A High-Sensitivity and Shielding-Free Rabbit Brain MIPS Scanner

The purpose of this article is to improve the detection sensitivity and quantitative assessment of different levels of cerebral hemorrhage (CH), and a high-sensitivity and shielding-free rabbit brain magnetic induction phase shift (MIPS) scanner was developed and validated. First, a uniform rotating magnetic field generated by a birdcage coil was utilized instead of the divergent magnetic field for the first time, and the birdcage structure has inherent characteristics of shielding external interference. Furthermore, the primary field was canceled, and the axial and tangential magnetic field components of the secondary magnetic field were synchronously detected and then synthesized for the first time using a magnetron sensor coil and a circular solenoid coil. Specifically, a field-programmable gate array-based spectrometer was used to guarantee the two-channel signal of high-precision quadrature excitation for birdcage coil, signal acquisition, and data processing. Experimental results indicated that the phase shift difference decreases linearly with the volume increase of blood injection, and the average MIPS caused by a 3-mL blood injection of rabbit inner capsule hemorrhage was 2.709°, which was 7.7 times higher than that of the traditional single excitation coil and single receiving coil (single coil–coil) method. The results have proven that this scanner has high sensitivity, strong anti-interference ability, and potential to realize the quantitative detection of hematoma volume.