German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany.
Max-Planck Institute for Biological Cybernetics, Tübingen, Germany.
Magn Reson Med. 2019 Nov;82(5):1741-1752. doi: 10.1002/mrm.27866. Epub 2019 Jun 14.
The aim of this work is to develop a fast and robust CEST sequence in order to allow the acquisition of a whole-brain imaging volume after a single preparation block (snapshot acquisition).
A 3D-CEST sequence with an optimized 3D-EPI readout module was developed, which acquires the complete k-space data following a single CEST preparation for 1 saturation offset. Whole-brain mapping of the Z-spectrum with 2 mm isotropic resolution is achieved at 68 saturation frequencies in 5 minutes (4.33 s per offset). We analyzed the distribution in order to optimize correction and to provide accurate CEST quantification across the whole brain.
We obtained maps for 3 different CEST contrasts from 4 healthy subjects. Based on our distribution analysis, we conclude that 3 sampling points allow for sufficient compensation of variations across most of the brain. Two brain regions, the cerebellum and the temporal lobes, are difficult to quantify at 7 T due to very low that was achieved in these regions.
The proposed sequence enables robust acquisition of 2 mm isotropic whole-brain CEST maps at 7 Tesla within a total scan time of 16 minutes.
本研究旨在开发一种快速且稳健的 CEST 序列，以便在单个准备模块（快照采集）后即可获取整个大脑的成像容积。
开发了一种具有优化的 3D-EPI 读取模块的 3D-CEST 序列，该序列在单个 CEST 准备后可采集 1 个饱和偏移的完整 k 空间数据。采用该序列在 68 个饱和频率下以 2mm 的各向同性分辨率实现了整个大脑 Z 谱的映射，采集时间为 5 分钟（每个偏移 4.33 秒）。我们分析了 分布情况，以优化 校正并在整个大脑中提供准确的 CEST 定量。
我们从 4 名健康受试者中获得了 3 种不同的 CEST 对比图。基于我们的 分布分析，我们得出结论，在大多数大脑区域，3 个采样点足以补偿 变化。由于在这些区域中达到的 非常低，因此在小脑和颞叶这两个脑区难以进行定量分析。
该序列可在 16 分钟的总扫描时间内实现 7T 下的 2mm 各向同性全脑 CEST 图谱的稳健采集。
