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

Abstract

23Na MR imaging with short echo times can be used to quantify absolute tissue sodium concentration in patients with brain tumors and shows increased sodium concentration in tumors relative to that in normal brain structures.

Low-Grade Glioma: Correlation of Short Echo Time1H-MR Spectroscopy with23Na MR Imaging

“…The increased sodium signal intensity observed in the current study is also consistent with previous reports 14,15,18 and probably indicates expansion of the extracellular space and increased intracellular sodium concentration. 23 Na signal intensity was inversely correlated with both NAA and Glu as expected.…”

“…[14][15][16] For example, neoplastic cell proliferation and packing, cell death, and necrosis expand the extracellular space in tumors. A defective blood-brain barrier in tumors also permits water, electrolytes, and proteins to enter the extracellular space leading to vasogenic edema.…”

“…Because both intracellular and extracellular sodium levels may be increased in tumors, 23 Na MR imaging represents a potentially sensitive and noninvasive means of monitoring tissue sodium content related to cancer pathology. [15][16][17][18] The purpose of this study was to prospectively characterize the metabolic profile of low-grade gliomas by using 1 H-MR spectroscopy and to correlate metabolite levels with MR imaging-measured sodium signal intensity. Based on previous studies, it was hypothesized that levels of NAA would be reduced, and levels of Cho, mIns, Glu, and 23 Na signal intensity would be increased in low-grade glioma compared with normal tissue.…”

A double-tuned1H/23Na dual resonator system for tissue sodium concentration measurements in the rat brain via Na-MRI

“…Using this technique, a TE of 853 μs was achieved, which helped to minimise T 2 -weighting effects on the measured signal intensity.T 1 -weighting effects were also minimised through the use of a relatively long TR of 200 ms, considering that the T 1 for 23 Na in vivo is in the region of 40 ms [11,12]. Typical TR values quoted in the literature for Na-MRI range from 100 to 120 ms, aimed primarily at maximising the SNR through the use of multiple signal averaging within a reasonable acquisition time [13,14]. In the current study, it was highly desirable to avoid any possible effects of T 1 -weighting on the TSC quantification, particularly in view of the realistic expectation that the T 1 values might change during the 8 hour time course of the experiment covering the acute stroke phase.…”

Neuroimaging of the Amygdala: Quantitative Mechanistic Approach

“…Although an important number of clinicians and researchers continue working at 1.5 Tesla (Korvenoja, et al 2006), there is an increasing tendency to study subjects under 3 Tesla units (Spampinatto, et al 2011), 7 Tesla and 9.3 Tesla in clinical settings. Preliminary results seem to suggest that ultra high field strength MR units will be able not only to improve signal to noise even more dramatically but also to obtain MR spectra from other elements as sodium, an apparent excellent marker of conditions as Alzheimer's type cognitive impairment years before the clinical onset, abnormality already proven to be detectable in brain tumors (Ouwerkerk, et al 2003). …”