Nagel E, Schneider U, Schalla S, Ibrahim T, Schnackenburg B, Bornstedt A, Klein C, Lehmkuhl H B, Fleck E
Department of Internal Medicine/Cardiology, German Heart Institute Berlin, Humboldt University.
J Cardiovasc Magn Reson. 2000;2(1):7-14. doi: 10.3109/10976640009148668.
New ultrafast gradient systems and hybrid imaging sequences make it possible to acquire a complete image in real time, without the need for breathholding or electrocardiogram (ECG) triggering. In 21 patients, left ventricular function was assessed by the use of a turbo-gradient echo technique, an echo-planar imaging (EPI) technique, and a new real-time imaging technique. End-diastolic and end-systolic volumes, left ventricular muscle mass, and ejection fraction of the ultrafast techniques were compared with the turbo-gradient echo technique. Inter- and intraobserver variability was determined for each technique. Image quality was sufficient for automated contour detection in all but two patients in whom foldover occurred in the real-time images. Results of the ultrafast imaging techniques were comparable with conventional turbo-gradient echo techniques. There was a tendency to overestimate the end-diastolic volume by 3.9 and 1.3 ml with EPI real-time imaging, the end-systolic volume by 0.9 and 5.0 ml, and the left ventricular mass by 2.6 and 23.8 g. Ejection fraction showed a tendency to be overestimated by 1.1% with EPI and underestimated by 4.5% with real-time imaging. Correlation between EPI real-time imaging and turbo-gradient echo were 0.94 and O.95, respectively, for end-diastolic volumes, 0.98 and 0.96, respectively, for end-systolic volumes, and 0.96 and 0.89, respectively, for left ventricular mass. Inter- and intraobserver variability was low with all three techniques. Real-time imaging allows an accurate determination of left ventricular function without ECG triggering. Scan times can be reduced significantly with this new technique. Further studies will have to assess the value of real-time imaging for the detection of wall motion abnornmalities and the imaging of patients with atrial fibrillation.
新型超快梯度系统和混合成像序列使得实时获取完整图像成为可能，无需屏气或心电图（ECG）触发。对21例患者使用涡轮梯度回波技术、回波平面成像（EPI）技术和一种新的实时成像技术评估左心室功能。将超快技术的舒张末期和收缩末期容积、左心室肌肉质量和射血分数与涡轮梯度回波技术进行比较。确定了每种技术在观察者间和观察者内的变异性。除了两名实时图像出现折叠的患者外，所有患者的图像质量均足以进行自动轮廓检测。超快成像技术的结果与传统涡轮梯度回波技术相当。EPI实时成像有高估舒张末期容积3.9 ml和1.3 ml、收缩末期容积0.9 ml和5.0 ml以及左心室质量2.6 g和23.8 g的趋势。EPI有高估射血分数1.1%的趋势，实时成像有低估4.5%的趋势。EPI实时成像与涡轮梯度回波技术在舒张末期容积方面的相关性分别为0.94和O.95，在收缩末期容积方面分别为0.98和0.96，在左心室质量方面分别为0.96和0.89。三种技术在观察者间和观察者内的变异性均较低。实时成像无需ECG触发即可准确测定左心室功能。使用这种新技术可以显著缩短扫描时间。进一步的研究将不得不评估实时成像在检测壁运动异常和房颤患者成像方面的价值。
