Division of Imaging Sciences and Biomedical Engineering, The Rayne Institute, King's College London, St Thomas' Hospital, 4th Floor, Lambeth Wing, London, SE1 7EH, UK,
MAGMA. 2013 Oct;26(5):419-29. doi: 10.1007/s10334-013-0370-y. Epub 2013 Feb 13.
A common approach to compensate for respiratory motion in free-breathing 3D magnetic resonance imaging (MRI) is navigator gating where MRI data is only acquired when the respiratory signal coincides within a small predefined acceptance window. However, this leads to poor scan efficiency and prolonged scan times. Here, we propose a method to reconstruct motion-compensated 3D MRI of the abdomen acquired during free-breathing with nearly 100% scan efficiency without increasing scan time.
The approach is based on a self-gated golden-radial phase encoding sampling scheme that allows for the reconstruction of multiple undersampled 3D images at different respiratory positions. Non-rigid image registrations and time-wise motion field interpolations are employed to form 3D motion models that combine all low-quality images into one high-quality motion-compensated image.
Our highly efficient technique allows reconstruction of 3D liver MRI with a high isotropic resolution of 1.75 mm from a short acquisition of 1.1 min. The approach is validated in 10 healthy volunteers by comparing image quality to data sets acquired with a self-gating approach.
Our method reduces scan time by 56% compared to the gating technique while similar image quality is preserved.
在自由呼吸 3D 磁共振成像（MRI）中，补偿呼吸运动的常用方法是导航门控，仅在呼吸信号在小预设接受窗口内匹配时才采集 MRI 数据。然而，这导致扫描效率差且扫描时间延长。在这里，我们提出了一种在不增加扫描时间的情况下，以近 100%的扫描效率重建自由呼吸期间腹部运动补偿 3D MRI 的方法。
该方法基于自门控金放射状相位编码采样方案，允许在不同呼吸位置重建多个欠采样 3D 图像。采用非刚性图像配准和时间运动场插值，形成 3D 运动模型，将所有低质量图像组合成一个高质量的运动补偿图像。
我们的高效技术允许从 1.1 分钟的短采集重建具有 1.75 毫米高各向同性分辨率的 3D 肝脏 MRI。该方法在 10 名健康志愿者中得到验证，通过与自门控方法采集的数据进行比较，评估图像质量。
与门控技术相比，我们的方法将扫描时间减少了 56%，同时保持了相似的图像质量。
