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AJNR - American Journal of Neuroradiology

Published ahead of print on September 3, 2008
doi: 10.3174/ajnr.A1131

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American Journal of Neuroradiology 29:1644-1648, October 2008
© 2008 American Society of Neuroradiology

Technical Note
BRAIN

Anomalous J-Modulation Effects on Amino Acids in Clinical 3T MR Spectroscopy

H.-S. Liu^a,b, H.-W. Chung^a, C.-J. Juan^b, S.-Y. Tsai^a, C.-Y. Wang^a,b, C.-C. Chan^c, G.-S. Huang^b, M.-C. Chou^a, C.-S. Lee^d, C.-W. Ko^e, N.-Y. Cho^f and C.-Y. Chen^b

^a Department of Electrical Engineering, National Taiwan University, Taipei, Taiwan
^b Department of Radiology, Tri-Service General Hospital, Taipei, Taiwan
^c Philips Medical Systems, Best, the Netherlands
^d Department of Chemistry, Tamkang University, Taipei, Taiwan
^e Department of Computer Science and Engineering, National Sun Yat-Sen University, Kaohsiung, Taiwan
^f Institute of Biomedical Engineering, National Yang-Ming University, Taipei, Taiwan

Please address correspondence to Cheng-Yu Chen, MD, Department of Radiology, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan, Republic of China; e-mail: sandy0928{at}seed.net.tw

SUMMARY: The signal-intensity loss from anomalous J-modulation effects due to chemical-shift displacement was investigated on amino acid groups (alanine, valine, leucine, and isoleucine) at 3T by using point-resolved ¹H spectroscopy in patients with brain abscess and phantom experiments. With a larger chemical shift between methyl and methine resonances, alanine shows a greater effect of signal-intensity cancellation compared with other amino acids around 0.9 ppm, resulting in noninverted doublets at a TE of 144 ms.