Mattingly Eli, Mason Erica E, Herb Konstantin, Śliwiak Monika, Drago John, Graeser Matthias, Wald Lawrence L
Harvard-MIT Division of Health Sciences & Technology, Cambridge, MA, USA.
Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, USA.
Int J Magn Part Imaging. 2022;8(2). doi: 10.18416/IJMPI.2022.2212001. Epub 2022 Dec 21.
Magnetic particle imaging noninvasively maps the distribution of superparamagnetic iron oxide nanoparticles with high sensitivity. Since the particles are confined to the blood pool within the brain, it may be well-suited for cerebral blood volume (CBV)-based functional neuroimaging with MPI (fMPI). Here, we present a magnetic particle imaging system designed to detect the CBV modulation at the hemodynamic timescale (~5 sec) in rodents. It has the capacity to record sufficiently fast image time-series for several hours continuously. The time-series imaging was achieved with an optimized drive coil that maintains ~0.01% per minute current magnitude stability. An electrical slip ring and rotary union for cooling water allows continuous mechanical rotation of the 2.83 T/m Field-Free Line (FFL) permanent magnets and shift coils. The system achieves a 6.7 ng Fe detection limit (SNR = 5) in a single 5 sec image in the time-series, a spatial resolution of 3.0 mm in a 3 cm diameter field of view. The designs have been made open-source to enable replication of this device.
磁粒子成像能够以高灵敏度无创地绘制超顺磁性氧化铁纳米颗粒的分布。由于这些颗粒局限于脑内的血池，它可能非常适合基于脑血容量（CBV）的磁粒子成像功能神经成像（fMPI）。在此，我们展示了一种磁粒子成像系统，该系统旨在检测啮齿动物在血液动力学时间尺度（约5秒）下的CBV调制。它有能力连续数小时记录足够快的图像时间序列。通过优化的驱动线圈实现时间序列成像，该驱动线圈每分钟的电流幅度稳定性保持在约0.01%。用于冷却水的电滑环和旋转接头允许2.83 T/m无场线（FFL）永久磁铁和移位线圈连续机械旋转。该系统在时间序列的单个5秒图像中实现了6.7 ng Fe的检测限（SNR = 5），在3厘米直径的视野中空间分辨率为3.0毫米。这些设计已开源，以便能够复制该设备。
