Reproducibility of magnetic resonance spectroscopy in correlation with signal-to-noise ratio

Okada, Tomohisa; Sakamoto, Setsu; Nakamoto, Yuji; Kohara, Nobuo; Senda, Michio

doi:10.1016/j.pscychresns.2007.03.007

« Previous Next »Psychiatry Research: Neuroimaging
Volume 156, Issue 2 , Pages 169-174, 15 November 2007

Reproducibility of magnetic resonance spectroscopy in correlation with signal-to-noise ratio

Tomohisa Okada
- Department of Molecular Imaging, Institute of Biomedical Research and Innovation, 2-2 Minatojima Minamimachi, Chuouku, Kobe, 650-0047, Japan
- Department of Diagnostic Radiology, Kyoto University, 54 Shogoin Kawaharacho, Sakyoku, Kyoto, 606-8507, Japan
- Corresponding author. Department of Diagnostic Radiology, Kyoto University, 54 Shogoin Kawaharacho, Sakyoku, Kyoto, 606-8507, Japan. Tel.: +81 75 751 4215; fax: +81 75 7514216.
Setsu Sakamoto
- Department of Molecular Imaging, Institute of Biomedical Research and Innovation, 2-2 Minatojima Minamimachi, Chuouku, Kobe, 650-0047, Japan
Yuji Nakamoto
- Department of Molecular Imaging, Institute of Biomedical Research and Innovation, 2-2 Minatojima Minamimachi, Chuouku, Kobe, 650-0047, Japan
- Department of Diagnostic Radiology, Kyoto University, 54 Shogoin Kawaharacho, Sakyoku, Kyoto, 606-8507, Japan
Nobuo Kohara
- Department of Neurology, Kobe City General Hospital, 4-6 Minatojima Nakamachi, Chuouku, Kobe, 650-0046, Japan
Michio Senda
- Department of Molecular Imaging, Institute of Biomedical Research and Innovation, 2-2 Minatojima Minamimachi, Chuouku, Kobe, 650-0047, Japan

Received 13 April 2006; received in revised form 10 March 2007; accepted 21 March 2007.

Abstract

An increased amount of myoinositol (mI) relative to creatine (Cr) by proton MR spectroscopy (¹H-MRS) measurement gives a useful aid for the diagnosis of Alzheimer's disease (AD). Previous results of test–retest measurement of mI, however, have shown variability more than twice as large as for other metabolites. The aims of this study were to analyze test–retest variability of ¹H-MRS measurements in correlation with signal-to-noise ratio (SNR). Ten subjects clinically suspected of mild AD were examined twice (2–14 days apart) with ¹H-MRS measurements of voxels placed at anterior and posterior cingulate cortex. The percent differences between two measurements (%differences) of mI/Cr showed a significant linear trend to decrease as average SNR increased, but %differences of N-acetylaspartate (NAA)/Cr and choline (Cho)/Cr did not. The average of %differences was 10.5, 15.0 and 20.8 for NAA/Cr, Cho/Cr, and mI/Cr, respectively, indicating a prominent deterioration of mI/Cr measurement reproducibility, which decreased to 6.96, 15.4 and 9.87, respectively, when the analysis was limited to measurements with SNR over 25. The results indicate that MRS measurements with high SNR should be used to obtain reliable assessments of mI/Cr as accurate diagnostic indicator of AD in clinical MR examinations.

Keywords: Magnetic resonance spectroscopy, Myoinositol, Alzheimer's disease, Reproducibility, Signal-to-noise ratio