title: [Usefulness of quantitative H-MR spectroscopy for the differentiation between radiation necrosis and recurrence of anaplastic oligodendroglioma].
abstract: We report a case, in which quantitative 1H-MR spectroscopy (MRS) was useful for the differentiation between radiation necrosis and a recurrent tumor. The present case is a 44-year-old man who underwent the subtotal removal of a mass lesion in the left frontal lobe. The histological diagnosis was anaplastic oligodendroglioma (WHO grade III). Postoperatively, a fractionated radiotherapy (total 64Gy) and chemotherapy were performed. MRI after the radiotherapy showed no contrast enhancing lesion. MRI, 5 years after the radiotherapy, showed a growing enhancing lesion and a T1 hypointensity lesion without enhancement, both of which indicated a recurrent tumor. MR spectroscopy was performed for the differential diagnosis of these lesions. The spectrum was acquired by the point resolved spectroscopy (PRESS) method by TR/TE=2,000 ms/68 ms, 136 ms, and 272 ms and evaluated with peak pattern and quantification value of metabolite. MRS of the enhancing lesion demonstrated a decrease of the Choline-containing compounds (Cho) concentration, disappearance of N-acetylaspartate (NAA), decrease of Creatine/ Phosphocreatine (t-Cr) and presence of Lipids (Lip) and Lactate (Lac), all of which are characteristic finding of a radiation necrosis. The histological diagnosis of this lesion showed evidence also of radiation necrosis. On the other hand, MRS of the T1 hypointensity lesion without enhancement showed, a marked high peak of the Cho concentration, which is characteristic for a recurrent tumor. The histological findings of this lesion showed a diffuse proliferation of recurrent tumor cells. Quantitative 1H-MRS is a useful tool for the differentiation between radiation necrosis and recurrent tumors.
authors.affiliation: Graduate School of Human Comprehensive Sciences, University of Tsukuba, Ibaraki, Japan.
authors.forename: Tomonori
authors.initials: T
authors.lastname: Isobe
authors.forename: Hiroyoshi
authors.initials: H
authors.lastname: Akutsu
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Yamamoto
authors.forename: Masanari
authors.initials: M
authors.lastname: Shiigai
authors.forename: Tomohiko
authors.initials: T
authors.lastname: Masumoto
authors.forename: Kei
authors.initials: K
authors.lastname: Nakai
authors.forename: Shingo
authors.initials: S
authors.lastname: Takano
authors.forename: Izumi
authors.initials: I
authors.lastname: Anno
authors.forename: Akira
authors.initials: A
authors.lastname: Matsumura
mesh_terms: D000328:Adult; D001224:Aspartic Acid / Q000031:analogs & derivatives / Q000032:analysis; D001927:Brain Diseases / Q000175:diagnosis* / Q000473:pathology; D001932:Brain Neoplasms / Q000175:diagnosis*; D002794:Choline / Q000032:analysis; D003401:Creatine / Q000032:analysis; D003937:Diagnosis, Differential; D005625:Frontal Lobe; D006801:Humans; D007773:Lactates / Q000032:analysis; D008055:Lipids / Q000032:analysis; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D009336:Necrosis; D009364:Neoplasm Recurrence, Local / Q000175:diagnosis*; D009837:Oligodendroglioma / Q000175:diagnosis* / Q000532:radiotherapy; D010725:Phosphocreatine / Q000032:analysis; D011832:Radiation Injuries / Q000175:diagnosis*
chemical_list: D007773:Lactates; D008055:Lipids; D010725:Phosphocreatine; D001224:Aspartic Acid; C000179:N-acetylaspartate; D003401:Creatine; D002794:Choline