title: [11C-methionine positron emission tomography in nontumorous brain lesions].
abstract: Positron emission tomography (PET) with L-[methyl-11C]methionine (MET) provides information on the metabolism of brain tumor. MET uptake reflects amino acid active transport and protein synthesis and is proportional to the amount of viable tumor cells. However, MET uptake can be increased as a result of increased density of inflammatory cells and disruption of the blood brain barrier (BBB) in nontumorous brain lesions. From October 2005 through November 2009, 438 MET-PET studies were performed for various brain lesions at our institution. Among them, 27 (6%) were finally diagnosed to be nontumorous by surgical exploration or their clinical course. Nine of 10 intracerebral hemorrhages and all 4 cerebral infarctions demonstrated mild to moderate MET uptake in or surrounding the lesions in the subacute or chronic stage after the ictus. Moderately increased MET uptake was observed in all 3 patients with brain abscess. Active lesions in multiple sclerosis and Beçhet disease showed mild MET uptake. Idiopathic orbital and optic inflammations showed mildly increased MET uptake in the lesions. Finally, a case of hypertrophic cranial pachymeningitis exhibited strong MET uptake in the lesions. We should keep in mind that high MET uptake is frequently observed in nontumorous brain lesions. Although differentiation from tumorous lesions is usually possible by laboratory and morphological examinations, nontumorous lesions should be included in the differential diagnosis when encountering patients with high MET uptake.
authors.affiliation: Department of Neurological Surgery, Faculty of Medicine, Kagawa University, Kagawa, Japan.
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Kawai
authors.forename: Masanobu
authors.initials: M
authors.lastname: Okauchi
authors.forename: Keisuke
authors.initials: K
authors.lastname: Miyake
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Sasakawa
authors.forename: Yuka
authors.initials: Y
authors.lastname: Yamamoto
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Nishiyama
authors.forename: Takashi
authors.initials: T
authors.lastname: Tamiya
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001922:Brain Abscess / Q000000981:diagnostic imaging; D001927:Brain Diseases / Q000000981:diagnostic imaging* / Q000378:metabolism; D002250:Carbon Radioisotopes; D002544:Cerebral Infarction / Q000000981:diagnostic imaging; D004677:Encephalocele / Q000000981:diagnostic imaging; D005260:Female; D005910:Glioma / Q000000981:diagnostic imaging; D006801:Humans; D008297:Male; D008715:Methionine / Q000378:metabolism*; D008875:Middle Aged; D009422:Nervous System Diseases / Q000000981:diagnostic imaging; D009901:Optic Nerve Diseases / Q000000981:diagnostic imaging; D009916:Orbital Diseases / Q000000981:diagnostic imaging; D049268:Positron-Emission Tomography
chemical_list: D002250:Carbon Radioisotopes; D008715:Methionine