High Field MR Center, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, 1090 Vienna, Austria.
Sensors (Basel). 2024 Aug 20;24(16):5377. doi: 10.3390/s24165377.
Investigations of human brain disorders are frequently conducted in rodent models using magnetic resonance imaging. Due to the small specimen size and the increase in signal-to-noise ratio with the static magnetic field strength, dedicated small-bore animal scanners can be used to acquire high-resolution data. Ultra-high-field (≥7 T) whole-body human scanners are increasingly available, and they can also be used for animal investigations. Dedicated sensors, in this case, radiofrequency coils, are required to achieve sufficient sensitivity for the high spatial resolution needed for imaging small anatomical structures. In this work, a four-channel transceiver coil array for rat brain imaging at 7 T is presented, which can be adjusted for use on a wide range of differently sized rats, from infants to large adults. Three suitable array designs (with two to four elements covering the whole rat brain) were compared using full-wave 3D electromagnetic simulation. An optimized static B shim was derived to maximize B in the rat brain for both small and big rats. The design, together with a 3D-printed adjustable coil housing, was tested and validated in ex vivo rat bench and MRI measurements.
采用磁共振成像技术对啮齿动物模型进行人类大脑疾病研究十分常见。由于样本体积小，且随着静磁场强度的增加，信噪比也会提高，因此可以使用专用的小口径动物扫描仪来获取高分辨率数据。超高场（≥7 T）全身人体扫描仪的应用也越来越广泛，它们也可以用于动物研究。在此情况下，需要专用传感器（即射频线圈）来实现足够的灵敏度，以满足对小解剖结构成像所需的高空间分辨率的要求。在这项工作中，展示了一种用于 7 T 大鼠脑成像的四通道收发线圈阵列，它可以根据需要调整大小，以适应从婴儿到大型成年大鼠的各种不同体型的大鼠。使用全波三维电磁场模拟对三种适合的阵列设计（包含 2 到 4 个元件，可覆盖整个大鼠大脑）进行了比较。得出了一个优化的静态 B 匀场，用于最大化大鼠大脑的 B 值，同时适用于小大鼠和大大鼠。该设计与 3D 打印的可调式线圈外壳一起，在离体大鼠台架和 MRI 测量中进行了测试和验证。
