Oechsner Markus, Pracht Eberhard D, Staeb Daniel, Arnold Johannes F T, Köstler Herbert, Hahn Dietbert, Beer Meinrad, Jakob Peter M
Department of Experimental Physics 5, University of Würzburg, Würzburg, Germany.
Magn Reson Med. 2009 Mar;61(3):723-7. doi: 10.1002/mrm.21846.
Respiratory motion and pulsatile blood flow can generate artifacts in morphological and functional lung imaging. Total acquisition time, and thus the achievable signal to noise ratio, is limited when performing breath-hold and/or electrocardiogram-triggered imaging. To overcome these limitations, imaging during free respiration can be performed using respiratory gating/triggering devices or navigator echoes. However, these techniques provide only poor gating resolution and can induce saturation bands and signal fluctuations into the lung volume. In this work, acquisition schemes for nonphase encoded navigator echoes were implemented into different sequences for morphological and functional lung imaging at 1.5 Tesla (T) and 0.2T. The navigator echoes allow monitoring of respiratory motion and provide an ECG-trigger signal for correction of the heart cycle without influencing the imaged slices. Artifact free images acquired during free respiration using a 3D GE, 2D multislice TSE or multi-Gradient Echo sequence for oxygen-enhanced T(2)(*) quantification are presented.
呼吸运动和搏动性血流会在肺部形态和功能成像中产生伪影。在进行屏气和/或心电图触发成像时，总采集时间以及由此可实现的信噪比是有限的。为了克服这些限制，可以使用呼吸门控/触发装置或导航回波在自由呼吸期间进行成像。然而，这些技术仅提供较差的门控分辨率，并且会在肺容积中引入饱和带和信号波动。在这项工作中，将非相位编码导航回波的采集方案应用于不同序列，用于在1.5特斯拉（T）和0.2T下进行肺部形态和功能成像。导航回波允许监测呼吸运动，并提供用于校正心动周期的心电图触发信号，而不会影响成像切片。展示了使用三维梯度回波（3D GE）、二维多层快速自旋回波（2D multislice TSE）或多梯度回波序列在自由呼吸期间采集的无伪影图像，用于氧增强T(2)(*)定量分析。
