%0 Journal Article %J Magnetic Resonance in Medicine %D 2011 %T Relaxivity of Gadolinium Complexes Detected by Atomic Magnetometry %A Michalak, D. J. %A Xu, S. J. %A Lowery, T. J. %A Crawford, C. W. %A Ledbetter, M. %A Bouchard, L. S. %A Wemmer, D. E. %A Budker, D. %A Pines, A. %K nmr %X

Laser atomic magnetomeby is a portable and low-cost yet highly sensitive method for low magnetic field detection. In this work, the atomic magnetometer was used in a remote-detection geometry to measure the relaxivity of aqueous gadolinium-diethylenetriamine pentaacetic acid Gd(DTPA) at the Earth's magnetic field (40 mu T). The measured relaxivity of 9.7 +/- 2.0 s(-1) mM(-1) is consistent with field-cycling experiments measured at slightly higher magnetic fields, but no cryogens or strong and homogeneous magnetic field were required for this experiment. The field-independent sensitivity of 80 fT Hz(-1/2) allowed an in vitro detection limit of similar to 10 mu M Gd(DTPA) to be measured in aqueous buffer solution. The low detection limit and enhanced relaxivity of Gd-containing complexes at Earth's field motivate continued development of atomic magnetometry toward medical applications. Magn Reson Med 66:605-608, 2011. (C) 2011 Wiley-Liss, Inc.

%B Magnetic Resonance in Medicine %V 66 %P 605-608 %8 Aug %@ 0740-3194 %G English %U ://WOS:000293256800033 %N 2 %M WOS:000293256800033 %! Relaxivity of Gadolinium Complexes Detected by Atomic Magnetometry %R Doi 10.1002/Mrm.22811 %0 Journal Article %J Journal of Magnetic Resonance %D 2009 %T Optical detection of NMR J-spectra at zero magnetic field %A Ledbetter, M. P. %A Crawford, C. W. %A Pines, A. %A Wemmer, D. E. %A Knappe, S. %A Kitching, J. %A Budker, D. %K cells %X

Scalar couplings of the form JI(1) . I(2) between nuclei impart valuable information about molecular structure to nuclear magnetic-resonance spectra. Here we demonstrate direct detection of J-spectra due to both heteronuclear and homonuclear J-coupling in a zero-field environment where the Zeeman interaction is completely absent. We show that characteristic functional groups exhibit distinct spectra with straightforward interpretation for chemical identification. Detection is performed with a microfabricated optical atomic magnetometer, providing high sensitivity to samples of microliter volumes. We obtain 0.1 Hz linewidths and measure scalar-coupling parameters with 4-mHz statistical uncertainty. We anticipate that the technique described here will provide a new modality for high-precision" J spectroscopy" using small samples oil microchip devices for multiplexed Screening, assaying, and sample identification in chemistry and biomedicine. (C) 2009 Elsevier Inc. All rights reserved.

%B Journal of Magnetic Resonance %V 199 %P 25-29 %8 Jul %@ 1090-7807 %G English %U ://WOS:000266890300004 %N 1 %M WOS:000266890300004 %! Optical detection of NMR J-spectra at zero magnetic field %R Doi 10.1016/J.Jmr.2009.03.008 %0 Journal Article %J Journal of Magnetic Resonance Imaging %D 2008 %T Flow in Porous Metallic Materials: A Magnetic Resonance Imaging Study %A Xu, S. J. %A Harel, E. %A Michalak, D. J. %A Crawford, C. W. %A Budker, D. %A Pines, A. %K mri %X

Purpose: To visualize flow dynamics of analytes inside porous metallic materials with laser-detected magnetic resonance imaging (MRI).Materials and Methods: We examine the flow of nuclear-polarized water in a porous stainless steel cylinder. Laser-detected MRI utilizes a sensitive optical atomic magnetometer as the detector. Imaging was performed in a remote-detection mode: the encoding was conducted in the Earth's magnetic field, and detection is conducted downstream of the encoding location. Conventional MRI (7T) was also performed for comparison.Results: Laser-detected MRI clearly showed MR images of water flowing through the sample, whereas conventional MRI provided no image.Conclusion: We demonstrated the viability of laser-detected MRI at low-field for studying porous metallic materials, extending MRI techniques to a new group of systems that is normally not accessible to conventional MRI.

%B Journal of Magnetic Resonance Imaging %V 28 %P 1299-1302 %8 Nov %@ 1053-1807 %G English %U ://WOS:000260566100033 %N 5 %M WOS:000260566100033 %! Flow in Porous Metallic Materials: A Magnetic Resonance Imaging Study %R Doi 10.1002/Jmri.21532 %0 Journal Article %J Applied Physics Letters %D 2008 %T Fluid-flow characterization with nuclear spins without magnetic resonance %A Crawford, C. W. %A Xu, S. J. %A Siegel, E. J. %A Budker, D. %A Pines, A. %K mri %X

A technique for noninvasive monitoring of flow inside metallic enclosures using laser-based atomic magnetometry is introduced. The analyte is labeled via nuclear magnetization by magnets, thereby combining the polarization and encoding steps. No radiofrequency or audiofrequency pulses are involved. We demonstrate detection of flow inside an aluminum pipe with an inner diameter of 4.9 mm that has a constriction with a diameter of 1.6 mm and a length of 6.4 mm. The results agree with a model of spin density and relaxation indicating that our technique allows for fast, quantitative, and noninvasive diagnostics of flow with potential applications discussed below. (c) 2008 American Institute of Physics.

%B Applied Physics Letters %V 93 %8 Sep 1 %@ 0003-6951 %G English %U ://WOS:000258975800042 %N 9 %M WOS:000258975800042 %! Fluid-flow characterization with nuclear spins without magnetic resonance %R Doi 10.1063/1.2977773 %0 Journal Article %J Physical Review A %D 2008 %T Submillimeter-resolution magnetic resonance imaging at the Earth's magnetic field with an atomic magnetometer %A Xu, S. %A Crawford, C. W. %A Rochester, S. %A Yashchuk, V. %A Budker, D. %A Pines, A. %K nmr %X

Magnetic resonance imaging in the Earth's magnetic field is achieved using a sensitive atomic magnetometer for detection. We demonstrate images with a submillimeter resolution by recording the flow of two water paths meeting at a T-shaped mixer. The high homogeneity of the Earth's field allows the use of weak gradient fields which circumvent the concomitant-field effect. To distinguish the two input channels, we employed selective polarization, which is a unique and noninvasive labeling method for low-field magnetic resonance imaging. Our technique imposes minimal physical constraints on the object under study, in contrast to conventional high-field magnetic resonance imaging. This technique is applicable for microfluidic imaging in laboratory-on-a-chip devices.

%B Physical Review A %V 78 %8 Jul %@ 1050-2947 %G English %U ://WOS:000258180300141 %N 1 %M WOS:000258180300141 %! Submillimeter-resolution magnetic resonance imaging at the Earth's magnetic field with an atomic magnetometer %R Doi 10.1103/Physreva.78.013404