A Miniature Multinuclei NMR/MRI Platform With a High-Voltage SOI ASIC

This article describes a miniature nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) platform with a customized high-voltage (HV) application-specific integrated circuit (ASIC) in a 180-nm silicon-on-insulator (SOI) process. To synthesize different advanced excitation sequences to support multinuclei MRI, it features a multiphase generator with phase interpolation (PI) for synthesizing composite pulses with a 0.7° phase resolution. In addition, to withstand the high-voltage stress on the front-end low-noise receiver from the NMR coil without utilizing off-chip switches, we integrate on-chip HV switches to protect the receiver during the excitation and shorten the NMR signal path to reduce the noise coupled by the conductor during the acquisition. The proposed multinuclei NMR/MRI platform features a 4.1-mm² ASIC. It attains an image resolution of $173{\times } 250{\times } 103~{\mu }$ m³ with a 42.6 dB signal-to-noise ratio (SNR). Meanwhile, we exhibit tracking of perfluorocarbons (PFCs)-labeled porcine samples from the ¹H/19F MRI results acquired by the proposed prototype.