A PXIe Based Scalable MRI Spectrometer for Inhomogeneous Imaging

Traditional MRI plays a significant role in clinic diagnoses for providing versatility of examinations. However, the high cost and complexity of the MRI system presents a challenge for most people to access. Low-field MRI with low cost and simplicity could be used in particular sites, e.g., on the ambulance or in the rural area, which would benefit more people. A spectrometer is one of the critical parts of a low-field MRI system. Even though the commercial spectrometers are available, they are usually expensive and their closed proprietary designs frustrate adaptation to new techniques or experiments.

To tackle these challenges, a scalable PXIe based spectrometer with a multichannel transceiver was developed for MRI research and development. Key features of the spectrometer include the use of a quad-channel digital receiver for parallel imaging, a dual-channel transmitter for spatial encoding, e.g., TRASE, a high-bandwidth protocol for data transactions and an Ethernet-based user interface.

A 2D MRI system was built to verify the spectrometer. In addition to the spectrometer, an RF coil system containing a solenoid coil for excitation and a receive coil array for receiving, detuning circuits, and pre-amplifiers were built. NMR magnetometry was used to measure the field map of a Halbach magnet. Based on the 2D imaging system, parallel MR signals were captured and verified.