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1. IntroductionIn our laboratory, the effort to pursue high magneticfields has been intricately tied to our interest in developingmethods for the acquisition of physiological and biochem-ical information noninvasively using the nuclear spins of thewater molecules and metabolites in the human body. In thiseffort, a relatively recent and unique accomplishment hasbeen the introduction of the ability to map human brainfunction noninvasively. The concurrent and independentwork performed at the University of Minnesota, Center forMagnetic Resonance Research [1] and at MGH [2], was, inour case, conducted at 4 Tesla. It was one of the firstexperiments performed at 4 Tesla in our laboratory. Today,functional images with subcentimeter resolution of the en-tire human brain can be generated in single subjects and indata acquisition times of several minutes using 1.5 TeslaMRI scanners that are often employed in hospitals for clin-ical diagnosis. However, there have been advantages inusing significantly higher magnetic fields such as 4 Tesla,and recently 7 Tesla in humans, and 9.4 Tesla in animalmodels. Similarly, over the last two-and-a-half decades,spectroscopy studies in intact cells have proven to be rich inbiochemical information. However, the most useful of thesestudies were performed in isolated cells or perfused tissues.Only recently, they were extended to small animal modelsusing high magnetic fields. In human applications, spectros-copy efforts pursued at the commonly available magneticfield of 1.5 Tesla were in general unable to produce datacomparable in information to the high field perfusedorgan or animal model data. This has changed with theavailability of ultrahigh magnetic fields for human appli-cations. While the use of very high magnetic fields suchas 7 Tesla in human studies is still in its infancy, the datagathered to date suggest that there are significant gainsfor spectroscopy studies in general and some of theseaccomplishments relevant to high magnetic fields arereviewed in article.2. Imaging using the hydrogen nucleus2.1. Signal-to-noise ratio (SNR)In all NMR experiments, especially in in vivo applica-tions, gains in SNR are the key to extending the applicationsof this phenomenon to new frontiers in research. SNR gainscan be achieved in going to higher fields. SNR, however,becomes rather complex when high magnetic fields (hencehigh frequencies) are considered with lossy biologic sam-ples such as the human body and the human head. Therelationship between SNR and resonance frequency, ,orequivalently field strength has been examined for biologicsamples in numerous studies [3–9], predicting increaseswith field strength. At high frequencies such as 170 MHz(

A novel single-shot spectral editing technique for in vivo proton NMR is proposed to recover resonances of low-concentration metabolites obscured by very strong resonances. With this new method, editing is performed by transferring transverse magnetization to J-coupled spins from selected coupling partners using a homonuclear Hartmann-Hahn polarization transfer with adiabatic pulses. The current implementation uses 1D-TOCSY with single-voxel localization based on LASER to recover the H1 proton of beta-glucose at 4.63 ppm from under water and the lactate methyl resonances from beneath a strong lipid signal. The method can be extended to further spin systems where conventional editing methods are difficult to perform.

Elevated tissue lactate concentrations typically found in tumors can be measured by in vivo nuclear magnetic resonance (NMR) spectroscopy. In this study, lactate turnover in rat C6 glioma was determined from in vivo 1H NMR measurements of [3-13C]lactate buildup during steady-state hyperglycemia with [1-13C]glucose. With this tumor model, a narrow range of values was observed for the first-order rate constant that describes lactate efflux, k2 = 0.043 ± 0.007 (n = 12) SD min-1. For individual animals, the standard error in k2 was small (

Recent developments in ultra-high field NMR have allowed researchers to explore the far field wave regime. Propagating waves are an effective way to deliver RF and provide a variety of propagation modes for field manipulation.

These are exciting times for biomedical MRI. The new decade has arrived with 3 T magnets in the clinics, with 4 T, 7 T, and 8 T magnets in the laboratories and 9.4 T magnets on the order books. The main reason for these high field magnets, now reaching the limits of niobium-titanium superconducting technology, is to gain higher signal-to-noise ratio (SNR) and the imaging speed, resolution and contrast that come with it. Magnetic field strength however, is only one of several instrument parameters affecting the SNR. Our objective is to design a more efficient RF volume coil for human head and body MRI at the highest fields available. A new TEM volume coil is reported which improves on performance, patient access, and magnet bore space requirements compared to conventional coils. The solutions explored for the head coil in this study carry to body coils with arm slots and to the extremity coils for the foot, shoulder, elbow etc.