、Lac/Cr有助于诊断早产儿HIE,为临床诊断早产儿HIE提供重要参考。