Munich School of BioEngineering, TUM, Boltzmannstr. 11, 85748 Garching, Germany.
Pure Devices GmbH, Kettelerstr. 5-11, 97222 Rimpar, Germany.
Rev Sci Instrum. 2020 Mar 1;91(3):033704. doi: 10.1063/1.5128046.
A bridged loop gap resonator (BLGR) was developed as a transmit and receive coil for a mobile insert to be used for small animal proton imaging by 1.5 T MRI devices. The insert system has its own gradient system, radio frequency (RF) transmit and receive coil, and control and signal processing unit. The reflection S and transmission S parameters, quality factor (Q), sensitivity, signal to noise ratio (SNR), and maps of the static (B) and RF (B) magnetic flux densities were measured. The RF coil was developed starting from a loop gap resonator (LGR) for a balanced LGR and a shielded balanced LGR for a shielded bridged balanced LGR. The purpose of developing this device is to minimize the influence of the sample and surroundings on the RF coil parameters. The final design of the BLGR does not require retuning after a sample change. A 3D image of a mouse in formalin was acquired with a fast low angle shot (FLASH) MRI sequence. The SNR was calculated from one FLASH image. The signal for SNR calculation was acquired from a gadolinium-doped water sample and the noise from the air outside of the sample. This article verifies that the BLGR is viable for small animal nuclear magnetic resonance imaging at 1.5 T and is independent of sample size and material.
一种桥接环隙谐振器（BLGR）被开发为用于小动物质子成像的移动插入物的发射和接收线圈，通过 1.5T MRI 设备使用。插入系统具有自己的梯度系统、射频（RF）发射和接收线圈以及控制和信号处理单元。测量了反射 S 和传输 S 参数、品质因数（Q）、灵敏度、信噪比（SNR）以及静态（B）和射频（B）磁通密度的图。RF 线圈是从用于平衡 LGR 的环隙谐振器（LGR）以及用于屏蔽桥接平衡 LGR 的屏蔽平衡 LGR 开始开发的。开发此设备的目的是最小化样品和周围环境对 RF 线圈参数的影响。BLGR 的最终设计不需要在样品更换后重新调谐。使用快速低角度拍摄（FLASH）MRI 序列获取了福尔马林固定小鼠的 3D 图像。从一个 FLASH 图像计算 SNR。用于 SNR 计算的信号是从掺钆水样品中获取的，而噪声是从样品外部的空气中获取的。本文验证了 BLGR 可在 1.5T 下用于小动物磁共振成像，并且与样品尺寸和材料无关。
