admin 发表于 2010-7-13 22:10:49

多排螺旋CT心脏解剖:放射科医师应该掌握什么?

本讲座内容全文翻译自Anatomy of the Heart at Multidetector CT: What the Radiologist Needs to Know.RadioGraphics 2007; 27:1569–1582

本部分内容仅供学习交流研究之用!译文中的错误和疏漏请大家在学习过程中指出。以下是中英文对照内容!

{:2_161:} Abbreviations:
AV :atrioventricular,CS: coronary sinus, LA : left atrium, LAD : left anterior descending, LCA : left coronary artery, LCx:
left circumflex, LV : left ventricle,MIP : maximum intensity projection,MPR : multiplanar reformation,MV : mitral valve, PACS : picture archiving and communication system, PDA : posterior descending artery, PV : pulmonary vein, RA : right atrium, RI : ramus intermedius, RV :right ventricle, VR : volume rendering, 3D : three-dimensional

{:2_161:} Abstract Continued improvements in multidetector computed tomographic (CT) scanners have made cardiac CT an important clinical tool that is revolutionizing cardiac imaging. Multidetector CT with submillimeter collimation and gantry rotation times under 0.5 seconds allows the acquisition of studies with high temporal resolution and isotropic voxels. The volumetric data set that is generated can be analyzed with a depth previously not possible, requiring a solid understanding of the cardiac anatomy and its appearance on CT scans and postprocessed images. 摘要
多排螺旋CT技术飞速发展,CT成为心脏影像学检查的重要手段。MDCT能进行亚毫米薄层扫描,球管旋转一周的时间不到0.5秒,因此MDCT扫描时间分辨率高,并且具有各向同性。MDCT扫描得到的是容积数据,我们能利用各种软件来处理这些数据,得到相应的图像,从多个方面来了解心脏疾病。因此,掌握心脏解剖及其MDCT表现是非常重要的。

admin 发表于 2010-7-13 22:11:35

Introduction The advent of multidetector computed tomography (CT), particularly with scanners having 64 or more detectors, has continued to improve temporal resolution and allows the acquisition of isotropic voxels. With these scanners, the heart and coronary arteries are routinely imaged as a motion-free volume of data. A variety of postprocessing techniques, including multiplanar reformation (MPR), maximum intensity projection (MIP), volume rendering (VR), curved reformation, and cine imaging, allow noninvasive assessment of every aspect of the cardiovascular system. This capability requires a thorough understanding of essential coronary arterial and cardiac anatomy. In this article, we review the anatomy of the coronary arteries, cardiac chambers, and cardiac valves from a three-dimensional (3D) imaging perspective, with an emphasis on imaging planes and postprocessing techniques used to interpret the relevant findings at dual-source 64-detector CT.
引言
多排螺旋CT,尤其是64排或更多排CT的问世,大大提高了时间分辨率,并且能进行各向同性采集,因此能在心脏静止期采集图像。利用多种后处理技术,如多平面重建(MPR)、最大密度投影(MIP)、容积再现(VR)、曲面重建和电影显示等,我们能从多个方面来无创地评价心血管系统疾病。因此,我们更有必要全面了解心脏及冠状动脉的解剖。
在本文中,我们复习双源64排CT上冠脉、心腔和心脏瓣膜的三维解剖,着重强调相关的显示平面和后处理技术。

admin 发表于 2010-7-13 22:13:49

Multidetector CT Postprocessing Techniques The interpretation of cardiac CT angiographic studies performed with multidetector scanners requires real-time interaction with the volumetric data set that is generated. Consequently, radiologists must become proficient with workstation applications and postprocessing techniques. At our institution, interpretation of the cardiac CT angiographic data is accomplished using a combination of the postprocessing techniques described in the following sections.

MDCT后处理技术
对MDCT扫描产生的容积数据进行实时处理,即能得到心脏CTA图像。放射科医生应该熟练掌握工作站的应用和各项后处理技术。我们常联合使用以下后处理:

admin 发表于 2010-7-13 22:14:32

Multiplanar ReformationMPR is the basic tool used to interpret cardiac CT angiographic studies. With use of retrospective electrocardiographic gating, data from specific phases of the cardiac cycle are retrospectively referenced to the electrocardiogram for reconstruction. Once the reconstruction is complete, the data are transferred directly to the workstation. The radiologist then interfaces with the reconstructed series in real time at the workstation. Because of variations in the orientation of the heart in the thorax, it is often useful to evaluate cardiac structures along the cardiac planes. The multiplanar capabilities of the workstation allow images of the heart and coronary arteries to be manually rotated for optimal evaluation of the cardiac anatomy. Most workstations with cardiac analysis capabilities can automatically orient volumetric image data sets along the cardiac axes and into the traditionally used cardiac planes (ie, short-axis, horizontal long-axis, vertical long-axis) with the click of a button. This feature is especially useful for evaluating the cardiac chambers and left ventricular (LV) function. Selected reformatted images are sent to the picture archiving and communication system (PACS) for review by the referring clinicians and for long-term storage.

MPR
MPR是诊断心脏疾病最基本的方法。利用回顾性心电门控技术,可以得到心动周期中不同时相的数据,把这些数据传到工作站,利用工作站上的软件便可重建各种图像。心脏在胸腔中的方向有所不同,因此,以心脏本身的平面来评价心脏结构是非常有用的。MPR可使心脏和冠脉任意旋转,能以最好的角度来显示心脏解剖。大多数心脏分析软件能利用鼠标,自动将心脏调整至常用的心脏平面,如短轴、水平长轴和垂直长轴等。MPR对评价心腔和左室(LV)功能非常有用。可选择性存储一些图像,并发送到图像传输和处理系统(PACS),以便发报告时参阅。

admin 发表于 2010-7-13 22:15:21

Maximum Intensity Projection

MIP is a postprocessing technique that takes the highest-attenuation voxel in a predetermined slab of data and projects it from the user toward the viewing screen, resulting in a two-dimensional image. MIP images are similar to traditional angiograms, which display intraluminal opacity values (1). Only the highest-attenuation objects, typically contrast material and bone, are preferentially displayed and retained in the image. The limitation of MIP images is that they lack depth and spatial information regarding relationships to adjacent structures (2,3). However, they can allow quick assessment for significant coronary artery stenosis. At our institution, MIP images of each coronary artery are created and transferred to the PACS for every study.

MIP
MIP能显示容积数据中具有最高CT值的体素,并将其透射到屏幕上来,形成二维图像。MIP图像类似传统的血管造影,能显示管腔全貌。只有CT值最大的结构,如造影剂和骨骼,能在MIP图像上显示出来。MIP图像的缺点是缺乏空间对比,但能大体评价冠脉严重的狭窄。我们对每例病人都进行MIP重建,并发送至PACS。

admin 发表于 2010-7-13 22:16:54

Volume Rendering
VR is a 3D technique in which the CT attenuation values for each voxel can be assigned a specific color (3), thereby producing an overall image of the heart. VR is the only true 3D technique and provides the depth and spatial information that is lacking with MIP (2,3). VR techniques facilitate surface evaluation of the heart and coronary arteries. With respect to diagnosis, we have found this technique to be the most useful for evaluating complex anatomy, including coronary artery anomalies, bypass grafts, and fistulas. At our institution, VR images of each coronary artery are transferred to the PACS. Our referring physicians have found that these images allow them to communicate the major findings of a study to the patient in an easily understandable format.
VR
VR是一种三维技术,它给不同CT值的体素加上不同的颜色,能生动地显示心脏的全貌。VR是唯一的一种能提供空间信息的3D技术,能弥补MIP的不足。VR有助于显示心脏和冠脉的表面。对于诊断而言,此技术有利于评价复杂的解剖,包括冠脉先天异常、桥血管和瘘等。我们常规重建VR图像,并发送至PACS。诊断医生认为,VR图像直观、易懂,有助于给病人解释病情。
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