冠状动脉管壁的磁共振成像技术进展

评价冠状动脉斑块稳定性可以预测急性冠状动脉事件的发生,近来,无创性影像学手段评价冠状动脉斑块成分成为研究热点.磁共振动脉硬化斑块成像技术已在颈动脉研究中得以很好地应用.但冠状动脉管壁成像因成像技术复杂,目前尚处于技术可行性探讨阶段.从动脉硬化斑块病理生理、磁共振冠状动脉管壁成像基本技术、磁共振冠状动脉管壁成像现状及未来发展趋势等几方面对磁共振冠状动脉管壁成像进行综述.     

磁共振冠状动脉成像的进展

自90年代早期首次报道以来，冠状动脉的磁共振成像技术已发展成为一项对显示冠状动脉及诊断冠状动脉疾病的无创性检查方式。目前研究的方向集中在最佳的呼吸补偿方式、改善时间及空间分辨率以及更快速地获取图像上。精确地显示狭窄并评价冠状动脉粥样硬化病变的严重程度正处在多中心的研究当中。磁共振成像技术有望成为临床心脏病学当中最重要的无创性检查手段。     

冠状动脉磁共振成像进展

冠状动脉性心脏病简称冠心病,是一类发病率和死亡率较高的疾病。该疾病的早期发现与治疗对于改善病人的生活质量和提高生存率有重要意义。磁共振成像以无创性、无电离辐射、具有良好的软组织对比度、多参数及任意层面成像等优势,逐渐被应用于冠状动脉成像检查。通过对冠状动脉磁共振成像的主要序列的归纳和分析,总结影响冠状动脉磁共振成像质量的各种因素,并比较各扫描序列与技术的优势及限度。     

冠状动脉管壁高分辨力磁共振成像的初步研究

目的：探讨冠状动脉管壁的高分辨MR成像方法,评价其在显示冠状动脉细微解剖结构方面的应用价值.方法：选取20例健康志愿者在1.5T MR设备上行高分辨冠状动脉管壁断面成像,由两位高年资MRI医师对图像质量进行评分,并在评分较高的图像上测量血管内径及管壁厚度等数据.结果：18例志愿者均完成检查,共获得冠状动脉管壁横轴面图像97帧,其中右冠状动脉（RCA）59帧,平均得分2.15分;左冠状动脉（LCA）38帧,平均得分1.39分,RCA图像质量优于LCA.在RCA图像中质量评分≥2分的图像上测量血管内径及管壁厚度,RCA近段内径平均值为（3.55土0.51）mm,管壁厚度平均值为（1.11±0.23）mm.结论：冠状动脉管壁MR高分辨成像可以显示冠状动脉管壁细微解剖结构,并可定量测量和分析相关数据,在冠状动脉疾病的-临床诊断及研究中具有较大的应用前景.     

磁共振成像评价冠状动脉硬化性心脏病的进展

对MR评价冠状动脉硬化性心脏病的进展进行综述。介绍了MRI血管内导管线圈、可同时采集多条K空间数据线的线圈的应用；回顾了包括K空间分割梯度回波成像、螺旋心脏成像、血氧水平依赖成像在心脏的应用、黑血技术、其他原子核的心脏MR成像和心脏MR频谱分析等的进展；对MRI血池对比剂的研究进行了介绍，同时论述了MRI心肌标记、心脏多巴胺负荷试验、心肌灌注成像和MR冠状动脉成像的临床应用。     

冠状动脉磁共振成像技术及其临床应用

冠状动脉磁共振成像 (CoronaryMagneticResonanceAngiogra phy ,CMRA)的研究始于 2 0世纪 80年代 ,近几年磁共振快速成像技术的实现使其成像质量开始具备临床实用价值[1] 。与其它影像学技术相比 ,它具有非创伤性、无电离辐射、任意层面成像等优势 ,结合电影成像、造影剂首次通过灌注和延迟增强等成像方式 ,可以实现包括心脏结构与功能、心肌灌注与存活性、冠状动脉成像在内的“一步到位”(one stop shop)的心脏影像学检查[2 ] 。目前 ,CMRA技术的发展完善和临床应用是磁共振成像研究的重点和热点[3 ] 。1　冠状动脉磁共振成像的技术要…     

磁共振成像评价冠状动脉硬化性心脏病的进展

对MR评价冠状动脉硬化性心脏病的进展进行综述。介绍了MRI血管内导管线圈、可同时采集多条K空间数据线的线圈的应用；回顾了包括K空间分割梯度回波成像、螺旋心脏成像、血氧水平依赖成像在心脏的应用、黑血技术、其他原子核的心脏MR成像和心脏MR频谱分析等的进展；对MRI血池对比剂的研究进行了介绍，同时论述了MRI心肌标记、心脏多巴胺负荷试验、心肌灌注成像和MR冠状动脉成像的临床应用。     

磁共振冠状动脉成像的进展

自90年代早期首次报道以来，冠状动脉的磁共振成像技术已发展成为一项对显示冠状动脉及诊断冠状动脉疾病的无创性检查方式。目前研究的方向集中在最佳的呼吸补偿方式、改善时间及空间分辨率以及更快速地获取图像上。精确地显示狭窄并评价冠状动脉粥样硬化病变的严重程度正处在多中心的研究当中。磁共振成像技术有望成为临床心脏病学当中最重要的无创性检查手段。     

磁共振自由呼吸冠状动脉血管成像技术的初步探讨

目的:探讨自由呼吸状态下运用超快速平衡式梯度回波序列(sBTFE/3D/NAVI)进行磁共振冠状动脉血管成像技术的可靠性.方法:20例健康志愿者运用sBTFE/3D/NAVI,结合呼吸导航技术,自由呼吸状态下对左右冠状动脉分别扫描,经MIP后处理获得冠状动脉图像.观察冠状动脉的显示率,测量各冠状动脉的显示长度及心肌,冠脉的信号强度及信噪比.结果:20例受检者均完成检查,右冠状动脉、左冠状动脉主干、前降支全部显示;左冠状动脉回旋支显示良好18例(90%).冠状动脉图像的信噪比为37.35±6.32,心肌组织的信噪比为20.03±7.25,两者比较有显著性差异(P＜0.01).结论:自由呼吸sBTFE/3D/NAVI冠脉成像方法显示成功率高,图像信噪比好,可作为不能屏气患者心脏冠脉检查的一种无创性手段.     

磁共振冠状动脉成像的研究进展

随着磁共振设备及其新技术的不断开发和进展,磁共振冠状动脉成像技术已成为显示冠状动脉形态的可靠的无创性影像检查方式。其可以精确显示冠状动脉狭窄部位并评价其血流储备情况,准确评估冠状动脉粥样硬化病变的严重程度,逐渐成为冠心病影像检查的重要方法。随着超高场磁共振设备的临床应用,当前研究主要集中于呼吸及心脏运动伪影抑制、快速数据采集等方面,以期获取高信噪比与高空间分辨力影像。     

Coronary magnetic resonance imaging: visualization of the vessel lumen and the vessel wall and molecular imaging of arteriothrombosis

Coronary magnetic resonance (MR) imaging has dramatically emerged over the last decade. Technical improvements have enabled reliable visualization of the proximal and midportion of the coronary artery tree for exclusion of significant coronary artery disease. However, current technical developments focus also on direct visualization of the diseased coronary vessel wall and imaging of coronary plaque because plaques without stenoses are typically more vulnerable with higher risk of plaque rupture. Plaque rupture with subsequent thrombosis and vessel occlusion is the main cause of myocardial infarction. Very recently, the first success of molecular imaging in the coronary arteries has been demonstrated using a fibrin-specific contrast agent for selective visualization of coronary thrombosis. This demonstrates in general the high potential of molecular MR imaging in the field of coronary artery disease. In this review, we will address recent technical advances in coronary MR imaging, including visualization of the lumen and the vessel wall and molecular imaging of coronary arteriothrombosis. First results of these new approaches will be discussed.     

Segment-specific progression of carotid artery atherosclerosis: a magnetic resonance vessel wall imaging study

Neuroradiology - This study aimed to investigate the segment-specific progression of atherosclerotic carotid plaques using serial multi-contrast magnetic resonance (MR) imaging. Symptomatic...     

Impact of bulk cardiac motion on right coronary MR angiography and vessel wall imaging

The purpose of this study was to investigate the impact of in-plane coronary artery motion on coronary magnetic resonance angiography (MRA) and coronary MR vessel wall imaging. Free-breathing, navigator-gated, 3D-segmented k-space turbo field echo ((TFE)/echo-planar imaging (EPI)) coronary MRA and 2D fast spin-echo coronary vessel wall imaging of the right coronary artery (RCA) were performed in 15 healthy adult subjects. Images were acquired at two different diastolic time periods in each subject: 1) during a subject-specific diastasis period (in-plane velocity <4 cm/second) identified from analysis of in-plane coronary artery motion, and 2) using a diastolic trigger delay based on a previously implemented heart-rate-dependent empirical formula. RCA vessel wall imaging was only feasible with subject-specific middiastolic acquisition, while the coronary wall could not be identified with the heart-rate-dependent formula. For coronary MRA, RCA border definition was improved by 13% (P < 0.001) with the use of subject-specific trigger delay (vs. heart-rate-dependent delay). Subject-specific middiastolic image acquisition improves 3D TFE/EPI coronary MRA, and is critical for RCA vessel wall imaging.     

Multiphasic cardiac magnetic resonance imaging: normal regional left ventricular wall thickening

Magnetic resonance imaging (MRI) is a completely noninvasive method for visualizing cardiovascular anatomy but has had limited use for assessment of cardiac function. The authors evaluated the use of gated MRI for the quantification of regional myocardial contraction. Nine normal subjects underwent gated MRI of five transverse sections (7 mm thickness) through the left ventricle at five intervals in the cardiac cycle using a new technique called rotating gated sequence. All five sections were examined, and the section that best demonstrated the midportion of the left ventricle in its maximum dimension was used to obtain measurement. This technique permitted assessment of regional wall thickening of various regions of the left ventricle in different phases of the cardiac cycle. The extent and percentage of wall thickening were calculated from measurements of the septum and anterior and lateral left ventricular wall in end-diastole and end-systole. The calculated mean values for extent and percentage of wall thickening for the septum were 0.40 cm and 40%; for the anterior wall, 0.61 cm and 73%; and for the lateral wall, 0.53 cm and 57%, respectively. A limitation of the current technique in wall thickness measurements is that the transverse MR plane of section is not perpendicular to the long axis of the left ventricle. Consequently, such oblique sections through the left ventricle may give inaccurate absolute wall thickness measurements but can provide reliable estimate of regional wall thickening dynamics. The ability to define left ventricular wall thickness and function without contrast media provides a noninvasive technique for the detection of segmental left ventricular myocardial dysfunction in ischemic heart disease.