Michaelis Thomas, Voit Dirk, Kollmeier Jost M, Kalentev Oleksandr, van Zalk Maaike, Frahm Jens
Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany.
Quant Imaging Med Surg. 2023 Jan 1;13(1):489-495. doi: 10.21037/qims-22-648. Epub 2022 Oct 8.
This work describes a dynamic magnetic resonance imaging (MRI) technique for local scanning of the human body with use of a handheld receive coil or coil array. Real-time MRI is based on highly undersampled radial gradient-echo sequences with joint reconstructions of serial images and coil sensitivity maps by regularized nonlinear inversion (NLINV). For this proof-of-concept study, a fixed slice position and field-of-view (FOV) were predefined from the operating console, while a local receive coil (array) is moved across the body-for the sake of simplicity by the subject itself. Experimental realizations with a conventional 3 T magnet comprise dynamic anatomic imaging of the head, thorax and abdomen of healthy volunteers. Typically, the image resolution was 0.75 to 1.5 mm with 3 to 6 mm section thickness and acquisition times of 33 to 100 ms per frame. However, spatiotemporal resolutions and contrasts are highly variable and may be adjusted to clinical needs. In summary, the proposed FLASHlight MRI method provides a robust acquisition and reconstruction basis for future diagnostic strategies that mimic the usage of ultrasound. Necessary extensions for this vision require remote control of all sequence parameters by a person at the scanner as well as the design of more flexible gradients and magnets.
这项工作描述了一种动态磁共振成像（MRI）技术，该技术使用手持式接收线圈或线圈阵列对人体进行局部扫描。实时MRI基于高度欠采样的径向梯度回波序列，通过正则化非线性反演（NLINV）对序列图像和线圈灵敏度图进行联合重建。在这项概念验证研究中，从操作控制台预定义了固定的切片位置和视野（FOV），同时为了简单起见，由受试者自己将局部接收线圈（阵列）在身体上移动。使用传统3T磁体的实验实现包括对健康志愿者的头部、胸部和腹部进行动态解剖成像。通常，图像分辨率为0.75至1.5毫米，切片厚度为3至6毫米，每帧采集时间为33至100毫秒。然而，时空分辨率和对比度变化很大，可以根据临床需要进行调整。总之，所提出的FLASHlight MRI方法为未来模仿超声使用的诊断策略提供了强大的采集和重建基础。实现这一设想所需的扩展包括由扫描器旁的人员远程控制所有序列参数，以及设计更灵活的梯度和磁体。
