Center for Pulmonary Imaging Research, Division of Pulmonary Medicine, Cincinnati Children's Hospital, Cincinnati, Ohio, USA.
Department of Pediatrics, University of Cincinnati School of Medicine, Cincinnati, Ohio, USA.
Magn Reson Med. 2025 Jan;93(1):276-288. doi: 10.1002/mrm.30277. Epub 2024 Sep 1.
To develop a robust 3D ultrashort-TE (UTE) protocol that can reproducibly provide high-quality images, assessed by the ability to yield clinically diagnostic images, and is suitable for clinical translation.
Building on previous work, a UTE sampled with Fermat looped orthogonally encoded trajectories (FLORET) was chosen as a starting point due to its shorter, clinically reasonable scan times. Modifications to previous FLORET implementations included gradient waveform frequency limitations, a new trajectory ordering scheme, a balanced SSFP implementation, fast gradient spoiling, and full inline reconstruction. FLORET images were collected in phantoms and humans on multiple scanners and sites to demonstrate these improvements.
The updates to FLORET provided high-quality images in phantom, musculoskeletal, and pulmonary applications. The gradient waveform modifications and new trajectory ordering scheme significantly reduced visible artifacts. Fast spoiling reduced acquisition time by 20%-28%. Across the various scanners and sites, the inline image quality was consistent and of diagnostic quality. Total image acquisition plus reconstruction time was less than 4 min for musculoskeletal and pulmonary applications with reconstructions taking less than 1 min.
Recently developed improvements for the FLORET sequence have enabled robust, high-quality UTE acquisitions with short acquisition and reconstruction times. This enables clinical UTE imaging as demonstrated by the implementation of the sequence and acquisition on five MRI scanners, at three different sites, without the need for any additional system characterization or measurements.
开发一种稳健的 3D 超短回波时间（UTE）协议，该协议能够通过提供临床诊断图像的能力，重复生成高质量的图像，适合临床转化。
基于之前的工作，选择 Fermat 环路正交编码轨迹（FLORET）采样的 UTE 作为起点，因为它的扫描时间更短，在临床合理范围内。对之前 FLORET 实现的修改包括梯度波形频率限制、新的轨迹排序方案、平衡的 SSFP 实现、快速梯度预饱和以及全内联重建。在多台扫描仪和多个站点的体模和人体上收集 FLORET 图像，以证明这些改进。
FLORET 的更新在体模、肌肉骨骼和肺部应用中提供了高质量的图像。梯度波形修改和新的轨迹排序方案显著减少了可见伪影。快速预饱和将采集时间缩短了 20%-28%。在各种扫描仪和站点中，内联图像质量始终如一，具有诊断质量。肌肉骨骼和肺部应用的总图像采集加重建时间不到 4 分钟，重建时间不到 1 分钟。
最近为 FLORET 序列开发的改进使得 UTE 采集具有稳健、高质量和短采集和重建时间。这使得临床 UTE 成像成为可能，该序列已在五台 MRI 扫描仪上实施，并在三个不同的站点进行了采集，而无需进行任何额外的系统特性描述或测量。
