Amino acid study of cerebral gliomas using positron emission tomography--analysis of (11C-methyl)-L-methionine uptake index.
Sixteen patients with gliomas (7 low grade, 9 high grade) were examined using positron emission tomography (PET) with intravenous administration of 22.2 MBq/kg (0.6 mCi/kg) of (11C-methyl)-L-methionine (C-11 Met). The tracer uptake in regions of interest was calculated on PET images taken 45 minutes after injection; the uptake index was represented as a percentage of the total count in the arterial blood summed over 45 minutes. C-11 Met uptake indices in the tumors ranged from 0.020 to 0.041% with a mean of 0.032% for the low-grade gliomas and from 0.013 to 0.044% with a mean of 0.036% for the high-grade gliomas. These indices significantly increased as compared with those in the contralateral gray matter (0.008-0.032% with a mean of 0.023%; p less than 0.01 vs. low-grade gliomas, p less than 0.001 vs. high-grade gliomas). In the low-grade gliomas, C-11 Met PET images clearly depicted the existence and even the extent of the tumors, although x-ray computed tomography (CT) did not always distinguish tumoral lesions. In the high-grade gliomas, the areas of tracer accumulation regionally extended to peritumoral low density on CT scans, where malignant tumor cell infiltration was proved by operative and follow-up CT findings. C-11 Met may be a useful radiopharmaceutical for differential diagnosis of gliomas, and the accuracy of tumor localization will give us a better rationale in therapeutic strategies for surgery and radiation therapy of gliomas.
Mineura
K
K
Neurosurgical Service, Akita University School of Medicine.
Sasajima
T
T
Suda
Y
Y
Kowada
M
M
Shishido
F
F
Uemura
K
K
D000293:Adolescent; D000328:Adult; D000368:Aged; D001932:Brain Neoplasms / Q000000981:diagnostic imaging*; D002250:Carbon Radioisotopes; D002648:Child; D005260:Female; D005910:Glioma / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D008715:Methionine / Q000031:analogs & derivatives* / Q000493:pharmacokinetics; D008875:Middle Aged; D014055:Tomography, Emission-Computed; D014057:Tomography, X-Ray Computed
D002250:Carbon Radioisotopes; D008715:Methionine; C038344:methionine methyl ester