Purpose: The purpose of this study was to characterize gliomatosis cerebri on magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS), and to analyze the value of these-two techniques in diagnosis and differential diagnosis of gliomatosis cerebri. Materials and methods: MR images of 14 patients with gliomatosis cerebri were reviewed retrospectively; seven of the patients also underwent MRS (single-voxel point-resolved spectroscopy, and chemical-shift imaging point-resolved spectroscopy). Tumorous were confirmed by surgery and biopsy. The distribution, extension and signal features of lesions were assessed, and the MR spectroscopy results were analyzed. Results: Tumors involved at least two lobes of the brain in all patients. Widespread invasion with isointensity or hypointensity on T1-weighted MR images and hyperintensity on T2-weighted images were found while no prominent necrosis, hemorrhage or contrast enhancement was found. All patients who underwent MRS showed elevated Cho/Cr and Cho/NAA levels as well as decreased NAA/Cr ratios in the abnormal areas on T2-weighted images, three of which showed a lactate doublet. Anaplastic lesions had higher Cho/NAA levels in three cases. Abnormality of metabolism was also seen in the margin of the lesion that was normal on T2-weighted images. Conclusion: MRI and MRS are valuable techniques for diagnosis and differential diagnosis of gliomatosis cerebri. Combining clinical information and MRI findings, as well as MRS, is crucial for making a definitive diagnosis. (c) 2006 Elsevier Ireland Ltd. All rights reserved.