Biomedical Translational Imaging Centre (BIOTIC), Halifax, NS, Canada; Dalhousie University, Halifax, NS, Canada.
Biomedical Translational Imaging Centre (BIOTIC), Halifax, NS, Canada; Dalhousie University, Halifax, NS, Canada.
Magn Reson Imaging. 2021 Jun;79:121-129. doi: 10.1016/j.mri.2021.03.017. Epub 2021 Mar 24.
Develop a magnetic resonance fingerprinting (MRF) methodology with R quantification, intended for use with simultaneous contrast agent concentration mapping, particularly gadolinium (Gd) and iron labelled CD8+ T cells.
Variable-density spiral SSFP MRF was used, modified to allow variable TE, and with an exp.(-TE·R) dictionary modulation. In vitro phantoms containing SPIO labelled cells and/or gadolinium were used to validate parameter maps, probe undersampling capacity, and verify dual quantification capabilities. A C57BL/6 mouse was imaged using MRF to demonstrate acceptable in vivo resolution and signal at 8× undersampling necessary for a 25-min scan.
Strong agreement was found between conventional and MRF-derived values for R, R, and R. Expanded MRF allowed quantification of iron-loaded CD8+ T cells. Results were robust to 8× undersampling and enabled recreation of relaxation profiles for both a Gd agent and iron labelled cells simultaneously. In vivo data demonstrated sufficient SNR in undersampled data for parameter mapping to visualise key features.
MRF can be expanded to include R, R, and R mapping required for simultaneous quantification of gadolinium and SPIO in vitro, allowing for potential implementation of a variety of future in vivo studies using dual MR contrast agents, including molecular imaging of labelled cells.
开发一种具有 R 定量功能的磁共振指纹识别（MRF）方法，旨在与同时对比剂浓度映射一起使用，特别是钆（Gd）和铁标记的 CD8+T 细胞。
使用可变密度螺旋 SSFP MRF，对其进行修改以允许可变 TE，并采用 exp.(-TE·R)字典调制。使用含有超顺磁氧化铁（SPIO）标记细胞和/或钆的体外体模来验证参数图、探针欠采样能力，并验证双重定量能力。使用 MRF 对 C57BL/6 小鼠进行成像，以证明在 25 分钟扫描所需的 8×欠采样下具有可接受的体内分辨率和信号。
在 R、R 和 R 方面，常规方法和 MRF 衍生值之间具有很强的一致性。扩展的 MRF 允许对负载铁的 CD8+T 细胞进行定量。结果对 8×欠采样具有很强的稳健性，并且能够同时重建 Gd 试剂和铁标记细胞的弛豫曲线。体内数据表明，在欠采样数据中具有足够的 SNR，可用于参数映射以可视化关键特征。
MRF 可以扩展到包括同时体外定量钆和 SPIO 所需的 R、R 和 R 映射，为使用双磁共振对比剂进行各种未来的体内研究提供了可能性，包括标记细胞的分子成像。
