Deuterium (2 H) double-quantum filtered (DQF) NMR spectros-copy of nucleus pulposus (NP) tissues from human interverte-bral discs is reported. The DQF spectral intensities, DQ build-up rates, and DQF-detected rotating-frame spin-lattice relaxation times are sensitive to the degree of hydration of the NP tissue, and display a monotonous correlation with age between 15 and 80 years. The implications of this work are that the changes in water dynamics as detected via DQF NMR spectroscopy may be used as a probe of tissue degeneration in NP, particularly in the early stages of degeneration to which most standard NMR methods are not sensitive. Magn Reson Med 57:990-999, 2007. The challenges to the physician in treating lower back pain due to degenerative disc disease (DDD) begin with diagnosis. Physical examination and MRI (T 2 imaging) are typical methods employed to detect a degenerated disc. However, little correlation exists between lower back pain and the structural changes that are visualized using current MRI techniques, leaving the clinician with less than desirable noninvasive diagnostic capabilities (1). Furthermore, de-generation of the disk is related to aging, but the correlation is not trivial, and multiple other factors contribute to the degeneration processes (2). To understand more detail about the degenerative state of the disc, an analysis of the water structure and dynamics in the disc may prove enlightening. Each tissue in the body has different forms of water within the cellular and extracellular matrixes that can be broadly categorized as bound, intermediately bound, or free water. Little is documented regarding the detailed water structure and dynamics of normal or degenerated nucleus pulposus (NP) of the intervertebral disc. The three main molecular constituents of the nucleus are collagen, proteoglycan, and water. The proteoglycan (aggrecan) consists of sulfated glycosaminoglycan (GAG) side chains attached to a protein core. The total water present in the nucleus is dependent, in part, on the charge density of the sulfated GAGs, which change in structure and reduce in quantity with degeneration of the NP, leading to a reduction in water content (3). Since changes in disc water content are critical for understanding the pathogenesis of DDD, it is important to consider the properties of this common molecule in the changing disc environment. 1 H and 2 H NMR spectroscopy have been established as probes of the dynamics of "bound" waters in the various connective tissues (4-7). For NMR investigations of the intervertebral disc, proton MRI has been the preferred method in nearly all published works (8-17). In an effort to develop imaging methods for the diagnosis of DDD (14), numerous quantitative MRI studies were undertaken to identify statistical correlations of the proton T 1 and T 2 relaxation times of the water signal with disc degradation grade (8,13,17), age (10), diurnal fluctuations (9,12), water content (8), GAG content (8), anatomical position (17), and mechanical properties (15). In addi...

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