Applied Science Laboratory, General Electric Healthcare, Milwaukee, Wisconsin, USA.
Magn Reson Med. 2013 Nov;70(5):1293-305. doi: 10.1002/mrm.24589. Epub 2013 Jan 16.
The proposed method is aimed at reducing eddy current (EC) induced distortion in diffusion weighted echo planar imaging, without the need to perform further image coregistration between diffusion weighted and T2 images. These ECs typically have significant high order spatial components that cannot be compensated by preemphasis.
High order ECs are first calibrated at the system level in a protocol independent fashion. The resulting amplitudes and time constants of high order ECs can then be used to calculate imaging protocol specific corrections. A combined prospective and retrospective approach is proposed to apply correction during data acquisition and image reconstruction.
Various phantom, brain, body, and whole body diffusion weighted images with and without the proposed method are acquired. Significantly reduced image distortion and misregistration are consistently seen in images with the proposed method compared with images without.
The proposed method is a powerful (e.g., effective at 48 cm field of view and 30 cm slice coverage) and flexible (e.g., compatible with other image enhancements and arbitrary scan plane) technique to correct high order ECs induced distortion and misregistration for various diffusion weighted echo planar imaging applications, without the need for further image post processing, protocol dependent prescan, or sacrifice in signal-to-noise ratio.
所提出的方法旨在减少扩散加权回波平面成像中的涡流（EC）引起的失真，而无需在扩散加权和 T2 图像之间执行进一步的图像配准。这些 EC 通常具有无法通过预强调补偿的显著高阶空间分量。
首先以协议独立的方式在系统级别校准高阶 EC。然后可以使用高阶 EC 的幅度和时间常数来计算特定于成像协议的校正。提出了一种前瞻性和回顾性相结合的方法，以便在数据采集和图像重建期间应用校正。
采集了各种具有和不具有所提出方法的体模、脑、身体和全身扩散加权图像。与没有该方法的图像相比，具有该方法的图像中始终明显减少了图像失真和配准错误。
所提出的方法是一种强大的（例如，在 48cm 视野和 30cm 切片覆盖范围内有效）和灵活的（例如，与其他图像增强和任意扫描平面兼容）技术，可用于校正各种扩散加权回波平面成像应用中的高阶 EC 引起的失真和配准错误，而无需进一步的图像后处理、协议依赖的预扫描或信噪比的牺牲。
