Beschreibung:
<jats:title>Abstract</jats:title><jats:p><jats:sup>1</jats:sup>H MR spectra obtained by chemical shift imaging (CSI) of contrast‐enhancing brain tumors before and after the administration of Gd‐contrast agent were quantitated and compared with the results in normal brain tissue included in the volume of interest. Twenty‐seven combined magnetic resonance imaging and spectroscopy (MRI, MRS) examinations of brain tumor lesions included <jats:italic>T</jats:italic><jats:sub>1</jats:sub>‐weighted MRI and CSI (TR/TE 1500/135 ms double‐spin echo) repeated 5–10 min after the administration of Gd‐contrast agent (0.1–0.2 m<jats:italic>M</jats:italic>). In <jats:sup>1</jats:sup>H MR spectra of contrast‐enhancing tumor Gd‐contrast induced a mean loss of 15% of the peak area of choline‐containing compounds (Cho, <jats:italic>P</jats:italic> < 0.001) that was correlated with precontrast Cho linewidth (<jats:italic>r</jats:italic> = −0.72, <jats:italic>P</jats:italic> < 0.00001). This phenomenon limits the diagnostic use of brain tumor MRS examinations performed immediately after contrast‐enhanced MRI.</jats:p>