Boxt L M
Division of Cardiac Radiology, College of Physicians and Surgeons of Columbia University, New York, New York, USA.
Magn Reson Imaging Clin N Am. 1996 May;4(2):191-216.
The complex motion of the beating heart provides a challenge to the clinical MR imager. Use of ECG gating, however, "stops" the heart, allowing for acquisition of diagnostic quality images of the cardiac chambers, valves, pericardium, and great arteries and veins and their branches. Attention to placement of chest wall ECG electrodes and the course of ECG-leads from the patient maximizes the quality of the gating signal and results in better quality imagery; however, ECG gating increases image acquisition time of the cardiac examination. Therefore, care must be taken to perform the most efficient possible examination. Prior to commencing the examination, the imager must have a clear understanding of the clinical question of the referring physician so that a clinical protocol can be applied to acquire relevant morphologic and physiologic data. The intracardiac anatomy may not always be best demonstrated using standard axial, coronal, and sagittal image sections. Therefore, with an understanding of basic intracardiac anatomy, standard imaging planes parallel or orthogonal to the intrinsic cardiac axes may be constructed and observation of abnormalities better appreciated. If care is taken in the planning and execution of the cardiac MR examination, the radiologist will be able to exploit this exciting new technology to its full potential as a noninvasive cardiac imaging modality.
跳动心脏的复杂运动给临床磁共振成像仪带来了挑战。然而，使用心电图门控可以“冻结”心脏，从而获取心脏腔室、瓣膜、心包、大动脉和大静脉及其分支的诊断质量图像。注意胸壁心电图电极的放置以及患者身上心电图导联的走向，可使门控信号质量最大化，并获得质量更好的图像；然而，心电图门控会增加心脏检查的图像采集时间。因此，必须注意进行尽可能高效的检查。在开始检查之前，成像仪必须清楚了解转诊医生的临床问题，以便应用临床方案来获取相关的形态学和生理学数据。使用标准的轴向、冠状和矢状图像切片并不总是能最佳地显示心脏内部解剖结构。因此，在了解基本心脏内部解剖结构的基础上，可以构建与心脏固有轴平行或正交的标准成像平面，从而更好地观察异常情况。如果在心脏磁共振检查的规划和实施过程中小心谨慎，放射科医生将能够充分发挥这项令人兴奋的新技术作为无创心脏成像方式的全部潜力。
