Fifteen percent loss in the peak area of choline containing compounds (Cho) was recently observed in 1H MR spectra of contrast-enhancing tumor at 5-10 min after Gd-contrast administration [Magn. Reson. Med. 37:222-225, 1997]. In this study, chemical shift imaging (CSI, 1500/135 ms PRESS) was used to assess the spectral changes in 47 Gd-enhancing glial brain tumors and metastatic brain tumors measured at 0-5, 5-10, and/or 10-15 min after administration of Gd-contrast. Percent Cho peak area losses measured at these times, 3 ± 3, 12 ± 2, and 14 ± 3 SEM, respectively, coincided with trends of line narrowing and up-field shift of the Cho peak. Significant changes in creatine and N-acetyl acetate signals were not observed. It is concluded that the Gd-induced loss of tumor Cho signal measured after 5 min, typically required for post contrast-MRI and the positioning of the CSI volume on tumor, shows little further change with time, if any.

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Magnetic Resonance Imaging
Department of Neurology

Sijens, P., Oudkerk, M., van Dijk, P., Levendag, P., & Vecht, C. (1998). 1H MR spectroscopy monitoring of changes in choline peak area and line shape after Gd-contrast administration. Magnetic Resonance Imaging, 16(10), 1273–1280. doi:10.1016/S0730-725X(98)00143-X