paper

SQUID-based instrumentation for ultra-low-field MRI

arXiv:0705.0661 · doi:10.1088/0953-2048/20/11/S13

Abstract

Magnetic resonance imaging at ultra-low fields (ULF MRI) is a promising new imaging method that uses SQUID sensors to measure the spatially encoded precession of pre-polarized nuclear spin populations at a microtesla-range measurement field. In this work, a seven-channel SQUID system designed for simultaneous 3D ULF MRI and magnetoencephalography (MEG) is described. The system includes seven second-order SQUID gradiometers, characterized by magnetic field resolutions of 1.2 - 2.8 fT/rtHz. It is also equipped with five sets of coils for 3D Fourier imaging with pre-polarization. Essential technical details of the design are discussed. The system's ULF MRI performance is demonstrated by multi-channel 3D images of a preserved sheep brain acquired at 46 microtesla measurement field with pre-polarization at 40 mT. The imaging resolution is 2.5 mm x 2.5 mm x 5 mm. The ULF MRI images are compared to images of the same brain acquired using conventional high-field MRI. Different ways to improve imaging SNR are discussed.

To appear in Proceedings of 11th International Superconductive Electronics Conference (ISEC 2007); 8 pages, 11 figures

References in corpus (1)

Cited by in corpus (12)