Detection of Metabolic Status by In Vivo H proton Magnetic Resonance Spectroscopy in Patients with Brain Tumors SAN-KAN LEE CHIH-MING CHIANG WEN-HSIEN CHEN JYE-WEN CHAI CLAYTON

Nuclear magnetic resonance (NMR) has been used to detect the chemicals earlier before the clinical application of magnetic resonance imaging (MRI). Since late 1980s, magnetic resonance spectroscopy (MRS) became popular with the advancement of MRI. Previous studies on in vitro NMR and in vivo MRS elucidate the effectiveness of its clinical application in different areas. We performed this study, which combines MRI and in vivo MRS, to evaluate the metabolic status of different brain tumors. We prospectively evaluated the patients with brain tumor by Single-Voxel Proton Brain Spectroscopy Exam (PROBE / SV) in 2000 and 2001. Eight glioblastoma multiformes, 5 astrocytomas, 3 meningiomas, 4 lung carcinomas with brain metastases, and 15 normal brains as the control group were included in this study. The spectra of metabolite peaks of the N-acetylaspartate (NAA), Creatine (Cr) and Choline (Cho) of the brain tumors were evaluated and compared with that of the control group. As compared with the control group, the quantitative peak ratio of NAA/Cho was significantly decreased in lesions of glioblastoma, astrocytoma, meningioma, and metastasis. The NAA/Cr and Cr/Cho peak ratios were also significantly decreased in glioblastoma and astrocytoma; on the contrary, the Cho/Cr peak ratio was increased. In patients with carcinoma of lung with brain metastasis, the NAA/Cho was significantly higher than the glioblastoma. When a focal mass lesion was detected on MRI, and the spectroscopy showed marked decrease of NAA/Cho, NAA/Cr and Cr/Cho ratios, either astrocytoma or glioblastoma should be highly considered. If the mass lesion showed higher NAA/Cho peak ratio, and the patient already had a primary malignancy, metastasis was the most likely diagnosis as compared with glioblastoma, astrocytoma and meningioma.