Jaffray Alexander, Kames Christian, Medina Michelle, Graf Christina, Clansey Adam, Rauscher Alexander
Department of Physics and Astronomy, University of British Columbia, Vancouver, Canada.
Department of Pediatrics, University of British Columbia, Vancouver, Canada.
Imaging Neurosci (Camb). 2024 Feb 12;2. doi: 10.1162/imag_a_00091. eCollection 2024.
Functional Magnetic Resonance Imaging (fMRI) is typically acquired using gradient-echo sequences with a long echo time at high temporal resolution. Gradient-echo sequences inherently encode information about the magnetic field in the often discarded image phase. We demonstrate a method for processing the phase of reconstructed fMRI data to isolate temporal fluctuations in the harmonic fields associated with respiration by solving a blind source separation problem. The fMRI-derived field fluctuations are shown to be in strong agreement with breathing belt data acquired during the same scan. This work presents a concurrent, hardware-free measurement of respiration-induced field fluctuations, providing a respiratory regressor for fMRI analysis which is independent of local contrast changes, and with potential applications in image reconstruction and fMRI analysis.
功能磁共振成像（fMRI）通常使用具有高时间分辨率的长回波时间梯度回波序列来采集。梯度回波序列在通常被丢弃的图像相位中固有地编码有关磁场的信息。我们展示了一种处理重建fMRI数据相位的方法，通过解决盲源分离问题来分离与呼吸相关的谐波场中的时间波动。结果表明，从fMRI得出的场波动与在同一次扫描期间采集的呼吸带数据高度一致。这项工作提出了一种同步的、无需硬件的呼吸诱导场波动测量方法，为fMRI分析提供了一个与局部对比度变化无关的呼吸回归器，并在图像重建和fMRI分析中具有潜在应用。
