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AJNR - American Journal of Neuroradiology

Publication Preview: Published September 3, 2008

American Journal of Neuroradiology 2008;29:1644.

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American Journal of Neuroradiology
DOI 10.3174/ajnr.A1131

BRAIN

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

H.-S. Liu, H.-W. Chung, C.-J. Juan, S.-Y. Tsai, C.-Y. Wang, C.-C. Chan, G.-S. Huang, M.-C. Chou, C.-S. Lee, C.-W. Ko, N.-Y. Cho and C.-Y. Chen

From the Department of Electrical Engineering (H.-S.L., H.-W.C., S.-Y.T., C.-Y.W., M.-C.C.), National Taiwan University, Taipei, Taiwan; Department of Radiology (H.-S.L., C.-J.J., C.-Y.W., G.-S.H., C.-Y.C.), Tri-Service General Hospital, Taipei, Taiwan; Philips Medical Systems (C.-C.C.), Best, the Netherlands; Department of Chemistry (C.-S.L.), Tamkang University, Taipei, Taiwan; Department of Computer Science and Engineering (C.-W.K.), National Sun Yat-Sen University, Kaohsiung, Taiwan; and Institute of Biomedical Engineering (N.-Y.C.), 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.