CALAMARI: Doing MRI at 130 microtesla with a SQUID

I've been dabbling in some ultralow field (ULF) MRI over the past several years, trying first to get functional brain imaging to work (more on that another day, perhaps) and more recently looking at the contrast properties of normal and diseased brains. We detect MR signals at less than three times the earth's magnetic field (of approximately 50 microtesla) using an ultra-sensitive superconducting quantum interference device (SQUID). The system is usually referred to as "The Cube" on account of the large aluminum box surrounding the entire apparatus; it provides magnetic shielding for the SQUID. But my own nickname for the system is CALAMARI - the CAL Apparatus for MAgnetic Resonance Imaging. Deep-fried rings or grilled strips, it's all good. Anyway, should you wish to know more about this home-built system and what it might be able to do, there's a new paper (John Clarke's inaugural article after being elected to the NAS) now out in PNAS. At some point I'll put up more blog posts on both anatomical and functional ULFMRI, and go over some of the work that's being done at high fields (1.5+ T) that may be relevant to ULFMRI.