23Na TQF NMR imaging for the study of spinal disc tissue

A method for acquiring triple quantum filtered (TQF) 23Na NMR images is proposed that takes advantage of the differences in transverse relaxation rates of sodium to achieve positive intensity, PI, NMR signal. This PITQF imaging sequence has been used to obtain spatially resolved one-dimensional images as a function of the TQF creation time, τ, for two human spinal disc samples. From the images the different parts of the tissue, nucleus pulposus and annulus fibrosus, can be clearly distinguished based on their signal intensity and creation time profiles. These results establish the feasibility of 23Na TQF imaging and demonstrate that this method should be applicable for studying human disc tissues as well as spinal disc degeneration.