Division of Cardiovascular, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts 02215, USA.
Magn Reson Med. 2011 Aug;66(2):467-75. doi: 10.1002/mrm.22854. Epub 2011 Feb 24.
In this study, we present a motion correction technique using coil arrays (MOCCA) and evaluate its application in free-breathing respiratory self-gated cine MRI. Motion correction technique using coil arrays takes advantages of the fact that motion-induced changes in k-space signal are modulated by individual coil sensitivity profiles. In the proposed implementation of motion correction technique using coil arrays self-gating for free-breathing cine MRI, the k-space center line is acquired at the beginning of each k-space segment for each cardiac cycle with 4 repetitions. For each k-space segment, the k-space center line acquired immediately before was used to select one of the 4 acquired repetitions to be included in the final self-gated cine image by calculating the cross correlation between the k-space center line with a reference line. The proposed method was tested on a cohort of healthy adult subjects for subjective image quality and objective blood-myocardium border sharpness. The method was also tested on a cohort of patients to compare the left and right ventricular volumes and ejection fraction measurements with that of standard breath-hold cine MRI. Our data indicate that the proposed motion correction technique using coil arrays method provides significantly improved image quality and sharpness compared with free-breathing cine without respiratory self-gating and provides similar volume measurements compared with breath-hold cine MRI.
在这项研究中,我们提出了一种使用线圈阵列的运动校正技术(MOCCA),并评估了其在自由呼吸呼吸门控电影 MRI 中的应用。使用线圈阵列的运动校正技术利用了这样一个事实,即运动引起的 k 空间信号变化被单个线圈灵敏度分布调制。在提出的用于自由呼吸电影 MRI 的线圈阵列自门控运动校正技术的实现中,在每个心动周期的每个 k 空间段的开始获取 k 空间中心线,重复 4 次。对于每个 k 空间段,使用在参考线之间计算 k 空间中心线的互相关来选择在最终的自门控电影图像中包括的 4 次采集重复中的一个,以获取的 k 空间中心线立即在之前。该方法在一组健康成年受试者中进行了测试,以评估主观图像质量和客观心肌边界锐度。该方法还在一组患者中进行了测试,以比较左心室和右心室容积以及射血分数测量值与标准屏气电影 MRI 的比较。我们的数据表明,与没有呼吸自门控的自由呼吸电影相比,所提出的使用线圈阵列的运动校正技术方法提供了显著改善的图像质量和锐度,并与屏气电影 MRI 提供了类似的容积测量值。