RT Journal Article
SR Electronic
T1 Low-Grade Glioma: Correlation of Short Echo Time <sup>1</sup>H-MR Spectroscopy with <sup>23</sup>Na MR Imaging
JF American Journal of Neuroradiology
JO Am. J. Neuroradiol.
FD American Society of Neuroradiology
SP 464
OP 470
DO 10.3174/ajnr.A0854
VO 29
IS 3
A1 Bartha, R.
A1 Megyesi, J.F.
A1 Watling, C.J.
YR 2008
UL http://www.ajnr.org/content/29/3/464.abstract
AB BACKGROUND AND PURPOSE: There is considerable variability in the clinical behavior and treatment response of low-grade (WHO grade II) gliomas. The purpose of this work was to characterize the metabolic profile of low-grade gliomas by using short echo time 1H-MR spectroscopy and to correlate metabolite levels with MR imaging-measured sodium (23Na) signal intensity. Based on previous studies, we hypothesized decreased N-acetylaspartate (NAA) and increased myo-inositol (mIns), choline (Cho), glutamate (Glu), and 23Na signal intensity in glioma tissue.MATERIALS AND METHODS: Institutional ethics committee approval and informed consent were obtained for all of the subjects. Proton (1H-MR) spectroscopy (TR/TE = 2200/46 ms) and sodium (23Na) MR imaging were performed at 4T in 13 subjects (6 women and 7 men; mean age, 44 years) with suspected low-grade glioma. Absolute metabolite levels were quantified, and relative 23Na levels were measured in low-grade glioma and compared with the contralateral side in the same patients. Two-sided Student t tests were used to test for statistical significance.RESULTS: Significant decreases were observed for NAA (P &lt; .001) and Glu (P = .004), and increases were observed for mIns (P = .003), Cho (P = .025), and sodium signal intensity (P &lt; .001) in low-grade glioma tissue. Significant correlations (r2 &gt; 0.25) were observed between NAA and Glu (P &lt; .05) and between NAA and mIns (P &lt; .01). Significant correlations were also observed between 23Na signal intensity and NAA (P &lt; .01) and between 23Na signal intensity and Glu (P &lt; .01). Ratios of NAA/mIns, NAA/23Na, and NAA/Cho were altered in glioma tissue (P &lt; .001); however based on the t statistic, NAA/23Na (t = 9.6) was the most significant, followed by NAA/mIns (t = 6.1), and NAA/Cho (t = 5.0).CONCLUSION: Although Glu concentration is reduced and mIns concentration is elevated in low-grade glioma tissue, the NAA/23Na ratio was the most sensitive indicator of pathologic tissue.