New Directions in NMR Imaging

IEEE Transactions on Nuclear Science, Vol. NS-31, No. 4, August 1984

NEW DIRECTIONS IN NMR IMAGING

Paul C. LauterburDepartment of Chemistry

State University of New York at Stony BrookStony Brook, New York 11794

Abstract

Spectroscopic NMR imaging, microscopic NMRimaging, and the NMR imaging of gases are underdevelopment and may have significant applicationsin biomedical research and clinical investigations.

Introduction

The practical utility of clinical proton NMRimaging has now been amply demonstrated, and itappears likely to replace a significant fraction ofthe x-ray computed tomography procedures now performed,as well as making possible new applications andinvestigations. A number of possible techniques andapplications have not yet been fully developed orwidely used, however. Some of these are discussedbriefly below.

Spectroscopi c Imaging

Spectroscopic, or chemical shift imaging, can

be carried out in a number of ways.1 9 The applica-tions that are of most interest at the present timeare to the localization of phosphorus NMR spectra inthe brain and other organs more precisely than can bedone with surface coils and "topical" field-shapingtechniques, and distinguishing between the proton NMRsignals of water and fat. The extra dimension ofinformation involved requires that much more time betaken to acquire the image data, or that resolutionbe significantly decrease. In practical investigationsthe latter option is usually the more appropriate.

Microscopic Imaging

Microscopic NMR imaging has been discussed from

time to time10' but little experimental work has beenreported. The resolution is limited fundamentallyonly by sensitivity, for practical instrumentaldesigns suitable for biological samples, and may beapproximately 10 pm in an isotropic volume image.Actual images at 20 to 30 ulm resolution have recentlybeen presented.11 Further development may lead to apractical NMR microscope useful for small, thick, andopaque wet biological specimens, and to specialapplications to non-destructive testing and in thephysical sciences.

Gas Imaging

Imaging of gases, despite their low nucleardensity at ordinary temperatures and pressures, ispossible if resolution lower than that obtainablewith liquids is acceptable. In isotropic volumeimaging, for example, volume elements an order of

magnitude larger in linear dimensions approximatelycompensate for the three orders of magnitude lowerdensity. The medical application that appearspromising is to lung ventilation imaging, using inertperfluorinated gases as breathable mixtures with

oxygen. The 19F NMR signal can be detected without

interference from the IH NMR signal from the tissues,and two- and three-dimensional images of the gas

distribution above12, or of thoracic anatomy as wellas ventilation, can be obtained.

References

[1] P. C. Lauterbur, D. M. Kramer, W. V. House, Jr.,and C. N. Chen, J. Am. Chem. Soc. 97, 6866(1975).

[2] A. A. Maudsley, A. Oppelt, and A. Gansen,Siemens Res. Dev. Rep. 8, 326 (1979).

[3] P. Bendel, C.-M. Lai, and P. C. Lauterbur,J. Magn. Reson. 38, 343 (1980).

[4] S. F. J. Cox and P. Styles, J. Magn. Reson. 40,209 (1980).

[5] T. R. Brown, B. M. Kincaid, and K. Ugurbil,Proc. Natl. Acad. Sci. USA 79, 3523 (1982).

[6] L. D. Hall and S. Sukumar, J. Magn. Reson.50, 161 (1982).

[7] A. A. Maudsley, S. K. Hilal, W. H. Perman, andH. E. Simon, J. Magn. Reson. 51, 147 (1983).

[8] I. L. Pykett and B. R. Rosen, Radiology 149,197 (1983).

[9] P. C. Lauterbur, D. N. Levin, and R. B. Marr,Radiology 149, 255 (1983).

[10] P. Mansfield and P. G. Morris, NMR Imaging inBiomedicine; Advances in Magnetic Resonance,Suppl. 2 (J.S. Waugh, editor). New York:Academic Press, 1982.

[11] L. K. Hedges, Ph.D. Dissertation, State Univer-sity of New York at Stony Brook, 1984.

[12] P. A. Rinck, S. B. Petersen, E. Heidelberger,V. Acuff, J. Reinders, M. L. Bernardo, L. K.Hedges, and P. C. Lauterbur, Magn. Res. inMedicine 1, 237 (1984).

Acknowledgements

This work was supported in part by Grant No.CA15300, awarded by the National Cancer Institute,DHHS; and by Grant No. HL19851, awarded by theNational Heart, Lung and Blood Institute, DHHS.

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