Earls James P
Fairfax Radiological Consultants PC, 2722 Merrilee Drive, Suite 230, Fairfax, VA 22031, USA.
J Cardiovasc Comput Tomogr. 2009 Jan-Feb;3(1):45-51. doi: 10.1016/j.jcct.2008.10.013. Epub 2008 Nov 5.
A prospective, electrocardiographically gated technique was recently adapted for use with coronary and cardiac multidetector row CT studies. The most widely available form of prospective gating uses "step-and-shoot" axial data acquisition, an incrementally moving table, adaptive electrocardiographic triggering, an improved image reconstruction algorithm, and multiphase reconstruction capability. Studies have shown a 77%-87% effective radiation dose reduction compared with retrospective gating and equal to significantly improved image quality. Comparison with conventional angiography has proven it to be as accurate as retrospective gating for coronary stenosis detection. The technique is not applicable to all patients because there are some restrictions for clinical use, including a limited number of reconstructed phases and a maximum scan heart rate of 68-75 beats/min. However, with careful patient selection and effective heart rate control, prospective gating can be used in a high percentage of cardiac CT examinations. This article reviews the scanning and patient selection protocols for prospective gating and discusses how it may be used in clinical practice.
一种前瞻性心电门控技术最近被应用于冠状动脉和心脏多排CT研究。前瞻性门控最广泛使用的形式是“步进-扫描”轴向数据采集、逐步移动的检查床、自适应心电图触发、改进的图像重建算法以及多期重建能力。研究表明，与回顾性门控相比，有效辐射剂量降低了77%-87%，且图像质量显著提高。与传统血管造影术的比较已证明，在检测冠状动脉狭窄方面，它与回顾性门控一样准确。该技术并非适用于所有患者，因为临床应用存在一些限制，包括重建期数有限以及最大扫描心率为68-75次/分钟。然而，通过仔细的患者选择和有效的心率控制，前瞻性门控可用于高比例的心脏CT检查。本文回顾了前瞻性门控的扫描和患者选择方案，并讨论了其在临床实践中的应用方式。
