@article {322,
	title = {SQUID-detected liquid state NMR in microtesla fields},
	journal = {Journal of Physical Chemistry A},
	volume = {108},
	year = {2004},
	note = {J Phys Chem A772FTTimes Cited:32Cited References Count:36},
	month = {Feb 12},
	pages = {957-963},
	abstract = {<p>Nuclear magnetic resonance (NMR) experiments performed in magnetic fields on the order of microtesla yield line widths comparable to the lifetime limit even in grossly inhomogeneous magnets. The potential loss in sensitivity is overcome by combining prepolarization in fields on the order of millitesla and signal detection with a Superconducting Quantum Interference Device (SQUID). The enhanced spectral resolution attainable in microtesla fields enables NMR studies of pure liquids and solutions without the need for strong magnets. We have investigated a variety of heteronuclear systems in both the weak and strong J-coupling regimes. Six different nuclear species have been detected with the same experimental apparatus. NMR signals of thermally polarized protons were obtained in fields as low as 554 nT.</p>
},
	keywords = {water},
	isbn = {1089-5639},
	doi = {Doi 10.1021/Jp035181g},
	url = {<Go to ISI>://WOS:000188831500005},
	author = {Trabesinger, A. H. and McDermott, R. and Lee, S. K. and M{\"u}ck, M. and Clarke, J. and Pines, A.}
}
@article {332,
	title = {SQUID-detected magnetic resonance imaging in microtesla magnetic fields},
	journal = {Journal of Low Temperature Physics},
	volume = {135},
	year = {2004},
	note = {J Low Temp Phys824TWTimes Cited:37Cited References Count:34},
	month = {Jun},
	pages = {793-821},
	abstract = {<p>We describe studies of nuclear magnetic resonance (NMR) spectroscopy and magnetic resonance imaging (MRI) of liquid samples at room temperature in microtesla magnetic fields. The nuclear spins are prepolarized in a strong transient field. The magnetic signals generated by the precessing spins, which range in frequency from tens of Hz to several kHz, are detected by a low-transition temperature dc SQUID (Superconducting QUantum Interference Device) coupled to an untuned, superconducting flux transformer configured as an axial gradiometer. The combination of prepolarization and frequency-independent detector sensitivity results in a high signal-to-noise ratio and high spectral resolution (similar to 1 Hz) even in grossly inhomogeneous magnetic fields. In the NMR experiments, the high spectral resolution enables us to detect the 10-Hz splitting of the spectrum of protons due to their scalar coupling to a P-31 nucleus. Furthermore, the broadband detection scheme combined with a non-resonant field-reversal spin echo allows the simultaneous observation of signals from protons and P-31 nuclei, even though their NMR resonance frequencies differ by a factor of 2.5. We extend our methodology to MRI in microtesla fields, where the high spectral resolution translates into high spatial resolution. We demonstrate two-dimensional images of a mineral oil phantom and slices of peppers, with a spatial resolution of about 1 mm. We also image an intact pepper using slice selection, again with 1-mm, resolution. A further experiments we demonstrate T-1-contrast imaging of a water phantom, some parts of which were doped with a paramagnetic salt to reduce the longitudinal relaxation time T-1. Possible applications of this MRI technique include screening for tumors and integration with existing multichannel SQUID systems for brain imaging.</p>
},
	keywords = {mri},
	isbn = {0022-2291},
	doi = {Doi 10.1023/B:Jolt.0000029519.09286.C5},
	url = {<Go to ISI>://WOS:000221710600023},
	author = {McDermott, R. and Kelso, N. and Lee, S. K. and Mossle, M. and M{\"u}ck, M. and Myers, W. and ten Haken, B. and Seton, H. C. and Trabesinger, A. H. and Pines, A. and Clarke, J.}
}
