JOURNAL OF MAGNETIC RESONANCE 78,205-212 (1988) Multiple-Volume-Selective Proton NMR Spectroscopy and Spectral Editing by Spin-Echo Double Resonance (VOSY + SEDOR) A. KNUTTELAND R. KIMMICH Universitiit Ulm, Sektion Kernresonanzspektroskopie, D-7900 Urn, Federal Republic of Germany Received July 20, 1987; revised October 19, 1987 A series of test experiments with the VOSY technique for volume-selective NMR spec- troscopy has been carried out. A critical test of volume selection under chemical-shift- induced offsets at 4.7 T is reported. It is demonstrated that several volume elements can LX probed in a single experiment so that metabolite concentrations can be related to other regions or to a calibration sample. The method can also be combined with spectral editing procedures such as the spin-echo double-resonance sequence (SEDQR). Q 1988 Academic Ress. Inc. INTRODUCTION A crucial prerequisite of biomedical applications of NMR spectroscopy is the avail- ability of a reliable and versatile method for the selective detection of signals from the region of interest. Recently we have proposed the VOSY technique (I, 2) for this purpose. This pulse sequence selectively excites the desired volume element rather than suppressing the undesired volume by saturation (3-6) or signal subtraction (7). As residual signal contributions from outside the volume element can be completely prevented and as the effective length of the RF pulses of the sequence is uncritical, the VOSY technique is considered to fulfill these requirements particularly well. The purpose of the present paper is to report further tests of the VOSY method. For applications, it is desirable to probe not only one, but a whole series of volume elements in a one-shot experiment, i.e., without the need of long recovery delays. Also, volume selection should be possible in combination with spectral editing and water signal suppression to permit the full exploitation of the potential of proton spectroscopy. Moreover, in order to become a tool for multinuclear spectroscopy, the sensitivity must be sufficiently high. This means especially that the volume selection part of the pulse sequence must be fast enough to avoid excessive T2 decays of the coherences finally transferred to the acquired signal. The latter point is still the subject of hardware developments. Nevertheless we are able to report considerable progress compared with our previous tests of the technique. TECHNIQUES VOSY pulse sequence. Figure 1 shows the sequences for the RF pulses and the programming voltages of the field gradients (I, 2). The gradients serve two purposes. Selective RF pulses irradiated during the subsequent application of gradients in the 205 0022-2364188 $3.00 Copyright 0 1988 by Academic Press, Inc. All rights of reproduction in any form reserved