Magnetic resonance imaging performance: a comparison of sodium and hydrogen.

Abstract

Although many nuclei can be used to produce magnetic resonance (MR) images, technical considerations dictate the choice of certain of these. Hydrogen is the most favorable, followed by sodium. We present an evaluation of the imaging performance of sodium MR imaging based on imager performance and biologic factors. Because it is hampered by high operating fields, low signal-to-noise levels, and radiofrequency power deposition constraints, careful clinical comparisons will be needed to identify a diagnostic niche that could take advantage of the large sodium differences known to exist within biologic systems.

Tissue Sodium Concentration in Human Brain Tumors as Measured with23Na MR Imaging

“…Therefore, no corrections for saturation or flip angle were applied. The T1 determined for CSF was much shorter than the longest T1 of 90 msec reported in the literature (26). Even assuming that the T1 of CSF is about 40 msec, saturation has an almost negligible effect on the signal of CSF at a TR of 120 msec, as can be seen in Figure 2.…”

Sodium T2*-weighted MR imaging of acute focal cerebral ischemia in rabbits

“…The optimum TR and flip angle were determined by simulating the SNR per unit time as a function of TR. A TR of 20 ms was chosen, corresponding to an Ernst angel of 45°, assuming a 60-ms T 1 for 23 Na at 4 Tesla [29,30]. An asymmetric (67%) kspace readout (43 of 64 points) was used to minimize TE and increase SNR.…”

Sodium MRI: Methods and applications

“…Biological tissues were already investigated with sodium NMR spectroscopy in the early 1970s [21,22] and with sodium MRI in the early 1980s [23–25], first on animals in vivo and then on human brain [26] and human heart and abdomen [27]. Sodium MRI was thereafter applied to brain tumor and ischemia detection in the late 1980s [28].…”