Necrotic tumor versus brain abscess: importance of amino acids detected at 1H MR spectroscopy--initial results

To assess the usefulness of the 0.9-ppm peak from amino acids (-CH3 moieties from valine, leucine, and isoleucine) for the differentiation of brain abscesses and tumors at in vivo hydrogen 1 magnetic resonance (MR) spectroscopy. Amino acid concentrations were determined in vitro in 13 purulent sampl...

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Bibliographic Details
Published inRadiology Vol. 213; no. 3; p. 785
Main Authors Grand, S, Passaro, G, Ziegler, A, Estève, F, Boujet, C, Hoffmann, D, Rubin, C, Segebarth, C, Décorps, M, Le Bas, J F, Rémy, C
Format Journal Article
LanguageEnglish
Published United States 01.12.1999
Subjects
Adolescent
Adult
Aged
Bacterial Infections - diagnosis
Brain - pathology
Brain Abscess - diagnosis
Brain Neoplasms - diagnosis
Diagnosis, Differential
Female
Humans
Isoleucine - analysis
Leucine - analysis
Magnetic Resonance Imaging
Magnetic Resonance Spectroscopy
Male
Middle Aged
Necrosis
Phantoms, Imaging
Sensitivity and Specificity
Valine - analysis
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Summary:To assess the usefulness of the 0.9-ppm peak from amino acids (-CH3 moieties from valine, leucine, and isoleucine) for the differentiation of brain abscesses and tumors at in vivo hydrogen 1 magnetic resonance (MR) spectroscopy. Amino acid concentrations were determined in vitro in 13 purulent samples from brain and nonbrain tissues and in nine aseptic fluids from necrotic brain tumors at two-dimensional (2D) 1H MR spectroscopy and liquid chromatography. Thirty-four patients with cystic intracerebral mass lesions (28 tumors, six abscesses) were examined at 1H MR spectroscopy in vivo. Amino acids were identified in vitro in both purulent and aseptic samples. Amino acid concentrations measured in the aseptic fluids at both liquid chromatography and 2D MR spectroscopy were far below the detection threshold of in vivo 1H MR spectroscopy. Quantitative results obtained at 2D MR spectroscopy showed no overlap in the ranges of amino acid concentrations in purulent and aseptic samples. In vivo, the proton spectra obtained with a 136-msec echo time (TE) revealed amino acids (inverted peak at 0.9 ppm) in only the abscesses. The detection of amino acid resonance at 0.9 ppm at in vivo 1H MR spectroscopy (136-msec TE) is a promising tool for distinguishing bacterial abscesses and cystic brain tumors.
ISSN:0033-8419